176 Scientific Proceedings, Royal Dublin Society. 



on sulphides, viz. : — those of sodium, magnesium, calcium, and iron, but in the 

 case of the last of these, the bicarbonate was also investigated, as it is soluble 

 in water, whereas the carbonate is insoluble. 



Action of Hydrogen Sulphide on Sodium Carbonate. 



An N/10 solution of sodium carbonate was employed. 50 c.c. of a solution 

 of this were saturated with hydrogen sulphide for 24 hours, with occasional 

 shaking, and the sulphur was then determined in the solution by means of a 

 standard solution of sodium arsenite, when it was found that, after allowing 

 for the dissolved hydrogen sulphide, 28 per cent, of the sodium carbonate 

 had been converted into sulphide, according to the equation : — 

 Na 2 CO s + H 2 S = Na 2 S + C0 2 + H 2 0. 



Action of Hydrogen Sulphide on Magnesium Carbonate. 



A stream of hydrogen sulphide, after having been washed by passing it 

 through water, was bubbled through a flask containing powdered magnesium 

 carbonate. 



When all the air had been driven out of the apparatus, it was corked and 

 left for 24 hours with occasional shaking. 



10 c.c. of the solution were then removed and evaporated to dryness with 

 sulphuric acid, the remaining magnesium sulphate weighed, when it was 

 found to correspond with 0-0919 grm. MgC0 3 . The following reaction had, 

 therefore, occurred : — 



MgC0 3 + H 2 S = MgS + C0 2 + H 2 0. 



Action of Hydrogen Sulphide on Calcium Carbonate. 



Two experiments were made under somewhat different conditions, 

 namely : — 



(1). So that carbon dioxide escaped. 



(2). „ „ ,, „ did not escape. 



(1). Hydrogen sulphide was passed through water in which - 259 grm. 

 calcium carbonate was suspended in 5 c.c. water for about 15 hours, when 

 a yellow solution resulted. 



This was filtered for the undissolved portion, and the filter and pre- 

 cipitate burned, when - 1135 grm. calcium oxide was obtained, corresponding 

 with 0'048 grm. calcium carbonate, and leaving 0'048 grm. calcium oxide 

 acted upon, or about 19 per cent. 



(1a). The experiment was repeated, only as the calcium carbonate was 

 dissolved, more was added. 



Eventually it was found that 50 c.c. of the solution contained a quantity 

 of calcium corresponding with 0409 grm. of the carbonate. 



