2*74 
Lavoisier, by ascertaining the true composition of 
carbonic acid, enabled us to determine in what way 
the acid gas, obtained in respiration, might be formed. 
Such is the order in which the facts, relating to our 
knowledge of the properties and uses of the air in 
respiration, have been successively disclosed. 
563. But we farther endeavoured to shew, that the 
actual quantity of carbonic acid, formed in respira- 
tion, corresponded very nearly (122.) with that of 
oxygen gas which had disappeared ; and that, allow- 
ing for a small degree of condensation, which we then 
supposed to attend the conversion of these gases into 
each other, " the whole of the oxygen gas lost (123.)* 
was employed to form the carbonic acid in question." 
This conclusion, we maintained, rested not only on 
his usual candour, admits. " Having made this discovery", says 
he, " some time before I was in Paris in 1774, 1 mentioned it at 
the table of M. Lavoisier,, when most of the philosophical people 
in the city were present, saying that it was a kind of air ia 
-which a candle burned much better than in common air ; but I 
had not then given it any name. At this, all the company, and 
Mr and Madame Lavoisier as much as any, expressed great sur- 
prise. I told them that I had gotten it from precipitate per se, 
and also from red lead. Speaking French very imperfectly, and 
being little acquainted with the terms of chemistry, I said plumb 
rouge, which was not understood till M. Macquer said I must 
mean minium. Mr Scheele's discovery was certainly independent 
of mine, though, I believe, not made quite so early*." Yet, when 
speaking of oxygen gas, M. Lavoisier observes, " This species 
of air was discovered, almost at the same time, by Dr Priestley, 
Mr Scheele and myself f." 
* Treat, on Phlogiston, p. 56. an. 1800. 
f Elem, Chem. p. 84. 4th edit. 
