138 



SCIENCE 



[N. S. Vol. XLIV. No. 1126 



had turned out as fine a piece of work as has 

 appeared in fifty years, so long will English 

 physics remain preeminent. 



The first chapter reviews briefly the older 

 theories of X-rays and presents Laue's dis- 

 covery and photographs. The second presents 

 the Bragg theory of the diffraction of X-rays, 

 the third describes in detail the Bragg X-ray 

 spectrometer, the fourth is a brief account of 

 the properties of X-rays. The fifth merely de- 

 scribes crystal structure, little known to most 

 physicists, and the sixth presents our present 

 knowledge of X-ray spectra, and includes an 

 admirable report on Moseley's work. The re- 

 maining six chapters present the Bragg an- 

 alysis of crystal structure made by means of 

 their spectrometer. 



Few books have ever appeared which repre- 

 sent in so high a degree the creative work of 

 the authors themselves. 



B. A. Millikan 



Byerson Physical Laboratory 



An Elementary Manual of Radio-Telegraphy 

 and Radio-Telephony for Students and 

 Operators. By J. A. Fleming, M.A., D.Sc, 

 F.B.S. Third edition. Longmans, Green & 

 Co., 1916. Cloth, 360 pages, 194 illustra- 

 tions. 



This is an excellent elementary text-book on 

 the principles of radio-communication, with 

 enough history inserted parenthetically to add 

 descriptive interest, without sensibly distract- 

 ing attention from the main line of exposition. 

 Like all of Dr. Fleming's writings, it is par- 

 ticularly strong on the quantitative side. 

 Nevertheless, the mathematics employed are 

 not difficult. 



The book is divided into nine chapters, re- 

 lating to the following topics : Electric Oscilla- 

 tions, Damped Electric Oscillations, Undamped 

 Electric Oscillations, Electromagnetic "Waves, 

 Radiating and Beceiving Circuits, Oscillation 

 Detectors, Badio-telegraphic Stations, Badio- 

 telegraphic Measurements, Badio-telephony. 



The chapter dealing with radio-telegraphic 

 measurements is particularly good. 



A blemish in the didactic method is the use 

 of English units of measure in a few of the 



examples. The complexity involved in the 

 arithmetic, by reference to such archaic and 

 unscientific units, repels the student more than 

 a transition from English to metric units be- 

 fore attacking the problem, and a final trans- 

 fer from metric to English units in stating the 

 results. 



The book will be of great value to students 

 of radio-telegraphy, and to operators seeking to 

 improve their knowledge of their work on the 

 scientific side. 



A. E. Kennelly 



The Institutional Care of the Insane in the 

 United States and Canada. By Henry M. 

 Hurd, W. F. Drewry, B. Dewey, C. W. 

 Bilgriji, G. A. Blumer and T. J. W. Bur- 

 gess. Baltimore, The Johns Hopkins Fress, 

 1916. Fp. 497, 30 pi. Edited by Henry M. 

 Hurd, M.D. $2.50. 



This is one of the few works in the English 

 language in which the history of a separate 

 branch of medicine has been exhaustively 

 treated. The editor, Dr. Hurd, prior to his 

 election as superintendent of the Johns Hop- 

 kins Hospital in 1889 and after, has had a 

 long practical experience in institutional psy- 

 chiatry, and there is probably no other author- 

 ity in this country so well fitted for the diffi- 

 cult task delegated to him and his associates. 

 The four volumes of this work, when com- 

 pleted, will comprise no less than a full set of 

 separate histories of all the insane hospitals 

 in the United States and Canada. The pres- 

 ent volume, although it professes to deal only 

 with the general history of institutional care 

 of the insane on this continent, is, in reality, 

 an exhaustive history of American psychiatry 

 in all its phases, and is therefore likely to re- 

 main the authoritative work on the subject for 

 an indefinite period. In this history, there are 

 no great outstanding names, like those of 

 Pinel or Tuke or Griesinger, unless it be that 

 of a woman, who was the prime mover of our 

 improved institutional care of the insane. 

 The record is one of collectivism, of the pa- 

 tient labors of societies, journals and individ- 

 ual propagandists for the good of a much- 

 neglected class of human suffering. Matthew 



