Natural History. | . 179 
ham, had occasion to remark in it the existence of two substances 
not fore observed in waters from that place; and though of no im- 
partoneain a medicinal point of view, yet as relates to the sources 
from whence the waters obtain their impregnations, and to the 
istration they afford of the use of two tests suggested by Dr. 
Wollaston but not very frequently, I believe, in the hands of che- 
mists, they may I think possess interest; one .of these substances 
is nitric acid, and the other potash. ' 
__ The source from which the water was obtained is called, I be- 
lieve, the Orchard Well. It had been some time in disuse, but has 
more lately been cleaned out and deepened, and is now about fifty- 
six feet to the bottom. ‘The solid contents of a pint of this water 
examined in London were, 
Carbonate of lime . WER Bes 
Sulphate of lime . . . . . 14°5 
Sulphate ef magnesia. . . . 12°4 
Sulphate of soda Tet ae 3°7 
' Mutiateofsoda . . . . . 97:0 
129:2 
‘Besides which, the water contained a portion of carbonic acid; and 
a small quantity of peroxide of iron had settled to the bottom of 
the bottle. 
On adding sulphuric acid to a portion of this water in quantity abun = 
dantly sufficient to decompose all the salts subject to its action, and 
boiling such acidulated water in a Florence flask, with a leaf of gold 
for half an hour or an hour, the gold either in part or entirely dis- 
appeared, and a solution was obtained which when tested by pro- 
_to-muriate of tin, gave a deep purple tint. Hence the presence of 
nitric acid, originally, in the water was inferred, and that no mis- 
take might occur, a solution was made in pure water of all the 
salts except the nitrate found in the water, boiled with some of the 
same sulphuric acid, and tested by the same muriate of tin; but 
in this case no colour was afforded, or any gold dissolved. 
The potash was ascertained to be present by evaporating a quan- 
rhe the water until reduced to a small portion, filtering it and 
then adding muriate of platina in solution, Three pints of water, 
evaporated until about one ounce of fluid remained, gave an abun- 
ae precipitate of the triple salt of potash and platina. In cases 
where small quantities of the water was tried, it was necessary to 
let the liquid stand an hour or two after applying the muriate of 
platina, but the triple salt always ultimately appeared. 
__ Two pints ef the water, evaporated to dryness in a silver cruci- 
ble, gave on re-solution of the residuum a decided though very 
minute trace of silica. 
4 « N 9 
