The unifying theme of the book is the control of energy as a factor in the sacial economy. "Energy is wealth . . . . yet this energy is fre-to him who can discover how to capture and control it. The scientist who is most concerned with the in- vestigation and control of energy is the physicist." Natural phenomena are exhibited as transformations of energy, and the discoveries and inventions of the physicist as providing the means for directing these processes to the betterment of mankind. So. in each case, the end result of the physicists' accomplishment is interpreted in terms of its contribution to human pleasure and human comfort.

Many signs indicate an ever-increasing interest on the part of the lay public in the work of the scientist, and the author has admirably achieved his purpose to offer a rational basis for this interest. Physicists will undoubtedly welcome the opportunity to place this work in the hands of their non-scientist friends.

S. L. QurMBv Co~uxal* UNIvaRslrv

Nnw Yoar CITY

A HISTORY OP SCIENCE, TECHNOLOOY, AND PHILOSOPHY IN THE EIGHTEENTH CENTURY. A. Wo% Professor and Senator, University of London. Head of the Department of History and Philosophy of Science, Former Fellow of St. John's College. Cambridge. Fellow of University College, London, Co-Editor of the Encyclopedia Britannica. 345 illustrations. The Macmillan Co., New York City. 1939. 814 pager. 14.5 X 24 cm. 88.00. This interesting and handsome book, bountifully illustrated,

will be a valuable addition to any school library. I t is something into which a young student may profitably be encouraged to look. He will almost certainly pause of his own accord and linger; he will wish to read much of it. If he likes machines, or chemistry, or botany, or if he seeks for material for a debate on social questions, he will find here much that is pleasant to know and profitable to think about. The older student will gain perspective from it; the mature person will collect from it in- tellectual dividends according to the degree of his maturity.

The eighteenth century was the time of the Lusty youth of that technology which now seems to have attained the fullness of its stature and vigor. I t was the time, too, of keen thinking, of vast inquisitiveness, of ardent speculation, and of rigorous inquiry. One of my friends, seeing the book upon my table, remarked, "There is a book which represents real humanism." Another found it "convincing ;vidence that the students of political history are missing the main @sue."

The bwk consists of thirty-two chapters which treat of mathe- matics, mechanics, astronomy, astronomical instruments, marine instruments, light, sound, heat, electricity and magnet- ism, meteorology, meteorological instruments, chemistry, geology, geography, botany, zoology, medicine, agriculture, rextiles, building, transport, power plants and machinery, the steam engine, mining and metallurgy, industrial chemistry, the making of lenses and specula, mechanical calculators, telegraphy, psy- chology, the national character, demography, economics, and philosophy. The hwk is truly encyclopedic in its scope. The reviewer has found the last few chapters to he especially interest- ing, for they contain inductive and thoroughly scientific material on subjects which are sometimes mistakenly considered to be entirely speculative.

The book does not contain a satisfying history of eighteenth century chemistry. Lomonosov's part in that history is not mentioned; his name appears only in connection with a de- scription of an anemometer which he invented. Phlogiston and Lavoisier are treated all t w conventionally, in a manner which indicates a lack of familiarity hoth with the sources and with the findings of recent research. But the book is already large, it can't contain evervthinr. and it does indeed tie thines torether , ". in a martcrly manner and eihihit their interrrlation,hip%. I t i gwatesr interest sill he ior the rtudent of the intellroual history of mankmd, and this ic true ahethcr thar studcnt is, or is nor.

already a specialist in some branch of science or of engineering or of the humanities.

Professor Wolf's earlier volume on the Sixteenth and Seven- teenth Centuries is reviewed in THrs JOURNAL, 13, 147-8 (March, 1936).

COLLOIDAL PHENOMENA. E. A . ha use^. McGraw-Hill Book Company, Inc., New York City, 1939. xx + 294 pp. 14 X 20 cm. $3.00. In the author's own words, it is not his intention to offer an-

other textbook on colloidal chemistry since a sufficient number already exist. He hopes "to acquaint the reader, in as simple a manner as possible, with the modern viewpoints in colloidal science and to show where and why they must differ from those so successfully applied in physico-chemistry, I t is further hoped that such discussions may be helpful in eliminating the belief. still prevalent in some circles, that the science of colloids must be considered either as a development entirely independent of any other branch of known science, or that colloidal phenomena must be fully ex~lained in accordance with laws of classical chemistrv . . ~~~

or phgriw. . . . Thesr courrrv at the Massachusrtt.; lnititutr of Technology) have provcd rllat the average studenr comprehends alogical prrunration of such a rthjrcr mvrc readily than a marhe. matical treatment."

Dr. Hauser has realized his hopes very successfully in this helpful book. He writes very clearly and expresses himself very positively. The colloid chemist may not always agree with his viewpoint, but he will understand exactly what the author is saying.

The reviewer liked particularly the very definite discussion of charge and hydration influences, the unusually good discussion of the theories of swelling, the treatment of the coacervation theories of Kruyt and Bungenberg de Jong, the section on the optics of colloids, and the treatment of colloidal aggregates.

Adsorption is not dealt with.at great length, although it is of major impqrtance. On the other hand, the principles and theories of adsorption are very well taught. "Quite frequently we find that physical adsorption is predominant at low temperatures, such as in the adsorption of oxygen on metal surfaces; whereas at elevated temperatures an activated adsorption on chemical locali- zation takes place. This difference finds its simple explsnation in the fact that chemical reactions proceed extremely slowly at low temperatures."

The reviewer is somewhat dismayed by the extreme brevity of treatment of emulsions and by the limited discussion of gels. Silica eels are touched noon verv Liehtlv. with no mention of , .. ~ ~

Parrick's important work in chis fcld The author irrms to be rarhcr more familiar wit11 European work in thr rolloicl field than with the very important American research.

The appendix is extremely useful, offering, as it does, many important formulas and technics. I t contains also an excellent discussion of infra-red spectroscopy, fluorescent light microscopy, and the theory of X-ray diffraction.

Dr. Hauser's book is clearly a useful addition to the colloidal Library. I t will justify future editions as the rapid advance of the subject makes such revisions necessary.

HARRY N HOMES OBBRLIN COLLBOB

OB*RUN, ORlD

EDUCATIONAL Acrrvrnes OP THE WORKS PROGRESS ADMINISTRA- TION. D. S. Campbdl, F. H. Bair and 0. L. Harvey. U. S. Government Printing Office, Washington, D. C., 1939. xiv + 185 pp. 15 X 23.5 cm. 8.25.

THE ENGINEERS' MANUAL. R. G. Hudsol~. John Wiley and Sons, Inc., New York City, 1939. Second Edition. iv f 340 pp. 12.5 X 20 cm. $2.75.