Some additional attention to air was also given by him, and in so doing he reached the conclusion that
The diamond and charcoal of copper are, as nearly as possible, pure phlogiston.
One wonders how he could so persuade himself, for these bodies surely possessed weight. Why did he not rely more upon his balance?
With Woodhouse he discussed the product from passing water over heated charcoal. He had been endeavoring to refute certain statements made by Cruikshank. There is no question but that he had carbon monoxide in hand, and had it as early as 1799, and that he had obtained it in several different ways. Observe this statement:
I always found that the first portion of the heavy inflammable air, resulting from the passage of steam over heated charcoal was loaded with fixed air (CO2), but that in the course of the process this disappeared, the remaining air (CO) burning with a lambent flame.
Scarcely had Priestley set foot in Philadelphia on his third visitation than the Port Folio, devoted usually to literature and biography, printed the following unkind words:
The tricks of Dr. Priestley to embroil the government, and disturb the religion of his own country, have not the merit of novelty.
To which the Aurora replied: