The Wind as a Mechanism

A burning ember lifted from the ruin of Thomas Farriner’s bakehouse, caught in the east wind that had blown steady through the dry summer, arced across the narrow gap between Pudding Lane and the riverfront warehouses. It landed on the thatched roof of a building that stored train oil in its lower storey. The straw caught. The flame found its fuel. Within minutes, the warehouse was alight.

This was not yet the firestorm that would come. It was something more deliberate: the wind acting as a mechanism, the buildings arranged as a machine for burning. The east wind blew at twelve to fifteen miles per hour that morning, a constant pressure that would not ease for three days. It pushed the flames westward, toward the heart of the City, and in those first hours after four o’clock, it began to sort the combustible from the merely vulnerable. This strong east wind, noted in diaries and accounts, would drive the flames with fury for four days and nights.

Samuel Pepys, asleep in his house on Seething Lane, half a mile to the east, would not learn of the fire for several hours. But others were already awake and watching. The watermen who slept in their boats along the Thames, the servants stoking kitchen fires for early risers, the market porters beginning their rounds—these were the first witnesses. What they saw was not yet catastrophe. It was acceleration.

The fire moved down Pudding Lane to the river not as a single front but as a series of probes. Each building that caught became a new source. The thatched roofs of the tenements, illegal but ubiquitous, served as wicks. The timber frames, dried by the summer drought to the moisture content of kindling, offered no resistance. The gaps between structures, mandated by law at sixteen feet but narrowed in practice by jetties and encroachments to four or six, allowed flames to leap without losing strength.

Thames Street was the critical threshold. Here the private disaster of Pudding Lane met the commercial infrastructure of the nation. The street ran parallel to the river for half a mile, lined with warehouses that held the materials of London’s trade. Oil from the Baltic. Tallow for candles. Hemp for rope. Sea-coal from Newcastle. These were not merely flammable; they were designed to burn. The oil fed liquid flame that could flow across floors and through drains. The tallow melted and spread. The hemp, loosely packed, drew air through itself like a bellows. The coal, once ignited, could not be extinguished with water.

The fire found these stores shortly after four o’clock. The exact sequence cannot be recovered. Contemporary accounts describe a sudden expansion, as if the fire had discovered a new element. The truth is more mechanical. The wind, blowing directly onto the riverfront, pressed the flames against the warehouse walls. The walls, timber-framed and tarred against damp, blackened and then caught. The contents, heated past their flash points, released vapors that ignited in rolling bursts. This was not arson. This was chemistry and physics, proceeding according to their own laws.

John Evelyn, the diarist and royal courtier, would later describe what he saw when he came to the scene. He had been awakened by the noise and light, though his house was two miles away at Deptford. The description in his diary, written that evening, records the horrid noise the flames made, and the cracking of houses at their ruins. He noted the wind specifically: the eastern wind that drove the fire with such violence against the houses. Evelyn was a man of precise observation. His account would be cited in the parliamentary inquiry. It established, for the official record, what the fire’s early victims already knew: the wind had become the decisive actor.

The trained bands, summoned by the parish constables, arrived piecemeal. They came with their hooks and ladders, their leather buckets, their fire engines that threw a continuous stream no farther than a man could piss. These tools had contained fires before. They would not contain this one. The wind-driven flames moved faster than word could travel. By the time a company reached one burning building, the fire had established itself three doors down.

The physics were implacable. A burning building in a strong wind creates a low-pressure zone on its leeward side. This draws air through any openings, feeding the flames from below while the wind drives them from above. The result is a chimney effect, accelerating combustion beyond any normal rate. The London houses, with their narrow fronts and deep plans, their central stairwells and shared party walls, were ideally shaped for this effect. Each house that caught became a bellows for the next.

The warehouses on Thames Street magnified this process. Their scale—three and four storeys, with attics piled to the roofline—created larger chimneys. Their contents, densely packed, released more heat. The fire that had begun in a baker’s oven, contained within a single room, now expanded to fill entire structures within minutes. The heat cracked window glass before the flames reached it. It warped lead roofing until molten drops fell like rain. It prepared each building for destruction before the fire ever touched it.

