Niter, conjoymng themfelves again by means of the Salt, to 
refutne their priftine forme. Nor m\\ Niter (adds he) or Al- 
lum, or Vitriol, if well purged, ever return into common efcu- 
len-t Salt. 
Yet this he grants to Kircher y that common Salt will turn 
into Niter, Alum, and Vitriol, when it hath changed its par- 
ticles by the motion of fub terraneous Fires, and lb being com- 
minuted into fmall particles hath converted its former Salt- 
tafte into a prefent acid one, yet fo as that for the compofici- 
on of Niter there muft be mixt fome r amenta of Lixiviac 
Salt 5 for that of Alum, fome r amenta of Lead 5 for that of 
Vitriol or Copperas^ fome of Iron or Copper. 
Yet however this be, he denies, that there fliould lye con- 
cealed in the Center of common or Nitrous Salt any thing 7 
that is unchangeable, coagulating and fixing all things \ be- 
caufe an Artift can without any great difficulty bring both 
thefe Salts wholly over the Helme, and reduce them into a vo- 
la til Spirit , with but a very little fediment left behind 5 and 
can aifo reduce them both into an infipid Earth deftitute of 
all venue or operation , but only that, which is a little ( but 
very little) adftringent 5 as may be feen by Blafius Vigenere* 
in his Iratt de igne & Sale 0 but by his own Experiment af- 
firmed to have been often and eafily made $ fo as that the 
moft purifyed fait, having its pungency obtunded by a fit and 
often repeated fire (whereby it may be often freed, diflfol- 
ved ? coagulated) will affect the tongue no more,than common 
Potters Earth, 
Here he cenfureth, what Kircher affirms in his Mund, Sub- 
ten, viz. That in fait, how much foever depurated , there 
will be found a true Earthy which though feemingly deftitute 
of all fait, yet being for fome dayes expofed to a clear sky 
and the Sun^ will be again impregnated with new fait. To 
which he declares, that if Kircher had continued his method 
of purging fait to the utmoft, he would have found, that the 
whole body of fait would have been at laft thus changed into a 
faltlefs Earth ; altogether inefficacious, fave a little adftringen- 
cy 5 directing withall, that he fliould have farther burnt the 
Earth, which he thought deftitute of all fait, thoroughly, 
