2)4 Mr. Majfey on Saltpetre. 
fort of faltpetre, which is fold to government for 
three-pence halfpenny per pound, and carried to 
the arfenal to be refined. 
The liquor remaining in the bafons, when'the 
faltpetre is cryftallized, is called Eau Mere , or 
mother water, and is poured upon the earths 
in fmall quantities, when difpofed in the tubs 
for elixiviation ; though fome makers think it 
beft to dilute it with water, and percolate it 
through a frefh bed of wood-afhes. The earths, 
when difeharged from the tubs, are thrown 
afide to dry under an hovel, and when dry, 
are fpread, about a foot thick, to receive the 
feummings, eau mere , putrid urine, or any 
other putrid liquor, they can get to throw upon 
them, and in a few months, we are told, are 
fit for ufe, a fecond time, particularly, if now 
and then turned over. 
To improve the colour of this faltpetre, and 
to cleanfe it ftill more from the marine fait, 
two thoufand weight is thrown into a large 
boiler, with one demiqueu of water, in which 
it difiolves, and, in the courfe of the boiling, 
another demiqueu is added by pailfuls, which, 
every .time it is thrown in, raifes a thick feum 
that is carefully removed. And now, the evapora¬ 
tion being pretty far advanced, and the marine fait 
taken out as before, a large pitcher of whites of 
eggs, or of a folution of ifinglafs or Englifh glue, 
is poured in, and well ftirred~up in it, which raifes 
a thick 
