The Smell that Changed London's Sewers Forever: London 1858

July, eighteen fifty-eight. London's river is an open sewer, and a heatwave is cooking it. Members of Parliament flee their own chamber. Curtains soaked in chloride of lime. This is the smell that changed London's sewers forever. Here is how it happened.

Start with the setting. In eighteen fifty-eight, London is the biggest city in the world, with well over two million people. Its population has doubled since eighteen hundred. And its waste has almost nowhere clever to go. Around two hundred thousand cesspits, which are underground pits for household waste, overflow into the drains, and the drains empty into the River Thames. Some of the city's drinking water comes from that same river. A few years earlier, the scientist Michael Faraday drops white paper into it, to test how cloudy it is. He writes that the whole river was for the time a real sewer. Nobody panics, because doctors believe disease travels in foul air, a theory called miasma. Bad smell, bad health. The river stinks, but not yet enough to matter. Then comes the summer.

It is hot, around thirty degrees Celsius for weeks, and some accounts say hotter. The waste in the river begins to cook. People are reported to have vomited if they went too close. Queen Victoria and Prince Albert try a pleasure cruise on the Thames, and are back on shore within minutes. The worst-hit building of all is Parliament. It stands on the riverbank, with its windows facing the water. The Times reports that the intense heat has driven the legislators out of their riverside rooms. So the government takes decisive action. It soaks the curtains in chloride of lime, a disinfectant. It does not work. One newspaper, The Examiner, spots the politician Benjamin Disraeli leaving a committee room with a handkerchief pressed to his nose. And remember what the doctors believe. If the smell is dangerous, the most important people in the country are breathing it.

To understand the fear, you need the history. Cholera, a disease spread through dirty water, has already come to London in waves. Records put the toll at more than fourteen thousand in eighteen forty-eight and forty-nine, and more than ten thousand in eighteen fifty-three and fifty-four. Almost everyone blames the air. One doctor, John Snow, disagrees. In eighteen fifty-four he traces a deadly outbreak in Soho to a single street pump, and the handle is removed. Four hundred and twenty people died. Afterwards, the authorities reject his theory anyway. So in eighteen fifty-eight, the official fear is still the air, and the air is in the House of Commons. Some Members reportedly discuss moving Parliament to Oxford or St Albans. Move the government, or fix the river. Which is cheaper?

Parliament chooses the river. A bill is brought by Benjamin Disraeli, and in the debate he calls the Thames a Stygian pool, reeking with ineffable and intolerable horrors. Stygian comes from the river Styx, the river of the dead in Greek myth. Not subtle, but it works. The bill lets a new body, the Metropolitan Board of Works, which runs London's sewers, borrow about three million pounds. Londoners repay it through a levy on their homes, over forty years. It becomes law on the second of August. How fast? Some sources say eighteen days. Counting from when it was first brought in, closer to seven weeks. Either way, for Parliament, that is a sprint. Historians add one point: the plans were already on the table. The Stink did not invent the solution. It sped it up. And the plan belongs to the Board's chief engineer, Joseph Bazalgette.

Bazalgette's idea is simple. Stop the waste reaching the river in the middle of the city. Build huge sewers along the banks, catch every pipe on the way, and carry it all east, downstream, to be released into the tidal Thames. Street by street, that means eleven hundred miles of smaller sewers feeding eighty-two miles of main brick tunnels. Pumps at Abbey Mills lift it thirty-six feet, so gravity can do the rest. More than three hundred million bricks go into it, by the usual count. On top of the tunnels, he builds the embankments, new riverside roads, to carry the pipes. In April eighteen sixty-five, the Prince of Wales opens the great pumping station at Crossness. The Victoria Embankment follows in eighteen seventy. Now, did it work?

Here is the twist. The theory behind it was wrong. The smell was never what was killing people. But by moving the sewage away from the city, the sewers fixed the real problem anyway. In eighteen sixty-six, cholera strikes the east of London one last time, and kills more than five thousand people. That area was not yet connected to the new system, and its water company drew water from a reservoir downstream of its own sewage. That outbreak convinced people that cholera travels in water. It was the last one in London. Today, with only small changes, Bazalgette's system is still the basis of the city's sewers, for more than nine million people. One historian, John Doxat, wrote that Bazalgette probably did more good, and saved more lives, than any single Victorian official. A heatwave, a river of waste, and a curtain soaked in chloride of lime. Now, back to July, eighteen fifty-eight.