28 



SCIENCE. 



[N. S. Vol. II. No. 27. 



tempts to replace the chlorine by the 

 cyanogen group by treatment with potas- 

 sium cyanide under various conditions were 

 only partially successful. The acid amide 

 was converted into caffeine carboxj^Uc acid 

 and a number of salts were prepared and 

 studied. All the compounds could be ex- 

 plained by the accepted structure for caf- 

 feine. 



Shober and Kiefer describe the results of 

 a series of experiments on the decomposition 

 of metadiazobenzene sulphonic acid. They 

 find that this acid when boiled with 

 methyl, ethyl and prophyl alcohols, at dif- 

 ferent pressures, gives both the methoxy 

 and hydrogen reaction, while the corre- 

 sponding para compound gives only the hy- 

 drogen reaction. Kastle and Keiser have 

 a paper on the colorimetric determination 

 of the affinity of acids by means of potas- 

 sium dichromate. The reaction depends 

 upon the fact that when a solution of potas- 

 sium dichromate is treated with a solution of 

 sodium acetate or the sodium salt of other 

 acids, the base is equally distributed and 

 the normal chromates are formed. They 

 used as a standard a solution of potassium 

 dichromate to which a solution of tenth- 

 normal sodium hydroxide was added until 

 an equal color was obtained. Thej^ could 

 determine the amount of decomposition 

 and, assuming the affinity of potassium di- 

 chromate as 1, could calculate the relative 

 affinities of the acids. For many of the 

 acids the results agree fairly well with those 

 obtained by Ostwald ; but for some acids 

 the method could not be used. Mixter gives 

 the methods of preparation and properties 

 of some azo and azimido compounds, and 

 Noyes contributes another article on cam- 

 phoric acid. He finds that in the formation 

 of campholytic acid, from di-hj^droamino- 

 campholytic acid, by the action of nitrous 

 acid, another acid is formed, whose reac- 

 tions, along with other facts, furnish strong 

 proof that the carboxyl groups of camphoric 



acid are combined with adjacent carbon 

 atoms. He considers the two isomeric 

 campholjiiic acids to be stereoisomeric. 



An article by Wheeler contains a descrip- 

 tion of benzimidomethyl ether and its action 

 on aromatic ortho compounds . No new com- 

 pounds were obtained, as the reactions took 

 place differently from what he expected. 



Curtiss has repeated some of Nef 's work 

 on the action of ethyl iodide on silver acetyl- 

 acetone 



CH3. CO Ag 

 HC. COCH3 



and explains the formation of two products 

 by the assumption that the molecule has 

 two points about equally susceptible of at- 

 tack, namely, the silver atom and the dou- 

 ble bond between the two carbon atoms. 

 The ethyl, therefore, replaces the silver di- 

 rectly, or the ethyl iodide is added to the 

 doubly bound carbonatom. He has also 

 shown that Claisen's objection to Nef's 

 statement, that oxymethylene compounds 

 and acetacetic ether, in the free state, 

 show close analogy, does not hold, as he 

 has obtained an ester by the action of dry 

 hydrochloric acid gas on acetacetic ether in 

 alcohol. Randall contributes a report of 

 articles by Ramsay on ' The molecular com- 

 plexity of liquids.' This number also con- 

 tains obituary notices of James A. Dana, 

 Lothar Meyer and Gerhard Kriiss. 



J. Elliott Gilpin. 



NEW BOOKS. 

 Fingerprint Directories. Francis Galton. 



London and New York, Macmillan &Co. 



1895. Pp< 123. $2.00. 

 Annual Report of the Department of Health of 



the City of Chicago. Arthur R. Reynolds. 



Chicago. 1895. Pp. lix + 268. 

 A Text Book of Phjsiology. M. Foster. New 



York and London, Macmillan & Co. 



1895. Pp. xlviii-f-1183. $5.00. 



