Before The Light Bulb, Cars Still Had Headlights. Here's How They Worked

The horse-drawn carriages that predated internal combustion vehicles were indispensable for mobility, but horses don't have headlights or any form of electric-powered headlamps that we've come to expect in our metal, rubber, and microplastic-laden steeds. Instead, early noblemen had to make do with candle-powered lamps, which, you can probably imagine, were not great at lighting a darkened path. For what it's worth, night-riding carriages needed light to be seen, and those candle lamps were pretty adequate for the time.

At about the same time that Thomas Edison conceived the incandescent light bulb in 1879 (decades before Henry Ford changed the world with the Model T in 1908), steam automobiles and the earliest gas cars moved on from candlepower to oil and acetylene. Machine-powered cars are faster than carriages, and we all know wind can blow out candles. This is where oil lamps had an edge, as they could keep burning in snow and rain. The oil headlamps on a vintage car are no different from a hand-carried torch, which draws oil to a wick and burns at the tip to produce light.

However, acetylene (or carbide) headlights became more mainstream. They burned a brighter, whiter light than the yellow flame of an oil lamp and were more unbothered by wind gusts or precipitation. Then again, they were more finicky than oil lamps and demanded persistent maintenance to work flawlessly without exploding and turning your beloved vintage car into a smoking mass of junk.

Long before the U.S. government mandated automakers to install a pair of 7-inch round sealed-beam headlamps, a standard that began in 1940, the earliest mass-produced cars, like the Ford Model T, came with carbide or acetylene headlights. To make them work, the system needs two things: Grayish lumps of calcium carbide and plain water. Mixing the two produces acetylene gas, and lighting up the gas produces a bright flame.

The most basic acetylene headlight assembly has an upper tank to store water, while the lower tank is for the calcium carbide. There's a valve on top to adjust how much water drips below the carbide tank, and the ensuing chemical reaction produces acetylene gas that routes inside the lens assembly. 

Before driving at night, the tanks needed to be filled with water and calcium carbide, and the valve adjusted to let the water drip. Drivers then had to swing open the front of each headlight's lens cover and light the wick with a match. Some vintage cars have acetylene generators on the running boards and the necessary piping to route acetylene gas, but the basic operating concept is the same.

As you can probably imagine, acetylene headlights were not without risks. Calcium carbide is highly flammable, and leaks in the system could be bad news. Improper handling could lead to explosions, too, and the lower tanks require frequent cleaning to keep everything running as it should.

Moreover, you have to get out of the car to turn them on, and that's not very practical in inclement weather. You must also physically fine-tune the water valve if you need more light, which, again, is not the most convenient method compared to automatic high beams. The tides began changing when C.A. Vandervell patented the first variable speed dynamo for motor cars in 1904. Real progress came in 1912, when Cadillac introduced the Model 30, the first car with an electric self-starter, electric-powered headlights, and electronic ignition.

Then, Chrysler debuted its first car with an alternator, the Plymouth Valiant, in 1960, which made car manufacturers switch from dynamo generators to alternators. Since then, vehicle headlights have shifted from sealed-beam types to halogen to HIDs and LEDs, but there's no denying that acetylene headlights and their warm glows have a charm of their own, for better or worse.