Note 72 — PART FIRST. (continued 3)

It is now acknowledged that common atmospherical air contains a portion of what Dr. Black and Dr. Priestley have called fixed air; but this portion is so small (not more than one fiftieth part, according to Dr. Anthony Fothergill’s Prize Dissertation, and none at all, according to Dr. Beddoes) I say, this proportion is so small, that we cannot suppose it to constitute the quantity of fixed air thrown out by the breath, which is very considerable. Besides, fixed air, of all others, is the most readily absorbed; and, indeed, if we could admit of absorption of any basis of air in the present case, it certainly ought to be that of fixed air; but where such a quantity is thrown out, we cannot well admit of any absorption.