234. ESSAYS anp OBSERVATIONS 
_of the precipitated marble were not owing 
to a lime into which the marble was con- 
verted, but to the alkali itfelf which was 
added, itis proper to obferve, that I mix- 
ed fo fmall a proportion of the ley with 
the folution of marble as made me ire: 
from certain experiments, that the whole 
of the alkali was fpent in performing the 
precipitation, and was confequently con- 
verted into a neutral falt by attracting the 
acid. The properties therefore of the 
mixture can only be referred to a lime, 
as is indeed fufficiently evident from the 
cruft which is peculiar to lime-water. 
I was therefore affured by this experi- 
ment, that an alkali does really lofe a part 
of its air, and acquire a degree of cautti- 
city, by the proper application of heat 5 
but finding, by feveral trials, that the de- 
gree of caufticity which it had thus ac- 
quired was but weak, and that the quick- 
lime produced in this experiment was ex- 
bauited and rendered mild by a fmall 
quantity of water, I expofed the crucible, 
together with that half of the alkali 
which remained in it, to a ftronger fire, in 
order 
