now days, demijohn is commonly used to describe the 5 gallon water jugs commonly used by office water coolers. the new one are plastic, but home vinters used to steal the glass ones on a regular basis, for fermenting wine...

the plasic ones are great for making bottle rockets.. the large interior volume can hold alot of fuel in the form of evaported alcohol, and the narrow neck hold a wick..

done right, they will shoot across the floor a rather high speed, with long blue flames trailing.. they make a most satisfactory whosh! as they take off.. now just how is it that i know this... i can't imagine.. i must have had a first hand encounter sometime..


my other obsession