REVIEWS 495 



Perhaps the most interesting part of the book, in view of the current dis- 

 cussions on radiation problems, consists of the chapters on radiation pyrometers, 

 which contain accounts of the classical and more recent researches instituted to 

 test the validity of Stefan's, Wien's, and Planck's laws, and also to determine to 

 what extent such radiators as oxide and metallic surfaces differ from the " full " 

 radiator as regards the amount of radiation and the distribution of its energy 

 among the elementary ranges of wave-length. Extrapolation has always been a 

 feature of temperature research, and a very excellent summary of the work which 

 has been done to test the validity of extrapolation, and to determine the true 

 values of melting points of such substances as sulphur, the refractory oxides, 

 platinum, tungsten, and tantalum, and also the temperature of the positive crater 

 of the electric arc will be found in this volume. 



There is rather an unfortunate definition of " perfect gas " in the text on 

 page i, which is, however, corrected in a foot-note, and one or two of the 

 descriptions of apparatus are not quite as lucid as they might be. Apart from 

 these minor faults, the book is one which can be heartily recommended to all 

 physicists as an extremely useful account of its subject. 



J. R. 



CHEMISTRY 



A History of Chemistry. By F. J. Moore, Ph.D. [Pp. xiv + 292.] (New 

 York: McGraw-Hill Book Company, 1 918. London: Hill Publishing Co. 

 Price 12s. bd. net.) 



Chemical history is not a subject which appeals to everybody, and, unless 

 presented in an attractive form, it is apt to be dry and uninteresting. Prof. Moore, 

 however, who appears to possess the gift of presentation in a remarkable degree, 

 begins by introducing his readers to the personal characteristics of the men whose 

 work he is about to describe, and thus invests the dullest of controversies and 

 hypotheses with a living interest. As stated in the preface, the book is the 

 outgrowth of a series of talks which the author has for several years given to his 

 senior students at the Massachusetts Institute of Technology; these lectures 

 have dealt in a direct informal way with the fundamental ideas of the science, 

 their origin, their philosophical basis, and the personalities of those who have 

 contributed to the development of these ideas. The book is divided into twenty- 

 one chapters ; the first three deal with the chemistry of the Ancients, Middle 

 Ages, and Renaissance respectively ; then follow two chapters on the phlogiston 

 theory and its supporters ; subsequent chapters are devoted to the work of 

 individual chemists, or the discussion of special subjects such as the type theory, 

 the valence theory, or the periodic law. The last four chapters deal respectively 

 with organic and inorganic chemistry since i860, the rise of physical chemistry, 

 and radioactivity and its influence upon the atomic theory. In these chapters are 

 to be found quite exceptionally good, though brief, accounts of modern work on 

 the rare gases of the atmosphere, on Werner's work on metal-ammonias, and the 

 very latest work on atomic disintegration, X-ray spectra, and atomic numbers. 

 All these subjects are dealt with in some detail, as the author rightly remarks 

 that they lie somewhat outside the field familiar to most undergraduates, and, 

 for this reason no doubt, the classical researches on organic chemistry are mainly 

 dismissed with a mere mention of their existence, as the serious student will have 

 already familiarised himself with them before reading this book. The book 

 contains a number of excellent likenesses, and also a selection of reproductions of 



