| on the Terra Ponderofa, &c. 295 
Hence it 18 probable, that its lofs of tranfparency was rather 
eccafioned by numerous fmall crack, than by any efcape of 
the water of cryftallization, or of its aérial acid. 
EXPERIMENTS. 
A. 500 grains, diffolved in muriatic acid, in fuch a manner 
that nothing but elaftic fluid could efcape, loft in folution 104. 
grains, and there remained an , moluble refiduum of eis 3 
grains. ee be : 
2. In another experiment 100 grains loft in folution 27, 
| grains, and there remained 0,6 of a grain of infoluble matter. 
_B. 100 grains diflolving 1 in dilute muriatic acid, gave out 25 
| ounce meafures of air. This aif was received in quick filver, 
and when the {par was wholly diffolved,. the folution was 
| boiled, in order to drive out what air might be lodged i im ‘ite 
2. This air was heavier than atmofpheric air; it was readily ~ 
abforbed by agitation in water, it precipitated lime from lime=. - 
water, and it extinguifhed flame. The water which, had ab-. 
forbed it changed the blue colour of litmus’ flowly * toa red; : 
fo that this elaftic fluid was undoubtedly fixed air. a6 
C. The folution (B) by the addition’ of mild’ foffil’ fixed 
alkaly, afforded a precipitaté which, after proper oo pig ‘ 
drying, weighed 100 grains. 
De = precipitate, Wes being ae diffolved i in marine 
pads @ 
.* Other acids turn the blue of litmus inftantly to a red, whilft water, | ‘imprega- 
died with fixed’ air; ‘does not change the litmus immediately ;° but, after fome 
Seconds, the red cotour begins’to appear, and then gradually grows more diftinch, . 
F ia v : rs x 
EW 4 sin Ret D: To. 
: “y i 3 
a Breit? ¥ spa e> J J ; Piphy 
oe | 
ee | 
. 
