188 ESSAYS anp OBSERVATIONS 
WHEN I firft tried this experiment, I 
was atthe trouble of digefling the mixture 
in the heat of boiling water, and did not 
then know that it would fucceed in the 
heat of the air. But Dr Alfton, who has 
obliged the world with many curious and » 
ufcful difcoveries on the fubject of quick- 
lime having had occafion to repeat it, I 
learned from him that heat is not neceflary; 
and he has moreover added an ufeful pur- 
pofe to which this property of magnefia 
may be apphed; I mean the {weetening 
of water at fea, with which lime may 
have been mixed to prevent its putrefac- 
tion. 
THaT part of the dried powder which 
does not diffolve in fpirit of vitriol, con- 
fifis of the lime feparated from the water, 
Quick-Limzitfelf isalforendered mild 
by magnefia, if thefe two are well rubbed 
together and infufed with a fmail quantity 
of water. 
By the following experiments, I pro- 
pofed to know whether this fubftance 
could be reduced to a quick-lime. 
ody 
