M I N E R A L O; G -Y. 
Fall to pov/der in the air, which is 
effedted by nothing elfe,- than that 
they eafily lofe their humidity. 
S.- Mixed' with the vitriolic acid, it 
makes the fal mirabile. 
It melts eafier, and is fitter for pro- 
ducing the fal commune regeneratum-^ 
nitrum cubicum^ &c. Perhaps it is 
alfo more conveniently applied in the'' 
preparation of feveral medicines, 
f o. It is fome what volatile in the fire 
SECT. CXXXVIL 
a. Mixed with a fmall quantity of the cal-^’ 
careous earth, Alcali falis communis terr^' 
calcar ea parvd portione combinutim. 
phronitrum. 
^ This fait is not met with pure in Europe, but it is faidi 
be found in both the Indies, not only in great quantity, but 
likewife of a tolerable purity : it is there collefled in form of 
an efflorefcence in the extenfive deferts, a profitable trade being:, 
carried on in it for the making of foap and glafs : and there** 
fore it is very probable, that the antients meant this fait by? 
their nutrow^ or Baurach; The calcareous earth is fufpecled 
either to contain this fait in its own compofition, or elfe to be 
able to generate it from itfelf : but this hypothefis cannot be 
demon Ufa tedv It is more probable, that the heat of the fua- 
ilnder the equator, and in the Countries on both fides of 
evaporates the humidity, and afterwards expels the acid out of 
forne common fait, which either is naturally mixed with the 
earth, or elfe has been depoilted there through the means of 
certain decayed vegetables, that always attraft this (alt 1 be- 
ca'ufe an earth from Palefdne, which Dr, Hafielqoill fome years 
ago fentto Sweden, as a matrix of the natron,, did upon trial 
yield nothing but a common fait:, and it mighh perhaps, have 
been taken at fuch a great depth, that it had not yet fuifered 
any decompofition. But this matter wants to be more illuf- 
trated by obfervations, which might be bell made in the Eaft- 
Indies, where the greateft quantity is to be had^. and alfo bj 
feme farther analyfes of the fubitance. 
This 
