[ 359 ] 
PROPOSITION THE FIRST. 
ffle ferruginous and abforbent earths contained in the 
Pouhon water are kept dijjohed therein , by means. < 
of the mephitic air , to which tbofe earths are united.. 
I N an Inquiry concerning the nature of the mineral 
and elajlic fpirit , or air , contained in this water,, 
published in the Tranfa&ionsof the Royal Society (a)i 
it hath been (hewn ( b ), that when the pouhon water 
is excluded from all contact with the common air,, 
in fuch manner that the mephitic air which it con- 
tains has free liberty to fly from it into an empty 
bladder, this air does not feparate from the water by 
any fpontaneous motion, as it would from its rare 
texture and elaftic force, was it at liberty to exert 
thefe its qualities : but, on the contrary, in this fitu— 
ation, it remains united to the other ingredients o£ 
of the water, when expofed to the moft intenfe heat 
that we ufually obferve, in the open air, 7 in this out 
climate. 
It hath been further fliewn (cj, that this elaftic 
fluid-, when excluded from common air in the. man- 
ner before related,, is but flowly expelled from the 
pouhon water by a heat of no degrees of Eahren-' 
heit's thermometer,, although fuch heat is fufficient: 
to raife water (a much heavier body) in diftillation 
( a ) Vol. LV. p. 233. 
( b ) Experiment the iirft of the faid Inquiry., 
(c) Experiment the fecond.. 
andi 
