It is not many years since the lucifer matches, as they were at first called, were invented. Before this we had a most inconvenient way of getting a light when there was no fire at hand. A flint was struck upon a piece of steel again and again over some tinder. The object was to make a spark which would set fire to the tinder. This was not always readily done, and I remember getting out of patience many a time in working over my tinder-box when I was a student in college.
Heat made in the earth.
There is a great deal of heat made inside of the earth, and it is supposed by some that all the middle of this great round ball that is called the earth is an immense fire like a furnace. The earthquakes are supposed to be caused by the heavings of this fire, and the volcanoes are so many chimneys where the fire of this great furnace gets vent.
Cold not a thing.
Heat is a thing, but there is really no such thing as cold. Any thing is cold when there is but little heat in it. Whether all the heat can get out of any thing we do not know. There is heat even in ice. This has been proved in this way: Two pieces of ice were rubbed together in a very cold day, and some of the ice became melted. How was this? The air all about the ice was too cold to melt it; and it must be, therefore, that it was the heat in the ice, waked up, as we may say, and brought out by the rubbing, that melted the ice.
What feels cold to you may feel warm to another. If, when your hand is very warm, you take hold of some one’s hand that is only moderately warm, it will feel cool to you, and perhaps even cold; but if some one whose hands are quite cold takes hold of the same hand, it will feel to him quite warm.
Experiment with three vessels.
Try a little experiment, which will show the same thing in another way. Take three vessels. Put into one water as hot as your hand can bear, into another ice-cold water, and into the third water that is a little warm, or that has had the chill taken off. Now put one of your hands into the vessel of hot water, and the other into the vessel of cold water. Keep them there a little while. Then take them out, and put both into the vessel that has the water which is slightly warmed. The water in this will feel cold to the hand which was in the hot water, and warm to the hand which was in the cold water.
Drinking water after eating ice-cream.