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LOGGINGBy Nelson C. Brown

Professor of Forest UtilizationNew York State College of Forestry

Principles and methods of harvesting timber in the United States and Canada are presentedin this book by Professor Brown and other experts. Emphasis is on recent advances inmechanized logging, especially in improved felling and bucking with power saws, newloading devices, and improved skidding methods.January 1949 Approx. 404 pages 180 illus. Prob. price, $5.00

ADOLESCENT CHARACTERAND PERSONALITY

By Professors Robert J. Havighurst and Hilda TabaBoth at the University of Chicago

This is the result of the study of the Committee on Human Development, University ofChicago, of all 16-year-old youths in "Prairie City". It constitutes a scientific approachto the problem of moral character development. To make the study, sociological andpsychological techniques were administered by specialists. The principal authors, Drs.Havighurst and Taba integrated the results.January 1949 Approx. 320 pages Prob. price, $3.50

PRACTICAL POULTRY MANAGEMENTBy James E. Rice, Emeritus Professor and formerly

Head of Department of Poultry Husbandry,and Harold E. Botsford, Professor of Poultry Husbandry

Both at Cornell UniversityThe fifth edition leads the reader step by step through all phases of poultry management.After directions have been given for each step, the authors explain why it is necessary.Numerous practical instructions are given, such as how to handle large flock units atlowest cost, and how to save labor by efficient construction and arrangement of equipment.Fifth Edition, January 1949 Approx. 616 pages 323 illus. Prob. price, $3.60

JOHN WILEY & SONS, Inc., 440 Fourth Ave., New York 16, N. Y.

SCIENCE, October 22, 1948, Vol. 108

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ROTARY w4o e WARBURG

APPARATUS

Patent Applied For

Manometer legs move radially, in a horizontal plane, aboutan axis centered between them. Each manometer legmoves in a direction opposite to the other, thus inertia ef-fects are balanced and there are no fluctuations of theliquid columns. The lateral movement of the manometer,as seen by the operator, is only 1/4 mm. at maximum flasktravel, thus manometers are more easily and accuratelyread (while in motion) than ever before. Maximum flaskmovement ( 10 times that of manometer legs) makes forthorough agitation of flask's contents.

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PLEASE!IF YOU ARE CHANGING YOUR

ADDRESS, please let us know, if possi-ble, four weeks in advance, giving old aswell as new address, and adding zonenumber to meet postal requirements. Ifyou are unable to notify us, so as to affectsucceeding issues, kindly leave instruc-tions and postage with your postmasterfor forwarding your copy. Second classmatter requires postage when remailed toa different address.

SCIENCE1515 Massachusetts Avenue, N. W.

Washington 5, D. C.

SCIENCE, October 22, 1948, Vol. 10810

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A TRUtion-pH MeterA DUAL INSTRUMENT

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SCIENCE, October 22, 1948, Vol. 108

TIME PROVENLaMOTTE SOIL

TESTING APPARATUSThe result of 27 years of extensive cooperative researchwith agronomists and expert soil technologists.The methods used are based on fundamentally soundchemical reactions adapted to the study of soils, and haveproved invaluable aids in diagnosing deficiencies in plantfood constituents.Methods for the following tests are available in singleunits or in combination sets:Ammonia Nitrogen IronNitrate Nitrogen pH (acidity and alkalinity)Nitrite Nitrogen anganeseAvailable Potash MagnesiumAvailable Phosphorus AluminumChlorides Replaceable CalciumSulfatesTests for Organic Matter in Soils and Nutrient Solutions (hydro-culture) furnished only as separate units.

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Information on LaMotte Soil Testing Equipmentwill be sent upon request.

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SCIENCE, October 22, 1948, VoL 108

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SCIENCE, October 22, 1948, Vol. 108

TRACERSFOR RESEARCH

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Personnel Placement

POSITIONS WANTED

Bacteriologist: Woman; B.A., M.S., degree; three years experi-ence in research unit university medical school; one year researchin microbiology in radiation laboratory. Box 478A, SCIENCE. X

Biochemist: Ph.D. Five years teaching experience: six yearsdirector of nutritional research, food manufacturers: for furtherinformation, please write Burneice Larson, Director, MedicalBureau, Palmolive Building, Chicago 11, Illinois. X

