London has had not one Great Fire, but many. The fire of 1212 exacted an appalling death toll of 3000; the famous conflagration of 1666 killed only six. For this dramatic reduction in mortality, Londoners could thank centuries of increasingly strict building codes – which, if they did not save most of the city, at least slowed fires enough to give people time to escape. But architects still grappled with the problem of fire. The best solution in the mid-18th century, the vaulted masonry ceiling, was limited by its expense to the most important public and commercial buildings. Fireproofing for homes and businesses was still desperately needed. In 1774, in an attempt to prove he had the answer, one member of parliament carried out a novel experiment: he set this house on fire – with the king and queen inside it.
DAVID HARTLEY is forgotten now, but both the US and Britain owe him a debt of gratitude, albeit for completely different reasons. The son of an eminent philosopher of the same name, the younger Hartley inherited his father’s eccentricities and keen scientific mind. He also cut a distinctive figure on the street. Hartley refused to powder his hair, which as one friend commented, made him “a perfect phenomena at the time”. And he insisted on wearing stockings with the feet cut out, a practice he declared was conducive to good health and “favourable to pedestrian exercise”.
In 1774, Hartley was elected an MP for Hull. He was a notoriously long-winded speaker: biographer George Guttridge noted that “Lord Liverpool left the House during a speech by Hartley, and after visiting his residence out of town, dined, and returned some five hours later to find the speaker in the same attitude addressing a grievously depleted audience”.
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Hartley was respected for his deeply held beliefs, however. He was the first MP to go on record with a bill opposing slavery, decades before others took up the cause, and he was a passionate critic of Britain’s policies in America. “You gave them no alternative but independence or unconditional submission,” he berated colleagues in the House of Commons in 1777. The Treaty of Paris ending the War of American Independence in 1783 was negotiated in part by Hartley and signed in his hotel room, for he was seen as the most likely person to be trusted by the American delegation.
But Hartley’s greatest impact in London began before he entered Parliament. In 1773, he was granted patent number 1037, for “Securing Buildings and Ships From Fire”. Focusing on the vulnerable joists under the floorboards, he proposed sheathing them in thin layers of iron plating. “A quantity of dry Rubbish of any Kind [such as sand or chalk] should be put over the Ceiling Plates,” he added, “which will deaden sound between Floors, and at the same Time, still further stop the Progress of Fire.” Fireproofing the joists would help prevent the floor from collapsing, and this combined with the dry filler would be effective in “stopping the free Supply and Current of Air, without which, no Fire can get to any great Height, or make any destructive Progress”.
The plates themselves were elegantly simple: thin iron plates overlapped the top of the joists, and were held firmly in place by the nails pounded through the floorboards and into these joists. Hartley’s fireproofing was also cheap. He estimated it would add 4 per cent to the cost of a building, and could be retrofitted to existing buildings, whether they were “a Magazine, a Merchant’s Warehouse, a Banker’s Shop, or a private Dwelling-house”.
The benefits of his invention, he argued, would be immeasurable. “A single Fire-Plate under a Crevice in a Floor, or a over a Crack in a Ceiling, might have prevented the Fire of London,” Hartley claimed in a pamphlet in 1774. This made his fellow MPs sit up and take notice. What Hartley was proposing could save entire cities. Parliament voted him a grant of £2500 to continue his experiments, and passed a special act to extend his patent from 15 to 31 years.
The best way to refine and prove his fireproofing, Hartley decided, was by setting houses on fire. He used his grant to erect and furnish two fire-plated houses in the Berkshire town of Buckleberry for the seemingly perverse purpose of burning them down. And so it was that one Saturday in April 1775 an entirely preventable fire broke out in Buckleberry. Hartley torched the furniture and wainscoting in one room of his house until, as one newspaper reported, “the inside of the room appeared a perfect mass of Fire”. Hartley invited witnesses inside his house as the fire burnt itself out inside the test room, leaving the rest of the house and its visitors quite untouched. A few weeks later, Hartley repeated his test with the same results.
Now it was time to show off. Emboldened by his trials in the countryside, Hartley erected another fire-plated house where no one could miss it. “I have built an House upon Wimbledon Common that every one may see repeated Trials and Proofs,” he announced in 1776. The Fireproof House attracted crowds of admirers, including the king and queen. George III was so delighted with Hartley’s results that, visiting Wimbledon one morning, he decided not just to see the house for himself but to test it out – with the royal family inside.
“Their majesties, with the Princes and Princesses, first breakfasted in one of the rooms,” reported a witness. “The tea kettle was boiled upon a fire made on the floor of an opposite room, which apartment they afterwards entered and saw a bed set on fire, the curtains of which were consumed with part of the bedstead…Their majesties then went downstairs and saw a horse-shoe forged in a fire made upon the floor, as also a large faggot was hung on the ceiling instead of a curtain; after this two fires were made upon the staircase and one under the stairs, all of which burnt out quietly without spreading.”
The royal family repaired to an upstairs room, while Hartley filled the downstairs with pitch, tar and kindling, and quickly had a roaring fire going. This soon went out, and the king and his family emerged none the worse for their experience. Hartley’s experiment was a resounding success, and fire plates were subsequently used throughout Britain. In 1776, an obelisk was erected on Putney Heath to commemorate his achievement.
As improved fireproofing measures such as cast-iron columns and terracotta roof tiles appeared in the 19th century, Hartley’s Fire Plates fell into disuse. “They may have performed OK under certain conditions – as in, better than nothing – but generally thin iron didn’t work as intended,” says Sara Wermeil, an expert on the history of fireproofing. Yet the plates themselves have held up well, says Lawrence Hurst, a structural engineer who has studied Hartley’s work.
Hartley faded from public view after the Treaty of Paris. He lived with his sister, tinkered with inventions and hid from would-be visitors. Eventually, the Fireproof House came to a predictably ironic end. The builders of Wildcroft Manor, a mansion erected around Hartley’s old test house, did not have the prudence to install fire plates. Hartley rushed out to Wimbledon Common on the morning of 21 December 1791 to find the mansion ablaze and collapsing on the fireproofed section, which, with the inrush of air…caught fire.