192 Mr. Majfey on Saltpetre. 
acid in all vegetables and animals, which being 
rendered volatile by putrefa&ion, afiumes the 
fpecific charader of the nitrous. And that, fince 
this acid conftantly arifes in vapour from putrid 
fubftances, hence it is, that the rubbifh of old 
houfes, and of old clay walls, become impregnated 
with it, as well as thofe earths that lie in con¬ 
junction with them. 
That the recent juices of vegetables and 
animals, are, in general, perfectly neutral, we fhall 
readily admit ; but from hence, we think it does 
not follow, that they contain neither an acid nor 
alkali y as is commonly concluded; on the con¬ 
trary, we apprehend, a more juft inference is, 
that being mixty they muft necefiarily contain 
loth. It is certain, that if we throw a calcareous 
earth, or fixt fait into any of thefe juices, the 
earth or fait will be neutralized by it; which 
we take to be a proof, that it contains an acid, 
which quits the ‘weaker to join with the fironger 
alkali, according to the law of affinities. 
And the cafe will be the fame, if thefe juices 
are putrefied. If we throw a fixt fait into any 
putrid liquor, it will be neutralized by it, and 
now, if we dip a piece of foft paper into this mix¬ 
ture and dry it, it will burn like a match, in the 
fame manner as if dipped into a weak folu- 
tion of faltpetre ; which ffiows, that it not only 
contains an acid, but one of the nitrous fort ; 
and provided this liquor were perfedly putre¬ 
fied. 
