July 11, 1913] 



SCIENCE 



57 



take at some future time. Of these three 

 types the first is the most rare, the second the 

 most familiar and the third the most popular. 

 Professor Miinsterberg's book belongs to the 

 third type, and its popularity is indicated by 

 the fact that during the month of April it was 

 reported among the six best selling non-fiction 

 books in the largest cities of Maryland, Massa- 

 chusetts, Illinois, Michigan, Florida, Minne- 

 sota and New York, along with " The New 

 Freedom," " The Promised Land," the Mon- 

 tessori books, " Zone Policeman 88 " and 

 " Auction Bridge of To-day." 



The book contemplates the ultimate devel- 

 opment of a science of " psychotechnics " 

 which shall handle the problems of industry 

 and economics by the application of the tech- 

 nique of experimental psychology. The vari- 

 ous chapters give a series of interestingly 

 presented illustrations of the psychotechnic 

 point of view, the selection of examples being 

 confined to those fields of industry which have 

 not yet been systematically explored by ap- 

 plied psychology. 



Tests for vocational guidance; methods of 

 scientific management; elimination of unfit 

 individuals from railway, ship and telephone 

 service; economy of movement; fatigue and 

 monotony; types of attention; the influence 

 of weather, drugs, entertainment, rhythm, and 

 other physical and social factors ; the efl'ective- 

 ness of advertisements; illegal imitation; 

 buying and selling; — all these topics, and 

 similar ones, are discussed from the point of 

 view of the three problems — " How to find the 

 best possible man, how to produce the best 

 possible work and how to secure the best pos- 

 sible results." Preliminary experiments are 

 described and the work of other workers briefly 

 summarized. The author frequently remarks 

 that most of the experiments represent only 

 the beginnings of investigations, which, it is 

 hoped, will in time yield significant and use- 

 ful results. 



Of particular interest is the author's recog- 

 nition of the importance of interests, inclina- 

 tions and emotional attitudes, and of the de- 

 sirability of devising tests which will measure 

 an individual's ability to grasp a general sit- 



uation. Tests of this sort will doubtless 

 prove to be of much greater diagnostic value 

 than the simple sensori-motor measurements. 

 More complete data are promised in forth- 

 coming reports of detailed investigations now 

 being carried on in the author's laboratory. 

 These reports will presumably belong to the 

 rare first variety of monographs, and will be 

 looked forward to with interest by professional 

 psychologists to whom the present book con- 

 stitutes not so much a contribution as a chal- 

 lenge to fulfil the prophecies of a fellow 

 worker. Perhaps the most immediate value of 

 the book comes from the ingenuity with which 

 its problems are conceived and the preliminary 

 tests devised. Professor Miinsterberg's hope- 

 fulness for the future possibilities of " psy- 

 chotechnics " does not keep him from placing 

 a commendably conservative value on the ac- 

 tual results and correlations of his own pre- 

 liminary studies. H. L. Hoimngworth 

 Columbia University 



SPECIAL ARTICLES 



THE EMISSION OF ELECTRONS FROM TUNGSTEN AT 



HIGH TEMPERATURES : AN EXPERIMENTAL 



PROOF THAT THE ELECTRIC CURRENT 



IN METALS IS CARRIED BY 



ELECTRONS 



That the carriers of the negative thermionic 

 current from incandescent solids are negative 

 electrons was first established by J. J. Thom- 

 son.' In 1901^ the writer developed the view 

 that this emission of negative electrons oc- 

 curred by virtue of the kinetic energy of 

 thermal agitation of some of the electrons in 

 the solid exceeding the work which was neces- 

 sary to overcome the forces which tend to re- 

 tain them in the body and which prevent them 

 from escaping at lower temperatures. This 

 conception has proved a very fruitful one and 

 its consequences have been verified in a num- 

 ber of ways. It has provided a quantitative 

 explanation of the variation of the number of 

 electrons emitted with the temperature of the 

 body. It led to the prediction of a cooling 



^PUl. Mag., Vol. 48, p. 547 (1899). 



'Camb. Phil. Proc, Vol. 11, p. 286 (1901); 

 Phil. Trans., A, Vol. 201, p. 497 (1903). 



