on the fpecijic Gravities, &c. of Saline Sub ft nces. 2 ’3 
eafily attracted by the dephlogifticated part of the common 
atmoiphcre, which is immediately imbibed by the water out of 
which its air had been boiled ; the phlogifticated air is thereby 
decompofed and partly turned into fixed air, which makes the 
lime-water turbid. Part alio of the fixed air is decompofed as 
will prelent ly be feen, and hence the degree of purity which it 
acquires. Further, if the eledlric (park be taken in fixed air, 
three- fourths of it will be rendered infoluble in water, and the 
whole will probably become fo if the operation be long 
enough continued. 1 pr. 248. This infoluble refiduum Mr. 
fontana found to be phlogifticated air; and that, if this 
phlogifticated air be agitated in water (whole furface is expofed 
to the atmofphere) it will become again common air. Recherches 
Phyjiques , 77. That is, it will acquire a degree of purity 
nearly the fame as that of common air. This fully confirms 
all that has been hitherto faid concerning thefe airs '; fo alfo, if 
a mixture of filings of iron and fulphur, made into a pafte, 
be expofed to fixed air, and made to ferment, part of the fixed 
air will be turned into phlogifticated air, 3 pr. 257. Juft as- 
i‘n another equally curious experiment he found, that vitriolic 
air was converted into fulphur by the gradual exhalation of 
phlogifton from a folution of that air in water, and as it daily 
happens in the hot baths at Aix la Chapelle. And hence we 
fee, that fixed air, even in its elaftic ftate, is capable of taking 
an excels of phlogifton, when this laft is infenfibly feparated 
from any fubftance, and then becomes phlogifticated air. Phlo- 
gifticated air may alfo be formed by a rapid and copious afflu- 
ence of phlogifton, in certain circumftances, as we (hall foon 
fee I fbould not omit, that phlogifticated air, after it has 
been purified from phlogifton by agitation in water, is again 
dimmiftiable by phlogiftic procefles, and that fixed air is preci- 
o pitatedi 
