It is an essential part of the antiphlogistic theory, that in all the cases of what I have called _phlogistication_ of _air_, there is simply an absorption of the dephlogisticated air, or, as the advocates of that theory term it, the oxygen contained in it, leaving the _phlogisticated_ part, which they call _azote_, as it originally existed in the atmosphere. Also, according to this system, _azote_ is a simple substance, at least not hitherto analyzed into any other.
No matter how deeply one venerates Priestley, or how great honor is ascribed to him, the question continues why the simpler French view was not adopted by this honest student. Further, as an ardent admirer one asks why should Priestley pen the next sentence:
They, therefore, suppose that there is a determinate proportion between the quantities of oxygen, and azote in every portion of atmospherical air, and that all that has hitherto been done has been to separate them from one another. This proportion they state to be 27 parts of oxygen and 73 parts of azote, in 100 of atmospherical air.
Priestley knew that there was a "determinate proportion." He was not, however, influenced by quantitative data.
Priestley's experiments were admirable, but his perception of their theoretical relations was entirely inadequate and, as we now think, quite erroneous.... In theory he had no instinct for guessing right ... he may almost be said to have had a predilection for the wrong end.
At present the French thought is so evident that it seems incomprehensible that Priestley failed to grasp it, for he continues--
In every case of the diminution of atmospherical air in which this is the result, there appears to me to be something emitted from the substance, which the antiphlogistians suppose to act by simple absorption, and therefore that it is more probable that there is some substance, and the same that has been called _philogiston_, or the _principle of inflammability_ ... emitted, and that this phlogiston uniting with part of the dephlogisticated air forms with it part of the phlogisticated air, which is found after the process.
Subsequently (1798), he advised the Society that he had executed other experiments which corroborated those outlined in his first two papers, adding--