5 6o 



THE POPULAR SCIENCE MONTHLY. 



undertake. The inquiry was originally un- 

 dertaken at a time when it was believed that 

 the individual mind was capable of almost 

 indefinite development, if only it was proper- 

 ly trained and had coupled with it the neces- 

 sary will power to urge it on. The outcome 

 of the researches was, however, to show that 

 the mental faculties of the individual are as 

 rigorously limited by ancestral conditions as 

 are those of the body. In support of his 

 conclusions Dr. Galton has examined the kin- 

 ship of a number of men who have attained 

 eminence in various fields of labor, and has 

 shown that the number of relatives who 

 have been above the average are greatly in 

 excess of the number of such relatives that 

 would exist if there were no causal relation. 

 The classes of eminent men passed in review 

 comprise the English judges, statesmen, 

 great commanders, literary men, men of sci- 

 ence, poets, musicians, painters, divines, 

 senior classics of Cambridge, oarsmen, and 

 wrestlers. While the range of Dr. Galton's 

 inquiries is necessarily limited, his main posi- 

 tion seems to be established and all our later 

 knowledge is in the direction of its support. 

 The important bearing of this research is 

 upon the future of the race, and Dr. Galton 

 therefore discusses the relation of fertility to 

 ability, and sees reason to believe that in the 

 course of evolution the race may attain a 

 level as high above the highest now existing 

 as this is above the lowest at the present time. 



ELECTRICAL PAPERS. By OLIVER HEAVISIDE. 

 Two volumes. London and New York: 

 Macmillan & Co., 1892. Pp. 560, 587. 

 Price, 80s. 



THESE volumes contain the contributions 

 of the author during the past ten years to 

 the mathematical development of electrical 

 theory. The papers have been contributed 

 to various scientific periodicals without any 

 intention originally of making them the basis 

 of a systematic treatise, but aside from a 

 few miscellaneous ones at the beginning of 

 the first volume they are of sufficient conti- 

 nuity to present the subject in an orderly, 

 logical development. The papers cover the 

 mathematical treatment of the relations be- 

 tween magnetic force and electric current, 

 the energy of the electric current, induction 

 of currents in cores, electro-magnetic induc- 

 tion and its propagation, and electro-mag- 



netic waves. The views of electrical action 

 and the propagation of electric disturbances 

 here worked out are those first propounded 

 by Clerk Maxwell, and which have in the 

 last decade come to be widely accepted by 

 scientific men, and are forming the basis of 

 all further research. Mr. Heaviside's discus- 

 sions are addressed only to the mathematical 

 physicist, and are quite beyond the lay 

 reader. They have been recognized as of a 

 high order of merit by scientific men, and 

 have taken their place as a valuable con- 

 tribution to the scientific literature of the 

 subject. 



ALTERNATING CURRENTS. By FREDERICK BE- 

 DELL, Ph. D., and ALBERT GUSHING CRE- 

 HORE, Ph. D. New York : W. J. Johnston 

 Co.; London: Whittaker & Co. 1893. 

 Pp. 325. Price, 



IN this work Drs. Bedell and Crehore, of 

 Cornell University, have undertaken to de- 

 velop the theory of the alternating current 

 in a more complete and logical form than 

 has hitherto been done. The work is mathe- 

 matical, and appeals only to the scientific 

 student of physics. The authors divide their 

 treatment into two main divisions, in the first 

 of which the problems of an alternating cir- 

 cuit are treated analytically, and in the sec- 

 ond graphically. In each mode of treatment 

 the simpler cases of circuits containing re- 

 sistance and self-induction only, and resist- 

 ance and capacity only, are first taken up, 

 and then the more complex cases "of circuits 

 containing resistance, self-induction and ca- 

 pacity, and resistance and distributed capaci- 

 ty are considered. The solutions obtained are 

 of universal application, though for the sake 

 of clearness the authors give numerous ex- 

 amples of the application of the general 

 formulas. Parts of the work have appeared 

 as separate papers in various scientific peri- 

 odicals, and have met with very favorable 

 reception from scientific men. 



AN ATLAS OF ASTRONOMY. By Sir ROBERT 

 STAWELL BALL. A Series of Seventy-two 

 Plates, with Introduction and Index. New 

 York : D. Appleton & Co. Price, $4. 



HAVING received an invitation to prepare 

 a new astronomical atlas, Prof. Ball under- 

 took the work with the view of supplying an 

 elementary series of maps, such as had been 

 asked for by the readers of his Starland. 



