328 



TRANSACTIONS OF SECTION A. 



This value, 1-01822, differs from that obtained at the National Physical 

 Laboratory by 4 in 100,000, ours being the higher. Whether this represents a 

 real difference in the results given by the two balances, or is an actual differ- 

 ence in the electromotive forces of the reference cells used, it is impossible at 

 present to decide ; but it is hoped that co-operative work by the two laboratories 

 will enable us to arrive at a definite conclusion before the next meeting of this 

 Association. 



The instrument was designed by Professor E. B. Rosa and the entire work 

 has been done under his direct supervision. 



2. On Peculiarities in the Adsorption of Salts by Silica. 

 By Professor F. T. Trouton, Sc.D., F.R.S. 



If the adsorption by silica of salts from solution is carefully examined 

 it is found to follow different laws according to the thickness of the adsorbed 

 layer on the surface of the silica. If a curve be plotted to show the adsorption 



Fjg. 1. 



by silica for solutions of various strengths of any salt, where the ordinates re- 

 present weight of salt adsorbed per gramme of silica and the abscissae the con- 

 centration of the solution, then up to a certain value of the layer the curve 

 on the whole runs concave to the concentration axis, becoming at this point 



