The Annus horribilis

It was a social occasion of a different nature, not attended by Priestley, that led to his rapid and necessary departure from Birmingham. A group of Birmingham radicals decided to hold a dinner on 14 July 1791 to celebrate the two-year anniversary of Bastille Day. The French Revolution and its aftermath aroused considerable fear in the British establishment, but others strongly welcomed the undermining of monarchical authority. And so it was that 80 gentlemen, calling themselves the Friends of Freedom, subscribed five shillings for dinner, including a bottle of wine each, at Dadley’s Hotel. Priestley was warned not to attend, and he spent the day with a friend, Adam Walker, a popular lecturer in science. Though an infallible alibi, it was of little use against irrationality. The diners left early. The mob that had assembled struck later, breaking the windows of the hotel and moving on to destroy buildings associated with those they believed to have been present. The New Meeting was burnt to a shell. The mob moved on to Priestley’s house, Fair Hill, destroying both it and his laboratory building. Priestley had been warned to leave in time. It meant the end of his career in Birmingham.

For today’s historians, the intolerance of the Birmingham mob has an unexpected benefit. A contemporary law allowed those whose property was destroyed by mob violence to claim financial recompense from the state, and Priestley put in his claim, listing all his goods and chattels and suggesting their value. So we know Priestley’s valuation of every one of his “Philosophical Instruments, Electrical Apparatus, Optical Instruments, Mathematical Instruments, Chemical Apparatus, and Chemicals.” The total came to £609 5s.

The list is extremely impressive and tells us a great deal about the conduct of late-18th-century laboratory chemistry. Most valuable was the air pump made by John Smeaton, at £36; a furnace to Joseph Black’s design came to £3 13s. 6d.; while four pounds of brimstone, or sulfur, was priced at only 1s. 4d. Particularly sad was the loss of a burning lens of 12 inches diameter, valued at six guineas. This lens was almost certainly the one with which Priestley discovered dephlogisticated air on 1 August 1774. The total claimed by Priestley was £4,083, and so his laboratory represented between one-sixth and one-seventh of his goods. Taking inflation into account, we can reckon that Priestley’s apparatus was worth about £60,000, or $110,000, at today’s prices. Unfortunately, his valuations were argued down by the courts, and he received 25 percent less than he had claimed.

For today’s historians, the intolerance of the Birmingham mob has an unexpected benefit. A contemporary law allowed those whose property was destroyed by mob violence to claim financial recompense from the state, and Priestley put in his claim, listing all his goods and chattels and suggesting their value. So we know Priestley’s valuation of every one of his “Philosophical Instruments, Electrical Apparatus, Optical Instruments, Mathematical Instruments, Chemical Apparatus, and Chemicals.” The total came to £609 5s. The list is extremely impressive and tells us a great deal about the conduct of late-18th-century laboratory chemistry. Most valuable was the air pump made by John Smeaton, at £36; a furnace to Joseph Black’s design came to £3 13s. 6d.; while four pounds of brimstone, or sulfur, was priced at only 1s. 4d. Particularly sad was the loss of a burning lens of 12 inches diameter, valued at six guineas. This lens was almost certainly the one with which Priestley discovered dephlogisticated air on 1 August 1774. The total claimed by Priestley was £4,083, and so his laboratory represented between one-sixth and one-seventh of his goods. Taking inflation into account, we can reckon that Priestley’s apparatus was worth about £60,000, or $110,000, at today’s prices. Unfortunately, his valuations were argued down by the courts, and he received 25 percent less than he had claimed.

Priestley tried to make a new life for himself in Hackney, near London. But the riots had affected him badly, and by 1793 he was seriously considering emigration. The problem was partly the increasing tension with France, Louis XVI having been executed in January. Priestley was perceived as bound up with the revolution. His son William had applied for French citizenship, and in the course of this process Joseph had been praised in the French Assembly. Later (and worse still) he was declared to be a citizen of France. It allowed the British press to make great mischief.

Priestley had also made his position known on the earlier American disturbances. Writing to Benjamin Franklin just months before the Declaration of Independence, Priestley said: “As it is most probable that you will be driven to the necessity of governing yourselves, I hope you have wisdom to guard against the rocks that we have fatally split upon; and made some better provision for securing your natural rights against the incroachment of power, in whomsoever placed.”