A really interesting article on the history of the breathalyzer and how it came into being.
The first serious scientific work on mechanizing the determination of whether someone was driving drunk took place in the 1920s. A doctor and researcher in Los Angeles by the name of Dr. Emil Bogen conducted a landmark study in 1927 on how to scientifically determine inebriation. By this time it was fairly well-established that testing blood gave you a solid idea of how drunk a person might be. But by testing urine, blood, and breath, Bogen found that the latter could indeed function as a reliable estimator for blood alcohol content (BAC).
Dr. Bogen’s breath test used a large football bladder that contained sulphuric acid and potassium dichromate. A patient would breathe into it, and as the chemicals in the football bladder changed from yellow to various shades of blue and green, they were compared to tubes of the same chemicals in which different amounts of alcohol had been added. Effective, but not the most practical for a traffic stop.
Drunk Driving and The Pre-History of Breathalyzers [via Gizmodo]