XVIII. Notice respecting the Decomposition of Sulphate of Iron by 

 Animal Matter. 



By W. H. Pepys, Esq. F.R.S. 

 Treasurer of the Geological Society. 



As the following circumstance, that took place in my laboratory- 

 appears to throw considerable light on the mode whereby organic 

 remains become penetrated by pyrites, it may not perhaps be foreign 

 to the objects of the Geological Society, and as such, I have taken 

 the liberty of offering it to their attention. 



I was engaged a few years ago in a course of experiments on 

 hydrogen gas, which was procured in the usual method, by the 

 solution of iron turnings in diluted sulphuric acid. The sulphate of 

 iron hence resulting, to the amount of some quarts, was poured 

 into a large earthen pitcher, and remained undisturbed, and un- 

 noticed for about a twelvemonth. At the end of this time, the 

 vessel being wanted, I was about to throw away the liquor, when 

 my attention was excited by an oily appearance on its surface, to- 

 gether with a yellowish powder, and a quantity of small hairs. 



The powder, on examination, proved to be sulphur ; and on 

 pouring off carefully the supernatant liquor, there was discovered at 



