690 BOOK REVIEWS. [J. F. I.

made a study of the equilibrium concentrations of lattice imperfections of certain simple types, first in crystals of a single component, and secondly in crystals of a typical salt. This proceeds to imperfections which consist of the presence of extra atoms of one component and extended to consideration of the presence of foreign atoms in a lattice present either on lattice points or in interlattice positions. Then one is led to the general study of the solubility of foreign atoms in crystalline solids, and especially of the solubility of hydrogen in metals, particularly in palla- dium. In the closing part of this topic the degree of disorder due to atomic inter- changes, as a function of temperature is studied.

The last chapter is devoted to electric and magnetic properties, where a some- what condensed treatment is given, a balanced description of the general principles and results. In the back of the book there is a comprehensive subject index.

The work assumes considerable prerequisites. For those qualified to follow it, there is an abundance of interesting and valuable material presented.

R. H. OPPERMANN.

MR. TOMPKINS IN WONDERLAND, OR STORIES OF c, G, AND h. 91 pages, illustra- tions, 17 X 22 ems. New York, The Macmillan Company, 1940. Price $2.00. Every one of us has set notions with regard to space, time and motion.

These are obtained from infancy when the senses began to function. So set are they that they are taken for granted and often we are inclined to believe that our concept of the outside world is the only possible one. Those who have knowledge of modern scientific observation however, have ample reason to realize that a change in fundamental concepts is necessary when dealing with phenomena ordinarily inaccessible to our everyday observation, this change being necessarily restricted to such phenomena. If another world could be imagined with the same physical laws as our own, but with different numerical values for the physical constants determining the limits of applicability of the concepts, then even a savage would be acquainted with the principles of relativity and quantum theory.

This book contains a story, built up from the imagination, in which the hero is transported to such a world through a series of dreams, after attending lectures by the author on relativity of space and time, curved space and gravitation, and the quantum of action. The lectures are included in the latter part of the book. The worlds of course, seem fantastic, but the story has a special appeal to the scientifically minded reader from both the standpoint of the manner of presenta- tion and the analysis of facts interpreted in a very real light.

R. H. OPPERMANN.

REFLEXION ET REFRACTION DES ONDES SEISMIQUES PROGRESSIVES, par L. Cag- niard. 250 pages, illustrations, tables, 17 X 25 ems. Paris, Gauthier- VihrS, 1939. Price 120 fr. In this work the author reacts against the usual tendency of theoretical seis-

mologists to consider an earthquake as a permanent harmonic phenomenon; whereas on the contrary it is a transitory occurrence-a motion gradually propa- gated in the midst of a medium which was originally in equilibrium.

Taking up by new methods a classic memoir of Lamb’s which supplies indis- pensable generalizations, M. Cagniard discusses, with extensive use of mathe-

blay, 1940.1 PUBLICATIONS RECEIVED. 691

matics, the solution of one of the fundamental problems of seismology-that of the reflection-refraction of a spheric wave on the plane surface which separates the two media.

The phenomena of propagation, so much discussed today, on which was founded the refraction method of seismic prospecting, are definitively explained by the formation of waves with conical fronts at the time of reflection. In addi- tion are studied the cinematic discontinuities, of which the various wave fronts may be the seat. These discontinuities become very complex when conical fronts are formed.

However, the essential part of the phenomenon consists neither in the propa- gation of wave-front surfaces nor in the cinematic discontinuities of which they are the seat. It lies rather in the subsequent phases of the disturbance which correspond to the “coda” of seismograms. This coda shows, at great distances from the epicenter, a characteristic aspect caused by the superimposing of complex phenomena designated by the author as pseudo-waves. The Rayleigh wave is a pseudo-wave whose structure is very different from that of the bermanent har- monic phenomenon generally studied under that name in seismology. Beside the Rayleigh wave, there are many other pseudo-waves of varying types. Some are superficial like the Rayleigh wave and similarly characterized by an annular propagation. Others travel through the interior of the two media and not along their inter surface-and these are spheric or conical.

E. E.

PUBLICATIONS RECEIVED.

Elements of Electra-Magnetic Theory, by A. Wilmer Duff and Samuel J. Plimpton. 173 pages, illustrations, 15 X 22 ems.. Philadelphia, The Blakiston Company. Price $2.75.

Elementary Photography, by Gilford G. Quarles. 350 pages, illustrations, plates, 16 X 24 ems. New York, McGraw-Hill Book Company, Inc., rg4o. Price $3.00.

The Pinpoint Plalteturium, by Armand Spitz. 110 pages, illustrations, plates, 26 X ZI ems. New York, Henry Holt and Company. Price $2.00.

Mechanics Applied to Vibrations and Balancing, by D. Laugharne Thornton. 529 pages, illustrations, 16 X 25 ems. New York, John Wiley & Sons, Inc., 1940. Price $7.50.

Science Front, 1939, by F. Sherwood Taylor. 310 pages, plates, illustrations, 13 X 19 ems. New York, The Macmillan Company. Price $2.50.

Radioactivite et Transmutation des Atomes, par Theodore Kahan. 224 pages, illustrations, II X 17 ems. Paris, Armand Colin, 1940. Price 17 fr.

Les Ha&es Temperatures, par G. Ribaud. 173 pages, illustrations, 12 X 19 ems. Paris, Felix Alcan, 1939. Price 18 fr.

Portraits of Famous Philosophers Who Were Also Mat+ematicians, by Pro- fessor Cassius Jackson Keyser. 12 portraits, unpages, 26 X 35 ems. New York, Scripta Mathematics, 1939. Price $3.00.

National Advisory Committee for Aeronautics. Technical Notes: No. 755, Wind-Tunnel Investigation of an N. A. C. A. 23030 Airfoil with Various Arrange-