IN THE CURE OF THE STONE. 3% 
When lime-water deftroys acids, we readily afcribe this effect 
to the alcaline earth which it contains : But to what principle in 
lime or lime-water are we to refer the precipitation which happens 
upon tlic mixture of Iiine*wäter with, u fixed älcäliue fhlt ? Does iu 
{hew that there is an acid in lime-water ? that this acid is united 
clofely with an alcaline earth, which it keeps invifibly fufpended 
in the water, but that being flrongiy attraded by the fixed alca¬ 
line fait, it leaves this earth, which then precipitates in the form 
of a white powder ? Are we to afcribe it to this acid, that fpirit 
of fat amnion, difiilled with quick-lime, has its nature fo changed, 
as not to- effervefce with acids: Does it feem probable, that certain 
Clones and animal-fhells are, by calcination, changed in quick¬ 
lime, becaufe, as alcaline earths,, they are peculiarly qualified to 
receive and unite with this acid l And may we conclude from the 
above experiment, that the adive properties of quick-lime are ow¬ 
ing to an alcaline earth heightened, perhaps, by the fire, and 
united with a fubtile acid fpirit l Whoever fhould anfwer thefe 
queries in the affirmative, would be* greatly too haffcy in his con- 
clufions ; for the following experiment will drew, that though fix¬ 
ed alcaline faits render lime-water turbid, and caufe a precipitation, 
yet their alcaline quality is not defiroyed by it« 
Having added forty grains of fait of tartar to twenty ounces, 
of flrong {lone lime-water, after fome hours, I poured off the clear 
water ; and boiled it into three ounces and a half ; when it effer- 
vefced flrongly both with vinegar and fpirit qf vitriol. Further5i 
if there was any acid in quick-lime, would a folution of potafh 
have its pungent corrofive qualities greatly heightened by being; 
poured upon it ? Ought not rather its alcaline nature to be thence: 
greatly impaired, or deflroyedd 
Mr Geoffrey thinks, that there is in quick-lime a fixed alca¬ 
lin e fait, formed of the aluminous, vitriolic, or nitrous acid of the 
flone, and of the acid in the wood or coals This fait he ima¬ 
gines to be, like the fixed alcali, united with flint and fand in ma¬ 
king glafs, fo intimately conjoined with the earthy parts of the 
lime 
> 
* Mémoires de. l’acad. des fciences 1720, edit. Svo. p. 28,