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The Drunkometer


Here’s an interesting piece of history. Today, New Year’s Eve, in 1938, police in Indianapolis, Indiana used the first commercial test to discover scientifically if a person had been drinking alcohol and if so, how much. December 31, 1938 saw the debut of the Drunkometer, designed by Rolla Neil Harger, a chemistry professor at Indiana University. He began working on the device in the 1930s, and patented it in 1936.

The drunkometer collected a motorist’s breath sample directly into a balloon inside the machine. The breath sample was then pumped through an acidified potassium permanganate solution. If there was alcohol in the breath sample, the solution changed color. The greater the color change, the more alcohol there was present in the breath. The drunkometer was manufactured and sold by Stephenson Corporation of Red Bank, New Jersey.


Dorothy Brengel helps W.D. Foden, Chairman of Statler Safety Committee, demonstrate the “Drunkometer”, a breath tests for alcohol, on display at the Greater New York Safety Council, Hotel Statler, March 28, 1950. For the preliminary test, the breath of the suspect is collected in a balloon and passed through a purple fluid (potassium permanganate and sulphuric acid) to see if it changes color. The breath of a non-drinking person will cause no change. If the purple color disappears, the amount of breath required to accomplish this indicates the approximate accumulation of alcohol in the blood. (AP/Carl Nesensohn)

In 1938, on New Year’s Eve, police in Indianapolis put a new piece of technology through its first practical test.

They used a breath analyzer to determine if someone had been drinking. What was then called the “Drunkometer” was based on the same idea as modern breathalyzers: a person blows into a bag, which contains chemicals that react according to how much alcohol is on a person’s breath.

The Daily Dose gives a good account of its early use:

Thanks to the end of Prohibition and a boom in car sales, drunk driving had become a fast-growing problem in America in the 1930s. But on this New Year’s Eve, police in Indianapolis, Indiana went out armed with a new weapon to fight against people who had gotten behind the wheel after having too much to drink.

It’s a contraption called a “drunkometer” and it’s the invention of an Indiana University chemist named Rolla Harger. He had been working on the device since the early 1930s and had patented it two years earlier. The concept behind the drunkometer was pretty basic. Drivers suspected of being drunk were asked to breathe into a rubber balloon, which was attached to a tube of purple liquid—a weak solution of potassium permanganate in sulphuric acid.

If there was alcohol on their breath, the chemical solution changed color–the darker it got, the more alcohol they had in their system. From the shade of the liquid, the cops could use a simple equation to estimate the alcohol level in a person’s bloodstream. Previously, the only way police could check a driver’s alcohol level was to get a blood or urine sample; Neither was a very practical option on the roadside. While the drunkometer looked a bit like a mini chemistry set, it was portable, able to fit into a small suitcase.

Harger made the device as simple as possible so that judges and juries would understand how it worked and police officers could easily be trained to use it. He also made the drunkometer hard to beat. Experiments showed that no illness affected the result, and that nothing a person might eat – garlic, cloves, strong onions – would make any difference. Once police started using it, the drunkometer was found to have another advantage. A dramatic change in the color of the liquid could often make people admit how much they had drunk.

Sometimes Harger would ride along with the police to see how his invention was being used. What he discovered was that a lot more people were driving drunk than he ever imagined.

The drunkometer was used by police departments all over the country until the 1950s when it was replaced by the breathalyzer, invented by another Indiana University professor, Robert Borkenstein. The breathalyzer is a much smaller and more sophisticated device that uses infrared spectroscopy to measure blood alcohol levels.


Tallahassee police officer with a Harger “Drunkometer” breathalyzer machine, photo taken in 1953.

The Drunkometer was replaced by the Breathalyzer in 1954, but for sixteen years was the way police nabbed drunk drivers. But who came up with that name? Happy New Year! Be careful out there.

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