380 



Transactions. — Chemistry. 



3. The stone, ground very fine, and afterwards subjected to 

 a red heat for two hours, gave a strong reaction of the gas 

 when placed in hydrochloric acid. 



4. When ground finely in a very small quantity of water, 

 no sulphuretted hydrogen was found in the water, and the 

 water appeared to be neutral. 



5. The gas does not appear to be present in the vapour 

 arising from the stone when heated to temperatures up to a 

 red heat. 



These facts appear to demonstrate that this gas (sulphu- 

 retted hydrogen) is retained in the stone in the free state, and 

 that at a temperature of about 2,000° F. it is not expelled. 



Had there been even a minute trace of it combined with a 

 base, the water in which the stone was pounded would not 

 have been found neutral to test-paper. 



That this gas, or that small part of it not oxidized near the 

 surfaces of the particles, adheres to the stone at a red heat is 

 remarkable, and almost goes to prove that it is occluded, and 

 adheres to the stone, in the same way that hydrogen is oc- 

 cluded and retained by red-hot palladium — that is, in some 

 manner dependent upon the exercise of chemical force. 



I have only to add here that a stone having all the quali- 

 ties of stinkstone can be prepared from certain argillaceous 

 limestones containing organic matter, by submitting them to a 

 red heat. 



The following is a statement of the composition of the 

 stone upon which my experiments were first performed : — 



* Principally clay-slate. 



t This represents about seven volumes of the gas, and this would, 

 but for some restraining influence, expand to more than twenty volumes 

 of tbe stone when heated to a red heat. It is evident that the influence 

 that keeps it in the finely powdered stone is of a very powerful nature. 



