296 Dr. Pearson's Experiments for 
add, that accidentally I found this powder, red hot, decom- 
posed water as charcoal does. 
The above filtered liquid was evaporated to one pint, and 
shewed signs of acidity : to it was added muriated lime till it 
produced no further precipitation. The dried precipitate 
weighed 130 grains, and was found to be phosphoric acid com- 
bined with lime ; and the liquor, in which this precipitation 
took place, was ascertained to be muriated and acetated fossil 
alkali, with a little redundant acetous acid, and a small por- 
tion of phosphoric selenite. 
The grey and white alkaline matter, with bits of melted glass, 
weighing 358 grains, as abovementioned, by solution in con- 
centrated acetous acid, afforded 41 ounce measures of carbonic 
acid, and a residue upon the filter, which, when well dried, 
weighed 44 grains. This residuum consisted of rough, sharp- 
pointed, black and white particles; it was much specifically 
heavier than the residue of the other part of the alkaline matter 
abovementioned to have been examined ; it deflagrated a little 
on being thrown upon boiling nitre, but left above \ of its weight 
of matter insoluble in water, and which I supposed was vitri- 
fied. The filtered liquor from these 358 grains of alkaline 
substance yielded to the precipitant muriated lime 21 grains 
of phosphoric selenite. 
To satisfy myself still further, that carbonic acid had been 
destroyed in this experiment, and to form some estimate of the 
quantity which had disappeared, I separated it, by concen- 
trated acetous acid, from 400 grains of mild alkali, taken from 
the same parcel as that was which afforded charcoal, and I 
found the quantity to be 104 ounce measures, or 2 6 ounce mea- 
sures in each 100 grains of mild alkali. 
