Springs at Lemingion Priors. 193 
IX. MANGANESE EXPOSED TO HEPATIC 
GAS. 
To complete the demonstration, it is necessary to 
examine the action of hepatic gas upon manganese. 
1. I digested some black oxyd of manganese in 
hepatised water: it had been previously purified, by 
being boiled repeatedly in distilled water.* The 
hepatic smell of the gas is quickly impaired; and, 
in twenty-four hours, if enough of the oxyd has 
been used, it is perfectly destroyed; still the liquor 
has a peculiar smell, which can hardly be called of- 
fensive: no gas is extricated in this process. The 
liquor, after filtration, was examined by the same 
reagents as the hepatised solution of iron (viit. 1.) 
with nearly a similar result; a minute quantity of 
sulphuric acid was detected ; prussiat of potash gave 
a small white cloud, tincture of galls a slight yellow 
tinge. Repeating the experiment with gas extricat- 
ed by muriatic acid, there was, in this case, no trace 
of sulphuric acid, and the liquor was not at all ren- 
dered turbid by prussiat of potash. From both 
these solutions pure potash separates a very minute 
white precipitate. 2. But, in one respect, these so- 
lutions differed from the solutions of iron; for, by 
* The readiest method of purifying this substance is, to 
boil it first in a very large quantity of rain water; after 
which, a single boiling in distilled water will be sufficient 
to extract every soluble impurity. 
VOL. V. AA 
