Transactions of the Geological Society, 1st series, vol. 1/On the Decomposition of Sulphate of Iron by Animal Matter

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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 unnoticed for about a twelve month. 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, together 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 the bottom of the vessel a sediment consisting of the bones of several mice, of small grains of pyrites, of sulphur, of crystallized green sulphate of iron, and of black muddy oxyd of iron. These appearances may with much probability be attributed to the mutual action of the animal matter and the sulphate of iron, by which a portion of the metallic salt seems to have been entirely deoxygenated.