the recent National Science Foundation survey (Science, 123, 133 (1956)) only 11,000 were classed as metallurgists. Most of these obtained their training in disciplines other than metallurgy becauseuntil recently courses and good textbooks in this fieldwere not common. Many s. chemist has through necessity become a metallurgist. The Manhattan Project greatly accelerated this transformation. Chemists in the process of being "converted" d l find these two hooks a great help in understanding the fundamentd metallurgical concepts. The short introductory chapter on The Atom will not surprise the chemist, except that the activity series based upon A F per kilogram ozwen looks quite different from one based on standard electrode potentials. The emphasis on crystallography, that begins on page 32 and continues unrelentingly throughout the first volume, gives the departure point from physical ohemistry. The location of atoms in space and the forces that bind them together become the clue to metallurgical behavior. While hesttreating of metals may still be s n art, the science of physical metallurgy is rapidly clarifying the peculiar behavior patterns of metals and alloys. The first volume is concerned with principles. They are a p plied in the second which begins with the phase rule and proceeds to Chapter 7 where iron-carbon alloys (steel) are taken up. This volume is not an encyclopedirt; no attempt has been made to compete with the "ASM Metals Handbook." I t is rather a study of what happens in representative alloy systems as the concentration of an alloying component or of an "impurity" is varied systematically. About a third of the book is devoted to the very complex ironcarbon system. The phase rule is not developed systematically but is illustrated by selected examples. The study of the nanequilibrium behavior of the steels is of necessity referred hack to the equilibrium phase diagram, even though the TTT (timetemperature-transformation) curves are of utmost importance in the understanding, far example, of the conversion of sustenite to martensite, both metastable "constituents" in steel. No apolog,~is needed for the disproportionate emphasis on the ferrous metals, which serve as the backbone of our present civilization. Chemista who are curious as to what "ductile" or "nodular" cast iron is or how additions of magnesium, cerium, calcium, or zirconium t o molten iron cause it to solidify in this condition will find a satisfactory explanation on page 287. This form of iron has a. tremendous promise for the future. The discussion of ternary systems is even more cursory than usual, and quaternary alloys are oovered in four pages. If one considers each element listed as an "impurity" to be a component in the phase rule sense, he realizes how far from complete is the sytematieation of knowledge of the metallic state from the standpoint of the phase rule. These two hooks for the first course, however, are sufficiently scientific and up to date to start the beginning metallurgist on the right foot. LAURENCE S. FOSTER BFLIIOYT. MABBACAUSETT~
DISCOVERIES AND INVENTIONS OF THE 20TH CENTURY 1. G. Crowther. Fourth edition. E. P. Dutton & Co., Inc., 432 pp. 129 figs. 2 tables. 1 5 X New York, 1955. mii 22.5 cm. $6. THISbook was written originally shortly after the turn of the century and probably was an important and excellent book a t that time. This revision leaves something to be desired. The subjects are covered only meagerly and with such s. strong slant toward English development that it does not offer much for the Bnlericm reader. The failure to personalize any of the discoveries and inventions would probably make it uninteresting reading for young people. 0
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E. C. HUGHES ST.,ND*~D on. COMP*XI C L ~ V B L *oxro ~~.
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