PHYSICAL axp LITERARY, 231 
wholly converted. into air; a part of which 
is probably joined to the alkali. In the 
 fecond, the acid is not properly feparated,, 
but rather deftroyed by the fre: A con- 
fiderable portion of it is converted into an 
inflammable fubftance ; and we learn 
from Dr Hales, that the bodies of this clafs 
contain alarge quantity of fixed air. 
Wa EN we confider that the attraction 
of alkalis for fixed air is weaker than that 
of the calcarious ear ths, and reflect upon 
the effects of heat in chymiftry, we are 
led to imagine, that alkalis might be en- 
tirely deprived of their air, or rendered 
“perfectly cauftic, by a fire fomewhat weak = 
er than that which is fufficient to produce 
the fame change upon lime; but this opi- 
Rion ‘does not feem agreeable to experi- 
: enée. ald, us 
lopas alkalis do, however, acquire fome 
dere of caufticity in a ftrong fire, as ap- 
pears from their being more eafily united 
of wine after having been kept 
Jour 
— for fome time.» For that ima 
C 
