Observations. 447

article, he says, that the agitation of fixed airin water makes it approach to the nature ofwholesome air, p. 254, and that a mixtureof nitrous air with common air converts itinto fixed air. He even expressly fays,p. 297, that the union of phlogiston with airdiminishes its quantity, increases its specificgravity, renders it unfit for respirationor combustion, and makes it approach tothe nature of fixed air, by pasting throughthe state of phlogisticated air.

On this subject, however, this ingeniouswriter does not give my opinion, or one that isagreeable to fact. For air simply injured byphlogiston is not heavier, but lighter thancommon air; and not making lime waterturbid, or being peculiarly liable to beabsorbed by water, it shews no sign of ap-proaching to the nature of fixed air, whichis, moreover, heavier than common air; norwill any length of time, or addition of morephlogiston, tend, in the least, that I know,to bring it to this state.

On the contrary, it will rather followfrom my observations, that fixed air is con-vertible