One of a pair of stone towers, built in 1879 and 1889, which once drew fresh air into the U.S. Capitol for ventilation. Keeping the big building comfortable has been a challenge. (John Kelly/The Washington Post)

In June of 1894, the Washington Evening Star noted that in an effort to beat the heat, more and more members of Congress started wearing clothes made from a fabric known as homespun.

“Nearly half of the Representatives have adopted the material to a greater or lesser extent,” the Star reported. “It is a sort of toweling, made of flax grown in Kentucky and Tennessee. It is very coarse and never wears out.”

The writer explained that before the Civil War, homespun was considered “only good enough for Negroes, slaves being commonly dressed in it. Though scarcely pretty, it is very cool. The Web of it is so loose that the breezes blow through freely.”

Today we would call the fabric linen. It remains the perfect material to wear while sitting in a room full of hot air.

From the day Congress moved to Washington, its members have been obsessed with keeping themselves comfortable. And little wonder: Our city runs hot and cold. You think your office battles over the thermostat? Imagine working in the U.S. Capitol in the 19th century.

After last week’s column on the handsome brick tower at Judiciary Square that was built in 1881 to suck ventilating air into a nearby courthouse, David Huckabee of Arlington, Va., directed Answer Man to two similar towers on the west side of the U.S. Capitol. The two stone shafts — the House tower was completed in 1879, the Senate tower in 1889 — were part of an effort to make working in the Capitol more bearable.

[What’s up with the odd brick tower near the Court of Appeals at Judiciary Square?]

To study the HVAC history of the Capitol is to encounter a litany of complaints about the building’s unhealthful atmosphere. Much brain power was expended on how to get bad air out and good air in, where to place ductwork, whether to have fresh air fall from the ceiling or rise from the floor, etc.

These were not minor concerns. Many offices had fireplaces, and smoke from dozens of chimneys would swirl around in the odd currents of the Capitol dome, often spiraling back down flues. Carbonic-acid gas, a byproduct of gaslights, would build up in the legislative chambers.

Various ventilation methods were employed. In the 1850s, the multitalented Montgomery Meigs created a system that used steam-powered fans to force air through the Capitol and across steam coils to warm the incoming air.

The system did not live up to expectations.

In 1868, Herman Haupt, chief engineer of the Pennsylvania Railroad, and ventilation expert Lewis W. Leeds were tapped to look into things. Leeds noted that inlets in the floor designed to admit warmed or cooled air “were more or less contaminated by the refuse tobacco and spittle which had accumulated in them, and the air which came into the room was offensive from that cause.”

Leeds urged that these inlets be abolished. (Apparently, it was too much to just ask politicians not to spit on the floor.)

The two stone shafts are about 400 feet from the Capitol and about 800 feet from each other. As the Star reported in 1908: “By taking the air through the stone towers out on the Capitol grounds away from all contaminating influences, a pure and fresh supply is assured.” (By “contaminating influences,” the reporter didn’t mean lobbyists, but dirt and dust from roads, as well as exhalations from the Capitol itself.)

Beneath the towers were conduits nearly as big around as a railroad terminal. Huge fans — 12 feet in diameter — spun at 110 rpm, drawing in fresh air at a speed “powerful enough to sweep a strong man off his feet.”

As impressive as this may have been, this was not “manufactured weather,” an early term for what we call air conditioning. It wasn’t until 1928 that the Carrier installed an air-conditioning system on the House side. The Senate soon followed suit.

There were predictions that a cooler environment would lessen political frictions, as senators and representatives found themselves literally less hotheaded. That seems not to have happened. Perhaps only nitrous oxide could improve the mood in the Capitol today.

Twitter: @johnkelly

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For previous columns, visit washingtonpost.com/johnkelly.