Botanist: Ph.D., age 31, with eight years successful teaching andresearch experience, some administrative experience, publications.desires permanent research-teaching position. Trained in morphol-ogy taxonomy, anatomy. Available June, 1949. Box 477A.SMENCE. X

Chemist: Ph.D. (Major, organic chemistry; Minor, microbiology);several years teaching experience; four years research fellow inbiochemistry and pathology; eight years director of research, largeindustrial company; for further information, please write BurneiceLarson, Director, Medical Bureau, Palmolive Building, Chicago1 1, Illinois. X

Illustrator: Medical, biological. Trained, experienced. Availablefor staff position or free-lance work for textbooks, papers, etc.Box 469A, SCIENCE. 10-29

Vice President-Position as college or university vice-presidentdesired by business man with independent means. Doctorate inpsychology, Columbia. Effective administrator, speaker, writer.Box 480A, SCIENCE. * X

POSITIONS OPEN

Bacteriologist: To head newly formed chemo-therapy group in thepharmaceutical division. Please state training and experience.Commercial Solvents Corporation, Terre Haute, Indiana. 10-29

Personnel PlacementPOSITIONS OPEN

Biology Instructor. Single woman with master's degree preferred.Maintenance provided on campus. Catholic Women's College.Middle West. Box 474-A, SCIENCE. 10-22Director: Nagpur University, Laxminarayan Institute of Tech-nology, Nagpur, India. Institute provides facilities for under-graduate and post-graduate courses and research in Technologywith special reference to Chemical Engineering and Oil Technology.Salary: Rs. 2,000/-per month (equivalent to approximately $600per month). In case of a candidate selected from abroad. salarywill be paid quarterly in advance. Higher salary may be given toa candidate with exceptional qualifications. Appointee will beeligible for benefits of University Provident Fund and leave, inaccordance with University Rules. Incumbent will contribute 8per cent of his salary to the Provident Fund, the University con-tributing 6 /4 per cent. Qualifications: Candidate must be tech-nologist of distinction with high academic attainments in ChemicalEngineering and experience in industry and administration andmust be able to organize teaching of different branches of Chemi-cal Technology and to guide and supervise research. Appointmentwill be made on contract basis for period of 5 years. Applicantsmust furnish the following details: (1) Age. (2) University de-grees. (3) Research and other academic qualifications (copies ofpublications to be enclosed). (4) Professional qualifications. (5)Teaching experience. (6) Experience in industry and administra-tion and (7) Previous and present appointments held. with theiremoluments. Box 476A. SCIENCE. XPlant Physiologist. Large industrial company in midwest seeksplant physiologist or biologist for study of grain problems, sprout-ing, etc. Excellent opportunity. Box 479A, SCIENCE.

R 11/5-11/19

TO AVOID DELAY .........Please be sure to enclose cash in advance with

all classified ads.

(a) Medical Research Director; physician with M.S. or Ph.D. orequivalent training in biochemistry, pharmacology or pathology;knowledge of antibiotics advantageous; pharmaceutical company.(b) Ph.D. in Physics; liberal arts college of Middle Western uni-versity; although rank depends upon qualifications, preference forsomeone qualified to direct department after becoming established.(c) Senior Pharmacologist and Immunologist with special trainingin bacteriology; research appointments, pharmaceutical company;candidates with Ph.D. degrees preferred; $5200-$7800; researchinvolves animal evaluation of new substances to be used forpharmaceuticals. (d) Biochemist and Physiologist for research onbiological effects of radiation; department of physics, state uni-versity; opportunity for working toward Ph.D.'s if candidates havenot obtained them; South. (e) Young men qualified in Physiology,Biochemistry or Pharmacology; university medical school; oppor-tunities in teaching or full-time research; Ph.D.'s or physicianswith scientific backgrounds required. (f) Biochemist; researchprogram, large institution located in university center; new re-search building; candidates with advanced degrees and experiencerequired; East. (g) Bacteriologist to become associated with newlaboratories of department of agriculture, Middle Western institu-tion; work in conjunction with the functions of animal diseasediagnosis. S10-4 Medical Bureau (Burneice Larson. Director)Palmolive Building, Chicago 11, Illinois. iYoung man 25-30 years old for publisher of Medical and Scientifictextbooks to act as assistant manager, Educational Department.Science background; teaching or business experience helpful butnot essential. Write P.O. Box 416, Phila. 5, Pa.

