eit ae 
exceedingly hard, and had a fmart alkaline tafte. When broken 
it looked black in the fra€tured part, and vifibly contained pretty 
large pieces of charcoal. 
To find the proportion of fixed air in this fubftance, having 
reduced a quantity of it to fine powder, I poured on an ounce 
of it a fufficient quantity of marine acid, and found it to lofe by 
the action of this acid 80 grains of its weight, confequently 
one pound troy of this fubftance contains 960 grains of fixed 
air, (mixed with a little that had an hepatic fmell) that is exactly 
* of its weight. Other parcels contained fomewhat more, and 
others fomewhat lefs. 
As this fubftance evidently contained fome parts that were 
foluble in water and fome that were infoluble therein, to dif- 
cover the weight of each I poured on one pound of it 
reduced to fine powder thirteen pounds of water moderately hot, 
fucceffively ; this water had previoufly been boiled and filtered, 
and contained no other impurity than a flight trace of common 
falt. This quantity of water was neceflary to exhauft all the 
foluble matter in the barilha. 
Tue folutions were taken in fix different portions, none of 
them: betrayed the fmalleft mark of fulphur, of which I was 
aflured by trying them with the nitrous folution of filver, nor 
did the Pruffian alkali difcover any veftige of iron, 
By eighteen fucceflive evaporations and cryftallizations, I ob- 
tained 4881 grains of faline matter, the different fpecies of which 
I fhall prefently mention, and 2903 of infoluble matter. 
Ir 
