Mr. Majfey on Saltpetre 19-3 
fied, and the marine fait, with which all ni¬ 
trous leys greatly abound, carefully removed, 
we cannot help thinking that upon being boiled 
down to a due confidence it would yield the 
cryftals of faltpetre. The author muft acknow¬ 
ledge he has boiled down many of thefe mix- 
. tures without fuccefs; but it was at a time when 
he was ignorant of the necefiity of attending 
to the above circumftances. 
That all putrid fubftances, and confequently, 
their juices, are of a volatile alkaline nature, 
is not to be denied, owing to an union of their 
acid and oily parts with their earth, which 
is equally fubtilized by the putrid procefs. 
But that the two former are fafely feparated from 
the latter, by adding a calcareous earth or fixt 
fait to them, the meaneft chemift can tell us, 
the earthy or alkaline part flying off, and leaving 
the acid and oily ones combined with the earth 
or fait, with which they have a greater affinity. 
And that thus calcareous earths, by lying in 
conjunction with putrid matters, become pof- 
felfed of a volatile acid, oily mix /, which is Stahl's 
precife defcription of the nitrous acid, muft be 
clear to conviction. 
But the ftrongeft proof of the exiftence of an 
acid in putrid juices, if the earths of (tables and 
cow-ftalls do not afford an equal one, muft 
be drawn from the foil at the bottoms of graves, 
which can certainly derive its nitrous acid quality 
Vol. I. O from 
