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. Sir Oliver Lodge said[4]-- 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-- Had the publication of your _Transactions_ been more frequent, I should with much pleasure have submitted to the Society a full account of these and other experiments which appear to me to prove, that metals are compound substances, and that water has not yet been decomposed by any process that we are acquainted with. Still, however, I would not be very positive, as the contrary is maintained by almost all the chemists of the age.... And thus he proceeds, ever doing interesting things, but blind to the patent results because he had phlogiston constantly before him. He looked everywhere for it, followed it blindly, and consequently overlooked the facts regarded as most significant by his opponents, which in the end led them to correct conclusions. The experimental results in the second paper also admit of an interpretation quite the opposite of that deduced by Priestley. He confidently maintained that air was invariably generated from water, because he discovered it and liberated it from water which he was certain did not contain it in solution. He was conscientious in his inferences. Deeply did his friends deplore his inability to see more than a single interpretation of his results!