368 On the Saline Impregnation 
About thesame time Mr. Blackwall brought 
me a quantity of rain-water which he had 
collected in a clean glass vessel in calm wea- 
ther. It was scarcely to be distinguished 
from distilled water, being unaffected by 
muriate of barytes, nitrate of mercury, and 
as nearly as possible by nitrate of silver, 
The same remarks apply to a quantity of wa- 
ter which I procured from some recently 
fallen snow. ‘These facts demonstrate that 
in ordinary circumstances the rain is destitute 
of salt, except we may find an infinitely 
small quantity from the efluvia of burning 
fuel, which in a large town may possibly be- 
come sensible in the rain falling through the 
atmosphere, and carrying along with it par- 
ticles of muriate or sulphate of ammonia. 
On the 24th Feb. we had another storm of 
wind not much inferior in force to that of the 
5th December. This too was accompanied 
' with rain, and from the 8S. W. or W.—The 
rain, a little diluted with what fell subse- 
quently, was taken from my gage and ex- 
amined. It indicated .55 parts of a grain of salt 
in 7500 of water. A specimen which Mr. 
Blackwall favoured me with from his gage the 
same day, contained 88 parts of a grain of salt 
