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:^7. It may be well to be provided in diips with 
fome filver diffolved in aqua-fortis, mixed with 
pure rain-water, or diftilled frefli water, in the pro- 
portion of* fixty drops'to an ounce of the water: 
though it is probable it may feldom be wanted, un- 
lels in lome doubtful cafes, w'hen the tafle may not 
be accurate enough to perceive, whether there be any 
fpirit of fait in the dilblled water. 
38. Since double the ufual quantity of vapour 
may by way of ventilation be carried off, common fait 
may thus be made muchfooner, cheaper, and better ; 
becaufe, as there is much lefs fire ufed, fo propor- 
tionably, lefs of the fine acid fpirit of the fait, in 
which its virtue con fills, will be evaporated away : For 
it is well known, that the fait is beff, which has un- 
dergone the leaft adtion of fire in making. 
39. This more fpeedy method of evaporating will 
alfo be ufeful, in making many other evaporations; 
as in making pot-afii, &c. 
40. But fome are apprehenfive, that this great 
improvement in diftilling may be of ill confequence 
in making thofe deffrudtive fpirits cheaper, which 
are already but too cheap. Had not the improve- 
ment been of great benefit to mankind in many 
other refpedls, I fliould have been far, very far, 
from endeavouring after it, or difcovering it. But 
fliould the event be to make thofe fpirits cheaper, 
and confequently, by fpreading farther, more de- 
ftrudlive, the confequence of that will be, that the 
increafed raging devaftation will the fooner neceffi- 
rily roiife the nations to put a flop to what mufi; be 
done hereafter : for if the ravages continue increaf- 
ing, as they have done for fixty years paft, the liu- 
man 
