of Saltpetre* S17 
In either case, the saltpetre must be incessantly stirred 
and shaken, that it may dry quickly and equally. 
General Remarks on the foregoing Process . 
A pretty long experience has shown us, that the pro- 
cess here described is the most simple, and the most eco- 
nomical. 
But, to spare others the trouble of trying such means 
of improving this process as have occupied our attention, 
but which we thought it right to reject, we shall submit 
to them the following reflections. 
1 . It has been tried to dissolve the crude saltpetre ; to 
crystalize it ; and afterwards to wash it, in order to sepa- 
rate the sea-salt from it. 
This process at first sight appears more advantageous, 
because it is then unnecessary to bruise the saltpetre, but 
it is attended with great inconveniences. First, the 
crude saltpetre, dissolved in fifty parts of water to a hun- 
dred, and poured into the crystalizing vessel, does not 
deposit the same quantity of saltpetre as when it i$ wash- 
ed before it is dissolved. This difference takes place, 
because the sea-salt, which exists in the crude saltpetre, 
facilitates the dissolution of the nitrate of potash; and 
consequently, the water in the crystalizing vessel must 
necessarily hold in solution a greater quantity of nitrate 
Of potash, when the crude saltpetre is dissolved, than 
when it is previously washed in cold water, and there- 
by deprived of the sea- salt it contained. Secondly, the 
washing of the saltpetre, when done after its dissolution 
and crystalisation, requires forty or fifty parts of water 
to a hundred, instead of thirty-five. 
%. It has been tried to dissolve the saltpetre in twenty 
or twenty-five parts of water to a hundred ; to take away 
the muriate of soda, as fast as it is precipitated by the 
boiling of the liquor ; to dilute this solution with ' thirty 
Yol. it. d d 
