Chemistry and Physics. 379 



nitrate, then into oxide, from which the chloride was prepared by 

 ignition with sugar-charcoal in a stream of chlorine. The 

 chloride was fused in quartz tubes for weighing. 



The results gave the atomic weight 9.018 for Be or Gl, which 

 is about 1% lower than 9.1 the value accepted in the Interna- 

 tional Table. The result obtained by Parsons, in this country, 

 from the conversion into oxide of the acetylacetonate, 

 Be(C 5 H T 2 ) 2 , and the basic acetate, Be 4 0(C 2 H 3 2 ) 6 , was 9.105; 

 hence it appears that further work is needed to establish the cor- 

 rect value. There appears to be no evidence as yet that beryl- 

 lium contains isotopes, and if it does not contain them the new 

 value for the atomic weight, since it is very close to an integer, is 

 perhaps more plausible than the old one. — Berichte, 55, 4. 



h. l. w. 



3. An Introduction to the Physics and Chemistry of Colloids; 

 by Emil Hatschek. 12mo, pp. 172. Philadelphia, 1922- (P. 

 Blakiston's Son & Co.). — This is the fourth edition, entirely 

 re-written and enlarged, of a little book originating in London, 

 the first issue of which appeared in 1913. It gives an excellent 

 account of the facts and theories of this rapidly developing and 

 exceedingly important branch of physical chemistry, and it is to 

 be highly recommended for the use of those who wish to obtain 

 a clear, fundamental knowledge of this very interesting subject. 



The historical part is briefly but very well presented, and men- 

 tion is made of the work of the American, Carey Lea, whose 

 papers on "Allotropic silver" were published in this journal in 

 1889 and were evidently very important in connection with the 

 colloidal condition of the metals. No attempt will be made here 

 to discuss the presentation of the description and theoretical 

 topics except to say that this has been very well done. h. l. w. 



4. Distillation Principles and Processes; by Sidney Young. 

 8vo, pp. 509. London, 1922 (Macmillan and Co., Limited). — 

 This very comprehensive work is the successor to the author's 

 excellent book on "Fractional Distillation" which appeared in 

 1903. The latter dealt chiefly with the details, and principles of 

 small-scale distillations, such as are carried out in the laboratory. 

 A revision of this part, with the addition of a chapter on sublima- 

 tion, comprises about one-half of the new book, while the remain- 

 der of it is devoted to the following sections prepared by specialists 

 in various lines of distillation on a manufacturing scale : Acetone 

 and w-Butyl Alcohol, by Joseph Reilly and F. R. Henley; Alco- 

 hol, by F. R. Henley and Dr. Reilly; Petroleum, by James Kew- 

 ley: Coal Tar, by T. Howard Butler; Glycerine, by Lieut. -Col. 

 E. Briggs; Essential Oils, by Thos. H. Durrans. 



The book contains no less than 210 illustrations. Its very 

 elaborate treatment of the principles and apparatus of laboratory 

 distillation, together with the accounts of technical operations, 



Am. Joub. Sct.— Fifth Series, Vol. Til, No. 17. — May, 1922. 