By half past four, the fire had established a continuous front along Thames Street from Pudding Lane westward to the Custom House. This was not yet the full extent of its reach. Sparks and burning fragments, lifted by the turbulence of the flames themselves, traveled ahead of the main fire. Evelyn noted the burning flakes that ran almost as fast as one could follow them. These embers, some as large as a man’s hand, landed on roofs two and three hundred yards ahead of the established line. Where they found dry thatch, they began new fires. Where they found tile or slate, they guttered and died.

The pattern of ignition became visible to anyone with a vantage point. The fire advanced not as a wave but as a series of outbreaks, each one consolidating into the main front as the wind permitted. This was the firestorm mechanism beginning to operate: the radiant heat from established fires preheating fuel ahead of the flames, the wind carrying embers to exploit this preparation, the multiple points of ignition overwhelming any attempt at systematic response.

The parish of All Hallows the Great, whose church stood near the center of the warehouse district, began to organize its defense. The churchwardens rang the bells backward, the signal for fire. The parishioners turned out with their buckets. They formed lines to the river, passing water hand to hand. They worked with the desperate energy of men and women defending their own property. They achieved nothing. The fire moved through their parish faster than their bucket chain could move water. Within an hour, the church itself was threatened.

The physical evidence of what happened survives in the Fire Court records, compiled in the years after the disaster. Depositions taken from survivors describe the speed of destruction. A merchant named John Smith, whose house stood on Thames Street near the Three Cranes, testified that he had been awakened by the noise of fire at his neighbor’s, and that by the time he had dressed and descended to the street, his own roof was alight. This was not hyperbole. A well-established building fire in a strong wind can progress from first flame to total involvement in ten minutes. The London houses, with their timber frames and internal voids, burned faster than modern structures.

The wind did not merely drive the flames. It shaped them. The east wind, blowing across the Thames, created a pressure differential that drew air through the streets running northward from the river. These streets—Bread Street, Friday Street, Watling Street—became channels for the fire’s advance. The flames moved up them like water through a pipe, finding fuel on both sides, creating a draft that pulled more air from behind. This was the mechanism that would carry the fire to the heart of the City. It was already operating before most Londoners had woken to the danger.

The human response, in these first hours, was fragmented by the scale of the challenge. The Lord Mayor, Thomas Bloodworth, had made his decision and returned to bed. The aldermen of the affected wards were rousing, but their authority extended only to their own precincts. The fire knew no such boundaries. It moved from the ward of Billingsgate into that of Dowgate, from Dowgate into Vintry, from Vintry into Cordwainer. Each transfer represented a failure of communication as much as a failure of defense. The parish officers of a threatened ward had no standing to commandeer resources from a ward not yet burning. The trained bands responded to their own captains, not to any central direction.

This fragmentation had been built into the city’s governance. The Corporation of London, for all its ancient privileges, was a federation of parishes and wards, each jealous of its autonomy. The Common Council could legislate for the whole city, but it could not command it in an emergency. The Lord Mayor possessed theoretical authority, but in practice he relied on the consent of the aldermen. Bloodworth’s refusal to create firebreaks by pulling down houses was not merely personal timidity. It was the default position of a system that privileged property rights over collective action.

The fire exploited this system. It moved faster than the city’s decision-making could adapt. By five o’clock, the warehouses along Thames Street were burning so intensely that no one could approach within fifty yards. The heat had driven back all attempts at bucket work. The fire engines, positioned where they could operate, found their streams evaporating before they reached the flames. The only remaining tactic was demolition, pulling down houses ahead of the fire to create a gap it could not cross. But demolition required men with axes and hooks, working in the teeth of the fire, and the wind was now so strong that burning material fell among them as they worked.

John Evelyn, who had traveled from Deptford by boat, recorded what he saw from the river. The warehouses were all in a light flame, and the fire so broad at the bottom, and so high as near the battlements of the Tower. This was hyperbole: the Tower stood some distance away, and was not yet threatened. But it conveyed the visual impact of the burning riverfront. The flames, fed by oil and tallow, rose in columns that bent under the wind and then straightened, reaching for the sky. The smoke, black with the combustion of coal and tar, rolled westward in a solid mass, blocking the dawn.

