370 On the Saline Impregnation 
collected in glass also gave a very minute 
trace of sulphuric acid. 
Finally, L examined my rain-gage water 
collected froin the 9th to the 16th of March, 
fallea in ordinary circumstances, and found 
it to yield a very sensible trace of sulphuric 
acid, but scarcely any of muriatic acid. 
The sulphuric acid is chiefly due, Lapprehend, 
to the earthenware bottle of thegage. Ihave 
on one or two occasions collected rain water 
in the town in clean glass vessels; it gives 
no trace of sulphuric acid, but generally a 
slight one of muriatic acid, which however 
is infinitely short of what has been shewn in 
the waters above mentioned on the occasion 
of storms. It is owing, Lapprebend, as has 
been observed, to the muriate of ammonia, 
sublimed by the combustion of coals, and 
mingled with the atmosphere, which is car- 
ried down again by the rain. 
If we calculate from the last specimen of 
water furnished by Mr. Blackwall, it would 
appear that .4,, part of the water which 
descended during the most violent period of 
the storm, March 4th, was sea-water, which 
had been brought mechanically by the wind 
for the distance of at least 30 miles. How 
much further it may be carried on such oc- 
casions we have not observations at present 
