How to Boll Water In Paper.
When we lay our hands upon a piece of metal on a table, says the St. Louis Post-Dispatch, we say it is “cold;” on a piece of flannel that it is “warm.” They are both of exactly the same temperature—neither is colder or warmer than the other. They are both at the same temperature as everything else in the room. We felt the metal cold because it is a good conductor and rapidly carries away the heat of our hands. The flannel does not, so we call it warm ; it does not withdraw warmth from us. Paper is a bad conductor ; water is a better one. Or, tospeak according to the card, water is not a good conductor, but, by a process which goes on in heated water, known as convection, it acts in the experiment, we shall discover, as well as if it were good. If we fold a piece of paper so that it will contain water we may boil the water in the paper. The water greedily uses up all the heat ; there is none left for the paper. The water cannot get hotter than boiling point—nor will it let the paper get hotter—and this is not hot enough for combustion. The experiment of melding lead on a playing card has the same explanation as that of boil ng water in a paper bag. The tenqieiature required for melding lead is higher than that required for boiling water, but even that tempeiature is short of what is required to set fire to the card.