316 ESSAYS ann OBSERVATIONS 
diffolved this falt in warm water, filtred the 
folution, and poured into it ftrong {pirit of 
nitre, a little at a time, until the alcaline li- 
quor was perfectly fatiated with the acid, 
which required one ounce and a half of the 
fpirit of nitre. From this faline liquor, by 
evaporation and chryftallization, I procured 
two ounces and a-half of falt, when it was 
all collected and well dried. The chryftals 
were long, fender and prifmatical; the falt 
had a pretty mild and cooling tafte; and bits 
of it put upon a burning coal, made it fpar- 
kle and give a bright flame. 
We. may-obferve by the way, that the 
compound falt exceeded the weight of the 
fixed falt by half an ounce or 240 grains; 
this additional weight it procured from the 
fpirit of nitre:. therefore one ounce and a 
half, or 720 grains of the fpirit of nitre 
which I ufed, contain 240 grains of true a- 
cid, which is capable to fatiate four times 
its weight of alcaline fixt falt. 
I put two ounces and a half of this faGti- 
tious nitre into a fmall glafs retort, and pour- 
ed upon it one ounce of oil of vitriol, which 
immediately begun to raife an ebullition with 
heat-and red fumes; a receiver was inftantly 
joined 
