80 Scientific Intelligence. 



determinations, wliere it is necessary to take into account even 

 the ainoiiiit of silver cliloride dissolved in cold water. G. S. 

 WniTHY of tiie Royal College of Science, in London, has found 

 a very delicate reaction for this purpose, which consists in adding 

 sodium hydroxide and an organic substance, preferably cane 

 sugar, to the silver solution and heating. He takes 50'='' of the 

 liquid, adds a drop of rather strong sugar solution, places the 

 150'^'= beaker containing the liquid in a boiling water bath for 

 2 minutes, then adds 6 drops of a normal solution of sodium 

 hydroxide, and heats for 20 or 80 seconds longer. The yellow 

 color produced, which appears to be due to colloidal silver, is now 

 put into a Nessler tube and compared with colors produced in 

 the same way from known amounts of silver. The colors are 

 accurately proportional to the quantities of silver present, and in 

 this way it is possible to determine 0-000002 g. of the meta'l in 

 50'='=, or 0-00004 g. in a liter. The author considers the delicacy 

 of the reaction to be about the same as that of the nephelometer 

 method of Richards and Wells, but he thinks that it is more 

 easily and quickly carried out, and involves no complications. — 

 Zeitschr. anorg. Cheni., Ixvii. h. l. w. 



3. Beryllium Formates. — It has been found by S. Tantar that 

 when beryllium carbonate is dissolved in an excess of formic acid 

 the normal formate Be(CH0j2 is formed, which is stable upon 

 evaporating the liquid even at a temperature of 100-110° C. 

 This behavior is entirely different from that of the acetate, pro- 

 pionate and isobutterate, which are all basic salts correspond- 

 ing to the acetate ^Q^(C^fi^^, even when anhydrous acids are 

 employed and the evaporation is carried out at a low tempera- 

 ature, and in order to obtain normal salts of these acids it is nec- 

 essary to heat the basic salts in sealed tubes with mixtures of the 

 anhydrous acids and their anhydrides. The normal formate, 

 however, is partly hydrolized with the formation of a basic salt 

 upon boiling with water, and when the dry salt is heated under a 

 diminished pressure of SO-So"""^ decomposition takes place and 

 the basic salt Be^O(CHO,Jj sublimes. Another organic salt of 

 beryllium is thus added to the list of its remarkable compounds 

 which volatilize without decomposition. This basic salt was pre- 

 pared in another way, by boiling a solution of the normal formate 

 with the calculated quantity of the carbontate. — Berichte, xliii, 

 1230, H. L. w. 



4. A Recalculation of the Atomic Weights ; by Frank Wig- 

 GLESWORTH Clarke. 8vo, pp. 548. Washington, 1910. Pub- 

 lished by the Smithsonian Institution. 



This is the third edition, revised and enlarged, of Dr. Clarke's 

 well-known work, which first appeared in 1882. There is no 

 doubt that the previous editions, in making manifest the imper- 

 fections of many of the data, and in pointing out in what direc- 

 tion new work was needed, have had a most important influence 

 upon recent activity in atomic weight research. This recent 

 work has been so extensive and important, particularly that of 



