Mr. Maffey on Saltpetre. 203 
jmere nitrous , but a true faltpetre earth, which 
required nothing but eiixiviation with water, 
and a fubfequent evaporation, to afford him 
the cryftals of this fait ; which practice is (till 
followed by many of his fucceffors ; though, 
as it feems, without any clear convi&ion of 
their ufe ; it being a point in difpute, whether 
they are of any ufe or not. 
The author of the article Nitre, in the French 
Encyclopaedia, boldly affirms, that the juices or 
deco&ions of all fuch plants, as yield much 
fixt fait by incineration, being putrefied and 
clarified with lime, according to Mr. Bolduc’s 
method, laid down in the Memoirs of the Academy 
of Sciences for the year 1734, will yield us the cry¬ 
ftals of a true faltpetre, without the affiftance of any 
fixt alkaline fait whatever; and that at Montpeli¬ 
er, and all over Languedoc, they make faltpetre 
without ufing the leaft particle of fuch fait. Upon 
which we can only obferve, that if this be a fadt, 
it muft be very furprizing, that it is not known in 
Paris, and that the Gentlemen of the Academy, 
who, fome time ago, drew up and publifhed 
by order of their monarch, an account of the 
feveral methods of making faltpetre in all 
parts of the world, fo far as they could arrive 
at the knowledge of them, ffiould not take the 
leaft notice of it; though they have thought 
proper to record one of a fimilar nature, Mr. 
Brown’s method of making faltpetre in Virginia. 
This 
