His position in the Society became eventually so irksome that he withdrew from it, as he explains in the preface to his Observations and Experiments on the Generation of Air from Water, which he published in pamphlet form at Hackney, with a dedication to the members of the Lunar Society.
In a letter to Withering, written from Clapton, October 2, 1792, he says:—
“... One of the things that I regret the most in being expelled from Birmingham is the loss of your company and that of the rest of the Lunar Society. I feel I want the spur to constant exertion which I had with you. My philosophical friends here are cold and distant. Mr Cavendish never expressed the least concern on account of anything I had suffered, though I joined a party with which he was, and talked with them some time. I do not expect to have much intercourse with any of them.
“I have, however, nearly replaced my apparatus, and intend not to be idle. I have already made some experiments relating to the doctrine of phlogiston, and when I have made a few more shall probably write something on the subject. I am surprised at the confidence with which the French chemists write; but I cannot yet learn what they have to object to my last paper in the Philosophical Transactions....
“I was in hopes to have been able to pay my friends of Birm. a visit long before this time, but was always discouraged, so that I have now given up the thoughts of it, and must content myself with seeing as many of them as I can here.... I do not, however, think I shall continue here long. Though unwillingly, I shall some time hence follow my son to France. But as I can do nothing there I will stay here as long as I can.”
To what lengths the Government were determined to go was seen in their banishment, in 1793, of Thomas Fyshe Palmer, a gentleman of a highly respectable and opulent family in Bedfordshire, to Botany Bay for seven years, because he had been concerned in publishing a paper in favour of Parliamentary Reform; and in their treatment of Mr Winterbotham, a Calvinistic minister of Plymouth Dock, on account of his political opinions. The mock trial of Mr Winterbotham at Newgate and the four years’ imprisonment which followed it, created a wide-spread feeling of indignation and alarm, and many families were constrained to leave the country in disgust. Among them was Priestley’s friend and fellow-sufferer, the worthy Mr Russell, who on his way to Boston, New England, was captured with his family by a French privateer and thrown into prison in Brest.
Priestley, at length, also determined to follow them. It was however with the greatest reluctance that he came to that decision. It meant parting from affectionate and devoted friends to whom he was warmly attached, whose zeal to serve him and to minister to his wants far outweighed the hatred of those who sought to cover him with oblivion. It meant too the relinquishment in large measure of his philosophical pursuits since he could not hope to procure elsewhere the same facilities for inquiry that he enjoyed here. More than all it seemed to mean the relinquishment of what was still dearer to him—his active efforts in the propagation of Unitarianism. Lastly it meant in all human probability a lasting severance from the daughter to whom he was so tenderly attached. He was largely guided to his decision by consideration for his sons, since, as he says, he found that the bigotry of the country in general made it impossible for him to place them here with any advantage. His second son, William, had been some time in France, but on the breaking out of the troubles in that country he had embarked for America, where his two brothers, Joseph and Henry, met him. They had a project of founding a settlement near the head of the Susquehanna in Pennsylvania, and several of Priestley’s friends at home, among them Mr William Russell of Birmingham, a leader of the New Meeting-House, were directly interested in the scheme.
Priestley at length decided to throw in his lot with his sons, and in the preface to his Fast and Farewell Sermons, which he delivered to his Hackney congregation on the eve of his departure, he gave his reasons for leaving the country:—
“After the riots in Birmingham it was the expectation, and evidently the wish of many persons, that I should immediately fly to France or America. But I had no consciousness of guilt to induce me to fly from my country. On the contrary, I came directly to London, and instantly, by means of my friend, Mr Russell, signified to the King’s ministers that I was there and ready, if they thought proper, to be interrogated on the subject of the riots.
“Ill-treated as I thought I had been, not merely by the populace of Birmingham, for they were the mere tools of their superiors, but by the country in general, which evidently exulted in our sufferings, and afterwards by the representatives of the nation, who refused to inquire into the cause of them, I own I was not without deliberating upon the subject of emigration; and several flattering proposals were made to me, especially from France, which was then at peace within itself and with all the world; and I was at one time much inclined to go thither, on account of its nearness to England, the agreeableness of its climate, and my having many friends there.
“But I likewise considered that if I went thither I should have no employment of the kind to which I had been accustomed; and the season of active life not being, according to the course of nature, quite over, I wished to make as much use of it as I could. I therefore determined to continue in England, exposed as I was not only to unbounded obloquy and insult, but to every kind of outrage; and after my invitation to succeed my friend Dr Price I had no hesitation about it....”
He then goes on to show how insecure his position was, and how impossible it was to follow his avocations in peace, in face of the odium and insult he continually met with:—
“These facts not only show how general was the idea of my particular insecurity in this country, but what is of much more consequence, and highly interesting to the country at large, an idea of the general disposition to rioting and violence that prevails in it, and that the Dissenters are the objects of it. Mr Pitt very justly observed, in his speech on the subject of the riots at Birmingham, that it was ‘the effervescence of the public mind.’ Indeed, the effervescible matter has existed in this country ever since the civil wars in the time of Charles I., and it was particularly apparent in the reign of Queen Anne. But the power of Government under the former princes of the House of Hanover prevented its doing any mischief. The late events show that this power is no longer exerted as it used to be, but that on the contrary there prevails an idea, well or ill founded, that tumultuary proceedings against Dissenters will not receive any effectual discouragement.
“After what has taken place with respect to Birmingham, all idea of much hazard for insulting and abusing the Dissenters is entirely vanished; whereas the disposition to injure the Catholics was effectually checked by the proceedings of the year 1780. From that time they have been safe, and rejoice in it. But from the year 1791 the Dissenters have been more exposed to insult and outrage than ever.
“The necessity I was under of sending my sons out of this country was my principal inducement to send the little property that I had out of it too; so that I had nothing in England besides my library, apparatus and household goods.
“By this I felt myself greatly relieved, it being of little consequence where a man already turned sixty ends his days. Whatever good or evil I have been capable of is now chiefly done; and I trust that the same consciousness of integrity which has supported me hitherto will carry me through anything that may yet be reserved for me. Seeing, however, no great prospect of doing much good, or having much enjoyment here, I am now preparing to follow my sons; hoping to be of some use to them in their present unsettled state, and that Providence may yet, advancing in years as I am, find me some sphere of usefulness with them.”
He then goes on to deal with the charge that he was a factious, political parson who preached sedition:—