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Printed in France by Imp. Firmin-Didot. Paris - Mesnil - Ivry. © Unesco 1968. SC.AVS.67/I.66/A

C O N T E N T S OF T H E PRECEDING ISSUES

Vol. XVII (1967), No. 1 Evolution and its importance to society, by Sir G A V I N D E B E E R . Some aspects of town reconstruction (Warsaw and Skopje), by A . C I B O R O W S K I .

Agrindus: integration of agriculture and industries, by H . H A L P E R T N .

The applications of nuclear energy—technical, economic and social aspects, by J. G A U S S E N S and R . B O N N E T .

Vol. XVII (1967), N o . 2 Science popularization in the atomic age, by E . R A B I N O W T T C H . Major research and development programmes as instruments of economic strategy, by D . L E C E R F . The menace of extinct volcanoes, by H . TAZIEFF. Geothermal power, by C . J. B A N W E L L . Chemistry and society: The development of the varnish and paint industry during the past two decades, by H . R A B A T É .

Vol. XVII (1967), N o . 3 Special issue on microbiology Microbiology in world affairs, by C . G . H E D É N . Microbiology and genetics, by F. J A C O B . Order out of confusion. A case for a systematic approach to microbiology, by V . B . D . S K E R M A N . Infectious diseases and human ecology, by A . M A C D O N A L D . Horizons of industrial microbiology, by M . J. J O H N S O N .

Vol. XVII (1967), N o . 4 Food, dietetics and industry, by H . B O U R . Akademgorodok and the development of Siberia, by M . L A V R E N T T E V .

Biology and humanity: the International Biological Programme, by J. G . B A E R .

The laser, by M . - Y . B E R N A R D .

vol. xviii (1968), No.i C o n t e n t s

5 Land-rescue agriculture: three-dimensional forestry by J. Sholto Douglas

Meeting the world's urgent need for expanded food supplies demands that m a n y land areas that are n o w either totally unutilized or only marginally productive must be rescued from disuse or misuse and m a d e to be fully productive of food and other agricultural wealth. H o w should this be done? The answer lies with trees: in uniting forestry and farming, joining m a n , trees and crops, and livestock into a productive, mutually-beneficial ecological unit. This is three-dimensional forestry, a modernized version of the symbiosis between m a n and environment that was so successfully worked out in the past by m a n y 'primitive' tribes before the advent of modern technology.

The system is simple, efficient and above all 'natural'— working with nature rather than against it. The author describes h o w three-dimensional forestry operates and shows it in practice in the Limpopo region of southern Africa, where it began to be tested in 1956.

Chemistry and society 27 VI : Polymers, review and preview

by H . Mark

The work of chemists over the past forty years to determine the structure of high polymers (both natural ones, such as rubber, starches, cellulose, proteins, etc., and synthetic ones) and to determine the relationship between composition and structure on the one hand and physical properties on the other, has led to the current ability to tailor-make synthetic resir.s, rubbers and fibres to serve an extremely broad variety of modern applications. The author first reviews the evolution of the field of high polymer chemistry and then previews the expanding future of high polymer materials in such applications

as clothing, packaging, briefcase-size computers, large boats, building construction, medicine, and audio-visual tools for education.

The manipulation and use of the atomic nucleus I: M a n - m a d e atoms by Georgi Flerov

M a n is n o w synthesizing in his laboratories chemical elements which have no present counterparts in nature, though they m a y have existed eons ago and disappeared as a result of radioactive decay. Moreover, m a n is creating never-before-known varieties—isotopes—of familiar chemical elements. F r c m the physical and chemical study of these h u m a n constructions, particularly of the transuranium elements, all of them radioactive—from artificial element 93, neptunium, to the heaviest n o w known, kurchatovium, element 104— major new insights are being gained into the forces that operate in the atomic nucleus. The author foresees that new techniques m a y enable the creation of even heavier synthetic elements.

II: Practical applications of radioisotopes by Lev Kostikov

M a n - m a d e radioactive atoms, as well as natural ones, are finding innumerable applications in every branch of h u m a n economic—as well as scientific—activity, performing m a n y tasks that could never be done before they came into use and providing enormous savings of time and money. This article, a companion piece to the previous one, discusses these applications, in the Union of Soviet Socialist Republics, in industry, agriculture, biology, medicine and chemistry.

The use of closed-circuit television and scientific films for university teaching in the Netherlands by Jan W . Varossieau

Large numbers of children born after the war reached maturity in the early sixties and flooded the universities, confronting the Netherlands with a problem c o m m o n to m a n y countries: h o w to ensure both the quantity and quality of university education, particularly in the sciences?

The answer lay in making efficient use of those modern educational tools, television and motion pictures. Fortunately, the groundwork for using these in the sixties had been laid in the fifties and a skilled and functioning organization for meeting the science-training needs of the new generation was already in existence.

The author provides a detailed case history of h o w tele­vision and films for university education were brought to their present state of highly rational application.

CONTRIBUTORS TO THIS ISSUE

J. Sholto Douglas, A n ecologist and agronomist n o w specializing in applied M e a d House, ecology for the development of unexploited areas. Since 1956 Hayesend Road, Hayes, he has been responsible, under the International Commission Middlesex, on Applied Ecology, for the development of new systems United Kingdom of forest-farming for regions of southern and eastern Africa.

Also a specialist in hydroponics, he developed the Bengal system of hydroponics in the forties and fifties at the West Bengal Agricultural Institute and wrote an article about the subject, 'The Possibilities of Soilless Cultivation', for Impact, Vol. V I (1955), N o . 1.

Georgi Flerov, Corresponding M e m b e r of the Academy of Sciences of the Joint Nuclear U . S . S . R . since 1953. Director of the Laboratory of Nuclear Research Institute, Reactions of the Joint Nuclear Research Institute. His main Dubna , work has been in nuclear physics and cosmic ray physics, in Moskovskaya Oblast, which fields he has published numerous papers. Co-discoverer U . S . S . R . (with K . Petrzhak, in 1940) of the phenomenon of spon­

taneous fission of heavy nuclei. In 1962 led a research team which discovered the existence of proton radioactivity.

Lev Kostikov, N o w a Project Officer in the Division of Engineering Research Department of Application and Studies in Unesco's Department of Application of of Sciences to Development. Sciences to Development. Until 1967 was Associate Professor Unesco, Place de Fontenoy, of Thermodynamics, Dean of the Department of Power 75 Paris-7e, France Engineering, and Head of the Industrial Research Laboratory

for Heat Transfer Problems in Power Generation at the B a u m a n Higher Technical Institute in M o s c o w . Conducted research on heat transfer problems in nuclear cores and taught courses on heat transfer problems and on the appli­cations of isotopes.

Dr. H . Mark , Dean Emeritus of the Polytechnic Institute of Brooklyn. Polytechnic Institute Since obtaining his P h . D . from the University of Vienna of Brooklyn, in 1921, he has devoted most of his scientific life to high 333 Jay Street, Brooklyn, polymer research. Has written some fifteen books and N e w York 11201, U . S . A . published some 450 papers on the subject. Editor of the

Journal of Polymer Science, of the Journal of Applied Polymer Science, of a series of monographs on high polymers, of Reviews in Polymer Science, of abstract services on resins, rubbers and plastics and on natural and synthetic fibres.

Jan W . Varossieau, President of the International Scientific Film Library in Director, Brussels and Scientific Director of the Film and Science Film and Science Foundation- Foundation in Utrecht. President of the Netherlands Scientific University Film ( S F W - U N F I ) Film Association. Senior Scientific Officer at the University 59, Catharijnesingel, Utrecht, of Utrecht. M e m b e r of the Audio-Visual Means Committes The Netherlands of the Foundation for Education Research. Past vice-presi­

dent of the International Scientific Film Association, and past president of the association's Research Film Committee. Has written m a n y articles and reports on the use of audio­visual techniques for higher education.

J. Sholto Douglas Land-rescue agriculture: three-dimensional forestry

H U N G E R A N D THE W O R L D ' S SHORTAGE OF FERTILE LAND

O f the earth's total land surface not more than 8 per cent is well suited, agriculturally and economically, for the profitable and intensive growing of essential field crops by conventional arable farming methods. This position has been for some time the cause of increasing concern and mounting alarm amongst workers responsible for the development and extension of the applied biological and the social sciences, w h o fear that unless nations and governments awaken soon to the gravity of the situation serious disasters of unprecedented magnitude will inevitably overtake mankind before m a n y years have passed.

Certain indisputable facts stand out. The first is the high level of present-day world population and its rapid rate of growth; secondly, the supplies of basic foodstuffs are apparently quite insufficient and inadequate to meet demand; thirdly, there is the inability of the comparatively small existing areas of good and fertile agricultural land to produce the vast quantities of extra nutriment that will be required to support a substantially larger number of inhabitants on this planet in the near future.

A s a consequence, it has been predicted authoritatively that food crises of calamitous proportions will arise in the Far East by the year 2000 and throughout the world by 2030.1 Indeed, these forecasts m a y err on the side of caution, and it is likely that wholesale starvation could c o m e in some places even before the turn of this century. A t the present time, between three and five hundred million persons suffer locally from actual lack of food, and up to one-half of the earth's peoples experience a greater or lesser degree

1. T . B . Paltridge, 'World population and the world food supply', and 'Population and food supply in the Far East', World Crops, 15(9), pp. 286-300, 402, and 15(12), pp. 413-23, 1963.

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Impact, Vol. XVIII (1968), N o . 1

J. Sholto Douglas

of hunger, combined with shortage of vital proteins and chronic malnutrition in various forms.1 These figures are emphatic enough to dispel any attitude of complacency. If production from currently operative farmlands is inade­quate to assure all h u m a n beings n o w alive of sufficient basic sustenance, it is hardly probable that even by the application of more intensive techniques it will be capable of supporting, unaided, a global population of over double that of today in another two generations, at reasonable or improved standards. Moreover, to meet this problem no real faith can as yet be put in policies of birth control, which are regarded by backward peoples merely as devices cunningly thought up by the rich nations to prevent the poorer countries from increasing their populations and so strengthening their power.

There is, therefore, an urgent need for m a n to develop additional ways of providing essential foodstuffs. During recent years, m a n y highly valuable suggestions worthy of consideration and practical development have been advanced. But there still remains the problem of the vast and virtually uninhabited or sparsely populated areas of the world which at present contribute little to h u m a n progress and well-being. T o continue to rely upon the small parts of this planet that offer facilities for the growing of food crops by conventional methods only would be both foolish and impro­vident. W h a t is required is a bold and imaginative effort to bring into profitable bearing the huge neglected and unexploited regions that n o w cover over three-quarters of the earth.

Apart from the fertile farmlands, the rest of the world's inhabitable rural areas, considered from the standpoint of their contributions to food and natural raw material supplies, are useful at the m o m e n t simply for pastoral and low-density ranching activities, the production of miscellaneous items from estates and plantations, orthodox or conventional forestry and orchard work, and various similar or related enterprises, which contribute only marginally to the nourishment of the h u m a n race. A n d some of these activities are notoriously inefficient in land usage, output, and operation.

Outside these less fertile regions thus utilized for various ancillary crops and livestock there remain the sandy deserts, the mountainous and hilly zones, the tropical forests and jungles, the great wooded or bush savannahs, and the open ranges or 'outback' of partly empty continents, together with other waste ground and unfruitful wildernesses not yet brought under any form of profitable cultivation or exploited for economic animal husbandry. Then, too, there are areas unlikely ever to be used, except as a last resort, such as the South Polar continent, the Arctic barren lands or tundras, and the extremely marginal districts which are so fiercely inhospitable to orga­nized settlement by m a n for a variety of edaphic, climatic, and topogra-

1. M . Autret, Preface to F A O Nutritional Study N o . 19 (Rome, Food and Agriculture Organ­ization cf the United Nations, 1964).

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Land-rescue agriculture: three-dimensional forestry

phical reasons. Despite the substantial progress m a d e to date in the fields of the agricultural and silvicultural sciences, all these different and non-arable regions are still neglected and largely undeveloped, and are certainly not playing their full part in the feeding of humanity.

Yet it is these hitherto little-used and virtually unexploited zones of the world that are likely to become of immense and vital importance to mankind. The successful incorporation of such territories within a scheme of global food production would go very far towards assuring the h u m a n race of adequate present and future standards of life. In the light of this considera­tion, a good deal of scientific research and experiment has been directed in recent years to evolving novel systems of farm and forest utilization for application in places where ordinary agriculture or silviculture would be impossible or uneconomic.

W H A T THREE-DIMENSIONAL FORESTRY IS

O n e of the most promising and effective of the new land-utilization methods is three-dimensional forestry. This is a practical and modern concept of muitiple-use forest-farming, involving the adaptation of food-yielding trees for cropping purposes and the use of their products for the feeding of livestock. T h e expression 'three-dimensional forestry' is designed to convey in popular language the fact of three main advantages to be derived from the introduction of this revolutionary w a y of producing foodstuffs. These con­stitute a kind of trinity of benefits, instead of the normal single one obtained from conventional field crops, and they illustrate graphically the favourable results of efficient integration of agriculture with forestry into one combined scientific system. T h e trees are valuable in themselves as conservers of the land from erosion, for providing some amelioration of local climates, and as sources of timber; the harvests gathered from them serve to nourish and fatten commercial types of livestock; and the animals living around and feeding on the woodlands become available for sale as meat, or else supply much-needed additional items of protein value such as eggs, butter, cheese, and milk. T h e forest-farmer thus secures a triple reward for his labours.

Following the initial research work and experimental trials in various areas, three-dimensional forestry schemes have been established during recent years in several parts of the world, with striking results. B y ending the unnatural cleavage that had existed for so long in modern times between farm and forest, three-dimensional forestry has eventually m a d e it possible for good crops to be grown and fine livestock to be raised in what, up to n o w , were considered to be barren wildernesses and wastelands.

It is no exaggeration to say that the introduction of this new technique on a massive scale can provide the solution to a major part of the earth's food and living space problems. Countries lacking enough fertile arable soils to

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J. Sholto Douglas

support their inhabitants m a y be able to produce alternative crops of equi­valent or better quality from novel forest-farm layouts. Excellent cereal substitutes can be grown on trees utilizing poor land, at low cost, and with a m i n i m u m of trouble and no expensive machinery, in places where ortho­dox methods of agriculture are impracticable. B y bringing extra supplies of cheap and nourishing foodstuffs within the reach of all peoples and by opening up the undeveloped regions of the world for profitable settlement and exploitation, three-dimensional forestry offers something of real value to humanity, and m a y well set in motion profound social and economic changes.

HISTORICAL ORIGINS OF THREE-DIMENSIONAL FORESTRY

Farming with trees is not essentially a new idea. Primitive m e n ate the fruits and nuts of forest species, while during his recorded history homo sapiens has relied upon the woods for a substantial portion of his o w n food supplies and for practically all those consumed by his domestic livestock until very recent days. Without these additional sources of diet, h u m a n beings and their animals would have died from hunger at certain seasons.

The Bible relates h o w John the Baptist survived in the deserts of- Palestine by eating 'locusts and wild honey'. The word 'locusts' here means 'locust beans', according to modern scriptural authorities. These beans are the edible fruits of the wild carob tree.

In the Middle Ages, when western Europe was still a continent of peasants, vast herds of pigs and other farm animals were fed almost entirely from the acorns, walnuts, chestnuts, and beech seeds produced by the great forests that then covered most of the land.

In both North and South America, the pods of the mesquite or native algaraba were known to the Aztecs and the Incas as palatable and nutritious additions to the h u m a n diet and of good use for stockfeed. Prior to the Spanish conquest, the only noteworthy farm animal in Peru was the llama. The State herds maintained by the government were pastured extensively upon the wild algarabas of the Andes.

African tribes have for long been aware of the merits of several indigenous trees, which yield crops of beans and seeds of high value as fodder for cattle in the dry periods when grazing is scarce.

In fact, all over the world, at various times and in different areas, the forests have contributed appreciably to man 's subsistence and often saved whole populations from starvation.

It was therefore natural in former days, and certainly until the advent of the Industrial Revolution towards the beginning of the mid nineteenth century, that the woodlands should have been looked upon by people generally as useful adjuncts to the farming economy. Drawing as they did a considerable

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Land-rescue agriculture: three-dimensional forestry

part of their daily foodstuffs from trees and being directly dependent upon their produce to fatten the animals that they killed for meat, everybody quite rightly considered the forested areas to be complementary to the cultivated arable farms and gardens. N o artificial dividing lines or barriers existed marking off into rigid limits the different features of the countryside.

Several factors combined during the past hundred years or so to destroy the self-sufficient subsistence economy of earlier times. Increases in urban populations created n e w demands upon rural areas for extra production of grains, v/hich could only be met by more intensive farming. The haphazard and careless gathering of forest fruits or nuts and the casual pasturing of flocks in the woodlands proved quite inadequate to cope with the large requirements of the freshly created industrial communities. Society changed both in organization and needs.

While this was happening food production became specialized, breaking up into separate practices and disciplines. Forestry, which had previously been an integral and useful part of the agricultural scheme, was virtually relegated to the role of firewood and timber supplier. The n e w town dwellers and urban populations, herded into the cities and factories and cut off from rustic life, came to regard the woodlands as rude and savage habitats, the haunts of wild beasts, fit only for the hunting of game , useless to progress, and quite opposed in every w a y to the comparative civilization of the farms. Imbued with such ideas it was only to be expected that industrial m a n would indulge in a further orgy of destruction, partially completing the work of former eras w h e n his more primitive ancestors had ruthlessly cut d o w n and burned the once vast forests of the Sahara, the Thar, the Middle and Near East, and north Africa, leaving in their places nothing but barren and ruined wastelands. The new blow fell mainly in southern and eastern Africa, n o w suffering from increasing desiccation as the result of the removal of m u c h of the local tree cover, the North American continent, where the notorious 'dust bowl' was created, and several other n o w devasted regions.

