The Salcs,Vitr iols and Alums,and other concrets f efolublc inAva(er,maf 
be ib mingled in the Mineral waters^as not to be well perceived there but 
in their fediments \ but the fulphurs and Bitums are alwaies obvious to be 
difcerned in the waters wherein they are, becaufe they reiide in them, ot 
fwim on them, not being capable to be mixed with them as Salts are. Of 
thefe we have perceived none in the waters that were fent yx\ Thofe that 
were Vjery hot in their fources, did not appear to us more fulphureous^ et 
more bituminous than the other. And if you meet withSulphuc or Bitumen 
in their Bafons againft the walls of their inclofures, or in their mud, poili- 
bly there are not fuch matters inflamed within the Earth that have heated 
thofe waters > it being more probable,that fuch waters contra^ their heat 
by the mixture of fome hot waters they meet with in the deep places 
where they pafs',and experience proving, that no combuftible matter takes 
iire, or any conliderable time keeps it without Airi and that^to extingui(h 
the fire of fulphurs and. bitums inflamed , there needs no more than to ex- 
clude the Air from them. And it any matter ( as Gun-powder in minesj 
takes iire ftrong enough not to be chok'd under ground, it burfts what 
covers it, thereby to be enlarged , and to take Air. 
If there be nocojiftant fubterraneal Fires, the heat of fome Mineral wa- 
ters, which continue to be hot in their fources, cannot be afcribed to them.- 
^Tis more likely, that in many places of the Earth there are hot vapors, 
the heat of which is conferv'd in deep and clofe places, where the Air hath 
noaccefsto ^ool them, and where thofe rarihed matters have not room 
enough to be more rarified, and foto become lefs hot or more diffipated. 
And that fuch hot vapor^ are the caufc of hot Springs and natural Baths, 
mi^ be confirmed hence:i.Becaufe thefe hotMineral waters do not burn the 
mouth of thofe that drink of them at theiffueof their fources, as common 
water would do heated by fire to the fame degree; Which feems to proceed 
from the thinnefs of the matter that caufes this heat in the water. And the 
flame of fpirit of wine doth not fo ftrongly burn the hand, as a live coal 
would do. 2. Becaufe the heat of Mineral waters works not upon certain 
tender fubftances> as doth that of common water, which is contraded by 
*ire in^thefame intenfenefe : For, whereas the leaves of Sorrel are 
foftn'd and quickly boyled in common water moderately heated by fire, 
they did notfo in the Mineral waters of Ne-r)» in the Country of '^mrhon^ 
which arc the hotteft in all France s but they only changed colour and be- 
came yellowilh. 3.Becaufc the Mineral waters have no greater difpofiiion 
to boyl upon the fire,thanx:ommon cold waters, there being as much, time 
requiiite for the one as the other to make theri^-boyl upon the ^x&^&c* 
Meantime, 'tis notfo obvious to know the Qualities of thefe vapors 
thus heating the Mineral waters. It feems not neceffary^ they (hould all be 
Bituminous or Sulphur eous,though feme be fo. There are many other (ub- 
fiances that grow hot- without takingfire, and the vapors. of which mix 
themfelvesin hot Mineral waters, but the qualities of which are not diC» 
ccrn'd but by the effeAs which they produce. 
As for the different Effeds of the Mineral waters, both hot, tcpid-and 
cold, in reference to H^altb^ the Parifian Academy left the obfervalions 
thereof 
