IN THE CURE OF THE STONE. 3fr 
the diiTolving virtue of fuch urine does not feem to confitl (as Dr 
Kirkpatrick and the French academifts think *) in its alcaline na¬ 
ture ; fmce we find in Mr Millar’s urine this power without that 
quality ; and fince Dr Hales has Aiown, that the potafli, which is1 
almofc the only alcaline ingredient in thefe medicines, has little ef¬ 
fect in difTolving the done f. 
Alt ho’ quick-lime appears, by its effeéïs, to have a very con- 
♦ 
Êderabîe affinity with fixed alcaline faits, yet in many refpe&s it 
differs from them and there are not wanting experiments' which 
feem to indicate an acid quality in it. Hence feveral chymical 
writers have been of opinion, that quick-lime contained both an 
acid and a fixed alcaline fait, and to the conflict between thefe op- 
pofite faits they have afcribed the ebullition and heat which is pro¬ 
duced Mien quick-lime is diflblved by pouring water upon it 
Nor is it any wonder, fay they,, that, by the affufion of water, no 
fait is got from quick-lime, becaufe its two oppofite faits are, by 
acting on each other,, deftroyed., and turned into a third fubftance,. 
which, like all magifteries, is infipid, and not diffolvable in water . 
Limie-water being mixed with fait of tartar, immediately be¬ 
comes turbid and whitifh, and after fome time lets fall a white in- 
fipid powder, which greatly refembles prepared oifter or egg fhellsj 
and the crufts of lime-water; for it is an abforbent alcaline earth 
which effervefces itrongly with vinegar and fpirit of vitriol, but is 
not diflblved by the latter.. It has been faid that this earthy powder 
which is precipitated by mixing fait of tartar with lime-water, pro¬ 
ceeds chiefly from the fait §. But the following obfervations will 
fliew that it comes chiefly, if not wholely, from the lime-water, 
1. Th e calcarious matter precipitated by mixing fait of tartar and 
lime-water, is in proportion to the quantity and flrength of the 
lime-water, but not of the fait. 
2. Soap-leys mixed with lime-water, produce the fame precipi¬ 
tation as fait of tartar, or a folution of it in common water : but it 
is 
* Kirkpatrick’s cafe ; and Mémoires de I’Acad, des fctences an, 1739 et 1740. 
t See below» No 62 £ Mayow open, cap. 14. de æltu calcis v.væ, 
I Idem ibid. § Alfton’s firft Diflertation on-quick-Jime?, edit. 2, p. C4»