The discarding of forestry as a factor in agricultural production continued until about three decades ago. Before that time, silviculture was looked upon generally by the bulk of this century's fanners as a separate technique, having no possible relevance to the growing of food. The culture of fruits had been allotted to the horticultural sphere and orchards were regarded as falling into the domain of garden work. There were few contacts at scientific level between foresters and agriculturists, and virtually none in the technical or practical fields. W o o d m e n had withdrawn entirely from the food production industries and held almost no communication with workers in forestry's sister disciplines. Such a state of affairs had most deleterious effects upon the whole applied science of silviculture and greatly retarded its development and its contribution towards the feeding of the world's peoples.

The first steps in the direction of the reinstatement of forestry as a factor of some importance for the production of basic foodstuffs were taken in

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J. Sholto Douglas

Japan in the mid-1930's, when Kagawa , experimenting with walnuts, succeeded in devising a method of utilizing the tree products as fodder for pigs, which were later sold as a source of cash income.1 These early trials represented a distinct reversal of previous agricultural and woodland policies, current since the industrialization of Japan, which then conformed to c o m m o n world practices and favoured the segregation of forests from farms. The experiments proved that the planned integration of economic tree species with commercial livestock had very considerable possibilities. The new concept had been carefully thought out and was based upon sound scientific principles.

It was obvious that the promise of the initial trials and demonstrations, conducted under severe and testing conditions and not without m a n y tech­nical difficulties, was sufficient to justify extension work both locally and in other countries. But contrary to what has so frequently occurred in the case of some startling or revolutionary discoveries, little publicity was given to this potentially important and novel system of forest-farming, or three-dimensional forestry, nor was m u c h encouragement forthcoming. The results achieved remained generally unknown to the outside world. This m a y well have been due to the fact that in those days few scientific workers and technologists realized exactly what the new concept involved or appreciated its value. The idea did not then become so widespread that it could have profound effects upon the national economies of nations or on the agrarian communities of backward regions. Indeed, the uses of forest-farming as a means of changing the social life of rural areas or its possibilities as an aid in the profitable development of unproductive land were more or less ignored.

Within a short space of time the war of 1939-45 intervened. Japan became an active participant in the conflict from December 1941 onwards, and communications with the scientists in other areas of the world were inter­rupted for several years. Although some limited work continued on three-dimensional forestry, the n e w applied science of agri-silviculture or forest-farming was overlooked and relegated to virtual obscurity, for the duration of the war.

DEVELOPMENT A N D EXTENSION'

After 1946, the world gradually returned to some semblance of order and it was possible to re-open contacts and exchange scientific information. The work undertaken in Japan on three-dimensional forestry at last attracted some of the attention that it deserved.

T h e first trials had been located in montane areas (below timberline) because of the need to find a method of supplying hill-land peasants with

1. T . Kagawa, Land of Milk and Honey, Methuen, 1935.

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Land-rescue agriculture: three-dimensional forestry

alternative means of livelihood. M u c h of the Japanese higher districts had been denuded of forest cover for fuel, timber extraction, and the sale of woods for furniture-making and shipbuilding. Once deprived of their natural protection, the mountain slopes began to erode rapidly, and large amounts of the scanty covering of soil were being washed away. There was a keen awareness of this danger, and quite apart from the objective of improving the standards of the farmers, which prompted these schemes, it was under­stood that active conservation measures were of vital urgency. The use of food-producing trees made it possible to coat the 'pill' of conservation— always an unpopular though necessitous affair—with a sugar coating of finan­cial returns within a comparatively short time. The extensive planting of nut trees and the use of their produce for the feeding of farm animals, which were then marketed as a source of cash income, appealed strongly to local smallholders and peasants. A s the plantations eventually matured, the plans envisaged the sale of timber and replanting, so that ultimately there would be a continuous succession of economic cropping, combined with a regular monetary reward.

In 1956-57 the concept of three-dimensional forestry was included in the experimental scheme then being started near Messina in the Transvaal for developing the semi-arid area of the middle Limpopo valley.1 North of the Zoutpansberg hills, beyond the small town of Louis Trichardt, lies the virtually undeveloped and backward region of the hot summer rainfall 'lowveld', typical of the southern African scrub savannahs.

About fifty years ago, this area supported a wide variety of big game, including elephants. There is evidence that the bulk of the smaller streams, n o w dry except in the wet seasons, used to contain running water at all times. Civilized man 's advent into these districts has, however, resulted in a general deterioration of the natural conditions, mostly as a result of mining, improper farming practices, indiscriminate cutting and clearing of bush trees and shrubs for fuel and other purposes, and until very recently, the absence of any conservation programme. In addition, it is highly likely that the over­all rainfall of South Africa has decreased in the past century. Dyer has stated that white settlement in southern Africa has been attended by increas­ing desiccation of the whole country.2

The Zoutpansberg hills intercept the bulk of the rainfall which is carried north from the Indian Ocean by the prevailing south-east winds during the period December to March, so that very little is left for the middle Limpopo valley. The average annual precipitation around Messina is 11 inches, and often it m a y be as low as 5 inches per year. About every five years, rather heavier falls m a y be expected—up to 20 inches. In the hot summer from October to March, temperatures rise to 110°F., while in winter from April

1. J. W . E . H . Sholto Douglas, 'Bold new 3-D forestry experiments', Veldtrust, Johannesburg, Sept.-Oct. I960, pp. 29-30.

2. R . A . Dyer, Report of the Botanical Survey of South Africa, 1957.

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J. Sholto Douglas

to September, a degree or two of frost can occur in low-lying lands, especially near river banks.

T h e Limpopo valley in its central reaches carries a bush type of vegetation, with some medium-sized trees. T h e dominant species there is the mopane , a drought-resistant, resinous tree, which seeds and regenerates freely. The average height of the mopane seldom exceeds more than 30 feet, but in areas of heavier rainfall it can grow up to 6 0 feet. During the dry winter, the leaves of the mopane provide a valuable supplementary cattle feed, but its drawback is that it uses up practically all the soil moisture, and so inhibits the growth and spread of the natural grasses.

Another tree of some interest from the picturesque point of view is the baobab (Adansonia digitata). This is to be found near Messina in great numbers. It is n o w a protected tree, and the same applies to the manila, which yields fruits suitable for jam-making and containing edible nuts of delicious flavour. These seeds can be crushed for oil, but unfortunately the extraction of the oil, which is of high quality and excellent for cooking, is considered to be uneconomic.

The water table near Messina varies from between 30 to 100 feet. There is ample evidence of extensive underground sources of water, but in the dry season this is frequently slightly saline. Nevertheless it is quite good for irri­gation although it could give rise to soil salinity problems were it ever to be used extensively and over prolonged periods for horticultural cropping.

There is virtually no intensive farming in the middle Limpopo area. A few enterprising growers cultivate small stands of oranges, tomatoes, and other vegetables. The soil is rich in minerals, and with the exception of a nitrogen deficiency—common in sub-tropical and tropical regions with bril­liant sunlight—all the essential nutrient elements are present in quantity. Most farms are merely low-grade cattle ranches, with one beast grazing over an area of up to 40 acres. Even so, in the dry winters following years of low rainfall, fanners often have to slaughter their cattle to prevent their starving to death.

Three-dimensional forestry along the Limpopo has n o w been in practice for over a decade. Already enough has been learned to show that it is thoroughly efficient in operation and, if energetically extended, will revolu­tionize the agricultural life of the region. O n the basis of previous trials and demonstrations elsewhere, and subsequent work in different countries, the system as a whole has been proved to be economic and profitable under varying conditions.

Mixed batches of trees considered to be suitable for the dry localities of the hot savannahs were introduced near Messina from overseas in 1956-57. Ecological investigations preceded the inception of the project and provided a guide to the choice of potentially suitable species of plants for testing.

T w o types of drought-resistant economic trees were selected, the algaraba and the carob. The former is quick-growing and yields large crops of edible

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Land-rescue agriculture: three-dimensional forestry

beans which, when ground into meal, are excellent for cattle fodder and also for h u m a n food. The latter is slower to mature, but also produces beans, the flour of which is a first-class livestock food and is also esteemed for invalids and babies and is utilized in m a n y industrial processes.

A t the age of four years, algaraba produces very substantial yields, and thereafter quickly approaches the m a x i m u m output. G o o d varieties of algaraba will yield up to 20 tons of cereal substitutes per acre yearly. The tree flourishes in low-rainfall areas and w a r m zones, but there are also frost-resistant kinds, notably varieties growing in Argentina. The value of algaraba flour or meal is quoted in the markets as equivalent to maize, barley, or wheat meals in price. The beans or pods m a y also be fed directly to animals. The tree exudes g u m of commercial quality in economic amounts, while if bees are kept as an ancillary industry the returns from apiculture in the form of honey and wax m a y be appreciable.

There are numerous varieties or types of algaroba, and selection is of paramount importance. The seeds for the Limpopo plantings were collected from Hawaii, which has over 50,000 acres of the trees under culture, from which as m u c h as 1 million tons of fodder are gathered annually.

After sowing in nursery beds, the seedlings were planted out in small locally-made grass baskets. W h e n about 18 inches high the seedlings were set out on contour strips cleared along the hillsides. The best planting-out period was January and the most suitable distances about 25 feet apart, or just over 50 trees to the acre.

Growth was rapid; at 16 months the young plants were in flower, and at 18 to 20 months the first beans were harvested. This was at least 50 per cent quicker than the best results secured in India, where algaroba plantings have been m a d e on the eastern borders of the Thar desert. The Hawaiian trees are of good stock, and selection work preserves the best and most vigorous, the thornless types being chosen for ease of harvesting. Propagation from these has resulted in the development of a new field crop eminently suited to dryland conditions.

The carob tree, or 'St. John's Bread', starts to bear at from four to eight years. It lives to a great age, and is drought resistant, but needs care in the early stages. Yields of good-quality carob trees can be as high as 20 tons per acre annually.

At Messina, seeds were sown in nurseries, transplanted into planting baskets when the seedlings were about 2 inches high, and later set out as young trees in prepared holes 30 feet apart in cleared areas. W h e n the trees are 2 - to 3-feet tall, they must be budded, with good high quality bud wood of proved varieties. The best source for this is California, where extensive work has been done in the raising of superior types of trees and the deve­lopment of economic plantations. The budding is a simple horticultural operation.

The roots of the young seedlings are delicate and must not be touched or

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J. Sholto Douglas

exposed to light; therefore, when transplanting them from the nursery beds into planting containers, care has to be taken to keep a ball of soil or compost around the taproot. Seeds need to be treated by pouring a kettle of boiling water over them and leaving them to soak for 24 hours before sowing. This causes the testa or hard seedcoat to rupture and ensures speedy germination. T h e same procedure also applies to algaraba and other similar species.

Both the algaraba and the carob have established themselves well in the Limpopo valley. The ecological conditions—climate, soil, temperature, and other general factors—are suitable, and as the local selections for a typical hot savannah region they appear well suited to the pattern of three-dimen­sional forestry.

Subsequent to the Limpopo valley trials and demonstrations, other work on forest-farming was initiated at several places in central and eastern Africa, including G w a n d a district near the southern edge of the Matopo hills in Rhodesia, the Shire and Zambesi central valleys in Nyasaland (now Malawi) and Mozambique, and belowe Lake Eyasi in the Iramba region of what is n o w Tanzania and some additional tests were conducted also at Morogoro. These extensive experiments combined with larger scale plantings have confirmed and even amplified the possibilities of the n e w concept. Other tree species such as the honey locust, the rain tree, the Indian beech, the tree lucerne, and m a n y more have been introduced in areas of different climatic conditions. The breeding of improved varieties of the indigenous African locust bean is also being undertaken.

GENERAL PRINCIPLES A N D ADVANTAGES

Today the novel methods of three-dimensional forestry are arousing great interest amongst agriculturists and foresters throughout the world. The main advantages of the system are that this type of culture, once established, gives a high return with no expensive field operations or outlay on machinery, and it can be introduced in places where orthodox farming would be impos­sible.

The general pattern of three-dimensional forestry is to have large forest belts or blocks of economic trees interspersed with narrower grazing strips of grasses or herbage along which move herds of livestock, fed from the woodlands and producing meat and other items. The cereal-substitutes harvested from the trees support the animals.

The system forms a natural biological cycle into which m a n fits perfectly; he can eat the food harvested from the trees and the flesh or produce of the forest-fed livestock or sell them. The manure of the cattle, pigs, sheep, goats, or poultry is returned to the earth and encourages healthy and vigorous growth of plants. In particular, the pastures soon increase their yields after this fertilization.

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Land-rescue agriculture: three-dimensional forestry

Labour needs are very low, large amounts of capital are unnecessary, investment in elaborate mechanization is more or less eliminated, and no backbreaking toil or long hours of work are involved.

While there are different trees for w a r m or cold climates and for wet and dry areas, the general principles remain the same. The aim is to m o v e into a locality which m a y be neglected, barren, marginal, or unproductive under its present system of farming. Sometimes the soil m a y be eroded or damaged by bad agricultural practices, or it m a y be lying useless because there are no other k n o w n techniques capable of developing it.

Certainly, one of the great advantages of forest-farming is its simplicity of operation, provided the general principles are followed and proper technical methods are applied. Such tasks as ploughing, harrowing, seeding and other mechanical cultivations are not required, nor is there any need to purchase combine harvesters, artificial fertilizers, special buildings or implements, and all the hundred-and-one items of apparatus essential to the arable farmer. The land does not have to be stumped in the forests or plantations; it needs simply to be cleared by cutting d o w n to ground level any existing vegetation, which is thereafter kept under control with agrocides until it withers away or dies. Once established, the woods demand no more attention that do conven­tional timber forests. The pasture strips are manured by the constant passage of grazing stock. The produce of the trees, used as cereal-substitutes for stock feeding, is ground up by ordinary h a m m e r mills at assembly and distribution points, stored under plastic polyethylene or butyl sheeting, and used as required. The electric fences for confining the animals are easy to m o v e , cheap to set up, and very effective, consisting only of strands of wire and light posts, powered by portable batteries. Proper planning will streamline daily routine and reduce work and suction harvesting with useful simple apparatus is both cheap and efficient.

T h e first essential is to survey the chosen localities and to assemble all the facts relative to the habitats and environment of each in order to undertake the proper ecological assessment. Then suitable types of trees for growing m a y be selected on the basis of their adaptability to the conditions in ques­tion and their produce. The trees m a y be grown in orchards—that is to say all over the land, preferably in quincunx or alternate manner with grassed spaces between each tree—or in long contour strips for hilly and undulating ground, or in squares and rectangles on flat areas with belts of open pasture separating the plantations. Until the trees begin bearing the farmer will get partial returns from the grass on the land for fodder and animal food, or he m a y even raise some other crops while the trees grow tall.

W h e n the first produce appears, the livestock are brought in gradually, only a few initially, then steadily increased up to the eventual production capacity of the land. This is based upon the yields per acre of the trees within the estimated m a x i m u m of 20 tons, and those of the grass strips of

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J. Sholto Douglas

ground herbage. It m a y be practicable in some places to introduce a secon­dary layer of low-type trees or shrubs underneath the main forest species, once these latter have attained their usual heights, if the principal canopy remains partially open to admit some light. The object is to be able to feed the animals on the farm from the cereal-substitutes harvested from the forests, not a difficult task in practice in view of the high yields of the specially bred trees and the supplementary source of nourishment in the form of grass.

At times of food shortage, the forest products can also be eaten by h u m a n beings. The flour or meal produced from m a n y of the trees used is both palatable and nutritious, with good amounts of protein and sugar.

Thus, three-dimensional forestry maintains a complete and satisfactory cycle of good husbandry. Each unit constitutes an ecosystem in conformity with natural demands.

CHOICE OF SPECIES

The practice of three-dimensional forestry has been m a d e possible and profi­table by the breeding of new and efficient tree varieties. Just as in any industry there are good and bad products, so, here, there are superior and inferior strains which yield excellent or poor crops. Naturally in forest farming only selected high-yielding, fast-growing varieties should be employed. A s the object is to provide substitutes for the c o m m o n cereals normally utilized by farmers to nourish livestock, it is vital to ensure that the trees grown produce fruits, pods, beans, or nuts that will be better or at least equal to ordinary food grains. A wide choice of species is available, and the actual selection of types will depend upon the factors prevailing in the local habitats. Generally, it is feasible to class areas according to their climates and soils. Other condi­tions, however, require due consideration, including ground water supply, wind, topography, market outlets, and situation.

The tree legumes

O n e of the most valuable and popular types of plantations, well suited to forest-farming, are the tree legumes belonging to the Leguminosae, the second largest family of the seed plants, containing about 600 genera with 13,000 species. A s is well known , the roots of m a n y of these species contain nodules which are the habitat of bacteria with the power of fixing atmospheric nitrogen. This is liberated w h e n the roots decay, so that poor soils are enriched. Legumes of all types are cultivated throughout the world in both the tropics and the temperate zones. They have a high protein content, ranging normally from 15 to 25 per cent, whereas the c o m m o n cereals offer only 6 to 14 per cent of protein.

Tree legumes have been utilized extensively in three-dimensional forestry

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Land-rescue agriculture: three-dimensional forestry

projects in m a n y regions, and two species—carobs and algarabas—have already been mentioned. It will be of interest here to discuss more fully the merits and productivity of economic tree legume species. The most important kinds include the following.

Carob. Ceratonia siliqua, the carob tree—called kharoub by the Arabs— is native to the eastern Mediterranean, but is n o w cultivated throughout the tropics and subtropics. It has pinnate leaves and bears crops of sweet, sugary pods from 6 to 10 inches in length, nearly 1 inch broad, dark brown in colour, and very palatable. These pods are a valuable fattening and nourishing food for cattle, but are also relished by h u m a n beings. C o m m o n l y termed beans, the pods (which contain over 50 per cent sugar) m a y be eaten whole or ground into flour and meal. Such products are excellent for incorporation in baby milks and foods, for diabetics and other invalids, and for employment in a number of industrial processes.

