78 
MINERALOG IC All 
V., .. ■^ *■,’ , 11 ■ \ ' ;• . v 1 'f ,/ ", •' 
Soap-rock from Cornwall*, 
> § i- 
One ounce of this foap-rock in pure 
pieces was heated to rednefs in a glafs 
retort. In the receiver was found a 
fmall quantity of pure taftelefs water. 
It had loft one dram 15 grains of its 
weight, and had acquired a darker co¬ 
lour, and a confiderable degree of hard- 
nefs. Pulverized and mixed with two 
ounces of fixed vegetable alkali, it was 
heated red hot in a crucible of porcelain, 
but not fuffered to melt: after this, it 
V 
was triturated with diftilled water, and a 
fuperabundant quantity of marine acid 
to faturate the alkali was added to it, 
and fufficiently digefted. 
