i S z Analyjls of the Air. 
Experiment LXVII. 
By the fame means alfo, I found plenty 
of air might be obtained from minerals. 
Half a cubick inch, or 158 grains of New- 
cafile coal \ yielded in diftillation 1 80 cu- 
bick inches of air, which arofe very faft 
from the coal, efpecially when the yel- 
lowifh fumes afccnded. The weight of this 
air is 5 1 grains, which is nearly j- of the 
weight of the coals. 
Experiment LXVIII. 
A cubick inch of frefh dug untried Earth 
off the common, being well burnt in diftil- 
lation, produced 43 cubick inches of air. 
From Chalk alfo I obtained air in the fame 
manner. 
Experiment LXIX. 
From a quarter of a cubick inch of An- 
timony , I obtained 2 8 times its bulk of air. 
It was diftilled in a glafs retort, becaufe it 
will demetalize iron. 
Experiment LXX. 
I procured a hard, dark, gray Tyrites, a 
\ yitriolick mineral fubfance, which was found 
7 feet 
