144: Scientific Intelligence. 



that some of the reactions expected to take place in this process 

 are absolutely impossible. — them. Neios, cxii, 265. i-i. l. w. 



4. An Introduction to Chemical Analyses, by Elbert W. 

 Rockwood. Svo, pp. 247. Philadelphia, 1913 (P. Blakiston's 

 Son & Co.). — This is the fourth revised edition of a work which 

 is intended for the use of students of medicine, pharmacy and 

 dentistry. The first part deals extensively with qualitative 

 analysis and gives, besides the usual metal and acid analysis, the 

 reactions of a considerable number of important organic sub- 

 stances, including a few of the alkaloids. The second part takes 

 up volumetric analysis, giving some of the more important 

 methods, while the third part deals with applied analysis, includ- 

 ing a fairly extensive course on sanitary water analysis, and brief 

 courses on the detection of poisons and blowpipe analysis. The 

 book appears to be well written and accurate in its statements, 

 and it seems to be well adapted for the purpose in view. It 

 would seem, however, that although the courses laid out give a 

 certain amount of practice in weighing, the book would have 

 been improved if a little gravimetric analysis had been included. 



H. L. W. 



5. Laboratory Manual, Arranged to Accompany " A Course 

 in, Chemistry" by William McPherson and William Edwards 

 Henderson. Svo, pp. 141. Boston, 1915 (Ginn and Company. 

 Price 60c. net.). — This book is a suitable companion to the 

 authors' well-known text book and it gives an excellent series of 

 experiments for laboratory work in connection with the study of 

 elementary chemistry. The experiments are very well chosen 

 and they are clearly described. The course laid out is rather ex- 

 tensive, and it includes a good proportion of quantitative exercises, 

 but the book may be used satisfactorily for shorter courses by 

 making proper omissions. H. L. w. 



6. Fluorescence and Resonance of Sodium Vapor. — In addi- 

 tion to the facts summarized in the last number of this Journal, 

 R. J. Strutt has recorded in another article the details of the 

 experiments which led to the following results : 



(a) When sodium vapor is excited by the D lines the centers 

 emitting resonance radiation lose their ability of sending out 

 light of observable intensity at the instant when they leave the 

 beam of stimulating radiation. Although this phenomenon had 

 been previously obtained by Dunoyer, the experimental procedure 

 of Strutt was not open to the objections which could be raised 

 against the method followed by the earlier investigator. In com- 

 menting on this phenomenon the later writer lays stress on the 

 facts that electrical excitation is persistent whereas fluorescent 

 stimulation is not so. Strutt says : " This will appear still more 

 remarkable and anomalous if we compare the behaviour of sodium 

 emitting the D line with mercury emitting the ultra-violet line at 

 X2536. Mercury through which the electric discharge is passing 

 emits this line along with the rest of the arc spectrum, and con- 

 tinues to do so for a time when distilled away from the place of 



