204 Animal Calculus. 
4. If Air do noc ari(e briskly from the Cal- 
cultis^ upon pouring on any of thefe Mixtures, 
the Rule to adjuft the Proportions accurately, 
is to drop in a few Drops of Oil of Sulphur ; 
if this Addition make more Air arife from the 
CalculuSy it is a fign (ome of it was wanting^ 
but if more Air does not arife, then it is a fign 
that more Solution of Sal Tartar is wanting. 
y. It fermented beft, when half the Water 
was poured on the Solution of Sal Tartary 
and the Spirit of Sulphur was dropped into 
the other half, and then both Mixtures pour- 
ed together. Warm Water was better than 
cold, tho* it fermented longer cold. 
6 . When there was a double Quantity of 
Oil of Sulphur, I have not found it more pow- 
erful in difTolving, and^when the Solution of 
Sal Tartar was much ftronger the Ferment 
was lefs. 
7. This Liquor has no EfFeft on the Calcu- 
lus after the Ferment is over, as I have found 
by laying feveral Calculi to foak in it for a 
whole Year. So that the Effeft it has on 
the Calculus while it is fermenting, Teems not 
to depend on the Ficnefs of the Particles of 
the Menftruum to enter the Pores of the Cal- 
fulus^ but rather to certain harmonic Pro- 
portions 