R 10/29, 11/5, 11/12U~

SCIENCE, October 22, 1948, Vol. 108

CHARGES FOR CLASSIFIED ADVERTISINGRegular setting 10¢ a word. Minimum charge $2.50 foreach insertion. A box number counts as 8 words of theadvertisement (e.g. 25 words plus box number equals 33words). Make checks payable to the AAAS. All iser-tions must be accompanied by correct remittance and sent14 days in advance of publication date to the AdvertuhDepartment, AAAS 1515 Massachusetts Avenue, N. W.,Washington 5. D. C.

Your oWn ad here will produceprompt aidpleasing results!An advertisement in these columns

will reach more than 30,700scientists.

Plan to use this economical medium for advertis-ing your wants and offerings for books, scientificequipment, and professional services. Publicationof notice within about 14 days of receipt of order.

Rates: 10¢ per word ($2.50 minimum) payablein advance. Box numbers, available for your con-venience, count as eight words of the advertise-ments. All replies forwarded to box holders onthe same day as received.

Address: Advertising Department, AAAS, 1515Massachusetts Avenue, N.W., Washington 5, D. C.

RADIOCHEMISTSNUCLEAR PHYSICISTSELECTRONIC EN6INEERS

Challenging positions in vital researchand development work open for scien-tists with Ph.D., M.S., or B.S. Specificexperience in nucleonics valuable butnot required. Write full details.

TRACERLAB, INC.,55 Oliver Street, Boston, Mass.

10-22

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The Market PlaceBOOKS

WANTED TO PURCHASE SCIENTIFIC BOOKSAND PERIODICALS

Entire libraries, and smaller collections; sets and rum;foreign and domestic.

WALTER J. JOHNSON,125 East 23rd Street, New York 10. tf

Your sets and files of scientific journals are needed by our libraryand institutional customers. Please send us lists and description ofperiodical files you are willing to sell at high market prices.J. S. CANNER AND COMPANY, 909 Boylston Street, Boston15, Massachusetts. tf

Send us your Lists of tfSCIENTIFIC BOOKS AND PERIODICALS

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and HARD-TO-FI NDUT - OF - PRINT books supplied. All sub-jects, all languages. Also incomplete sets completed, genealogiesand town histories, all magazine back numbers, etc. Send us yourlist of book-wants-no obligation. We report quickly. Lowestprices.

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All Amino Acids (natural and synthetic, rare sugars. biochemicalproducts and reagents, new pharmaceuticals in stock. Write forcomplete price list. BIOS LABORATORIES. 607 West 43rdStreet. New York 18. tf

We wish to purchase 10,000 clean and well fixed Fern prothallia,half with sex organs and half with sporophytes. Top price forreally good material. We are also in the market for preservedstocks of various Myxomycetes, Plasmodiophora, Saprolegnia,Peziza, Empusa, Tilletia (various species), Ustilago (various spe-cies), Nemalion, Sphaerella, Draparnaldia, Polysiphonia (allstages), Chlamydomonas, Pandorina, fruiting Lycopodium andLmany other botanical forms. We wish to contact botanists, espe-cially in the southern states and in the tropics who can collectmaterial for us. Write to GENERAL BIOLOGICAL SUPPLYHOUSE, 761 East 69th Place, Chicago 37, Illinois, U.S.A. 11-12:

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FOR SALEBargains in high-grade Medical and Research Microscopes andAstronomical Telescopes. Send for lists. Guaranteed repairservice. RASMUSSEN & REECE, Amsterdam, New York.

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SCIENCE, October 22, 1948, Vol. 108

LUNAR CATASTROPHIC HISTORYBy J. E. SPURR

244 pages 1 plate 46 text figures

Price $5.000

The Rumford PressConcord, New Hampshire

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PROCEEDINGS ISSUE!The November 26th issue of Science will contain

a complete summary of the Proceedings of theA.A.A.S. Centennial Celebration, held in Wash-ington, D. C., September 13th-17th, 1948.

