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THE POPULAR SCIENCE MONTHLY, 



Sight, an Expositiox op the Principles of 

 Monocular and Binocular Vision. By 

 Joseph Le Conte, LL. D. With numer- 

 ous Illustrations. Pp. 275. D. Applcton 

 & Co. lutcrnational Scientific Series, 

 No. XXII. Price, $1.50. 



Dr. Le Conte has for many years made 

 the eye a subject of special study, from the 

 point of view assumed in this book. And 

 this is the way this wonderful organ will in 

 future have to be studied. Its interest as 

 an object of investigation is inexhaustible. 

 Its mechanism and action are roughly ex- 

 plained in every physiology ; but, to state all 

 that is known about it, in its several aspects 

 in health and disease, would require whole 

 libraries, nelmholtz has made a large and 

 a profound book on physiological optics, 

 devoted to an elucidation of the relations of 

 light to the visual organism, while the psy- 

 chological relations of the organ of vision 

 have yet to be explored. The eye is, there- 

 fore, a subject so complex, obscure, and ex- 

 tensive, that it must in future be approached 

 on different sides by separate investigators. 

 In taking up the eye with a view of explain- 

 ing the mechanism and process of sight as 

 single and double, our author declares that 

 he does not know the existence of "any 

 work covering the same ground in the Eng- 

 lish language." He, therefore, claims that 

 it meets a real want, and fills a real gap in 

 scientific literature. 



In regard to its form. Dr. Le Conte says : 

 " I have tried to make a book that will be 

 intelligible and interesting to the thought- 

 ful general reader, and at the same time 

 profitable to even the most advanced special- 

 ist in this department." It must be admit- 

 ted that that the author has fairly attained 

 to his ideal. Ilis explanations are so clear, 

 and his facts and principles so interesting, 

 that they will be sure to engage the atten- 

 tion of ordinary readers, while at the same 

 time he gradually passes to the consideration 

 of questions and the presentation of views 

 that will' appeal to instructed critics as new 

 contributions to the subject. 



Another point in regard to this work 

 strikes us as most important. It is largely 

 a book of experiments ; the effects discussed 

 and illustrated with the woodcuts are such 

 as can be tested by the reader who will take 

 some pains to practice. This is an impor- 

 tant means of education, by which the reader 



not only learns how to do things, but be- 

 comes acquainted with the subject at first 

 hand, and knows what he knows. On this 

 feature of his book. Dr. Le Conte remarks ' 

 " As a means of scientific culture, the study 

 of vision seems to me exceptional. It makes 

 use of, and thus connects together, the sci- 

 ences of physics, physiology, and even psy- 

 chology. It makes the cultivation of the 

 habit of observation and experiment possible 

 to all ; for the greatest variety of experi- 

 ments may be made without expensive ap- 

 paratus, or, indeed, apparatus of any kind. 

 And, above all, it compels one to analyze the 

 complex phenomena of sense in his own 

 person, and is thus a truly admirable prep- 

 aration for the more difficult task of analy- 

 sis of those still higher and more complex 

 phenomena which are embraced in the sci- 

 ence of psychology." 



Sketches and Reminiscences of the Radi- 

 cal Club of Chestnut Street, Boston. 

 Edited by Mrs. John T. Sargent. Bos- 

 ton: James R. Osgood &; Co. 1880. Pp. 

 418. Price, $2. 



The Radical Club was founded in the 

 spring of 1867, with the purpose of bring- 

 ing together occasionally a few persons who 

 were known to be daring thinkers on sub- 

 jects of high import, and of furnishing them 

 " an opportunity for uttering their thought 

 to an audience capable of appreciating its 

 scope, of criticising its worth, and of devel- 

 oping its relations." It was composed of 

 members of all religious denominations, and 

 enjoyed an attendance of two hundred at 

 the closincr sessions of 1880. This volume 

 contains about fifty of the essays which 

 were presented at the meetings, with notices 

 of the discussions which followed the read- 

 ing. The authors, whose names are append- 

 ed, are, as a rule, men and women known 

 in literature, science, or the forum, whose 

 words never fail to command attention. The 

 subjects of their papers represent a wide 

 range of thought in literature, art, theology, 

 metaphysics, science, and sociology, and are 

 of degrees of practicality of which " Color- 

 blindness " may be taken to represent one 

 extreme and " The Impossible in Mathe- 

 matics " the other. The reports of the in- 

 formal discussions are full of conventional 

 life, and are hardly less interesting than the 

 essays. 



