(152) , 
. neither from rotten or putrified Wood ; the adlive Salts , bjr 
whole combination the Alcaliis piodueed, being either expi- 
rtid or evaporated. 
T^ext, I am to enquire, How the Fire produces this^/# 
cdi: Whether by the changing of one fmgle prae-exifting 
principle ; or by enabling any among them to make fo notable 
an alteration upon or antheoiher; or lartly, Whether it is 
effeded by the Union of twoortnoreaftive principles,which 
thereby become different from what they were before the faid 
Combination? _ 
i fhall not at prefent trouble you with the Reafons, Expe- 
riments, and Obfervat ions, which have induced me to rejeft 
the former; but, briefly fuggeft tbofe , which incourage and 
difpofe me to believe and affent unto the latter: So that this 
is my Pofition ; That, Alcali Salts do refuU from the Combine* 
tion or Union of the Saline ani Sulphureous Principle. But, 
whether it is the or A/W Salt, which combines with the 
Oyl or Sulphur, is now the fubjeft of our Inquiry. The 
enfuing Confiderations feem to determine in favour of thc^- 
cids, 
Firjly Tartar, which is fenfibly Acid, and from which a 
Volatil Salt cannot be feparated by any commonly known me- 
thod, by bare Calcination becomes a ftrong and perfeft 
Jlcali. Secondly ^ Niter, an undoubted Acid with a fmall 
proportioji of Mineral or Vegetable Sulphur, is converted 
into a genuin fiery Alcali. Hoirdly^ Niter, which is made 
by the affufionof an Acid Spirit upon anAlcali^ may be al- 
moft totally diftill'd into an Acid Spirit, there appearing not 
the leaft foocftepscf a Volatil Salt, and fcarceany of the Al- 
cali , out of which it was chiefly produced. 
But thefe are very weak and inconfiderable , compared 
with Arguments, which /^^r^i^SV^^^ me to believe, that it emer- 
ges from the Union of the Salt with the Oleaginous or 
Sulphureous Principle. For, 
r. There feems to be a great Contrariety between Acids and 
Alcalies : Being mixt, they heat, fight and mortifie each o- 
ther^ what foever one difTolves, the other precipitates: 
-Whereas, were the Salt of AlcaJies pfa nature approaching 
to 
