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THE POPULAR SCIENCE MONTHLY. 



lence ; Chapter VI. to maxims of justice ; 

 and Chapter VII. is a kind of essay on the 

 ancient philosophy. The compiler has raked 

 together from all sources a mass of fragmen- 

 tary proverbs, aphorisms, sentiments, and 

 wise sayings, which are no doubt quite as 

 sound and instructive, but not half as pun- 

 gent and readable, as the saws of Sancho 

 Panza. On the whole, we think that Mill is 

 about right, and that people will appreciate 

 this wisdom a great deal higher after they 

 have mastered a couple of languages in order 

 to get at it. 



The Temperaments ; or, The Varieties of 

 Physical Constitution in Man consid- 

 ered in their Relations to Mental 

 Character and the Practical Affairs 

 of Life. By D. H. Jacques, M. D. 

 New York: S. R. Wells & Co. 1878. 

 Pp. 239. $1.50. 



The editor of this volume, in the intro- 

 duction, remarks that the "literature of the 

 temperaments is very scanty." The reason 

 of this doubtless is, that scientific investi- 

 gators have not hitherto regarded the tem- 

 peraments as a very fruitful field of study. 

 According to Dr. Jacques, however, there 

 is no study, not even, perhaps, phrenology 

 itself, which can be of greater service to us 

 in acquiring a knowledge of ourselves and 

 our fellow men. Those who may happen 

 to coincide with this view, and suppose 

 that they can gain " practical guidance in 

 the affairs of life " by closely observing dif- 

 ferences of temperament, will do well to con- 

 sult Dr. Jacques's well-written little work. 



Color-Blindness, its Dangers and its De- 

 tection. By B. Joy Jeffries, A. M., 

 M. D. Boston : Houghton, Osgood & Co. 

 Pp. 312. Price, $2. 



This subject, which is one of much sci- 

 entific interest and practical importance, has 

 engaged the attention of many inquirers 

 during the past and present generations. 

 That defect of vision by which certain col- 

 ors can not be discriminated, and by which 

 one is mistaken for another, and which is 

 now well established as congenital and as 

 very common, has no doubt existed at all 

 times, though its detection is modern and 

 its scientific elucidation comparatively re- 

 cent. The first well-authenticated case of 

 color-blindness was of an English shoe- 

 maker, named Harris, one hundred years 



ago. But the first marked instance attract- 

 ing general attention was that of the Eng- 

 lish chemist, Dalton, who described his own 

 case in 1Y94, so that this chromatic defect 

 went for some time under the name of 

 Daltonism. The tests of this deficiency 

 have now been carefully worked out and 

 observations made in different countries 

 upon great numbers of persons, bringing 

 out the general result, that about four per 

 cent, of the persons inspected suffer from 

 this defect in a greater or less degree, some 

 being incapable of recognizing one color, 

 and some another. Dr. Jeffries treats the 

 subject systematically and fully in his vol- 

 ume, giving great numbers of cases and 

 digesting all the results of the investigation 

 in different countries. It is found that this 

 failure of vision is so frequent that it has 

 been necessary to institute government in- 

 spection of men in all those public employ- 

 ments where erroneous vision might lead to 

 danger, as where colored signals are em- 

 ployed upon railroads and in navigation. 

 In Chapter XXIII. of his book, Dr. Jeffries 

 gives an account of the European and Mas- 

 sachusetts legislation which has been re- 

 sorted to, to obtain security from errors of 

 this kind. 



Money, Trade, and Industry. By Francis 

 A. Walker, Professor of Political Econ- 

 omy and History in the Sheffield Scien- 

 tific School of Yale College. New York : 

 Henry Holt & Co. Pp. 339. Price, $1.25. 



We have here from the pen of the Su- 

 perintendent of the United States Census, 

 and author of " The Statistical Atlas of the 

 United States," a very important contribu- 

 tion to certain aspects of political economy 

 that are of the highest moment to the peo- 

 ple of the United States. Professor Walker 

 published a work on " Money " last year, 

 written from the historical standpoint, and 

 designed to introduce the student to the 

 literature of the subject. The present work 

 aims to make a direct popular statement of 

 principles, without giving the history of their 

 derivation ; and it differs from the other 

 book also by taking in the relations of mon- 

 ey to trade and industry. The volume is 

 therefore practical in its scope, and has been 

 adapted, with excellent judgment, both to 

 the popular capacity of apprehending eco- 

 nomical inquiries and to the most urgent 



