454 Scientific Intelligence. 



lead ; lead is not entirely absent from the product, but its spec- 

 trum is very faint. They observed that the active substance 

 obtained does not give rise to induced radio-activity, nor to anv 

 appreciable emission of penetrating- rays, but they noticed an 

 extremely minute disengagement of radium emanation. A por- 

 tion of the solution was utilized for a study of the gases disen- 

 gaged. Bubbles were observed to come off continuously from 

 the decomposition of water by the a-rays of polonium, and the 

 product given off in 100 days was purified from ordinary gases 

 and found to consist of 1*3 cu. mm. of practically pure helium, an 

 amount which agreed closely with the calculated quantity. This 

 work establishes the production of helium from polonium. A 

 curious effect of the rays was observed. The polonium product 

 was kept dry in a small quartz capsule, and this was found to be 

 cracked in a large number of places under the substance, pre- 

 sumably dn account of electric discharges. An abundant disen- 

 gagement of ozone was noticed in the neighborhood of the sub- 

 stance. — Comptes Rendas, cl, 386. h. l. w. 



2. Introduction to General Chemistry, ; by John Tappan Stod- 

 dard. 12mo, pp. xviii, 432. New York, 1910 (The Macmillan 

 Companjr). — This is a text book of moderate scope, intended for 

 a first year's work in chemistry. The author has endeavored to 

 give the student a fair idea of the nature of chemical study, of 

 the methods by which our chemical knowledge has been gained, 

 and of the relations which chemistry bears to every-day experi- 

 ences and to industrial activities. He has aimed to develop the 

 subject in a natural manner, introducing new facts and ideas 

 gradually, and discussing their relations and the theoretical 

 explanations at points where such discussions will be welcomed 

 by the student as summing up and interpreting what has gone 

 before. The quantitative relations of chemistry have been 

 emphasized by frequent reference to a little book dealing with 

 simple quantitative experiments, which the author has recently 

 published. The synthesis of sulphuric acid and the study of its 

 composition is made the basis for the study of other acid sub- 

 stances, thus placing sulphuric acid, in the development of the 

 subject, in a position which it occupies in actual practice, and in 

 general, substances which are most familiar, or from which others 

 are derived, are first described, and the other related substances 

 follow somewhat in the order of their importance. 



The book appears to be an excellent one in its clear and interest- 

 ing presentation of facts and theory. A noticeable feature is the 

 entire absence of pictures and of detailed descriptions of experi- 

 ments. Their equivalent is expected to be supplied in the lec- 

 ture-room and the laboratory, or by means of the author's little 

 book, previously referred to. h. l. w. 



3. iJie Beziehvngen zwisc.hen Faroe und Constitution beiorgan- 

 ischen Verbindungen ; von Dr. H. Ley. 8vo, pp. 364, Leipzig, 

 1911 (Verlag von S. Hirzel). — This book discusses very fully and 

 satisfactorily the present facts and theories in connection with the 



