There could be, with larger columns, small spirit-lamps or gas introduced. Let a tube in the column fit into an orifice in your table, and ignite the gas thus admitted by a spark of frictional electricity. The heat would be continuous during many hours.
BLUE TO WHITE.
Dissolve a small lump of indigo in sulphuric acid by the aid of moderate heat, and you will obtain an intense blue colour; add a drop of this to half a pint of water, so as to dilute the blue; then pour some of it into strong chloride of lime, and the blue will be bleached with almost magical velocity. This trick is called “The Restoration”—of the Bourbons understood, since their colour, the Royalist white, replaces the Republican blue.
HEAT IN POWER.
Cork a brass tube, holding water, and attached to a whirling table, and if it chafes against a wooden rubber in its motion the frictional heat will make the water boil, and the stopper will be blown out.
GREEN TO BLACK.
Make a cup of strong green tea; dissolve a little green copperas in water, which add to the tea, and its colour will be black.
COLOURS VANISHING AND REAPPEARING.
Dissolve brass filings in volatile alkali, which will be a liquid of a blue colour while exposed to the air, but, on corking a phial of it, the colour will disappear.