the Water of the Mere of Biss. 
the presence of sulphur, which I have no doubt abounds in 
every part of the Mere. 
“ The peculiar smell of the mud gives me reason to sup- 
pose, that a great deal of hepatic air is produced ; which, pro- 
bably, uniting with the iron held in solution in the water of 
the Mere, may account for the martial pyrites found on the 
flints. 
“ By what affinity the copper wire, laid in this water, is at- 
tacked, I am not chemist enough to determine. 
“ I have begun a set of experiments, with the view of pro- 
ducing the same effects upon copper wire by artificial means \ 
but whether I shall succeed, I am not able at present to say. 
“ I am, &c. 
" BENJ. WISEMAN.” 
P. S. By experiments I have lately made, I find hepatic gas 
precipitates carbonate of iron in the form of a black flocculent 
matter; 71 parts of which are iron, and 29 sulphur. 
The silver plate I found (as Mr. Wiseman has mentioned) 
much tarnished, and in many places almost black, but I could 
not detach any part of it. I succeeded better with the wire, and 
collected a small portion of a black scaly substance, which, as 
far as the smallness of the quantity would allow it to be ascer- 
tained, was sulphuret of silver ; and was similar, in every re- 
spect, to the sulphurated or vitreous ore of silver, called by the 
Germans Glasertz. 
4 E 2 