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SYMPOSIA(7¼2 x 10%, illustrated, cloth bound)

A considerable fraction of the Symposium Volumes and Research Conferences publishedby the A A AS have been exhausted by orders not only from libraries and from specialistain their respective fields, but also from foreign libraries and scientists. The titles remain-ing in print are shown below with prices.Two new volumes are, "Approaches to Tumor Chemotherapy", a comprehensive discus-sion by more than 60 participants, and "The Rickettsial Diseases of Man", a survey of animportant group of serious infectious diseases which have recently become importanthealth problems.

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Liebig and After Liebig-A Century of Progress inAgricultural Chemistry ..........................

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16 SCIENCE, 22, 1948, Vol. 108

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16 SCIENCE, October 22, 1948, Vol. 108

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40mm. Assorted focal lengths.Stock #S-W 45lenses $5.00PostpaidStock #10-W 80 lenses $10.60 PostpaidCONDENSING LENSES -* Seconds,but suitable for Enlargers and Spot-lights.Stock #1061-W .... 6'A" dia.. 9 FP.L.

ORDERING $2.50 Postpaid14FORMATION Stock #1060W 5".. din.. F.L.$1.00 Postpaidoe carefully each We have a Limited Quantity of Con-b often new Items densing Lenses seconds rangingsure to specify from 4'A to 8M" In dia. with variousand enclose pay- focal lengths. Send for Free Bulletinrder. Buy with titled '"MISCENEOUS, CON-ce that merchan- DENSING LENSES-W."

ly as represented. LENS CLEANING TISSUE -1stGUARANTEED lquality, sheet sine 11"1 x 7A". Made

to Govt. specs.E.CATALOG-W High wet strength.

Stock #721-W ........ 500 shedts$1.60 Postpaid

CONDENSING LENS SET-Consistsof 2 Condensing Lenses with diam-

eter of 2". Used for making 35mm projector or many otherpurposes.Stock #404-W ........... 75 Postpaid

TERRIFIC BARGAIN!BUBBLE SEXTANTS

These Army Air Forces Bubble SextantscotteGovt. about

$12.00 each. A real bargain atour price of $12.5 Included

with Bubble Sextant shipment is

wooden Carrying Case. 5 sparewaxed paper discs. flashlightwith rheostat for night use

(uses ordinary flashlight cells-

not furnished) aux. 2-powerGalilean Telescope, Allen wrench,

1 spare marking point. War-

time used, BUT COMPLETELYREPAIRED, COLJATED J:-AND PUT IN GOOD WORK-

ING ORDER. If not satisfied that Sextant is exactly asrepresented, return within 10 days and money will be re-funded. Full directions for use accompany each shipment.Stock #924W-0 i............ W POpdSame SEXTANT as above, but BRAND NEW and with Auto-matic Electric Averaging Device and Illuminated AveragingDisc for nighttime use. Govt. cost $217. Though brand newwe have re-checked Bubble and Collimation and GUARAN-TEE perfect working order._ Stock #98-W 822.50 Postpaid

IF YOU'RE INTERESTED IN OPTICAL BARGAINSW~~~te CATAL~~~~~~~W Yav SETr OR STOCK NO.arSurluWrite for FREE CATALOG W Lenses and Prisms for iipe at Bargain ORDER BY SET OR STOCK NO,

Prices . s lttInstruments Tool B

SPENCER No. 735 LAMP

Here is the illuminator for advanced microscopy you

knew was bound to come . . . with convenient precise

controls for critical adjustment . . . with essential opticaland mechanical qualities to complement a fine microscope.

COOLER OPERATION. Sturdy die-cast housing dissipates heat.

CRITICAL FOCUSING FROM EITHER SIDE. Rack & pinion movement.

NO TRANSFORMER. Lamp operates from 110 volt outlet.

PRECISION REFLECTOR ADJUSTMENT.So quick, simple, and accurate. +

RAPID BULB CHANGE. Lamphouse separates.

Hinged lamp chimney opens to reveal bulb and reflector.

*PRECISE TILTING. Screw adjustment maintains any angle.

QUALITY OPTICAL SYSTEM. Two plano-convex lens elements.

IRIS DIAPHRAGM. Knurled ring control.

FILTER HOLDER. Choice of single or multiple holder.

Correct illumination is essential for thebest results from any microscope objective,eyepiece and condenser. Your instrumentdeserves the Spencer No. 735. For furtherdetails write Dept. K123

American V OpticalCOM PANY

Scientific Instrument DivisionBuffalo i5. New York

wtAFIFAM