Proof?  Proof of what? In America, the potency of alcohol is measured in degrees of proof.  Proof measures the amount of alcohol within spirits, a measure that runs from 0 to 200.  0 proof would be absolutely free of alcohol; 100 proof would be half alcohol; 200 proof would be pure alcohol.  But why 200? This dates back to 16 th century England, when spirits were taxed differently according to the amount of alcohol in them.  Tax collectors would perform a test to determine how much alcohol was in particular spirits.  To conduct the test, a pellet of gunpowder would be soaked in the spirit, then removed to see if it would still burn.  If the pellet burned after being soaked in rum, it was said to be “100 degrees proof”, and higher taxes were levied on it. The proof test was applied to other spirits, but rum was the one that was used to set the standard.  At this time, there was no such thing as “200 proof”.  The English...