The carob seeds contained in the beans yield g u m of commercial quality and can be used as a substitute for coffee. The sweet, mucilagenous pulp which has such a high sugar content after drying is sold as a confection called 'St. John's Bread'. The tree is dioecious, and in cultivation it is essential to graft selected varieties on to strong seedling stocks, or male trees m a y have branches inset from a good female tree, reserving two or three male branches so as to ensure pollination. The species is especially important to the economy of Cyprus, where large g u m factories utilize the seeds for the making of adhesives for export. The trees have also been naturalized in Queensland, California, parts of north India, and to some extent in southern Africa. Carobs m a y remain productive for over a hundred years.

Algaraba (Prosopis species). There are m a n y species and types of algarobas. Most favour a w a r m climate but some kinds are frost-hardy. The tree origi­nates in South and Central America and the West Indies. Said to be 'more nutritious than corn' by those farmers w h o cultivate it, the algaroba is a medium-sized tree, generally yielding crops of yellow pods, something like w a x beans in shape and size, extremely palatable and with a fresh cereal odour. The sweet pulp contains about 25 per cent grape sugar, together with 15 to 17 per cent protein. The pods or beans are a good cattle food and are also consumed by native Americans. Algaroba has m a n y uses: apart from its food value, the wood is a satisfactory fuel, the lumber is used for piles, and the flowers, which are pale yellow and are borne on long cylindrical spikes, are the source of delicious honey. The best varieties are thornless. The bark contains tannin, and also a g u m suitable for varnish and glue and as a medicine for dysentery. Algaroba species mostly tolerate dry waste places. W h e n ground into flour, the beans give a meal of delightful taste similar to maizemeal.

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J. Sholto Douglas

O n e species, Prosopis spicigera or the Sami tree, growing in north India, is sacred to the Hindus. P. africana seeds are used in some parts of northern Nigeria for food; P. dulcis pods are esteemed in South America as cattle fodder, and the seeds ground into powder are an important part of the diet of h u m a n beings in some areas of Brazil. In Argentina, there are plantations grown in colder areas under irrigation for the raising of algaroba beans for stockfeed.

A belt of algarobas 400 miles long by 2 miles wide is being planted in India under United Nations auspices to check the spread of the Thar and Rajputana deserts towards Delhi and to provide additional nourishment for the local population.

Rain tree {Pithecolobium saman). Also called the Guango, Inga Saman, and Penikaral, the rain tree was introduced from tropical America to South-East Asia about 1850. It has a rather shallow root system and grows rapidly. The brown, flattish pods, about 6 to 8 inches long, contain a quantity of sweet sugary pulp, and are relished by cattle. Quantities are exported from South America for livestock food. The tree has small pinnate leaves, which form a canopy of shade in the daytime but close up at night, so that during a period of drought a patch of green grass m a y be seen beneath the branches, while the surrounding ground is parched and dark. This led to the supposition that the tree mysteriously produced rain at night, hence its name .

P. saman thrives on fair soils in dry districts, but can attain very great size in hot, moist regions. In Indonesia, the seeds of P. lobatum are eaten in an unusual way. It is necessary to bury them for several days, after which they are washed and the sprouts cut off and thrown away. Steeping the raw grains in salt water for 2 hours is also practised. W h e n fried in oil, the treated seeds also make a pleasant dish.

Other important tree legumes suited for three-dimensional forestry include: The acacia of which many tree and shrub species grow in Africa, Asia, and

Australia. Mostly they are cultivated for the production of g u m arabic, but in some places, the seeds of Acacia concinna are eaten after roasting, while those of A. leucophloea are ground up and consumed mixed with other flours. Wattle bark, produced by acacia trees, is an important article of commerce, being rich in tannin.

The jehebnut, a small desert tree which grows north and east of the Sahara, whose one-seeded pods are eaten as a dry legume in Somalia and Ethiopia, and whose seeds or nuts, about the size of beans, form a popular local article of food.

The tallow tree, or dattock, another African species, c o m m o n in the tropical zone, and including both savannah and forest varieties. The fruits of the former kinds are eaten either fresh or dried. The seeds are sometimes eaten, or the oil can be extracted for h u m a n consumption and the residues

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employed as animal fodder. The tree furnishes excellent timber, often called 'African mahogany'.

The Polynesian chestnut, or Tahiti chestnut. This species (Inocarpus editlis), popularly known as kayam, grows in the Pacific islands. The large, fleshy seeds, one or two to a pod, taste like chestnuts and are an important food in Samoa, Tahiti, and neighbouring places. The tree has been introduced into areas of southern Asia.

The lucena, variously called the wild tamarind, wild popinac, lead tree, horse tamarind, jumpy bean, West Indian lead tree, white popinac, jumbai, and tantán, is a native of tropical America and West Indies which n o w grows throughout m u c h of the hot zones. Quick maturing, the lucena furnishes good fuel, its foliage is relished by cattle, and the young fruits are eaten in the East Indies and parts of Africa by h u m a n beings. The ripe seeds are edible as well, and when roasted are used as a substitute for coffee.

The African locust bean (several Parkia species). These species are popularly called nitta trees. P. africana and P. filicoidea grow in tropical Africa. The brown pods, which grow in long hanging clusters, contain a sweet yellow pulp, which turns into a white powdery substance. It is edible and tasty.

The tamarind, a large tree, probably a native of India (where it is called 'simbalaya') which is n o w cultivated in many w a r m areas. The pulp of its pods, pressed and preserved in large masses, is commonly sold in eastern bazaars and is the 'tamarind' of commerce. It is sweetish-acid in flavour. The seeds contain oil and can be ground into a palatable meal. Tamarind is used to m a k e cooling beverages, as a seasoning in chutneys and preserves, and as a native medicine. In Ceylon it is made into a brine for keeping fish.

The honey locust, a very valuable tree legume, suited to cooler zones, which is found in North America from Ontario d o w n to Texas. The trees bear pods or beans, about 12 to 18 inches long, containing a sweetish succulent pulp, with a content of 27 per cent sugar. M u c h attention is n o w being given to the economic use of the species.

This list of important tree legumes is by no means exhaustive; still other species, less well known and not yet bred or tested for improvement or economic potential, are available in various regions of the world.

The hawthorns

The rose family makes a contribution to three-dimensional forestry with the hawthorn trees. The generic name Crataegus (derived from the Greek kratos or strong) indicates their hard wood . Hawthorns are found in North and Central America and in Eurasia. O n e type of particular economic value is the Mexican hawthorn, currently under investigation for selective breeding and introduction to forest cropping. Another hawthorn, the manzanilla

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J. Sholto Douglas

(C. stipulosa), a native of Guatemala but n o w fairly widespread, bears small apple-like fruits, yellow when ripe, which are eaten and m a d e into jams and preserves. Other hawthorns m a y prove useful for forest-farming in the future. The leaves are edible and palatable as cattle fodder. Individual trees can be traced which are thornless, and these should form the basis for breeding and selection work.

Nut-bearing trees

A wide range of trees available for forest-farming fall within the group termed nut-bearing. Nuts are of great commercial importance in the world economy. There are well known types, as well as others not yet appreciated outside their local habitats. S o m e nuts are rich in carbohydrates, such as the chestnuts, the chufanut and the singharanut, the lychee—famous for its pulp—and the water chestnut, c o m m o n on the Yangtze and the Potomac river banks. Over 105 kinds of nut-bearing trees are frequently utilized for foodstuffs in various countries. S o m e of these valuable trees have been incorporated into three-dimensional forestry schemes. A m o n g the most important are:

The walnut, of which seventeen species are commonly grown throughout the world. Successful culture depends upon the choice of the right varieties to suit local environments, the presence of good pollinizers, proper grafting on to rootstocks of the same variety, and low heading to bring on early bearing.

The chestnut. There are four Castanea species and these are the only trees that should properly be called chestnuts or sweet chestnuts. They are prolific seeders. The European chestnut (C. sativa), sometimes called the Spanish chestnut, plays a vital role in the food economy of m a n y regions. The largest nuts, termed 'marrons', are eaten raw or cooked. They are commonly dried and milled into flour or meal, which m a y be used for soups, bread, and as livestock feed. The other three chestnut species, all quite useful, are natives of Japan, China and North America.

The pines. It is not generally realized that some species of pines yield crops of food nuts. These trees belong to the Pinaceae, a genus of conifers, containing about ninety different species. M a n y are valuable for their yields of resin, turpentine, and timber. Pine nuts are fairly rich in oil, and have a pleasing taste. Ground into meal, they form an excellent stockfeed. Food nuts are obtained from some eighteen species of pines, to be found in many parts of the world. The Italian stone pine nuts are sold as pignolia for export. A considerable number of food-producing pines are suitable for three-dimensional forestry.

The Auraucarian pine {Araucaria araucana) of the Andes of Chile which bears a nut which is a popular food amongst the indigenous Indians.

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The hickory, which is found in the United States, Canada, and China, and whose delicious nuts are important food crops. The timber is tough and elastic. The hickories or pecans include seventeen species of value.

The hazel, filbert, or cobnut. Comprising at least eleven species, growing in North America, central and west China, Europe, the Himalayas, Japan, China, Siberia, and Turkey, the hazelnuts are suited to temperate zones. Hazel will form dense thickets as a second ground layer beneath the upper canopy of larger deciduous trees in woodlands. It attains a height of about 15 feet. The branches are supple and can be employed for making baskets or in weaving.

The butternut, also called the long or white walnut. C o m m o n in north-eastern North America, this is a valuable tree for forest-farming.

The beeches. There are both American and European beech species which yield nuts, but production is apt to vary from year to year. In the Middle Ages, beech nuts formed an important part of the diet of village livestock.

The breadnut. This is a seed-bearing variety of the breadfruit tree, c o m m o n in the West Indies. A solid, white fleshy mass is obtained from the fruits, which on roasting resemble the crumbs of a new loaf. It m a y be ground into meal or flour, and constitutes, as does the breadfruit in the South Pacific, an important article of local diet.

The oaks. The acoms of several species of oak trees are a c o m m o n item in the diet of small wild game and because of their high nutritional value used to be employed in the fattening of pigs.

Fodder trees

It is often useful to include in the three-dimensional forestry pattern some additional species of fodder-producing trees in order to furnish supplemen­tary green roughage or dried hay substitutes. These help out at different seasons and constitute a valuable supplement to the diet of the farm livestock. There are m a n y kinds of trees yielding nutritious fodder. Amongst them m a y be noted the lettuce tree, a small evergreen species with striking pale yellow foliage, especially suited to coastal lands. It can be readily propagated by cuttings. Cattle eat the leaves with relish.

The Indian beech (Pongamia glabra) is a handsome tree with glossy pinnate leaves, a good bearer of heavy foliage, which is m u c h liked by livestock.

The tree lucernes (three species) are a small leguminous type, appropriate to higher elevations, which produce ample fodder. Their leafy branches are commonly used as food for cattle. Called 'tagasaste', they are indigenous to the mountains of the Canary Islands.

Dates are fed to animals in Arabia, Iraq, and Egypt, while the fruit of the jak (Artocarpus integrifolia), and of other Artocarpus species are relished by cattle in India, Ceylon, and Malaya.

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Pastures and herbage

The three-dimensional forestry technique demands the alternation of grass or pasture strips between the wooded blocks or belts to provide spaces for the herding of livestock, such as cattle, sheep, pigs and goats.

There are m a n y species of excellent high-yielding pasture grasses suitable for all kinds of climates and conditions. W h a t is not so well k n o w n is that there are other types of herbage and forage plants which provide useful quantities of supplementary greenfood which can be eaten fresh or made into hay and silage. Outstanding plants of this type are Desmodium gyrans, an erect leguminous perennial, enjoyed by cattle; cabbage broccoli or kale; certain varieties of soya beans; sulla clover, which gives a yield up to as m u c h as 50 tons per acre and is valued in Australia; alfalfa or lucerne where some irrigation is available; the Lyon bean, an excellent source of fodder; and the berseem, well-known throughout the Middle East, which thrives on saline land. In addition, there are a number af good browse plants, among them the notorious prickly pear. Prickly pears are best ensiled, the succulent spiny growths being well crushed, flavoured with salt, or mixed with other fodder, and put into pits. The silage so prepared is very fattening. The spineless form, first bred by Burbank in California, is superior for cultivation.

The foliage and flowers of the c o m m o n alder, the berries of which are used for wine making, and the leaves as substitutes for spinach, also form good cattle fodder. The by-products of sisal plantations, the leaves of rubber trees, gorse, tea bush cuttings, and palm fronds, to mention only a few lesser k n o w n items, can all, after processing, be employed for the efficient feeding of livestock as supplementary rations and roughage.

It will, therefore, be apparent that there are a very large number of utilitarian plants that can provide valuable foodstuffs in the multiple-use concept of forest-farming, at little outlay or expense, and only requiring the exercise of m i n i m u m ingenuity to turn them to good account and commercial exploitation.

Livestock

A wide variety of economic livestock can be kept profitably on a forest farm. The usual methods of animal husbandry are applicable in general, and beasts require normal care and attention, but expensive housing and appa­ratus m a y be dispensed with.

Cattle, pigs, sheep, goats and other large animals are kept within electric fences, to prevent them from damaging the trees or eating indiscriminately. These grazing enclosures must be moved periodically, according to a planned rotation schedule, to avoid exhaustion of the ground cover. Also, if left too long in one spot, the beasts will foul the land and m a k e it 'sick', as well as causing erosion. Poultry, however, m a y be allowed free range through the

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forests, returning at nights to sleep in conveniently sited houses, or for daily egg-laying purposes. Rabbits, of course, the meat of which contains 17 per cent protein and is superior in food value to most other flesh eaten generally by h u m a n beings, run wild, but have to be trapped and controlled regularly so as to prevent over-multiplying. Rabbit meat sells well, and the fur is marketable.

Breeds should be selected according to their adaptability to local condi­tions and the main items that it is desired to market. There is ample scope for apiculture, and other ancillary industries. In certain areas it m a y be economic to maintain g a m e animals under domesticated care, such as elands and other types of economic value.

THE SYSTEM IN PRACTICE

The concept of three-dimensional forestry has been designed to conform to accepted ecological principles of land care and management. It does not conflict with Nature; it works instead with the approved laws of applied biology.

In discussing the practical details of three-dimensional forestry, the basic essentials involved in establishing any scheme should first be emphasized. These are: 1. A thorough ecological survey of the given area, including assessments of

the climate, soils, water supplies, prevailing winds, natural vegetation, social and economic factors, markets, and general conditions of impor­tance.

2 . The preparation of a list of suitable species for introduction, bearing in mind their prospects of adaptation to the environment, their economic value and the demand for their produce. This should include both plants and livestock.

3. The establishment of a flexible plan and working programme for the commencement, development, and day-to-day working of the project.

4 . Tentative schedule of techniques to be employed. 5. Assessment of costs and returns, together with capital needed, and the

estimated income as the scheme develops. 6. Equipment and apparatus essential to the work. Buildings and other

facilities. 7. A n y further considerations. T h e success of projects depends largely upon the original planning and the proper apportionment of resources. But the work of establishment m a y be said to be progressive, and no scheme of applied biological scientific intent can ever be truly said to be static or complete in itself. While the general principles of three-dimensional forestry hold good for any region, it is necessary to m a k e m a n y local adaptations in respect of practical detail.

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J. Sholto Douglas

These concern for the most part the species of plants and animals selected and the lay-out of projects. A short account of the conception and progress of some of the Limpopo valley work will illustrate clearly what is involved.

After completion of the preliminary surveys in that area, the factors of the environment were closely scrutinized. B y comparing them with lists of possible species prepared by the International Commission on Applied Ecology, it was possible to choose certain types for initial introduction work. In addition, a comprehensive plan could be prepared and transferred to maps and charts showing exactly in what places different plantations could be established with reasonable prospects of success. Arboreta and multipli­cation nurseries were laid out, seeds and planting material collected, and the work of marking and demarcation of forest plots, blocks, and contour belts was begun.

The plan called for the introduction of a wide range of species in order to test their responses in the local environment. Only the best adapted were retained. W h e n ready for planting out, the young trees were transferred to the belts or blocks according to a defined schedule. W h e n these had been prepared, the intervening pasture strips were sown with grasses, either indigenous or introduced, or with appropriate herbage mixtures.

The first part of the programme envisaged a five-year period of initial development within an area of 50 square miles, stretching back from the alluvial river bank to the higher ground to the south, which included some low hills and an extensive section of undulating ground, with narrow stream valleys running through it. Each part was mapped, and localities were chosen for the forest belts or blocks, the pasture strips, roads, working points and buildings, propagation nurseries, and other facilities. Eleven nurseries and arboreta were established to cover the whole area, provide planting stock, serve as assembly units, and as direction centres.

The work in the Limpopo valley was complicated by the fact that, except for the directorate, the supervision and labour were all unskilled, and had to be taught elementary silvicultural practices from the very beginning. These included tree nursery work, budding and grafting, planting out, field cultural care, and simple surveying for the laying out of contour strips, belts, and blocks.

With the coming of the first harvests, forest products were collected, the pods or beans of the trees being processed into meal by grinding in a h a m m e r mill.

The livestock introduced were cattle of southern African acclimatized stock, mostly Boran, and Hereford crosses with native Zebu types, local goats, and poultry of the Leghorn, Sussex, Australorp, and Rhode Island R e d breeds. The cattle and goats did well in the hot climate, but it was necessary to hybridize the fowl with indigenous breeds, and undertake selection work to fit them for survival in the w a r m conditions. This proce­dure improved their hardiness and capacity for foraging without lowering egg

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yields. It was found that the meal produced from the algaroba trees was well liked by the livestock. Inquiries were m a d e concerning the market prospects for the sale in quantity of produce. Prospective buyers were eager to obtain regular supplies.

INTANGIBLE SOCIAL VALUES

U p to n o w w e have been discussing the technical advantages and economic benefits of forest-farming. In addition, however, it has certain intangible social values which are worthy of mention. Let us note that not only does three-dimensional forestry make possible the development and exploitation of n o w useless areas; it can also provide populations with a rewarding and purposeful kind of life. This, in itself, is a vital consideration.

Modern m a n is already tending to become just a m e m b e r of the 'admass', a mere cog in the wheel, losing his individuality and initiative in the vast and unthinking conglomerations of twentieth-century society. The coming of the n e w megalopoli will further reduce his independence and his contacts with Nature. Three-dimensional forestry, by opening up n e w avenues of employment in the rural regions can do m u c h towards conterbalancing the deleterious effects of excessive urbanization, and m a y well succeed in attracting people back into the countryside or to pioneer in the undeveloped zones.

