7i 



SCIENCE. 



[N. S. Vol. XXII. No. 572. 



that, while our knowledge has been greatly 

 extended' in recent years, not a single estab- 

 lished doctrine has been upset. The doctrine 

 of the indivisible atom never existed even with 

 Dalton, the father of the atomic theory. A 

 belief in the ultimate possibility of the trans- 

 mutation of some at least of the elements has 

 been held as firmly by modern scientists, from 

 Faraday down, as by ancient alchemists. 

 Even the doctrine of the conservation of mass 

 in the strictest sense has not been held since 

 Maxwell's time. I am a bit sorry, therefore, 

 that Mr. Duncan does not take more pains to 

 point out that the new discoveries supplement 

 and extend established doctrines instead of 

 setting them aside, and I am particularly 

 sorry that in a book intended for the general 

 reader and purporting to popularize existing 

 scientific views, a chapter like that on ' the 

 reconstruction of the universe ' should have 

 been introduced. In this chapter, which to my 

 mind, mars a book which is otherwise valuable, 

 ■despite its enthusiasms, the impression is given 

 that modern discoveries have led us to suspect 

 that perpetual motion raay still be possible. 

 As a matter of fact, in the light of all recent 

 discoveries, there is not one iota more of prob- 

 ability that the second law of thermodynamics 

 is invalid than there was before any of these 

 discoveries had been made. In spite of these 

 criticisms, and in spite of the fact that 

 throughout the book speculation often wears 

 the air of certitude, I wish to recommend it 

 heartily, not so much to the general reader, 

 for whom it is intended, as to the scientist. 

 Every investigator whose work in a narrow 

 field has limited his outlook will find it im- 

 mensely suggestive and inspiring. Its author 

 shows himself to be a man of wide reading, 

 thorough scholarship, broad horizon and un- 

 mistakable literary talent. I do not find in 

 it one single incorrect statement of fact. The 

 features which differentiate it from books of 

 its kind are: (1) its remarkably fine treatment 

 of the periodic law in its relation to the divisi- 

 bility of the atom; (2) its popularization of 

 J. J. Thomson's Philosophical Magazine ar- 

 ticle on the constitution of the atom, a diffi- 

 cult but very successful piece of work; (3) 



its presentation of the bearing of celestial 

 phenomena upon the hypothesis of the evolu- 

 tion of the elements; (4) its statement of 

 Arrhenius's views as to the effect of light, 

 pressure and corpuscular emission upon com- 

 ets' tails, aurora borealis and other allied phe- 

 nomena; (5) its capital concluding chapter 

 on the validity of the new knowledge. 



The remaining books which deal with the 

 physics of the electron may be briefiy men- 

 tioned in the order of importance. Frederick 

 Soddy's ' Kadio-activity ' (The Electrician 

 Printing and Publishing Co., London, 1904, 

 pp. 1-214) is an attractively and ably written 

 book, the outline of which coincides closely 

 with that of Rutherford's, from which it dif- 

 fers chiefly in that it is considerably more, 

 elementary and popular. To those who find 

 Rutherford's book a trifle too difficult this will 

 be distinctly helpful. 



A. Righi's ' Modern Theory of Physical Phe- 

 nomena ' (translated from the Italian by A. 

 Trowbridge, Macmillan, 1904, pp. 1-165) is a 

 very unpretentious but thoroughly wholesome 

 little book written for the purpose of pop- 

 ularizing for the Italians recent scientific 

 work done mainly by Anglo-Saxons. It de- 

 votes a relatively larger space to the discussion 

 of electrolysis and the Zeeman effect than do 

 most of the other popular books of the briefer 

 sort. 



Paul Besson's little book, ' Le Radium et la 

 Radioactivite ' (Gauthier-Villars, Paris, 1904, 

 pp. 1-166), is written by the man under whose 

 direction the work of extracting radium from 

 pitchblende for the Curies was done. It is 

 the only book upon the subject with which I 

 am familiar which is addressed especially to 

 medical men. The earlier portion follows very 

 closely the outline of Mme. Curie's book, of 

 which it is in fact but an abridgment and 

 simplification, while the last half is devoted to 

 a statement of the uses which radium has 

 found in therapeutics. 



Baskerville's ' Radium and Radioactive 

 Substances' (Williams, Brown and Earle, 

 Philadelphia, 1905, pp. 1-161) covers about 

 the field of the last book, but differs from it 

 in presenting more of Rutherford's work and 



