Part 19

The harder the frost was the more air I procured.

Further, he announced that on heating manganese (dioxide) in inflammable air

no water is formed,

and what is rather astounding, he was certain that azote consisted of hydrogen and oxygen.

To the Medical Repository, which he regarded highly, there was sent a rather thoughtful disquisition on dreams. In it the idea was expressed

that dreams have their seat in some region of the brain more deeply seated than that which is occupied by our waking thoughts.

A "Pile of Volta" had been sent out from England. It amused him and he studied it carefully when he was led to remark upon the theory of this curious process as follows:

The operation wholly depends on the calcination of the zinc, which suffers a great diminution in weight, while the silver is little affected, and all metals lose their phlogiston in calcination, therefore what remains of the zinc in metallic form in the pile and everything connected with that end of it, is supersaturated with phlogiston.

More need not be quoted. It was phlogiston and that only which occasioned the electric current. It may properly be added that in this connection he wrote:

It is said the inventor of the galvanic pile discovered the conducting power of charcoal, whereas it was one of my first observations in electricity, made in 1766.

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 (CO_2), 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:

When Porcupine rioted in the filth of a debauched and corrupt faction in this city, no person experienced so much of his obscene and vulgar abuse as Dr. Priestley. There is not a single fact on record or capable of being shewn, to prove that Dr. Priestley was guilty of any other crime than being a dissenter from the church of England, and a warm friend of American Independence. For this he was abused by Porcupine--and Denny is only Porcupine with a little more tinsel to cover his dirt. It is worthy of remark, that after a whole sheet of promises of "literary lore" and "products of the master of spirits" of the nation--the first and second numbers of the Portable Foolery, are stuffed with extracts from British publications of an ordinary quality.

The attack of the Port Folio was most ungracious. It may have been due to irritation caused by the appearance of a second edition of Priestley's "Letters to the Inhabitants of Northumberland." Nevertheless the thoughtful and dignified men of the City--men who admired Priestley's broad catholic spirit and brave attitude upon all debatable questions, men who appreciated his scientific attainments, invited him to the following subscription dinner, as announced in the Aurora, March, 6th:

At 4 o'clock in the afternoon about one hundred citizens sat down to an elegant entertainment prepared by Mr. Francis to celebrate the commencement of the administration of Mr. Jefferson. The Governor honored the company with his presence. Several respectable Foreigners were invited to partake of the festival.... A variety of patriotic songs were admirably sung; and the following toasts were drank with unanimous applause.

1. The Governor of Pennsylvania

2. Dr. Priestley: The Philosopher and Philanthropist....

He was present and enjoyed himself, and sad must it have been to read on March 30th:

Some weeks ago, Dr. Priestley having caught cold by attending a meeting of the Philosophical Society on a wet evening, was taken ill of a violent inflammatory complaint which rendered his recovery for a long time dubious. We announce with sincere pleasure the returning health of a man, whose life hath hitherto been sedulously and successfully devoted to the interests of mankind.

He had, indeed, been very ill. The trouble was pleurisy. Dr. Rush was his physician. By his order the patient was bled profusely seven times. During this trying and doubtful period there came to him a cheery letter from President Jefferson who had only learned of his illness. Among other things the President wrote--

Yours is one of the few lives precious to mankind, and for the continuance of which every thinking man is solicitous. Bigots may be an exception.... But I have got into a long disquisition on politics when I only meant to express my sympathy in the state of your health, and to tender you all the affections of public and private hospitality. I should be very happy to see you here (Washington). I leave this about the 30th to return about the 25th of April. If you do not leave Philadelphia before that, a little excursion hither would help your health. I should be much gratified with the possession of a guest I so much esteem, and should claim a right to lodge you, should you make such an excursion.

But Priestley journeyed homeward on April 13th, and en route wrote the following letter, addressed to John Vaughan, Esq. 179 Walnut Street, Philadelphia, Pa.: