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decompounding fixed Air. 
in the calcareous earth, and between the phosphoric acid, thus 
composed, and the quick-lime of the calcareous earth. That 
the black matter produced is really charcoal, the author has 
proved by adequate experiments. The inference, however, does 
not appear to me to be just, that the charcoal and phosphoric acid 
are the necessary result of the agency of the affinities, as stated 
by Mr. Tennant. For the well known fact, that phosphorus 
cannot be produced from bone-ashes by the application of char- 
coal and heat, I think, only proves that the powers of affinity 
between respirable air and phosphorus, together with the affi- 
nity between the compound formed by their union (namely, 
phosphoric acid,) and quick-lime, are not inferior to the joint 
affinities between the respirable air, in the phosphoric acid, and 
charcoal, and between the compound of respirable air and 
charcoal (namely, carbonic acid) and quick-lime. Hence, from 
the principle referred to, it could not be concluded, that car- 
bonic acid, combined with quick-lime, would be decompounded 
by phosphorus attracting its respirable air, and the phosphoric 
acid, thus formed, attracting the quick -lime. Experience only 
could determine the result of these affinities, but no proof has 
been given, from the examination of the mixture, after apply- 
ing phosphorus to red hot marble ; such as finding that car- 
bonic acid was really decompounded, because there was a defi- 
ciency of this elastic fluid, and that the charcoal and phosphoric 
acid corresponded to this deficiency. Accordingly some che- 
mists have conjectured that the small quantity of charcoal af- 
forded in this experiment pre-existed in the phosphorus, which, 
it is well known, is distilled from charcoal ; and others have sus- 
pected that it might have arisen from accidental impurities. 
As experience, also, has taught us that phosphorated mineral 
