phlogiston

Thus we say that the union of phlogiston to a particular kind of earth is the cause of its becoming a metal.

It dissolves many substances containing phlogiston, as iron, dry flesh, &c. and thereby forms a little inflammable air.

These facts shew that alkaline air consists chiefly of phlogiston.

The nitrous acid unites with phlogiston, alkalis, metallic substances, and calcareous earth.

It is less capable of concentration than the vitriolic or nitrous acids, perhaps from a more intimate union of phlogiston with it.