The forest-farmer is a technician, working to a scientific plan, fully c o m ­parable in status to town dwellers. This m a y prove to be a powerful attraction to the technically minded youth of today.

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Chemistry and society,1 V I

H. Mark Polymers Review and preview

REVIEW

Organic polymers (macromolecules or giant molecules) have been feeding, clothing and housing m a n ever since the earliest days of civilization. W o o d consists of polymers; so do meat, starch, vegetables and fruit, and also cotton, flax, fur, wool, silk and rubber. All these materials are the oldest and most necessary attributes of our existence and yet until a hundred years ago next to nothing was known about their chemical composition and structure. A s products of living systems and as the substances which maintain life they are obviously of a highly complicated character, and it is just this complexity which endows them with wonderfully versatile, highly effective properties. A s a consequence they present a great challenge to chemists—not only to learn the secrets of their design and activity but even more to devise new materials which Nature, for one reason or another, has neglected to create. A n d , in fact, during the last forty years, the chemistry of high polymers—natural and synthetic—has m a d e such rapid strides that it is today one of the most exciting branches of all natural sciences.

This progress caps a century of remarkable developments in organic chemistry. Chemical understanding of organic compounds began in the early decades of the nineteenth century w h e n the first test tube synthesis of urea was achieved, a substance already k n o w n to be a product of animal metabolism. Later it was possible to work out with full success and in great detail the structure and the activity of numerous comparatively simple organic molecules: sugars, fats, fruit acids, soaps, alcohols, the coal and petroleum hydrocarbons, natural dyestuffs, drugs, and others. Over the past century m a n y thousands of scientists all over the world became absorbed in organic chemistry, developing ingenious and efficient techniques of

1. See Impact, Vol. XVII (1967), N o . 2, and Vol. X V I (1966), Nos. 3 and 4.

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Impact. Vol. XVIII (1968), No. 1

H. Mark

investigation and constructing a general theory of the structure and behaviour of the simpler organic substances, based on the simple concept of the four-valent, tetrahedral carbon atom. This theory m a d e it possible to classify the properties of hundreds of thousands of substances, from the exhalations of gas wells to the colouring of flowers, the foam of soaps and the poisons of snakes. But beyond this it gave birth to immeasurably valuable synthetic products such as dyes, perfumes, drugs, fuels, detergents, etc., and also m a d e it possible to predict their properties quantitatively. Indeed, m u c h of our present civilization—medical care, sanitation, printing, photography, radio, television, motor transport and aviation—relies heavily on materials provided by 'classical' organic chemistry.

All these substances were found to consist of relatively small molecules and, hence, represented comparatively simple members of the organic family. Their larger, more complicated relatives—cellulose, starch, proteins and others—received only minor active attention from chemists, mainly because throughout that period they were too difficult to deal with. The experimental methods on which organic chemists relied for separation and analysis of organic substances—solution, melting, crystallization, filtration and the like —did not work with these natural polymers. For example, cellulose, the chief component of wood , does not melt w h e n heated; instead it carbonizes and decomposes. N o r can it be dissolved, except in chemicals which change it irreversibly to something different. The same is true of other organic polymers, such as wool, silk, starch and rubber.

It often happened that chemists did produce large organic molecules accidentally during their experiments. In fact, the literature of organic chemistry is full of references to reactions which gave 'resinified' materials which covered the glassware with waxy, gluey or sticky messes. These products were a clear disappointment to the experimentalist w h o was looking for products which he could purify by well established methods in order to get his desired substance in nice crystalline form; they were also a distinct nuisance to the bottle-washer w h o had to clean the glassware.

In short, up to about fifty years ago the big organic molecules offered little attraction to chemists. Classical organic chemistry was fun of interesting and attractive problems. With so m a n y green pastures around, w h y should a chemist invest his career in the risky and sticky business of investigating the macromolecules?

But, after the First World W a r , in the early 1920's the study of large molecules such as cellulose, proteins and rubber started to look promising and intriguing. In 1923 the writer of these lines (then 28 years old) confessed to his professor at Berlin, Wilhelm Schlenk, that he was strongly tempted to start some work in this n e w field. Schlenk, w h o had long been regarded as one of the most ingenious experimentalists in organic chemistry, said: 'If I were twenty years younger' (he was 55), T might be very m u c h attracted myself. Wait until you are ten years older, and meanwhile demonstrate

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Polymers, review and preview

with classical investigations that you are capable of tackling a problem of such proportions.' It proved to be excellent advice.

Scattered attempts to analyse the chemical composition of cellulose, rubber, starch and proteins had begun in the 1880's w h e n chemists established that these substances, like all organic compounds, were composed mainly of carbon, hydrogen and oxygen; that cellulose was essentially a polymeric sugar; that starch was another carbohydrate; that natural rubber was basically a hydrocarbon and that proteins contained considerable amounts of nitrogen and sometimes a little sulphur or phosphorus. The investigators soon decided that the main distinguishing feature of all these substances—what made their properties so different from other organic materials—must be the size of their molecules. The insolubility of the substances and their resistance to fusion argued for large molecular size, because it had been found that ordinary organic compounds such as petroleum hydrocarbons became less and less soluble and acquired higher and higher melting points as they were combined into larger and larger mole­cules. The mechanical strength of cotton, wool and silk also suggested that they were m a d e of very large, strongly coherent molecules.

It was a logical deduction that each of the big molecules consisted of certain building blocks: glucose in the case of cellulose and starch, isoprene in the case of rubber, and amino acids in the case of proteins. Chemists, therefore, began to call these compounds 'poly' something; starch and cellu­lose, for instance, were identified as polysaccharides, meaning that they are composed of m a n y sugar units. This is the basis of the present general terminology for the classes of compounds with which w e are concerned: a m o n o m e r is a substance which can serve as a building unit (e.g., glucose); a polymer (from the Greek, meaning ' m a n y parts') is a combination of such units and a high polymer contains very m a n y monomers , i.e., it is a compound of high molecular weight.

O n e of the earliest promoters of polymer chemistry was Emil Fischer, the great organic chemist of the late nineteenth and the early twentieth century, w h o in his later years became fascinated by the mysterious chemistry of proteins and other organic macromolecules. Although loaded d o w n with administrative duties for the German Academy of Sciences, the Ministry of Education and the National Research Council, he would go to his private laboratory early every morning to carry out his tests with his o w n hands. Sitting on a stool and watching thoughtfully as faint precipitates appeared in his reaction flasks, or white powders reluctantly crystallized out of solution, he saw visions of the chemistry which was to c o m e twenty years later. Fischer induced some of his ablest co-workers to study rubber, starch, proteins, cellulose and lignin (the other major component of wood) . At about the same time the great organic chemist Richard Willstaetter was beginning to synthesize polysaccharides and to discover n e w methods for isolating lignin and enzymes. These pioneers worked largely by intuition. Willstaetter was

29

H. Mark

once asked, at a seminar where he reported a certain experiment, h o w he had happened to choose acetonitrile as solvent, cobalt acetate as catalyst and 75° C as temperature. His answer was: 'Just a thought, sir, just an idea.'

Ignorance of the chemical structure of natural and even some synthetic polymers did not, of course, debar their exploitation at the empirical level. Inventors discovered ways to convert cellulose into acetate fibres, films and coatings, into nitrated explosives and plastics and m a n y other useful products. Between 1870 and 1920 enterprising m e n (including Alfred Nobel) developed large industries based on cellulose derivatives. Meanwhile rubber also became a prominent article of commerce and financial prosperity thanks to Charles Goodyear's discovery, early in the nineteenth century, of the fact that heating it with sulphur (vulcanization) gave it useful properties. A n d proteins and starches likewise served as raw materials of other substantial manufacturing industries—leather, sizings, glues, adhesives, casein plastics and so on.

At the turn of the century there occurred another event which was to prove significant in the development of polymer chemistry and technology. Leo H . Baekeland, a young Belgian chemist, was not repelled but was attracted rather by some sticky, resinous by-products of his reactions which were such a bother to other chemists. H e gave up a project on which he had been working and devoted himself to investigating the material that had fouled up his glassware. It was a g u m m y liquid, formed by a reaction between c o m m o n chemicals such as phenol and formaldehyde in aqueous solution. Baekeland found that by applying heat and pressure he could turn the liquid into a hard transparent resin which proved to be an excellent electrical insulator and to have good resistance to heat, moisture, chemicals and mechanical wear. This discovery was the birth of the synthetic plastics industry; other chemists went on to synthesize m a n y other useful plastics of a similar (thermosetting) type, using formaldehyde with urea, aniline or melamine instead of phenol.

Thus, by the second decade of this century, factories all over the world were producing polymers in the form of fibres, films, plastics, lacquers, coatings, adhesives, and so on. Most of them were only modifications of natural high polymers—conversions which transformed such natural substances as cellulose, proteins and rubber into n e w materials of more valuable practical properties. Baekeland's invention, on the other hand, paved the way for the actual synthesis of polymers from low molecular weight substances which were readily available and inexpensive. The basic principles governing the structure and behaviour of polymers were still undiscovered. Chemists knew something about the ' h o w ' but nothing about the 'why ' .

But it became increasingly important to k n o w the w h y in order to improve processes and products, to reduce costs and to permit the establishment of predetermined properties without costly and tedious trial and error methods.

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Polymers, review and preview

Whenever chemists in factories tried to find out h o w they should best handle their systems and w h y they behaved as they did, they were disappointed by the lack of fundamental knowledge about polymers. Their academic colleagues in the universities had to confess that the exploration of large molecules was still in its infancy.

Soon after the First World W a r a number of far-seeing leaders in science and industry recognized that a systematic exploration of polymer chemistry would pay large returns, scientifically and industrially. Several of the leading organic chemists, Haworth, Staudinger, Meyer, Carothers, abandoned their successful careers in classical organic chemistry to gamble on full-time basic study of large molecules. Their studies were richly rewarded. Haworth and Staudinger emerged eventually as Nobel Prize winners, K . H . Meyer as a high executive of a giant Ge rman company and Wallace H . Carothers as the eminently successful leader of a research group in the D u Pont labora­tories. Supported by the vast resources of that organization and by a large group of brilliant associates he developed systematic knowledge in the chemistry of polymerization and synthesized m a n y hundreds of polymers. His efforts produced polyesters, nylon and neoprene. While the scientific world was impressed by the wealth and clarity of the resulting fundamental k n o w ­ledge, the D u Pont C o m p a n y drew great satisfaction and profit from its practical applicability.

These events of the 1920's and 1930's encouraged m a n y academic scientists and industrial researchers to turn to the large molecules. After having been a stepchild for m a n y years, polymer chemistry became fashionable. Under the leadership of Freudenberg, Flory, Haworth, Marvel, K . H . Meyer, Staudinger, Svedberg and others, it moved rapidly ahead on a broad front—in experiment and in theory. Polymerization processes were developed and refined, their mechanisms explored, their products meticu­lously described (after having synthesized n e w molecules one is naturally curious to k n o w exactly what one has made) . Very precise methods of describing the properties and behaviour of polymers were developed, based on measurements of osmotic pressure, diffusion, sedimentation, light-scattering and viscosity.

Chemists could n o w discern a general pattern in the formation of giant molecules. Basically all high polymers are built by the linking of monomers end-to-end in chains, sometimes several thousand units long. But the chains themselves can behave in different ways. They can either fold or coil up to lamella or ball-shaped entities (like a mass of folded or inter-twined spaghetti), or they can line up in straight, more or less rigid bundles (like wires in a cable). In general the coiled or folded polymers led to the characteristics of a rubber, while the straight-bundle type formed fibres or rigid plastics. The chemical character of the chains determined whether they would fold or coil or whether they would have the tendency to align them­selves in bundles: if the chains were relatively rigid and contained mutually

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H. Mark

attracting groups along their length, they would attach themselves to one another side by side in bundles.

PREVIEW

A s the principles governing the properties of polymers began to shape up in the minds of the investigators, an exciting n e w prospect emerged, namely, the capacity to formulate rules and laws which control the synthesis and behaviour of polymeric materials, thus making it possible to reduce the behaviour of these substances to certain principles and predict it with almost mathematical precision. This paved the way for the discovery of a new and eminently useful creative power to produce n e w materials. Mankind's technological progress has been largely a history of trial and error in the attempt to put available and existing materials to use. It is a considerable step forward to invent and create the building materials themselves, on order. A n d this is the stage w e have n o w reached in polymer chemistry and technology. Starting from a need for some material of specified properties, w e are in a position to create a n e w material tailored to fill that need.

A s the building stones for this enterprise, w e n o w have some fifty readily available inexpensive monomers , largely derived from coal and oil, and with the aid of our synthetic k n o w - h o w w e can produce an almost limitless number of combinations of these units. Already they have given us scores of important n e w m a n - m a d e materials: all the synthetic fibres, films, rubbers, plastics, coatings and adhesives. All fields of present application will greatly profit from the new approach because of the lower costs and the superior adaptability of these materials to specific uses.

There are already available, and there will be more in the future, textile fibres which have higher strength, better abrasion resistance and improved wash and wear characteristics. All garments, from underwear to topcoats, will become more beautiful, longer lasting and less expensive. Carpets which are flameproof, antistatic, brightly coloured, crush-proof, washable and less expensive will soon be used in practically all indoor living quarters. For the out-of-doors lawn-like floor covers will be available in varying density, colour and softness to replace natural lawns around swimming pools, in front and back gardens, on golf-course greens and sports fields. They are vastly superior to their present counterparts in durability, resistance against insects and weeds and insensitivity to rain, snow and drought.

N e w industrial fibres permit the construction of giant tyres for supersonic airplanes, fast railway trains and more efficient earth-moving equipment; they will serve to build large transport belts for heavy goods and for h u m a n mass transportation in factories, airports and subways. Nobody will have to walk with his suitcase in a railway station or in an airport for 15 minutes before reaching his gate; he will be carried away at 10 feet a second safely and comfortably.

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Polymers, review and preview

Films and sheets of higher strength, superior wearability, improved che­mical resistance and optional optical and electrical properties will further simplify and expand the art and industry of packaging, printing and document reproduction.

Using fast-running magnetic tapes automatic message recorders will be attached to every private telephone at low charge. Ultra-thin ribbons and sheets of m a n y types will advance the technology of computers, copying and printing machines to such an extent that a computer which today is the size of a large shipping crate will be conveniently carried in a brief-case. In bathrooms and kitchens there will be m a n y types of brilliantly transparent bottles, plates, dishpans and pots—light, heat resistant, easy to clean, sani­tary, unbreakable and inexpensive.

All boats up to the size of several thousand tons will be m a d e from reinforced plastics—light, beautiful, unsinkable, unbreakable and m u c h less expensive than n o w .

In houses, hotels, office buildings and factories, partitions, ceilings, floors, side walls and roofs will consist of light, infusible, non-flammable porous plastic bricks and sheets and the entire piping and ducting will be m a d e from unbreakable, rigid, non-flammable corrosion-resistant polymers which are light, easy to install, to repair and to alter and, in the long run, will cost less than the metallic and ceramic materials n o w used. But besides these m a n y conveniences which polymers will introduce into daily life, they will also greatly contribute to progress in medicine, public health and the solution of urban problems. Hard and soft implants of superior strength, toughness and durability are already being applied in surgery with resounding success; dentistry is spectacularly advanced by the use of fast-setting plastic c o m p o ­sitions which adhere to the native tooth material in a satisfactory manner and permit the construction of light, extremely efficient and attractive prostheses. Experiments are being m a d e with blood plasma extenders and substitutes which render the blood resistant to m a n y diseases and enable the hardening of blood vessels and the tendency for the formation of blood clots to be successfully combated. Public health and problems of urbanization will be aided by the use of polymeric membranes, filters and exchange columns for the effective purification of air and water and for the prevention of the most severe cases of air pollution. Commercial water desalination is another burning problem the solution of which is on the verge of being discovered with the aid of polymeric filters and membranes.

Education on all levels stands to profit enormously through the availability of inexpensive durable books, audio and video tapes and the progressive use of small, all-plastic portable television sets to be used in the same w a y as a pocket transistor radio and based on micronized transistor techniques using very thin polymeric fibres as a base for the semi-conducting metal layers. Students will be able also to take lecture notes at high speed, without disturbing the class-foom, on small, noiseless photoelectric typewriters.

33

The manipulation and use of the atomic nucleus, I

Georgi Fierov M a n - m a d e atoms

The diversity of matter existing in nature is known to be entirely made up of a relatively small number of different varieties of atoms called the che­mical elements. K n o w n today are 104 elements, of which some are the products of nature and some are man-made . Yet all of these elements, whether natural or m a n - m a d e , fit into a kind of 'table of organization'—the famous Periodic Table, which was established in 1869 by the eminent Russian chemist, Dmitri I. Mendeleyev.

The discovery of the Periodic Table represented a fundamental step forward in our understanding of those basic building bricks of the entire universe, the elements. H o w fundamental an advance it was is shown clearly by what followed after Mendeleyev had laid out the table.

After studying the chemical and physical properties of the 63 elements known in 1869, Mendeleyev was able to show that these properties tended to repeat themselves in periodic fashion, in a kind of rhythm, as one went up the scale of atomic weights. H e laid out the table based on this periodicity of pro­perties, leaving gaps for elements not yet known to exist. Then, on the basis of the law of periodicity he had established, he predicted the existence of then unknown elements with certain chemical and physical properties to fill three of the gaps in the table. Before m a n y years these predicted elements, n o w known as gallium, scandium and germanium, were found.

In the following decades, 22 other elements were discovered, so that by the 1930's the only gaps left in the Periodic Table were those corresponding to the atomic numbers 43, 61, 85 and 87 . The periodic series itself termi­nated with uranium, the heaviest natural element, having an atom number, Z , equal to 92.1

1. It should be remembered that the atomic number states the number of protons in the nucleus of an atom of the particular element: thus hydrogen, the lightest atom, has one proton in the atomic nucleus; helium, the next in line, has two, and so on up to uranium.

