^hus I find it defcrib'd by a Pliny^ ^ Mathielus b and ^gru 
cola.z 
Its principles I take to be chiefly two, W;^. a Sal ma- 
rine, and an urinous Salt. 
That it contains a marine feems manifeft by thefe 
experiments ^ firft becaufe a folution of the Natron has 
the fame taft that a folution of Sal marine hath i fecond- 
ly in evaporation the particles of the Natron incruftated 
upon the furface of the water as the particles of Sea-Salt 
do in evaporation. Thirdly becaule the Natron is per- 
forated, which proceeds (as I fuppofe) from a Sal ma- 
rine, for that whenit cryftallizeth, ftioots with little ca- 
vities. Fourthly if the Natron be mixt with Salt of Tar- 
tar it emits the fame fpirit, as SalArmoniac when mixt 
with the fame Salt And lafily, that it contains a Sea-Salt 
feems plain from ^^/^///^2^/. fays he, efflorefcit etiam fpon- 
te non folum in falijiis adfimilitudinem lanuginu canefcentisy 
fed etiam in vafis in quibus fa I continetur^ 
But here it is to be noted that though the Nitrian Wa» 
ter is of a blufhy colour, and makes a brisk fermentati- 
on with an i^ cid; yet a folution of Natron looks clear 
and will not ferment with an Acid. The reafon why a 
folution of the Natron looks clear, though the Nitrian 
Water which is but a folution of the lame lalt is of a blufliy 
colour, may perhaps be this j 
I fuppofe that the water of Latron receives its rednefs 
from a red clammy lubftance, which ferves chiefly to ce- 
ment the two falts together, and this I the rather con- 
jedure becaufe after a folution of the Natron had paft 
through a filtre there ftuck to it a red clammy matter, 
and the folution was clear j and the reafon why a folu- 
tion of the Natron-^'iW not ferment with an Acid, I con- 
ceive to be this; becaufe that in a perfect diffoJution its 
parts being feparated one from another by the parts of 
the water, their ftruglings are too weak to make aneffer- 
natjjijf. (h) comment, in Dio/cor. (^c) cap, demtra. 
vefcencv 
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