678 report— 1884. 



CaCSj, together with a large excess of water. The solution of calcium sulpho- 

 carhonate in water gave with hydrochloric acid a red oil, probably sulphocarbonic 

 acid, described by Berzelius and Zeise, dark brown precipitates with solutions of 

 bismuth, stannous, lead, copper, mercurous, silver, platinum and gold salts, olive 

 green solutions with nickel and manganese salts, with zinc salts golden white- 

 precipitates. These substances, some of which have been described by Berzelius, 

 are presumably the sulphocarbonates of the various metals. The author hopes 

 shortly to enter into a more minute examination of the composition and chemical 

 properties of these substances. 



11. On the Action of Sulphuretted Hydrogen upon Silver. 

 By Professor F. P. Dunnington. 



In view of the rapidity with which silver decomposes sulphuretted hydrogen 

 under ordinary conditions, it appeared of interest to ascertain what would take- 

 place if water was completely excluded. 



Three experiments were made under varied conditions, the results of which 

 indicated that it was peculiarly difficult to remove all the moisture from the silver- 



A fourth experiment was made as follows : — a piece of pure silver was- 

 flattened and carefully polished on each face, this was placed in the middle of a 

 two-foot glass tube, in each end of the latter was put a plug of five inches of 

 phosphoric anhydride, confined by glass wool. Pure dry hydrogen was slowly- 

 passed through this tube while it was gently heated throughout, the hydrogen was 

 then removed by a Spreugel pump, the silver being heated to about 300° 0. ; again 

 dry hydrogen was let into the tube, and again exhausted while the silver was 

 heated ; again hydrogen was let into the tube, and then pure dry sulphuretted 

 hydrogen was slowly passed through the apparatus for an hour, and the tube 

 finally drawn off and sealed at each end so as to leave the silver confined between 

 the plugs of phosphoric anhydride. After several days the silver was darkened 

 only a little near its edges, and after five months (as exhibited to the Section) the 

 silver is blackened on its edges, while the main portion of the surface is still white. 



Attention is also drawn to the fact that when the silver was heated to about 

 300° C, and the pressure removed, the brilliant polish of the silver was destroyed 

 by a blistering of its surface, no doubt due to the oxygen which had been occluded.. 



From the above we may infer that in absence of water silver does not decompose 

 sulphuretted hydrogen at common temperatures. The foregoing work was conducted 

 by Mr. J. M. Cabell, a student in my laboratory. 



SATURDAY, AUGUST 30. 



The Section did not meet. 



MONDAY, SEPTEMBER 1. 



The following Beports and Papers were read : — 



1. Report of the Committee upon the present state of ottr Immoledge of 

 Spectrum Analysis. — See Reports, p. 295. 



2. Second Report of the Committee on Chemical Nomenclature. — 

 See Reports, p. 39. 



3. On Coal-Tar Colouring Matters. By W. H. Perkin, Ph.D., F.B.S. 