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Impact, Vol. XVIII (1968), No. 1

G . Flerov

Research into the properties of atomic nuclei revealed that if the missing elements could not be found this was not because the search for them had been insufficiently thorough, but because no such elements existed in nature. Having come into existence 5 milliard (5 X 10°) or more years ago along with the other elements in the universe, these elements have not survived, but instead, in the course of time, have been converted into the nuclei of other elements as a result of radioactive decay. In order that the properties of these elements could be studied, they had to be created anew—by m a n .

It was in 1934 that the French physicists Irène and Frédéric Joliot-Curie found out that it was possible to produce n e w atoms from the k n o w n elements artificially, thus, giving life to the alchemists' centuries-old dream of trans­muting matter. Their discovery started numerous experiments in m a n y physics laboratories throughout the world aimed at the synthesis of new elements and of the new isotopes1 of known elements.

A s a result of these experiments in the synthesis of elements, the four vacant places in the Periodic Table were finally filled. T h e four missing elements are technetium (Z = 43), promethium (61), astatine (85) and francium (87). In addition, the number of k n o w n natural or man-created radioactive isotopes of k n o w n elements underwent a vast expansion. M o r e ­over, it was found that while the c o m m o n process of radioactivity was decay of larger nuclei into smaller ones, there were a few cases where the nuclei of natural elements 'built up ' under the effect of radioactivity towards higher atomic numbers.

Today 276 stable and about 50 radioactive natural isotopes are known . In addition, about 1,500 radioactive isotopes have been synthesized by m a n . The latter number is in fact an approximation, not only because the improvement of the experimental facilities regularly results in the discovery of n e w isotopes, but also because in some cases it is impossible to classify radio­active isotopes unambiguously into the natural and the artificial. For instance, plutonium-239, an isotope k n o w n to be artificially produced in atomic reactors, is also identified in microscopic quantities in natural minerals con­taining uranium, where, as in reactors, the plutonium forms as a result of the irradiation of uranium-238 by neutrons. O n the other hand, polonium-210, first discovered among the products of the natural radioactive decay of uranium, can n o w be artificially produced in nuclear reactors.

A special place among m a n - m a d e atoms belongs to the new transuranium elements, i.e., elements lying next to uranium in the Periodic Table. Their special importance in nuclear physics is due to the fact that the nuclei of

1. Isotopes—the word being derived from a Greek word meaning 'similarly arranged'—are variant forms of one and the same element. While all the isotopes of a given element will necessarily have the same atomic number, meaning the same number of protons in their atomic nuclei, they will have different numbers of neutrons in their nuclei. Isotopes, therefore, differ only in their mass numbers, M , this number expressing the total of both protons and neutrons in the nucleus. Uranium, for example, with Z = 92, has three naturally-occurring isotopes with M = 234, 235 and 238.

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Man-made atoms

these heavy elements demonstrate most prominently the laws of nuclear forces and nuclear structure.

The synthesis and investigation of the properties of the first nine trans­uranium elements, starting with the element Z = 93 (neptunium) and ending with the element Z = 101, was done in 1940-55 by American researchers headed by Professor Glenn Seaborg.

In recognition of Mendeleyev's outstanding service in developing the periodic system of chemical elements, whose principles furnished a clue to the discovery of most of these transuranium elements, the 101st element was named mendelevium.

Soviet researchers could not start experiments of this kind until 1956, when intensive beams of accelerated carbon, nitrogen and oxygen ions were produced in the cyclotron at the Atomic Energy Institute in M o s c o w . The work in the synthesis of new elements, carried on by the scientists of the U . S . S . R . and socialist countries, received a new impetus in 1960 after a large cyclotron specially designed for the acceleration of heavy ions went into service at the Nuclear Reactions Laboratory of the Joint Nuclear Research Institute in Dubna . Out of several possible methods for synthesizing the far transuranium elements, irradiation by heavy ions had by then become a main technique. The synthesis of n e w transuranium elements, by the technique of irradiation with intensive neutron fluxes, m a d e it possible to go only as far as the creation of element number 100. A n y further progress with the aid of this technique proved to be impossible.

The advantage of using heavy bombarding particles—ions instead of neutrons—for the synthesis of heavy transuranium elements is that such available and convenient elements as uranium and plutonium m a y be used as the starting matter for the experiment. The formation of a new element results from the fusion of two complex nuclei: the target uranium or plu­tonium nucleus with the bombarding nucleus. The atomic number of the element thus initially created increases at one stroke by several units—six, seven, eight or ten, depending upon whether the heavy ions used to irradiate the target are those of carbon, nitrogen, oxygen or neon.

Having identified the main laws underlying the formation of transuranium elements in the reactions under the impact of heavy ions, the Soviet resear­chers proceeded to carry out experiments designed to produce the 102nd element. Previously, attempts to synthesize it had been made as early as 1957 by a team of scientists from the United Kingdom, the U . S . A . and Sweden, conducting their experiments on the cyclotron in Stockholm. Those experiments indicated the existence of new radioactive atoms with the assumed chemical properties of the 102nd element. The experimental results were regarded by this joint group as proof of the discovery of the 102nd element.

The experiments m a d e by this group were later repeated by American researchers at the University of California in Berkeley. Although in the latter

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G . Flerov

case the experimental conditions were more favourable for the synthesis of the 102nd element, the experimental results obtained by the joint group were not confirmed.

The first results of the experiments staged in the U . S . S . R . for the synthesis of the 102nd element were obtained in the autumn of 1957. About the same time the work for synthesizing another isotope of the 102nd element was in progress at Berkeley. The latter terminated with the publication in the summer of 1958 of a report on the synthesis and properties of an isotope of the 102nd element with the mass number 254.

A new stage in experiments concerning the 102nd element began in 1963 with the synthesis by Soviet physicists at the Joint Nuclear Research Institute in D u b n a of an isotope with the mass number 256, the heaviest among today's isotopes of the 102nd element.

The experiments in D u b n a yielded some n e w and far more accurate data on the decay characteristics for a total of five isotopes of the 102nd element.

The synthesis of a new element with Z = 103, named lawrencium in honour of the late American physicist, E . O . Lawrence, was first effected in Berkeley; soon afterward another isotope of this element was derived by a Soviet research group at Dubna .

The last of the elements known today, number 104, was synthesized in 1964 by Soviet physicists at the Joint Nuclear Research Institute. The authors proposed that the new element be named 'kurchatovium' in memory of the outstanding Soviet scientist, Academician Igor Kurchatov.

The new element was synthesized by irradiating plutonium-242 with accelerated neon-22 ions. The kurchatovium isotope 104260 disintegrates very rapidly through spontaneous fission, so that in 0.3 second only one-half of the original number of kurchatovium atoms remain. This is quite a short half-life.

The synthesis and identification of kurchatovium were m a d e particularly difficult because of the very low probability of the formation of its nuclei. This probability is so low, indeed, that it was possible to synthesize only one atom of kurchatovium for each several hours of operating time of the equipment.

In initial experiments the identification of kurchatovium was effected by physical methods, similar to those used for the identification of the 102nd element and lawrencium by the American researchers. Later the physical evidence testifying to the synthesis of the 102nd element was supplemented by the investigation of its chemical properties with the aid of very fast chemical reaction techniques.

The experiments revealed the 104th element to be an analogue of hafnium, in agreement with the periodic law. They also produced information about some of its physical and chemical properties.

The synthesis of the far transuranium elements represents a fairly c o m ­plicated scientific and engineering problem whose solution calls for the

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Man-made atoms

use of complicated and accurate equipment. Nevertheless, the synthesis and investigation of the properties of transuranium elements are of great practical and scientific importance. T o give an idea of the practical significance of this work, it is sufficient to say that today m a n - m a d e nuclear fuel, such as pluto­nium, is fed into nuclear reactors to set into motion the generators at atomic power stations as well as on atomic ships, and in the future it m a y be used to drive ground vehicles and space ships as well. Nuclear fuel is extremely high in thermal energy; one g r a m m e will yield in 'burning' as m u c h thermal energy as do three tons of bituminous coal.

There are a few points concerning the scientific importance of research into transuranium elements which should be mentioned. T h e first point is that transuranium elements, being a continuation of the series of natural elements, have shown h o w orbital electrons fill up the electron shells in this new portion of the Periodic Table. A s one goes up the scale of increasing atomic numbers, each element differs from its predecessor by having one additional orbital electron in the atom. In the case of the transuranium elements, it was found, by analysing their physical and chemical properties, that as successive orbital electrons are added, these fall, not into the outer electron shell, but into places in one of the inner shells. T h e outer electron shells of these very heavy elements, up to 103-lawrencium, remain the same. Since it is the outer shell which very largely determines the physical and chemical properties of an element, all these man-created heavy elements differ but slightly in their basic properties.

It might be remarked that this group, beginning with 89-actinium and up to lawrencium, resembles the family of naturally-occurring rare-earth elements in the middle of the Periodic Table, for here, too, the successively-added orbital electrons fall into an inner shell, while the outer electron shell remains unchanged.

W h e n one comes to 104-kurchatovium, the situation changes. Here, the added orbital electron falls into the outer shell. This gives kurchatovium different characteristics from its predecessor transuranium elements. M o r e ­over, kurchatovium's outer electron shell is similar to that of 72-hafnium and indeed these two elements resemble each other in their physical and chemical properties.

The second point which should be mentioned is that the atomic nuclei in transuranium elements are intricate formations comprising from 93 to 104 protons and from 140 to 150 neutrons, both these particles being called 'nucléons'. In such multinucleonic nuclei the forces interacting between the particles are likely to become m u c h more manifest. It is because of these intranuclear forces that heavy nuclei such as uranium, neptunium, plutonium, etc.—and only such heavy nuclei—are subject to spontaneous fission. This phenomenon, discovered in 1940 in the U . S . S . R . by Konstantin Petrzhak and Georgi Flerov, involves the occasional splitting apart of a heavy nucleus as a result of its o w n inner oscillations into two nuclei of smaller mass.

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G . Flerov

Extensive data on the spontaneous fission of transuranium elements have added to our understanding of nuclear structure and nuclear stability. Such data have, for instance, provided sound evidence for considering an electri­cally-charged drop of liquid as a good model of the nucleus. In this drop of liquid the forces of electrostatic repulsion tending to break the drop apart are countered by the surface-tension forces which tend to keep the drop intact.

The narrow limits of this article do not allow m e to dwell on the practical benefits resulting from the synthesis and study of the properties of more than one thousand m a n - m a d e radioactive isotopes of the other, natural elements. These are discussed in the next article. However, from the viewpoint of pure science, it is safe to say that investigation of the radioactive decay of these atoms, as of the transuraniums, has given m a n y insights into the laws underlying the structure of atomic nuclei and has contributed to our understanding of nuclear forces.

Today, n e w radioactive isotopes are constantly being synthesized and it is quite legitimate to ask: H o w m a n y n e w radioactive nuclei might yet be obtained? The answer to this question depends upon numerous factors; particularly upon h o w rapidly atomic nuclei decline in stability as the atomic number increases; and upon h o w stability declines as the neutron excess or deficiency in the nucleus increases—for there are certain preferred stable ratios between the number of nuclear protons and neutrons.

Apparently, the number of possible isotopes is m u c h greater than the number of known isotopes. There must be among them a great m a n y nuclei with interesting properties: nuclei with an abnormally large or abnormally small content of neutrons for instance, and radioactive nuclei which emit a proton in decay. This is an unusual phenomenon as compared to the decay of natural radioactive nuclei by the emission of an alpha particle (helium nucleus). The phenomenon of radioactive decay with proton emission was first discovered in D u b n a in 1962.

Emerging from the classification of the nuclear properties of existing transuranium elements, it can be predicted that the lifetimes of new trans­uranium elements yet to be created, with Z = 105 to 108, will vary from some microseconds to several seconds. Transuranium isotopes having from 160 to 184 neutrons in the nucleus m a y be expected to show a higher stability, as far as spontaneous fission is concerned. There are grounds for believing that the nucleus with Z = 126 and M = 310 will be especially stable.

U p to this time, the synthesis of new radioactive isotopes of the k n o w n elements, as well as the synthesis of new elements, has not been affected to any great extent by the short lifetimes of possible atoms. However, the identification and investigation of the physical properties of atoms yet to be created m a y call for new and more rapid research techniques.

The answer to the question of h o w m a n y new isotopes can yet be syn-

40

Man-made atoms

thesized is also dependent on the potentialities of the synthesizing faci­lities. The well-known technique for obtaining n e w nuclei is the irradiation of target nuclei with intense fluxes of neutrons or small charged particles. The potentialities of the neutron method have, however, been largely exhausted not only for the synthesis of n e w transuranium elements, but also, as stated above, for obtaining n e w isotopes of k n o w n elements. M o r e promising for the synthesis of n e w atoms today appear to be the reactions of nuclei with heavier charged particles, a m o n g these heavier particles being large ions.

Heavy ion accelerators of diverse types—cyclotrons, linear resonance acce­lerators, electrostatic accelerators, etc.,—are being widely used today for the synthesis and investigation of n e w atoms in m a n y physical laboratories all over the world. T h e cyclotron at the Nuclear Research Laboratory of the Joint Nuclear Research Institute is one of the best accelerators of this type. This cyclotron is used to accelerate ions of boron, carbon, nitrogen, oxygen, neon and argon up to energies which are sufficient to investigate all kinds of physical problems. Record currents of accelerated ions have been attained.

Until today, the synthesis of n e w atoms by means of reactions effected by heavy ions usually involved a complete fusion of the bombarding particle nucleus and the target nucleus. Such reactions primarily gave rise to the neutron-deficient isotopes. Far greater possibilities for the synthesis of all kinds of isotopes—either neutron-deficient or neutron-excessive—will be opened by incomplete-fusion reactions following from the use of accelerated super-heavy ions, such as those of xenon, tungsten, lead and uranium. The collision of such super-heavy ions with the target will sometimes lead to the capture by the bombarding nuclei of heavy nucleonic complexes of the type of argon-50—complexes greatly over-enriched in neutrons. (It should be remembered that the natural isotopes of this element are argon-36 and argon-38). This will expand the boundaries of the possible products of nuclear reactions towards neutron-excessive isotopes.

N o less important for satisfactory progress in the study of the properties of n e w atoms is the elaboration of methods for their rapid investigation and identification. A s a rule, complete identification of an unknown nucleus requires a chemical analysis to determine the atomic number, Z , as well as the use of mass-spectroscopic techniques to determine the mass number, M . A s more and more short-lived nuclei are subject to investigation, classical methods of chemical analysis and conventional mass-spectroscopic analysis are meeting with increasing difficulties. This accounts for the considerable progress that has been m a d e in the development of special methods for the rapid identification of nuclear-reaction products.

Examples of successful applications of the rapid gas chemical techniques are the experiments used for the identification and study of the chemical properties of kurchatovium, whose half-life is only 0.3 second.

The next step in the development of the rapid identification techniques

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G . Flerov

opening up great prospects for the investigation of radioactive nuclei must be the creation of high-speed electromagnetic isotope separators. Such sepa­rators must permit a rapid and accurate determination of the mass numbers of the nuclei under investigation, and in some cases of their atomic numbers. T h e basic principle of such separators is that the products of nuclear reactions arising from irradiation either by accelerated charged particles or by neutrons must immediately m o v e directly from the irradiated target to the electro­magnetic separator to be sorted out according to mass. The study of the nuclear characteristics of the radioactive-reaction products will have to be effected at once in the separator within fractions of a second.

High-speed separators are being worked upon in numerous laboratories all over the world. There is every reason to expect that such isotope sepa­rators will substantially broaden our possibilities for studying new atoms which will be synthesized in the future.

T h e study of new atoms will undoubtedly add to our understanding of matter and will be a n e w step towards placing nature's mysteries and forces under man ' s control.

42

The manipulation and use of the atomic nucleus, II

Lev Kostikov Practical applications of radioisotopes

The astonishingly rapid advances m a d e in the last few decades in atomic science and technology have created the necessary conditions for establishing radioactive isotopes as a recognized feature of the national economy. They are n o w widely used in industry, agriculture, engineering and research, so widely in fact that not all their applications have been fully classified.

Perhaps the following three main factors explain the interest in radio­isotopes: 1. It is relatively easy to track radioactive atoms in virtually any process;

hence the present wide use of tagged or labelled atoms. 2 . A s ionizing radiation has a high penetrating power in virtually any

medium, isotopes can be widely used in process monitoring, for automa­tion, and in measuring equipment, wherever the property observed is thickness or density.

3. The ionizing radiation given off by isotopes can alter the properties of both biological and non-biological materials, often in ways that can be controlled; hence their value in- radiation genetics and radiation chemistry.

These factors have m a d e the employment of radioisotopes and nuclear radiation one of the most effective of the peaceful applications of atomic energy.

But n e w techniques are advantageous only if economically efficient, i.e., if they allow a rational and economic employment of labour, materials and funds. A s w e shall see below, radioactive isotopes do.

There is not space enough to go into all the present uses of isotopes in the Soviet economy and w e shall accordingly confine ourselves to the most typical and perhaps most important ones, under the following headings: isotopes in process monitoring and measurement; tagged atoms; isotopes in agriculture, biology and medicine; isotopes in radiation chemistry.

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Impact, Vol. XVIII (1968), No. 1

L . Kostikov

ISOTOPES IN PROCESS MONITORING A N D MEASUREMENT

All measuring or monitoring instruments based on radioisotopes consist of a radiation source, a receiver or detector, an amplifier and an impulse counter. Depending on the use to which it is to be put, the apparatus m a y use isotopes giving off either alpha particles (helium nuclei), beta particles (electrons) or g a m m a radiation. Ionization chambers, gas-discharge counters, proportional counters, photographic emulsions and so on are used as detectors.

Isotope equipment for measuring the thickness of a covering or coating by the reflection or back-scattering of beta radiation is highly efficient, techni­cally and economically. Beta particles from a radioisotope are reflected from the inner surface of the covering to be measured into the detector, the quantity reflected indicating the thickness of the coating layer.

