Mineral Subflance from New South Wales. sqq 
excepting a very few, and very fmall, fparkling, black particles, 
fufpedled to be thole which had eluded the adtion of the pellle ; 
it loft in weight fix grains, or one-fourth. 
The mineral, thus ground and calcined, was found to be 
juft as difficult of folution as in its crude ftate ; with this 
additional difadvantage, that the undiflolved fine particles are 
indiipofed to fettle from the liquor. 
In all the experiments of diflolution, as often as the heat 
was at or near the boiling point of the acid, frequent, and 
pretty fingular, burfts or explofions happened, though the 
matter lay very thin in a broad-bottomed glafs. They were 
fometimes fo confiderable as to throw off a porcelain cup with 
which the glafs was covered, and once to lhatter the glafs in 
pieces. Ill a heat a little below this, the extraction feemed 
to be equally complete, though more flow; but a heat a little 
below that in which wax melts, or below 140° of Fahren- 
heit s thermometer, appeared infufficient. 
To determine the degree of dilution neceffary for the preci- 
pitation of the diffolved fubftance, and whether the precipita- 
tion by water be total, a meafure of the folution was poured 
into a large glafs, and the fame meafure of water added 
repeatedly. The third addition of water occafioned a flight 
milkinefs, which increafed more and more to the fixth. The 
liquor being then filtered off, another meafure of water pro- 
duced a little freffi milkinefs ; and an eighth rather increafed 
it ; a ninth and a tenth had no effedh The liquor being now 
again palled through a filter, folution of fair of tartar did not 
m the leaft alter its tranfparency ; fo that, after the folution 
meter; and feme idea maybe formed of their value, by recollecting, that they 
commence at viable rednefs ; and that the extreme heat of a good air-furnace 
w the common conftruaion, is 160°, ora little more. 
has 
