h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The business about mixing spirit with gunpowder and then determining if it would ignite as a way of establishing alcoholic strength is an old Royal Navy trick. Rum was shipped on RN ships until about 1967. Back in the days of Nelson, the Ships Purser, as the officer in charge of stores, had to make sure the rum shipped on board was of the proper strength, as suppliers in those days were incredibly dishonest - almost as bad as estate agents these days. Not being chemists, to test the spirit the Pursers would mix one ounce of the spirit to be boarded with one ounce of fine milled gunpowder. If the mixture ignited, then there was clearly enough alcohol in the spirit to ensure the crew was kept happy. If the spirit merely wetted the powder, the supplier had some explaining to do, followed by the usual bribe. If the spirit ignited, it was 'proved' to be of the required strength - and so we have 'proof' spirits, or 57.7% alcohol by volume.

Incidentally, the rum ration was one pint of spirits, together with either a gallon of beer or the equivalent in wine, per man per day. I have a theory that Trafalgar was just a massive alcoholic hallucination.

I joined the navy well after the rum ration was done away with, but to be honest, I have the suspicion that things hadn't changed much, 5 years of my life seem to have been a massive alcohol induced hallucination...

Having said that, I could probably say that about most of my life since the age of 18