500 abstracts: electro-chemistry 



Experiments on a vacuum galvanometer, in which a sensitivity 

 was attained which is more than 10-fold that used in the writer's pre- 

 vious work on stellar radiation, are described. W. W. C. 



METROLOGY. — Report of the tenth annual Conference on Weights and 

 Measures, May 25-28, 1915. Bureau of Standards. Bur. 

 Stds. Special Publication. Pp. 254. 1916. 



The report is a record of the proceedings of the Conference, which 

 is composed of State and local weights and measures officials and 

 weights and measures manufacturers from various parts of the United 

 States. 



The report consists of the papers presented and of the general 

 record of the conference proceedings. It includes short reports of 

 about twenty-five State delegates on the progress made in the enforce- 

 ment of local laws during the year and a report of the Bureau of Stand- 

 ards showing the progress made in the track scale tests for States, 

 railroads, and industrial corporations; papers on the methods of testing 

 track scales, on the construction of automatic scales, and on the mean- 

 ing and effect of the standard barrel law recently enacted by Congress; 

 a general discussion of legislation pending in Congress and of the 

 proper limits for suggested legislation. The tolerances and specifica- 

 tions for commercial weighing and measuring apparatus and a model 

 State law on weights and measures adopted by the conference are 

 given in full in the appendix. L. A. F. 



ELECTRO-CHEMISTRY.— The volume effect in the silver voltameter. 



E. B. Rosa and G. W. Vinal. Bureau of Standards Scientific 



Paper No. 283 (Bull. Bur. Stds. 13: 447-457). 1916. 



Some years ago the Bureau discovered that the silver deposits in 



large size voltameters were consistently heavier than the deposits 



in small voltameters which were used in series with them. The cause 



of this effect was attributed to impurities in the solution, but this 



explanation was not accepted by all the observers who have worked 



with the voltameter. Because the evidence rested principally on the 



results with the porous cup form of voltameter, Jaeger and von Stein- 



wehr thought that the effect was due to the porous cup. Richards, 



on the contrary, thought that the greater surface of the large cathodes 



permitted greater inclusions and therefore the deposit appeared heavier. 



The recent experiments of Vinal and Bovard have shown that Richards' 



