During grammar school science experiements into properties of different alcohols:

The residue of each test was tipped down the sinks, which were groupedin threes. There were no U-bends, but each group of sinks emptied intoa single box, which overflowed into the mains sewers. Presumably thiswas intended to retain things like droplets of mercury, which was notbanned from use when I was 16.

During the session, my bunsen went out, so I re-lit it with a splintlit from the teacher's bunsen. For safety's sake (!) I dropped theburning splint into the sink, intending to extinguish it with water,instead of waving it around in the alcohol fumes. A small blue flamedisappeared down the plughole. Hum, thinks I, I wonder where that'sgoing?

I opened the cupboard 'neath the sink, only to find the drain box, fullof alcohol, a roaring mass of flame. Shutting the doors, I called out,"Er, Sir..." just as the inch-thick wooden lids blew off the adjacentun-used sinks. Fortunately, the back-blast extinguished the flamesunder the cupboard, so the box only sagged slightly!