Since measurements are not affected by the electrical, magnetic or other properties of the covering or of the material covered, the beta-radiation instruments can be used to measure the thickness of the most varied coverings on different materials, provided that the material covered is above a min imum thickness and that the atomic numbers of their respective c o m p o ­nent elements differ by two or three units.

The layer of tin deposited on sheet iron in the tin-plating process can, for example, be measured at a thickness of only 5 microns to within an accuracy of 0.1 micron.

The U . S . S . R . Academy of Sciences Institute of Economics has found that a single one of these beta-radiation thickness-gauges saves an average of 28,500 roubles1 per year in industry.

Isotopes are being increasingly used to measure weight. Without actual contact, the measuring device can determine the weight, for example, of a moving, loaded, freight train. Such devices operate on the principle that the ability of a quantity of material to absorb g a m m a rays depends on its density and thickness. A g a m m a source (cobalt-60) is placed under the railway track and a scintillation counter above. There is a constant g a m m a beam passing between source and counter which the moving train diminishes in intensity to a degree dependent at any given instant upon the weight of the material (the load) interposed into the g a m m a flux. It only remains to take the readings, which are converted directly into units of weight by a suitable device.

Apparatus of this type used at the Krasnogorsk paper mills showed that it is feasible to produce paper weighing 50 g / m 2 with a tolerance of only — 2 per cent instead of the =t 5 per cent prescribed by the U . S . S . R . State Standard. Therefore, paper which would previously have weighed 52.5 g / m 2

at m a x i m u m tolerance will n o w have a m a x i m u m weight of 51 g / m 2 so that up to 1.5 grammes of raw material can be saved for every square metre. A s

1. At the official rate 1 rouble = U.S.S1.111.

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Practical applications of radioisotopes

a result of this a single paper-making machine at Krasnogorsk can n o w pro­duce an additional 2,100 kg of paper every 24 hours—equivalent to hundreds of tons a year. In general, the use of radioisotope equipment in industry for measuring the thickness of sheet materials and coverings and for weighing saves tens of millions of roubles every year.

In application of the same principle, radioisotopes are used for measuring the level of substances in closed containers. This technique has become parti­cularly widespread in metallurgy, where it is impossible to measure the level of liquid metal by other methods because of the high temperatures.

The charging of blast furnaces with coke is n o w also being monitored by this method. Accurate data on the level to which the furnace has been charged makes it possible to maintain optimum operating conditions. At the Dzershinsky and Novotulsky steelworks where multipositional level-measuring instruments have been installed, constant monitoring has enabled the quantity of coke consumed per ton of pig-iron produced to be cut by 1.5 per cent (approximately 10 kg). Furnace productivity has increased by 2 per cent, and by cutting fixed expenses it has been possible to lower the production cost per ton of pig-iron by 1 per cent. The annual savings are about 160,000 roubles on just one furnace. Applied to all Soviet blast furnaces, radioisotope control of quantity of charge would save over 20 million roubles a year.

G a m m a radiation instruments are widely used to test for flaws in welded seams, castings, and so on. Throughout Soviet industry, these instruments n o w save over 30 million roubles a year. Portable apparatus using thulium-170 or europium-155 as the radiating isotope is employed to m a k e flaw examinations of steel from 1 to 15 m m thick and of aluminium from 5 to 50 m m thick. Thicker-walled pieces can be examined by either stationary or mobile apparatus.

Over 2,000 stationary or portable gamma-defectoscopes are n o w in use in Soviet industry. A g a m m a photograph costs 20 kopeks less than an X-ray picture—the use of X-rays being a standard technique in industry for detect­ing internal flaws. Visual gamma-defectoscopy has recently come into use for practical inspection purposes; using a scintillation screen as detector instead of a photograph, it makes the continuous automated inspection of any product potentially feasible.

TAGGED ATOMS

Radioactive isotopes introduced into a substance or produced within it by neutron bombardment m a k e it possible to study either its properties or the course of various processes in which it participates without, for all practical purposes, affecting these properties and processes at all. A use has been found for this tagged atoms method in nearly all branches of science and industry because of its versatility, accuracy and reliability.

45

L. Kostikov

Radioactive indicators have opened up n e w ways of obtaining high-purity metals—zinc, tin, lead, nickel, tellurium, thallium and m a n y others. Older indirect methods for checking on production techniques provided no quanti­tative evaluations, making it difficult to bring about improvements.

At the Donetsk steelworks, output has been increased by 750,000 roubles' worth a year by speeding up smelting, following tagged atoms studies of what happens during smelting. Futhermore, there has been an additional annual saving of about 90,000 roubles in reduced overheads and about 180,000 roubles as a result of using slag in place of iron ore. All in all, overheads have fallen and productivity has risen by 1.8 per cent.

It has been found that for every rouble spent annually on process research and n e w production techniques, the enterprise saves ten. T h e tagged atoms method accounts for about 70 per cent of the total saving m a d e by the metallurgical industry from the use of radioisotopes.

Radioactive indicators are very useful in the oil industry, especially for checking the condition of the oil-wells and the quality of major repairs. They are used to locate the points where drilling pipes have snapped and where water is entering wells; to determine the zone of liquid circulation around the pipe; the height to which the cement rises after the plugging of the bore­hole; and the thickness of the cement ring around the pipe. It is very important in oil extraction to check that the deposit is being correctly worked, and radioisotope instruments are excellent for this purpose. The Institute of Economics of the U . S . S . R . A c a d e m y of Sciences has calculated that the use of radioactive indicators in the oil industry saves over 30 million roubles a year.

It is a matter of the highest importance to prolong the service life of machinery, instruments and equipment. Thousands of millions of roubles are spent every year repairing machines and replacing instruments. W e a r and corrosion are the two main causes.

Tagged atoms play a very important part in studying wear in machines, radioactive indicator methods requiring only a twelfth to a twenty-fifth or even a fiftieth of the time taken by ordinary methods. T h e quantity of expensive materials wasted in grinding or cutting is also considerably reduced. The cutting laboratory of the All-Union Tool Research Institute has esta­blished that a total of between 1,000 and 1,500 kg of workmetal and of high­speed tool steel, valued at 30,000 roubles, is used to determine the relation­ship between the durability of a cutting tool and its cutting speed by ordinary methods; the radioactive indicator method for making the same determination is so low in cost that nearly the entire s u m is saved.

T h e technique is applied both for measuring the wear on rubbing or rotating contact surfaces, such as bearings, and for determining the rate of wear of a cutting tool. In either case, a few units of the bearing or of the cutting tool are produced which incorporate radioactive isotopes in their metal composition. W e a r of the bearing surface or of the edge of the cutting

46

Practical applications of radioisotopes

tool is then determined by measuring the radioactivity of the lubricants and of the metal cuttings (in the second case) while the bearing or tool is put to its regular use. This radioactivity results from the tiny metal particles torn off the bearing or tool.

A variant technique which is also applied is to measure the loss of radio­activity of an isotope-tagged bearing or cutting tool itself while it is in use. Similarly, the rate of wear of a radioactivated metal surface can be checked by measuring the rate of increase in radioactivity of a non-activated metal part which is in rubbing contact with it. This increase will obviously be proportional to the amount of metal worn off the radioactive piece and picked up by the other part.

The main advantage of the tagged atoms method is that it can determine wear on machinery actually in operation, without dismantling the machine, to an extremely high degree of accuracy (within hundredths of a milligramme or better).

RADIOISOTOPES IN AGRICULTURE, BIOLOGY A N D MEDICINE

Tagged atoms are similarly important in agriculture, where they are n o w widely used in research on agricultural methods and processes.

They are of value in working out the most efficient uses of all kinds of fertilizer—when and h o w to apply them, the quantity to be used, the size of granules—all of these factors being of great economic importance. In such experiments, isotope-labelled organic compounds m a y be used as well as tagged mineral fertilizers. For example, nucleic acid and methionine, tagged respectively with radioactive phosphorus-32 and sulphur-35, were used to determine h o w undecomposed molecules of organic compounds enter the root systems of plants. It was found that plants supplied with organic substances through the roots assimilate them completely, so obtaining a ready-made bunding material and energy source.

A simple, accurate and efficient isotope method has been devised for checking on the effectiveness of the chemical spray treatment of crops. A s a result, Uzbek scientists have found a way of controlling the red spider mites on cotton plants by combining an insecticide with a superphosphate top-dressing for the soil. In this way, four or five times less insecticide is used than the quantity recommended when applied to the cotton plant by dusting. According to the Uzbek Ministry of Agriculture, it has thus been possible to treat an area five times greater than before with the same quantity of insecticide, saving 400,000 roubles on chemicals alone. B y adding a small quantity of short-lived isotopes to the insecticides, normal requirements per hectare for specific methods of cultivation, meteorological conditions and crops can be worked out.

Tagged atoms are also used to determine residual quantities of insecticides

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L . Kostikov

remaining in harvested crops, vegetables, milk, meat, fruit and so on, and also to determine the rate at which molecules of insecticides are decomposed within living vegetable and animal organisms.

Isotopes therefore offer fresh opportunities for increasing the efficiency of agricultural processes, and n e w techniques resulting from tagged atom research will considerably increase agricultural production without extra manpower.

Radioisotopes have m a n y additional applications in agriculture. Research shows, for example, that nuclear radiation (which causes high rates of mutation) can produce new forms of plants with higher yields and higher resistance to various forms of disease.

In another application, the irradiation of seeds before sowing, even early results show that the yields of cabbage crops are increased by 5 to 10 per cent, of cucumbers by 15 to 30 per cent, of tomatoes by 10 to 15 per cent, of carrots by 25 to 30 per cent, and of radishes by 6 to 11 per cent. Calculations by the Institute of Economics of the U . S . S . R . A c a d e m y of Sciences indicate that if only a quarter of the area under these crops were to be sown with irradiated seeds, an extra 100,000 to 200,000 metric tons of vegetables would be produced. The higher yields would not only offset the comparatively small irradiation costs but save 15 to 30 million roubles a year by lowering production costs.

G a m m a radiation is being used in U . S . S . R . to get rid of insect pests in grain by exposing the grain to a cobalt-60 35,000 curie source which can treat up to 400 kg of grain per hour.

Radiation has interesting effects on the development of living organisms. H e n eggs, for example, when exposed to very small doses of g a m m a radiation show a 3.5 per cent increase in the number that hatch; moreover, the egg-laying rate of hens hatched from such eggs increases by 12 to 17 per cent. O n a nation-wide scale these figures would represent millions of roubles.

Isotopes have at present two main uses in medicine: for diagnosis; and for the treatment of various diseases. Radioactive iodine-131 is being successfully used to determine the extent of cancer damage to thyroid glands. The isotope, introduced into the body in a harmless dose, rapidly concentrates in the tissue of the tumour, since thyroxine, the hormone produced by the thyroid gland, contains iodine. The pathological process can then be localized from the radiation emitted by the radioactive iodine.

Radioactive isotope treatment of malignant growths is one of the more effective methods. O n e technique consists of introducing the isotope into the affected area in liquid form by injection or in a tiny glass ampoule. The ionizing radiation destroys the cancerous cells and impairs their ability to multiply. It is n o w current practice to use g a m m a radiation from a cobalt-60 gun to treat malignant tumours in certain internal organs at advanced stages of development when surgical intervention is no longer possible.

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Practical applications of radioisotopes

RADIATION CHEMISTRY

It has been k n o w n for a number of years that radioactivity can have strong effects on m a n y chemical reactions and on chemical processes. This fact has led to radiation chemistry, and radioactivity is already being used in the chemical industry. For example, irradiated polyethylene is n o w a fairly well-known product; it has a number of mechanical properties superior to those of the non-irradiated material.

In early work, natural radioisotopes with an activity of up to one milli-curie were used as radiation sources. A n e w phase opened with the harnessing of nuclear energy and the production for the first time of artificial radio­isotopes in large quantities. Nuclear reactors have become radioisotope factories and produce the two g a m m a sources most commonly used in radiation chemistry—cobalt-60 and caesium-13 7. Units with an activity of hundreds of thousands of curies are n o w in use in the U . S . S . R . , and there are plans to build units with an activity of up to 10 million curies which will be vital factors in tomorrow's industrial-scale radiation chemistry.

The radioisotopes used in radiation chemistry or in experimental industrial plants are usually obtained in one of two ways: either by subjecting certain stable chemical elements to neutron radiation in the reactor, thus inducing radioactivity; or by processing used-up uranium reactor fuel. T h e highly radioactive reactor fuel can also be used directly as a g a m m a source without processing.

Intensive work has been done in recent years to produce the very large radiation sources needed to operate radiation chemistry processes on an industrial scale. The first technical and economic trials indicate that in m a n y cases valuable chemical products can be obtained more cheaply by means of big radioisotope sources than by any other method.

This article has considered only a fraction of our present information on radioisotope applications in the Soviet economy. Radioisotope technology has already saved m a n y millions of roubles, but its potentialities are far from being fully explored. Radioisotopes will undoubtedly play an increasingly important part in the development of the economy and in technical progress.

49

Jan W . Varossieau T h e use of closed-circuit television and scientific films for university teaching in the Netherlands

THE PROBLEM

During the early post-war years there was an enormous increase in the birth­rate in the Netherlands, as in most other countries, and this implied that children born in that period would reach university age between 1963 and 1966. It was apparent that the teaching staff was too small for this wave of new students and that there were not enough lecture halls to accommodate them. A quick solution was imperative.

It was also certain that after this first wave, greater numbers would enrol for university education, since university studies had been democratized and were no longer a privilege of the well-to-do and the middle classes. In comparison to the pre-war period, far more scholarships were being granted and m a n y students had part-time jobs which enabled them to pay for their studies.

A t this time, the Ministry of Education and Sciences which subsidizes all thirteen universities, whether State, sectarian or municipal, and including the technical ones and the Agricultural University at Wageningen, was receiving requests from institutes at various universities to supply funds for expensive colour television apparatus. It did not k n o w , however, h o w to meet these requests, since there were no available specialists in this field w h o could evaluate and co-ordinate them. There were specialists w h o had technical experience with black-and-white and sometimes colour television, but they were employed by commercial firms. Nobody had any experience at all in educational television.

It became very clear that what needed was: (a) a trained staff of technicians to work the complicated apparatus; (b) a programme director w h o could also introduce a lecturer and the experiments presented in an integrated show, which would catch and hold the attention of viewers; and (c) a substantial amount of money for investment in a rather risky business—at that time

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Impact, Vol. XVIII (1968), N o . 1

J. W . Varossieau

closed-circuit colour television was ten times as expensive as black-and-white and in the process of rapid technical development. This factor of ten has n o w been reduced to two and a half.

It was at this stage, in 1960, that the Government asked our organization, S F W - U N F I (described below), to experiment with a closed-circuit television ( C C T V ) mobile unit, staffed by specially-trained technicians. The unit would contact those professors w h o wanted to k n o w what could be done with the new medium and naturally, first of all, those w h o had asked for a colour C C T V . It was comparatively easy to serve all the universities in our small country with a mobile unit as the m a x i m u m distance by car from Utrecht was only three hours, the Netherlands having a very good road system.

THE EVOLUTION OF SFW-UNFI

In January 1950 the University of Utrecht had the foresight to start a modest film unit in its faculty of medicine, called 'Universitaire F U m ' (University Film or U N F I ) . U N F I was staffed by two m e n only, Willem de Vogel and the author, working under the guidance of Professor H . W . Julius, at that time director of the Institute for Bacteriology and Hygiene. The curators of the university gave the newly appointed film-makers two years in which to develop convincing evidence that scientific films should be given a place in medical education.

A start was m a d e with a simple teaching film on bacteriological inoculation techniques for a practical course in microbiology given to all medical and dental students. T o begin with, a live demonstration was performed; after this a simple black-and-white film w e had made was shown twice; and then the students went ahead and themselves did what had been demonstrated and shown on film.

This simple instruction film was a success and was followed by many others, including colour films on surgical techniques. Within two years w e had even w o n a prize with one of our colour films in the scientific documen­taries section of the Venice Film Festival. This convinced the Government and the university that films could contribute to teaching at university level.

Át about the same time, in 1951, the Nederlandse Vereniging voor de Wetenschappelijke Film (Netherlands Association for Scientific Films) was founded. Its first president was the pioneer of scientific film-making in this country, Jan C . M o l , w h o in the thirties had m a d e excellent films of great beauty, e.g., about the growing of plants, the movements of protozoa and, in colour, the growing of crystals under a microscope. The association^ membership included producers and teachers anxious to use films in edu­cation; various individuals w h o often used cine-cameras in their work; and many others w h o just wanted to know more about scientific films. The sec­retariat of the association was and still is at the same address as the S F W -

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T h e use of closed-circuit television and scientific films for university teaching in the Netherlands

U N F I , since the directors of the film unit played an important part in its foundation. The association, which became the Netherlands branch of the International Scientific Film Association (ISFA), picked up m u c h valuable information through contacts with other national scientific film associations, most often at the annual congresses of the ISFA.

Meanwhile, U N F I was constantly being requested by other universities to produce films. W e m a d e research films for biologists and psychiatrists, engaged a secretary, a still-photographer and a medical illustrator, and—most important of all—got more and more work, not only from the medical faculties but also from other faculties.

At this time our only charge to the lecturer or research worker w h o needed a teaching or research film was for raw stock, lamps, transport, travelling expenses and film laboratory costs. There was no charge for overheads and salaries. Since a bare min imum was charged to the client institution, the films m a d e for other universities placed a heavy burden on the budget of the University of Utrecht. In other words, Utrecht was giving an invisible subvention to other universities which were making use of the film unit.

In the beginning a film was made simply by filming the lecturer. Later on, scenarios were written which were submitted for approval to other specialists in the same field, to make sure that the film would have the widest distribution and not meet with criticism after completion. A normal film took four to six months to complete. If the animation was complicated it took m u c h longer; for example, the film 'Basic Mechanisms in Neurophysiology' took two and a half years to produce and could not possibly have been m a d e by a commercial firm because of the cost.

At this stage, in 1956, Stichting Film en Weterschap ( S F W , meaning Film and Science Foundation) came into being, with an initial subsidy from the Ministry of Education and Sciences equivalent to $28,000. The day-to-day work was placed under an administrative director, P . M . E . B . M . Janssen, and two scientific directors, W . de Vogel and the author.

