Have you ever wondered where the term proof for alcoholic beverages comes from?

[Xipe Totec]

According to wiki, in the 18th century and until 1 January 1980, the United Kingdom defined alcohol content in terms of "proof spirit", which was defined as the most dilute spirit that would sustain combustion of gunpowder. The term originated in the 18th century, when payments to British sailors included rations of rum. To ensure that the rum had not been watered down, it was "proofed" by dousing gunpowder in it, then tested to see if the gunpowder would ignite. If it did not, then the rum contained too much water and was considered to be "under proof". It was found that gunpowder would not burn in rum that contained less than 57.15% abv. Therefore, rum that contained this percentage of alcohol was defined to have "100 degrees proof".

http://en.wikipedia.org/wiki/Alcohol_proof

But I have found a different definition of proof, in old Spanish texts:

Aguardiente Refino, a prueba de aceite: Refined aguardiente (fire water), by oil proof.

Meaning, a concentration of alcohol so high, as to be able to dissolve oil without clouding. Three drops of oil into one thousand drops of liquor without clouding is the proof.

http://books.google.com/books?id=dEkfsduRyX8C&pg=PA367&lpg=PA367&dq=aguardiente+refino&source=bl&ots=40UrOihIQh&sig=rYyfCw8Z9EOWS-AbcKOFj2RWoaw&hl=en&ei=3G_aTO-4HoS8lQeD_bTaCQ&sa=X&oi=book_result&ct=result&resnum=2&sqi=2&ved=0CBwQ6AEwAQ#v=onepage&q=aguardiente%20refino&f=false

Have you ever wondered why Everclear is called by that name?