The light of the fire was now visible across the city. Pepys, still asleep, would later reconstruct the timeline from witnesses. He would learn that his own household had been disturbed by the noise, his servants having heard the bells and the shouting, but that they had not thought to wake him. This was the pattern of the morning: the fire visible to those who looked, audible to those who listened, but not yet comprehensible as a general threat. Each witness saw a local emergency. The integration of these local views into a picture of city-wide catastrophe would require hours more.

The wind continued. It was not a gusty wind but a steady pressure, the product of a large-scale weather system that had settled over southern England. Such winds can persist for days, and this one would. It would drive the fire through Monday and into Tuesday, carrying embers across the widest firebreaks, rekindling fires that had appeared extinguished. The meteorological records, such as they are, confirm what the diaries report: high pressure, dry air, sustained easterly flow. The fire had found its perfect partner.

By six o’clock, the fire had established a front nearly half a mile wide, from the Tower in the east to the Steelyard in the west. Its depth varied. Some streets had burned to their northern ends, others had been touched only by embers. But its general direction was clear. It was moving west, up from the river, into the densest part of the old city. The medieval street pattern, with its narrow ways and sudden widenings, channeled and accelerated its progress. The building materials, timber and thatch and plaster, offered no significant resistance. The water supply, dependent on cisterns and the river, could not match the rate of combustion.

The human cost was still, by the standards of what would follow, limited. The maidservant who had died in Farriner’s house was the first confirmed fatality. Others would follow, but in these first hours, the speed of the fire was in some ways a protection. Those who woke to the danger had time to escape. The houses burned so quickly that they did not trap their occupants in collapsing structures. The real destruction was of property: warehouses full of goods, shops full of stock, houses full of the accumulated possessions of lifetimes.

The economic geography of the fire’s first hours is recoverable from the insurance records and the Fire Court depositions. Thames Street was the great warehousing district, where the goods of the port awaited distribution or re-export. The value concentrated there was enormous, tens of thousands of pounds in a single building. This value was now being converted to smoke and ash at a rate that no individual could comprehend. A merchant who had invested his capital in Baltic oil or Newcastle coal, watching his warehouse burn, was witnessing not merely a personal disaster but the destruction of a market. The supply would not be replaced. The contracts could not be fulfilled. The credit built upon these goods would fail.

The wind drove all of this before it. The firestorm effect, fully developed by six o’clock, created a roar that witnesses would struggle to describe. It was not like the crackling of a hearth fire, or even the rushing of a house fully alight. It was a continuous explosion, the sound of air being consumed faster than it could be replaced, of combustion proceeding at the physical limit of its possibility. Those who heard it knew, without needing to be told, that they were in the presence of something beyond normal experience.

The trained bands, in these first hours, performed the only service that remained possible. They helped evacuate the threatened houses, carrying goods to the river or to open spaces where they might be safe. They assisted the watermen, who had begun to offer their boats for the transport of property. They maintained some order in streets where panic might otherwise have prevailed. But they could not fight the fire. That possibility had passed with the burning of the first warehouses.

The light of the approaching dawn, when it came, was extinguished by the smoke. The sun rose into a sky that was already dark with it, the disc visible only as a dull red spot. This was the first of the fire’s transformations of the ordinary world. The day that should have followed night did not come. In its place was a continuous twilight, lit from below by the flames, through which the burning city moved toward its second hour of destruction.

The wind had taken command. Human decisions had created the conditions, the crowded buildings, the combustible materials, the inadequate water supply, the refusal to create firebreaks. But human decisions could no longer alter the outcome. The fire was now a physical process, governed by the interaction of wind, fuel, and heat. It would continue until one of these elements failed. The fuel would not fail; the city was built of it. The heat would not fail; the fire generated its own. Only the wind might change, and the wind held steady.

What remained was witness. The diaries of Pepys and Evelyn, begun in ordinary times, now became instruments of record. The parliamentary inquiry, not yet conceived, would depend on the testimony of those who saw these hours. The Fire Court, established years later to adjudicate the destruction of property, would work from the traces left in these first moments. The city that would rise from the ashes would be shaped by the memory of what the wind had done.

From his window on Seething Lane, Samuel Pepys finally woke to the sound of church bells ringing backward. He would dress, he would walk out to see, he would carry what he found to the king. But that lay ahead. For now, the fire’s glow and scale had become unmistakable, breaching the awareness of those outside the immediate City.