It must be borne in mind that U N F I , as a department of the University of Utrecht, was a fully governmental agency. A s such, under laws controlling the disposition of government property, it was virtually impossible for U N F I to exchange or sell films. S F W , however, was considered semi-governmental and was not subject to the same restrictions.

W h e n S F W was formed, it was amalgamated with U N F I , so that n o w S F W - U N F I is, in effect, one body. This made it immediately possible for the joint body to pursue the necessary activities of selling films and entering into exchanges, and this, in turn, has made it possible to build up a large scien­tific film library, open to all the universities in the Netherlands. The short distances between centres in this country m a k e it easy to put films, shipped by railway express, into the hands of a borrower within a few hours.

W h e n the S F W - U N F I amalgamation was achieved, it was placed under

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J. W . Varossieau

the tutelage of a Board headed by Professor Julius and composed of repre­sentatives of all the Dutch universities (then ten in number) and represen­tatives of the Ministry of Education and Sciences, the Ministry of Finance and the Ministry of H o m e Affairs.

Within a year, S F W - U N F I acquired more sophisticated equipment and developed into a government-subsidized central institute for audio-visuals, serving all the universities in the Netherlands on a non-commercial basis. (However, since our work continues to expand, it is increasingly felt that the n a m e of the institute should be changed and that 'film', for example, should be replaced by 'audio-visual media' and 'science' by 'higher edu­cation'.)

In 1958, m y colleague, Willem de Vogel, m a d e a study-tour of the United States of America, concentrating on the use of C C T V in universities and in medical education. H e came back with an enormous amount of information and an overwhelming enthusiasm for this n e w medium. W h e n the government invited S F W - U N F I to consider the formation of a mobile C C T V unit, there­fore, the decision raised no problems.

With an adequate full-time staff, the C C T V unit has the following objectives: (a) to probe the possibilities of C C T V for scientific educational purposes and research work in the universities; (b) to introduce the n e w medium into those university departments which have displayed interest in a permanent installation, without their having to rely on the not very objective advice of commercial firms. This is the advisory aspect. The practical side consists, inter alia, of: (c) broadcasting televised lectures and courses a few times a year for those institutions for w h o m a permanent installation would not be practical.

SELECTION OF THE INITIAL MOBILE CCTV APPARATUS

In order to select the C C T V equipment best suited to our needs, w e established a careful analytical procedure. A well-known professional pro­ducer of television programmes was engaged to direct a test show composed of parts of scientific lectures and experiments, to be transmitted live to a mixed audience on five consecutive Thursdays. Each Thursday, apparatus manufactured by a different firm was used. O n e of the firms was Dutch, one Danish, one German (Federal Republic) and two British.

The testing programme itself was opened by a professor in electronics from the Technical University of Delft, w h o explained what was to be expected to the audience in the ground floor lecture hall. H e also instructed the spectators on using the test-chart w e developed and on filling in the rather elaborate questionnaires with which they were provided. The audience consisted of representatives from all the universities and ministries mentioned earlier plus specialists in the field of electronics, education and the arts.

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T h e use of closed-circuit television and scientific films for university teaching in the Netherlands

It was hoped that the questionnaires would indicate the instructional and artistic value of the programme as well as the most satisfactory type of apparatus.

The competing firms had ample time (from M o n d a y till Thursday) to set up their apparatus, test it and make trial transmissions. Each programme consisted of an introduction in the studio, a demonstration of part of a course on microscopy, a shot of a precipitate forming during a chemical reaction in a test tube, a close-up of living insects, a scene showing a panel-discussion between a neurologist, a psychiatrist and a radiologist (with a student playing the part of a patient) and, finally, views of a dentist demonstrating the exact way, in close-up, to drill for the filling of a cavity. T h e session lasted one hour.

Of course, the important things w e paid attention to were: the resolution, the clarity and the continuity, uninterrupted by interference or breaks, of the various installations. These varied greatly in the five different transmis­sions. Another important factor was the time needed to adjust the electronic apparatus before the optimal quality of the image was reached and transmis­sion could start. The shows were transmitted from the S F W - U N F I studio, high up in the building.

W e chose the apparatus that was of the highest quality and easiest to manipulate. It had become clear from the beginning that 625-line apparatus was to be preferred. T h e cameras were black-and-white vidicons. Four complete units were purchased, consisting of a camera, control apparatus and one or more monitors and receivers (one unit having remote controls) and a special van was ordered to transport cameras, monitors, control-apparatus, tripods, cables, sound apparatus, lights, etc. Our crew consisted of a chief electronics engineer, two television technicians, one a specialist in video and the other in sound, and a cameraman. A s a rule, the sound technician also acted as second cameraman although a still-photographer was later added to the team and took over this job.

FIRST YEARS

F r o m the very beginning, it was apparent that the main problem of educa­tional television for universities was not connected with finance or techniques, but presentation. B y trial and error and with the greatly valued help of lecturers and educators, the head of the television crew, Willem J. Speelman, developed into a highly capable programme director.

The early stages are always difficult. There is a hidden or open resistance from m a n y people against lecturing in this n e w medium, which—if it is analysed—can mostly be imputed to a large component of fear. These people feel, at first, as if somebody is keeping a strict eye on them and, of course, in a way this is true. O n the other hand, those w h o are ambitious to develop

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J. W . Varossieau

into television lecturers constantly correct the failures m a d e in previous transmissions and in the end feel as m u c h at ease as if they had never given a lecture in the conventional way.

W e found that long televised surgical operations are uninteresting and very tiring, so w e n o w prefer to show only particularly important sections on monitors in the operating theatre itself. W e also discovered that if a surgical operation is transmitted to monitors in another room, the tension of the operating theatre is missing and, after a while, students lose interest.

Although C C T V was originally used to carry lectures to other rooms if the lecture hall was too small to accommodate all the students, it became clear that even for limited groups C C T V served a purpose, as it could, for example, magnify details which otherwise would have remained unobserved.

Television therefore has three functions of educational importance: its ability to multiply the number of viewers; to magnify details; and to show things as they are actually happening. In this particular respect, it was considered important to have monitors of sufficient screen diameter perma­nently hung from the ceiling in the existing lecture halls. W e preferred large monitors to large-screen television since the latter necessitates the halls being completely darkened, which prevents the students from making notes during the session.

A s an extensive programme for building n e w premises for the universities was well under w a y , w e were just in time to advise the builders to m a k e the ceilings of sufficient strength to hold monitors and also to put plastic conduits of an approximate diameter of three or four inches in the walls between the rooms, so that even if C C T V was not considered necessary at the m o m e n t , it could be installed at a later stage without having to break up the walls.

APPARATUS N O W IN USE

A t the m o m e n t the television department has the following mobile equipment: 1. A Danish installation, consisting of three independent camera units, first

used in November 1961. 2 . A Dutch installation, consisting of two high-quality units, each consisting

of two plumbicons and three vidicon cameras, a mixing panel and control apparatus. O n e of the vidicons can be replaced by a special infrared camera. (This installation was first used in 1963).

3. The colour television apparatus, also of Dutch origin, in use since 1964; the camera is a so-called medical camera.

4 . For the recording of television images, an American quadruplex video tape recorder.

5. Twelve 21-inch monitors. It proved to be very difficult to find a place in the old university buildings

56

T h e use of closed-circuit television and scientific films for university teaching in the Netherlands

where the technicians could sit with their control apparatus during broadcasts. In the lecture hall itself they were disturbing and, if they used the adjacent rooms, others usually had to m a k e way for them. Last year, therefore, a second van was bought and installed with all the necessary facilities for directing and controlling the show, including a video tape recorder.

APPLICATIONS IN EDUCATION

Especially for the practical courses, such as laboratory courses, in which time is always short, C C T V has proved to be an invaluable help. For instance, in a course in embryology at the Zoological Institute of the Uni­versity of Utrecht hundreds of axolotl eggs are used each year. These have to be operated upon and given a colour mark which disappears at a later stage of cleavage. Previously, the demonstrator had to show the procedure under a binocular microscope to every single student. N o w , the procedure is shown twice on television while the students remain at their laboratory tables, only having to turn ninety degrees on their stools in order to go ahead and perform the operation themselves. The result is an enormous gain of time and of material.

Remarkable results were also obtained with courses for dental students. It very soon appeared that the impact of television in this sector was so great that a permanent installation was needed. This, moreover, would have to be one in which each student had his o w n individual monitor and at the same time was able to talk to the instructor. The course is a so-called 'step-by-step method' and consists of manipulating materials for prostheses. In future, the course will be put on a video tape and then played back when needed.

In 1965 and 1966 it appeared that the time needed to absorb the material could be reduced by 23 per cent through the use of individual monitors. This percentage can rise to more than 25 per cent by using the above-mentioned semi-programmed instruction. Since 23 per cent represents almost a quarter of the total time involved, an advance of three months a year could be gained. However, students are instead given half a day off every week so as not to interfere with other courses, which cannot be compressed in the same way.

C C T V is not only used with success in the faculty of medicine and in the science faculties, but also in the social sciences. It has proved to be an invaluable help to sociologists and psychologists, in the teaching of statistics and probability theory, and for teacher training. Similarly, students can see injured or sick animals, such as a lame horse, at the test farm of the veterinary faculty, without having to leave the lecture hall.

M a n y courses outside the university have been given to medical and auxiliary personnel (e.g., nurses) and to biologists, physicians and vete-

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J. W . Varossieau

rinarians for their postgraduate education. Physicians, for instance, were given a course on sexology, in which advice was given on h o w to m a k e patients familiar with contraceptives.

A total of 227 actual hours of television lectures were transmitted in 1966, against 180 in 1965, these figures not including the preparatory work. In 1966 advice on television questions was given in 52 cases to 21 institutions, 402 man-hours being involved. (A point worthy of mention is that in ordering a permanent television installation m a n y institutions forget to m a k e provision in the budget for more staff to operate it.)

Although it has been suggested in the Netherlands that traditional lectures would be eliminated, w e still regard C C T V only as an excellent supplemen­tary medium for university education. The gain of time is its greatest asset. W e do not find that students learn better via television than by the conven­tional method, but the time needed for a course of instruction is shorter.

Students' reactions are indicated by the following remark which was often found in the questionnaires which they filled in: ' W h y didn't w e have this earlier?' It should be noted that teaching via television is a challenge to the lecturer; also that the personal contact between lecturer and student is felt more intensely, because the student feels that the lecturer is looking directly at him and not staring into a large lecture hall, without really seeing any one individual.

I should also mention that with the increasing number of postgraduate courses there is a growing tendency to record lectures and experiments on video tape so that they can be shown again at a later date.

APPLICATIONS IN RESEARCH

S o m e of our most interesting work has been in rendering service to research. W h e n w e obtained an infrared vidicon, for example, it became possible to observe the behaviour patterns of bats in complete darkness, the only source of illumination being a small infrared spotlight1 (see Fig. 1). A pneumatic telescoping mast was erected near a tree where bats were nesting. In a farm some distance away, the behaviour was studied on a monitor; anything of particular interest was recorded by a motion picture camera. A special transistorized device was constructed to eliminate the moving bar across the image which almost always appears w h e n cameras film a television monitor because a television camera and a motion picture camera operate at a different number of frames per second. W h e n the recording camera starts, the bar disappears within 2 seconds.2

1. W . J. Speelman and S. W . Bowler, 'Closed circuit television and research film production', British Journal of Photography, 30 July 1965.

2. W . J. Speelman, 'Television recording on film', Research Film, Vol. 5, N o . 4 , 1965.

58

Fig. 1. A n infrared television system for observing nocturnal creatures.

1. Observation box. 2. Micro-spotlight with infrared filter. 3. Television camera with infrared vidicon.

Variable transformer for lighting control. Camera control unit. 9-inch monitor. 23-inch monitor. Film-camera with synchronous motor. Telescoping camera mast.

It was also possible to record births which only take place in complete darkness and which had never been observed before. In this way it was possible to follow the birth of a jackal in the zoo in Amsterdam. The experiment was led by D r . C . Naaktgeboren, of the Zoological Laboratory of the University of Amsterdam.

That this infrared system also had practical implications was proved when it was used in a dark stable to find out what abnormal behaviour led to tail-biting in pigs.

Another project involving television was initiated in perception research. In 1958, two brothers, Professors J. F . and N . H . Mackworth of the Uni­versity of Cambridge, invented a method called the TV-eye-marker, to record the movements of the eyeballs in a case where the subject's head was in a fixed position.1

T h e principle of the TV-eye-marker is as follows: a tiny spot of light shines on the cornea of the subject's eye and is observed by a vidicon camera. A second vidicon observes a scene and projects an image of it on a monitor placed in front of the subject. T h e latter's head is fixed in position but, as he moves his eyeballs while examining the picture on the monitor, the spot moves in the same way. Electronically the separate images of spot and scene are superimposed on a second monitor, with the result

1. J. F . and N . H . Mackworth, 'Eye fixation recording', Journal of the Optical Society of America, Vol. 48, pp. 439-45, July 1958.

59

J. W . Varossieau

that an observer viewing the second monitor sees the bright spot moving along the scene in exactly the same way as the subject scans it.

This installation was modified by our television department in such a way that it took only a few minutes to trim it. The method of head fixation was also improved. O f course, the psychologists and psychiatrists were the first to m a k e use of this instrument, which was hitherto unknown in the Netherlands.

Professor N . H . Frijda and Professor A . D . de Groot, of the University of Amsterdam, carried out interesting experiments during a course called 'Thinking and M e m o r y ' . They proved that there was a large difference between a chess-master's view of a chess board and that of an amateur chess-player: the former grasps the over-all situation at a glance whereas the latter looks at the pieces one by one in order to evaluate the position. The results of this research will be published by the University of Amsterdam. A film on this subject was also produced.

The TV-eye-marker is also an amazing tool for psychoanalysis. In an institute where children with impaired eyesight are educated, it became possible to determine what they actually perceived of colours, shapes, etc., or if they saw them at all.

Our animation department found in colour television a superb new device for producing special effects for motion picture titles. (It had already been demonstrated that if enough attention could be attracted during the first three or four minutes of a film it was easier to hold such attention during the rest of the screening.) The method is as follows: three separate black-and-white vidicon cameras are trained from different angles on one or on three different subjects. Their outputs are then fed into one single colour television monitor, where the three black-and-white images are transformed into three separate basic colours. O n the monitor, the three images are of course superimposed and this combined colour image is filmed with a 16 m m camera loaded with colour film. The result is a highly intriguing opening title for a scientific film.

O u r television department also used two-way mirrors in combination with 'Transflex', a screen of highly reflective material, to form a composite picture, for instance of a living person with a projected motion-picture or still background.

W e learned to use endoscopes coupled with a vidicon camera in order to show internal views of the body directly on a monitor. W e also developed a technique which w e call electronic filming where the view-finder on the film camera is supplemented by an attached small vidicon camera, so that the director can actually m a k e a kind of 'pre-montage' at the mixing panel, by selecting which camera or cameras will run at a certain m o m e n t . This saves a lot of film stock.

In places where film cameras are too bulky, too noisy or merely trouble­some, a small vidicon camera can be set up and the whole scene recorded on video tape. This was done, for instance, in a student course on hypnosis,

60

T h e use of closed-circuit television and scientific films for university teaching in the Netherlands

where silence and concentration are imperative. This course was recorded by us to help the Institut für den Wissenschaftlichen Film in Göttingen (Federal Republic of Germany). The interesting parts were played back on the video tape recorder and this time recorded on motion picture film. Remarkable quality was achieved.

O n e of the latest experiments in which w e have taken part consisted of examining secondary school pupils with the help of C C T V , under the scientific direction of Dr . J. Ph . Steiler and Dr . W . Y . Zandstra of the Educational Department of the Physics Laboratory of the University of Utrecht. For this examination various experiments in physics were shown on the monitors and the pupils had to fill in forms offering a choice of six possible answers to each of six questions. The answers were noted in such a way that the results could be computerized.

W e also assisted in an experiment by D r . R . T . Schneemann, of the Psychiatric Clinic of the University Hospital of Utrecht, using the film medium for group therapy. Patients were provided with loaded 8 m m cameras and their reactions, while filming each other and during the pro­jection of the results of their film work, were observed. A 16 m m film was m a d e of these experiments.

A total of 118 man-hours were spent on scientific research with television in 1966, preparatory time not included.

SOME FINANCIAL INFORMATION

A s w e are a service-rendering non-profit institute completely subsidized by the Government, only the cost of raw stock, laboratory costs (printing and developing only), travelling-expenses, and lights and material used are charged to the institute requesting a film. N o salaries or overheads are calculated in these charges.

Television transmissions are not charged at all, but the estimated cost to us is $335 for a one-hour television lecture. If video recorded, the cost is $475 an hour. The initial television installation cost about $23,700. T o date (July 1967) the equivalent of $112,000 has been invested in television apparatus. The price of the quadruplex video tape recorder alone is about $45,000.

CO-OPERATIVE ACTIVITIES

A film library catalogue in Dutch is produced for use in the Netherlands every two years. A four-language catalogue of S F W - U N F T s productions is published every five years for foreign circulation and is available on request.

T h e excellent co-operation which exists between S F W - U N F I and the Ministry of Foreign Affairs makes it possible to use the diplomatic pouch

61

J. W . Varossieau

to send scientific films produced in the Netherlands to interested people in other countries for preview purposes. N o costs are involved. Medical and veterinary film packages are distributed to Dutch embassies where they can be screened, also without charge.

Most of our films are post-synchronized into English, and sometimes into French or German. They can be bought by university institutes; prices and conditions of sale are available on request.

There are two other scientific film centres in the Netherlands. O n e of these, supported by public funds and producing films for primary and secondary education, is the Nederlandse Onderwijs Film (Netherlands Educational Film), Sweelinckplein 31, The Hague. The other, supported by private industry, is the Technisch Film Centrum (Technical Film Centre), Stadhouderslaan 152, The Hague, which has films for industrial and technical schooling and management training. S F W - U N F I enjoys good relations with both of these organizations.

