514 
Proceedings of the Royal Society of Edinburgh. 
possibilities of the methods, values for water, which agree with the best previous determination, 
were obtained by the static method, and values for benzene and for ammonium chloride by the 
dynamic method. 
The fourth paper describes a determination of the vapour pressures of mercury. These were 
made because exact values were required for the subject of the sixth paper, and the existing results 
[eg., those of Regnault, Ramsay and Young, and others) were highly inconsistent with one 
another, and the methods used were open to serious criticism. 
The sixth paper deals with the constitution of calomel vapour, a matter long but inconclusively 
discussed by chemists. By making measurements of the vapour pressures of mercury, of calomel, 
and of a mixture of the two, and applying the laws of chemical equilibrium to the resulting data, it 
was shown inclusively that the vapour is wholly composed of mercury and corrosive sublimate. 
The close quantitative correspondence showed that in these measurements the order of accuracy 
was much higher than in any previous measurements of vapour pressures at elevated temperatures. 
The seventh paper shows that, as the laws of chemical equilibrium applied to the result bjf the 
preceding paper predict, calomel, when dried in the most rigorous manner, exercises, even at high 
temperatures, no measurable pressure whatever. This is the only successful experimental con- 
firmation of a familiar and important application of the theory. 
At the request of the Council an Address was delivered : — 
On Pigments Old and New, and their Identification in Pictures. ( With Lantern Illustrations.) 
By Principal A. P. Laurie, M. A., D.Sc., Heriot-Watt College, Edinburgh, Professor of Chemistry, 
Royal Academy. 
The following Candidates for Fellowship were balloted for, and declared duly elected : — 
Arthur Dukinfield Darbishire, M.A. ; Edmund Taylor Whittaker, Sc.D., F.R.S. ; The 
Most Hon. The Marquis of Linlithgow ; Robert Black Thomson, M.B. (Edin.). 
