Part 10

Here, though I am as happy as this country can make me ... I do not feel as I did in England.

By May, 1796, he had finished his discourses, although he proposed concluding with one emphatically Unitarian in character. This was expected by his audience, which had been quietly prepared for it and received it with open minds and much approval.

On his return to Northumberland he promptly resumed his work on the "Church History," but was much disturbed because of the failure of his correspondents in writing him regularly, so he became particularly active in addressing them. But better still he punctuated his composition of sermons, the gradual unfolding of his Church History, and religious and literary studies in general, with experimental diversions, beginning with the publication (1796) of an octavo brochure of 39 pages from the press of Dobson in Philadelphia, in which he addressed himself more especially to Berthollet, de la Place, Monge, Morveau, Fourcroy and others on "Considerations on the Doctrine of Phlogiston and the Decomposition of Water." It is the old story in a newer dress. Its purpose was to bring home to Americans afresh his particular ideas. The reviewer of the Medical Repository staff was evidently impressed by it, for he said:

It must give pleasure to every philosophical mind to find the United States becoming the theatre of such interesting discussion,

and then adds that the evidence which was weighty enough to turn such men as Black and others from the phlogiston idea to that of Lavoisier--

has never yet appeared to Dr. Priestley considerable enough to influence his judgment, or gain his assent.

Priestley, as frequently observed, entertained grave doubts in regard to the constitution of metals. He thought they were "compounded" of a certain earth, or calx, and phlogiston. Further he believed that when the phlogiston flew away, "the splendour, malleability, and ductility" of the metal disappeared with it, leaving behind a calx. Again, he contended that when metals dissolved in acids the liberated "inflammable air" (hydrogen) did not come from the 'decompounded water' but from the phlogiston emitted by the metal.

Also, on the matter of the composition and decomposition of water, he held very opposite ideas. The French School maintained "that hydrogenous and oxygenous airs, incorporated by drawing through them the electrical spark turn to water," but Priestley contended that "they combine into smoking nitrous acid." And thus the discussion proceeded, to be answered most intelligently, in 1797, by Adet, whose arguments are familiar to all chemists and need not therefore be here repeated. Of more interest was the publication of two lectures on Combustion by Maclean of Princeton. They filled a pamphlet of 71 pages. It appeared in 1797, and was, in brief, a refutation of Priestley's presentations, and was heartily welcomed as evidence of the "growing taste in America for this kind of inquiry." Among other things Maclean said of the various ideas regarding combustion--"Becker's is incomplete, Stahl's though ingenious, is defective; the antiphlogistic is simple, consistent and sufficient, while Priestley's resembling Stahl's but in name, is complicated, contradictory and inadequate."

Not all American chemists were ready to side track the explanations of Priestley. The distinguished Dr. Mitchill wrote Priestley on what he designated "an attempt to accommodate the Disputes among Chemists concerning Phlogiston." This was in November, 1797. It is an ingenious effort which elicited from Priestley (1798) his sincere thanks, and the expressed fear that his labours "will be in vain." And so it proved. Present day chemists would acquiesce in this statement after reading Mitchill's "middle-of-the-road" arguments. They were not satisfactory to Maclean and irritated Priestley.

In June 1798 a second letter was written by Priestley to Mitchill. In it he emphasized the substitution of zinc for "finery cinder." From it he contended inflammable air could be easily procured, and laid great stress on the fact that the "inflammable air" came from the metal and not from the water. He wondered why Berthollet and Maclean had not answered his first article. To this, a few days later, Mitchill replied that he felt there was confusion in terms and that the language employed by the various writers had introduced that confusion; then for philological reasons and to clarify thoughts Mitchill proposed to strike out azote from the nomenclature of the day and take septon in its place; he also wished to expunge hydrogene and substitute phlogiston. He admitted that Priestley's experiments on zinc were difficult to explain by the antiphlogistic doctrine, adding--

It would give me great satisfaction that we could settle the points of variance on this subject; though, even as it is, I am flattered by your (Priestley's) allowing my attempt 'to reconcile the two theories to be ingenious, plausible and well-meant.... Your idea of carrying on a philosophical discussion in an amicable manner is charming'....

But the peace-maker was handling a delicate problem. He recognized this, but desired that the pioneer studies, then in progress might escape harsh polemics. This was difficult of realization for less than a month later fuel was added to the fire by Maclean, when in writing Mitchill, who had sent him Priestley's printed letter, he emphatically declared that

The experiment with the zinc does not seem to be of more consequence than that with the iron and admits of an easy explanation on antiphlogistic principles.

And he further insisted that the experiments of Priestley proved water to be composed "of hydrogene and oxygene."

Four days later (July 20, 1798) Priestley wrote Mitchill that he had replaced zinc by red precipitate and did not get water on decomposing inflammable air with the precipitate. Again, August 23, 1798, he related to Mitchill

that the modern doctrine of water consisting of oxygene and hydrogene is not well founded ... water is the basis of all kinds of air, and without it no kind of air can be produced ... not withstanding the great use that the French chemists make of scales and weights, they do not pretend to weigh either their calorique or light; and why may not phlogiston escape their researches, when they employ the same instruments in that investigation?

There were in all eight letters sent by Priestley to Mitchill. They continued until February, 1799. Their one subject was phlogiston and its role in very simple chemical operations. The observations were the consequence

of original and recent experiments, to which I have given a good part of the leisure of the last summer; and I do not propose to do more on the subject till I hear from the great authors of the theory that I combat in America;

but adds,--

I am glad ... to find several advocates of the system in this country, and some of them, I am confident, will do themselves honour by their candour, as well as by their ability.

This very probably was said as a consequence of the spirited reply James Woodhouse made to the papers of Maclean. As known, Woodhouse worked unceasingly to overthrow the doctrine of phlogiston, but was evidently irritated by Maclean, whom he reminds--

You are not yet, Doctor, the conqueror of this veteran in Philosophy.

This was a singularly magnanimous speech on Woodhouse's part, for he had been hurling sledgehammer blows without rest at the structure Priestley thought he had reared about phlogiston and which, he believed, most unassailable, so when in 1799 (July) Priestley began his reply to his "Antiphlogistian opponents" he took occasion to remark:

I am happy to find in Dr. Woodhouse one who is equally ingenious and candid; so that I do not think the cause he has undertaken will soon find a more able champion, and I do not regret the absence of M. Berthollet in Egypt.

Noble words these for his young adversary who, in consequence of strenuous laboratory work, had acquired a deep respect and admiration for Priestley's achievements, though he considered he had gone far astray.

The various new, confirmatory ideas put forth by Priestley need not be here enumerated. They served their day.

Dr. Mitchill evidently enjoyed this controversial chemical material, for he wrote that he hoped the readers of the Medical Repository, in which the several papers appeared, would

participate the pleasure we feel on taking a retrospect of our pages, and finding the United States the theatre of so much scientific disquisition.