I should like to mention, finally, that w e are always willing to give advice to foreign centres which are just beginning to set up educational television and film facilities.

THE FUTURE

S F W was originally housed in a small room in the Laboratory of Hygiene at the University of Utrecht, but between 1950 and 1957 w e enlarged our working space and rebuilt an old attic in the building as a kind of studio, lecture hall and post-synchronization room. Space, however, was still too limited to locate the television department so that it had to be installed in another building a few kilometres away.

W e n o w have under construction a completely new building on the outskirts of the city with a total surface area of 4,750 m 2 and a volume of 21,500 m 3 . This will include a modern studio, fully equipped with the latest type of false ceiling, from which lighting can be lowered by mechanical means. There will also be an experimental lecture theatre, equipped with television monitors hanging from the ceiling, and provision for multiscreen simultaneous projection. The lecturer will have a wireless microphone, his voice being transmitted to a receiver which will amplify it and feed it into loudspeakers in the hall. It will also be possible to test n e w audio-visual or tutorial systems in the lecture theatre which will have about 100 seats.

A separate school will be attached to the building, so that it will be possible to include courses in scientific photography, cinematography and the use of television for students and scientists, without disturbing normal operations in the main building.

In addition to the rooms for animation, still-photography, post-synchro­nization and recording, workshops and service rooms for cameras, television

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T h e use of closed-circuit television and scientific films for university teaching in the Netherlands

equipment, etc., there will also be six rooms for guest scientists wishing to study special techniques such as high-speed photography, time-lapse photo­graphy, cinematography, etc. W e will even be able to provide bed and breakfast for one guest, as there will be a guest-room and a cafeteria on the premises.

The cost of the building when completed, including heating and air-conditioning systems, the fixed installations, furniture, carpenting, etc., will run, it is estimated, to about $1,370,000.

S F W - U N F I n o w has a staff of 36 ; in the new building, this will be gra­dually expanded to a m a x i m u m of 60. A s soon as the n e w building is ready, it is hoped early in 1970, there will also be opportunities to take on trainees.

Looking ahead, it is more and more evident that the need for films at the universities is so great that one central organization cannot cope alone with production. Starting with the Technical Universities of Delft, Eindhoven and Twente, annexes will be set up to house a complete unit with cameras and editing equipment, although such work as post-synchronization, studio work and specialized animation will be carried out at the main centre in Utrecht.

Education is on the m o v e and the importance of individual studying methods is increasingly apparent (teaching machines and language labo­ratories). It is certain that the cassette-loaded Super-8 film projector will play a role in teaching small groups or individuals and in providing an opportunity to repeat a film seen during a lecture. W e will see h o w the production of films suitable for this purpose might be fitted into our pro­gramme . Short series of technical films explaining certain specialized techniques would constitute wonderful audio-visual material for engineering students.

A s far as television is concerned, w e will work with colour television where this is essential and record more and more courses and lectures with expe­riments on video tape.

The merging of our institute with related bodies, such as the Institute for Scientific Audio-Visual Documentation, m a y be considered in the future.

FOR FURTHER READING

Educational television in the next ten years. Stanford, Calif., Stanford Institute for Communication Research, 1962.

M U R P H Y , J.; G R O S S , R . Learning by television. N e w York, The Fund for the Advancement of Education, 1966.

Newer educational media. Pennsylvania, Pennsylvania State University, Uni­versity Park, 1961.

Television in the university, report of a graduate seminar on C C T V in universities. Manchester 3, Granada Television Ltd., 1963.

The new media: memo to educational planners. Paris, Unesco, International Institute for Educational Planning, 1967.

63

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Haiti Honduras

Hong Kong Hungary

Panuzai, Press Department, Royal Afghan Ministry of Education, K A B U L . N . Sh. Botimeve Nairn Frasheri, T I R A N A . Institut pédagogique national, 11, rue Ali-Haddad (ex-rue Zaâtcha), ALGER. Editorial Sudamericana S.A., Humberte 1-545, T . E . 30.7518, B U E N O S A I R E S . Longmans of Australia Pty Limited, Railway Crescent, C R O Y D O N (Victoria) 3136. Sub-agent : United Nations Association of Australia, Victorian Division, 4th Floor, Askew House, 364 Lonsdale Street, M E L B O U R N E (Victoria) 3000. 'The Courier' only : Dominie Pty Ltd., 463 Pittwater Road, B R O O K V A L E ( N . S . W . ) . Verlag Georg Fromme & Co . , Spengergasse 39, Wien 5. Editions 'Labor', 342 rue Royale, B R U X E L L E S 3; N . V . Standaard Wetenschappelijke Uitgeverij, Belgiëlei 147, A N T W E R P E N I. For 'The Courier' and slides: Louis de Lannoy, 112, rue du Trône, B R U X E L L E S 5. Librería Universitaria, Universidad San Francisco Xavier, apar­tado 212, S U C R E . Fundaçao Getúlio Vargas, 186 praia de Botafogo, Río D E J A N E I R O , G B Z C - 0 2 . Raznoíznos, 1 Tzar Assen, SOFIA. Burma Translation Society, 361 Prome Road, R A N G O O N . Librairie Albert Portail, 14, avenue BouUoche, P B N O M - P E N H . Papeterie moderne, Maller et C , e , B . P . 495, Y A O U N D E . The Queen's Printer, O T T A W A (Ont.). Lake House Bookshop, Sir Chittampalam Gardiner Mawata, P . O . Box 244, C O L O M B O 2. All publications : Editorial Universitaria S.A., avenida B . O'Hig-gins 1058, casilla 10220, S A N T I A G O . 'The Courier' only : Comisión Nacional de la Unesco, Mac-Irer 764, dpto. 63, S A N T I A G O . The World Book C o . Ltd., 99 Chungking South Road, Section 1, T A I P E H (Taiwan/Formosa). Librería Buchholz Galería, avenida Jiménez de Quesada 8-40, B O G O T A ; Ediciones Tercer M u n d o , apartado aéreo 4817, B O G O T A ; Comité Regional de la Unesco, Universidad Industrial de Santander, B U C A R A M A N G A ; Distrilibos Ltda., Pfo Alfonso García, carrera 4.», n.os 36-119 y 36-125, C A R T A G E N A ; J. Germán Rodríguez N . , oficina 201, Edificio Banco de Bogotá, apartado nacional 83, GrRARDOT Cundinamarca; Librería Universitaria, Universidad Pedagógica de Colombia, T U N J A . La Librairie, Institut politique congolais, B .P . 2307, K I N S H A S A . Ail publications: Librería Trejos, S.A., apartado 1313, S A N J O S É . 'The Courier' only : Carlos Valerin Sáenz y Co. Ltda., 'El Palacio de las Revistas', apartado 1924, S A N J O S É . Instituto del Libro, Departamento Económico, Ermita y San Pedro, Cerro, L A H A B A N A . Archbishop Makarios 3rd Avenue, P . O . Box 1722, NICOSIA. S N T L , Spalena 51, P R A H A 1 (Permanent display) Zahranicni literatura, Bilkova 4, P R A H A 1. Ejnar Munksgaard Ltd., 6 N0rregade, 1165 K 0 B E N H A V N K . Librería Dominicana, Mercedes 49, apartado de correos 656, S A N T O D O M I N G O . Casa de la Cultura Ecuatoriana, Núcleo del Guayas, Pedro Mon-cayo y 9 de Octubre, casilla de correo 3542, GUAYAQUIL. Librería Cultural Salvadoreña, S.A., Edificio San Martín, 6.a calle Oriente no. 118, S A N S A L V A D O R . International Press Agency, P . O . Box 120, A D D I S A B A B A . Akateeminen Kirjakauppa, 2 Keskuskatu, H E L S I N K I . Librairie de l'Unesco, place de Fontenoy, Paris-7". C C P 12598-48. Librairie J. Bocage, rue Lavoir, B . P . 208, F O R T - D E - F R A N C E (Marti­nique). R . Oldenbourg Verlag, Unesco-Vertrieb für Deutschland, Rosen-heimerstrasse 145, M Ü N C H E N 8. Methodist Book Depot Ltd., Atlantis House, Commercial Street, P . O . Box 100, C A P E C O A S T . Librairie H . Kauffmann, 28, rue du Stade, A T H I N A I . Librairie Eleftheroudakis, Nikkis 4, A T H E N A I . Comisión Nacional de la Unesco, 6.» Calle 9.27, zona 1, G U A ­T E M A L A . Librairie ' A la Caravelle', 36, rue Roux, B . P . 111, P O R T - A U - P R I N C E . Librería Cultura, apartado postal 568, T E G U C I G A L P A D . C . Swindon Book Co. , 64 Nathan Road, K O W L O O N . Akadémiai Könyvesbolt, Váci u. 22, B U D A P E S T V . A . K . V . Konyvtárosok Bcltja, Népkoztársaság utja 16, B U D A P E S T VI .

Iceland India

Indonesia

Iran

Iraq

Ireland Israel

Italy

Ivory Coast

Jamaica

Japan

Jordan

Kenya Korea

Kuwait Lebanon

Liberia Libya

Liechtenstein Luxembourg Madagascar

Malaysia

Malta Mauritius

Mexico M o n a c o

Morocco

Mozambique Netherlands

Netherlands Antilles

N e w Caledonia N e w Zealand

Nicaragua

Nigeria Norway

Pakistan

Paraguay Peru

Philippines Poland

Portugal

Puerto Rico

Snaebjörn Jonsson & C o . , H . F . , Hafnarstraeti 9, R E Y K J A V I K . Orient Longmans Ltd. Nicol Road, Ballard Estate, B O M B A Y 1; 17 Chittaranjan Ave. , C A L C U T T A 13; 36A Mount Road, M A D R A S 2; Kanson House, 1/24 Asaf All Road, N E W D E L H I 1. Sub-depots: Indian National Commission for Co-operation with Unesco, Ministry of Education, N E W D E L H I 3; Oxford Book and Stationery C o . , 17 Park Street, C A L C U T T A 16, and Scindia House, N E W D E L H I . P . T . N . 'Permata-Nusantará', c'o Department of Commerce, 22, Djalan Nusantara, D J A K A R T A . Commission nationale iranienne pour l'Unesco, avenue du Musée, TÉHÉRAN. McKenzie's Bookshop, al-Rashid Street, B A G H D A D . University Bookstore, University of Baghdad, P . O . Box 75, B A G H D A D . The National Press, 2 Wellington Road, Ballsbridge, D U B L I N 4. Emanuel Brown, Formerly Blumstein's Bookstores, 35 Allenby Road and 48 Nahlat Benjamin Street, T E L A V I V . Librería Commissionaria Sansoni S.p.A., via Lamarmora 45, casella postale 552, 50121 F I R E N Z E ; Librería Intemazionale Rizzoli, Galeria Colonna, Largo Chigi, R O M A ; Librería Zanichelli, Piazza Galvani 1/h, B O L O G N A ; Hoepli, via Ulrico Hoepli 5, M I L A N O ; Librairie française, piazza CasteUo 9, T O R I N O . Centra d'édition et de diffusion africaines, boîte postale 4541, ABIDJAN P L A T E A U . Sangster's Book Stores Ltd., P . O . Box 366, 101 Water Lane, K I N G S T O N . Maruzen Co. Ltd., 6 Tori-Nichome, Nihonbashi, P . O . Box 605, Tokyo Central, T O K Y O . Joseph I. Bahous & Co. , Dar-ul-Kutub, Salt Road, P . O . Box 66, A M M A N . E S A Bookshop, P . O . Box 30167, N A I R O B I . Korean National Commission for Unesco, P . O . Box Central 64, S E O U L . The Kuwait Bookshop Co . Ltd., P. O . Box 2942, K U W A I T . Librairies Antoine, A . Naufal et Frères, B .P . 656, B E Y R O U T H . Cole & Yancy Bookshops Ltd., P . O . Box 286, M O N R O V I A . Orient Bookshop, P . O . Box 255, TRIPOLI. Eurocan Trust Reg., P . O . B . 125, S C H A A N . Librairie Paul Brück, 22 Grande-Rue, L U X E M B O U R G . Commission nationale de la République malgache, Ministère de l'éducation nationale, T A N A N A R I V E . For 'The Courier': Service des œuvres post- et péri-scolaires, Ministère de l'éducation nationale, T A N A N A R I V E . Federal Publications Ltd., Times House, River Valley Road, S I N G A ­P O R E ; Pudú Building (3rd floor), 110 Jalan Pudú, K U A L A L U M P U R . Sapienza's Library, 26 Kingsway, V A L L E T T A . Nalanda C o . Ltd., 30 Bourbon Street, P O R T - L O U I S . Editorial Hermes, I ganado Marisca 41, M É X I C O D . F . British Library, 30, boulevard des Moulins, M O N T E - C A R L O . Librairie ' A u x belles images', 281, avenue M o h a m m e d - V , R A B A T (CCP 68.74). For 'The Courier' (for teachers): Commission nationale marocaine pour l'Unesco, 20, Zenkat Mourabitine, R A B A T (CCP 324.45). Salema and Carvalho Ltda., caixa postal 192, BEIRA. N . V . Martinus Nijhoff, Lange Voorhout 9, ' S - G R A V E N H A G E . G . C . T . Van Dorp and Co. (Ned. Ant.) N . V . , W I L L E M S T A D (Cura­çao, N . A . ) . Reprex, avenue de la Victoire, Immeuble Painbouc, N O U M É A . Government Printing Office, 20 Molesworth Street (Private Bag), W E L L I N G T O N ; Government Bookshops: A U C K L A N D (P.O. Box 5344); C H R I S T C H U R C H (P.O. Box 1721); D U N E D I N (P.O. Box 1104). Librería Cultural Nicaragüense, calle 15 de Septiembre y avenida Bolivar, apartado n.° 807, M A N A G U A . C M S (Nigeria) Bookshops, P . O . Box 174, L A G O S . A . S . Bokhjornet, Akersgt. 41, O S L O 1. For The Courier': A . S . Narvesens Litteraturjeneste, Box 6125, O S L O 6. The West-Pak Publishing Co. Ltd., Unesco Publications House, P . O . Box 374, G . P . O . L A H O R E . Showrooms: Urdu Bazaar, L A H O R E & 57-58 Murree Highway, G/6-I, Islamabad. Agencia de Librerías Nizza, S.A., Estrella n.° 721, A S U N C I Ó N . Distribuidora I N C A S.A., Emilio Altahus 470, apartado 3115, L I M A . The Modern Book Co. , 928 Rizal Avenue, M A N I L A . Osrodek, Rozpowszechniania Wydaunictw Naukowych P A N , Palac Kultury i Nauki, W A R S Z A W A . Dias & Andra de Lda., Livraria Portugal, rua do Carmo 70, LISBOA. Spanish English Publications, Eleanor Roosevelt 115, apartado 1912, HATO REY.

Romania

Senegal Singapore

South Africa

Southern Rhodesia Spain

Sudan Sweden

Switzerland

Syria Tanzania Thailand

Tunis Turkey Uganda

U . S . S . R . United Arab Republic

United Kingdom

United States of America

Uruguay

Venezuela

Republic of Viet-Nam

Yugoslavia

Cartimex, P . O . Box 134-135, 3, rue 13 Decembrie, B U C U R E S T I . (Telex: 226.) La Maison du livre, 13, avenue R o u m e , D A K A R . See Malaysia. Van Schaik's Bookstore (Pty) Ltd., Libri Building, Church Street, P . O . Box 724, P R E T O R I A . Textbook Sales (PVT) Ltd., 67 Union Avenue, S A L I S B U R Y . Librería Científica Medinaceli, Duque de Medinaceli 4, M A D R I D 14. For 'The Courier': Ediciones Iberoamericanas S .A. , calle de Onate 15, M A D R I D . Al Bashir Bookshop, P . O . Box 1118, K H A R T O U M . All publications : A / B C . E . Fritzes Kungl. Hovbokhandel, Freds-gatan 2, S T O C K H O L M 16. 'The Courier' only : The United Nations Association of Sweden, Vasagatan 15-17, S T O C K H O L M C . Europa Verlag, Rämistrasse 5, Z Ü R I C H ; Librairie Payot, 6 rue Grenus, 1211 G E N È V E 11. Librairie internationale Avicenne, boîte postale 2456, D A M A S . Dar es Salaam Bookshop, P . O . Box 9030, D A R E S S A L A A M . Suksapan Panit, Mansion 9, Rajdamnern Avenue, B A N G K O K . Société tunisienne de diffusion, 5 ave. de Carthage, T U N I S . Librairie Hachette, 469 Istiklal Caddesi, Beyoglu, I S T A N B U L . Uganda Bookshop, P . O . Box 145, K A M P A L A . Mezhdunarodnaja Kniga, M O S K V A G-200. Librairie Kasr El Nil, 38, rue Kasr El Nil, C A I R O . Sub-dépôt: La Renaissance d'Egypte, 9 Sh. Adly Pasha, C A I R O (Egypt). H . M . Stationery Office, P . O . Box 569, London, S.E.I. Government bookshops: London, Belfast, Birmingham, Cardiff, Edinburgh, Manchester. Unesco Publications Center, 317 East 34th St., N E W Y O R K , N . Y . 10016. Editorial Losada Uruguaya, S.A. , Colonia 1060, M O N T E V I D E O . Teléfono 8-75-71. Distribuidora de Publicaciones Venezolanas D I P U V E N , avenida Libertador, edit La Línea, local A , apartado de correos 10440, C A R A C A S . (Tel. 72.06.70 — 72.69.45.) Librairie-papeterie Xuàn-Thu, 185-193 rue T u - D o , B . P . 283, S A I G O N . Jugoslovenska Knjiga, Terazije 27, B E O G R A D ; N A P R D E D , Trg. Repu­blike 17, Z A G R E B ; Drzavna Zaluzba Slovenije, Mestni Trg. 26, L J U B L J A N A .

U N E S C O B O O K C O U P O N S

Unesco Book Coupons can be used to purchase all books and periodicals of an educational, scientific or cultural character. For full information please write to: Unesco Coupon Office, place de Fontenoy, 75 Paris-7e, France. [57]