LESSON XVIII.
The same subject, concluded.
Daughter. Well, mother, I understand, now, how the match is set on fire. It is rubbed on the sand-paper, and that produces heat, and the heat sets the match on fire. But I always thought that fire makes heat, and not that heat makes fire.
Mother. Heat does not always make fire, Caroline; for, if it did, everything would be on fire.
Daughter. Everything on fire, mother! why, what do you mean?
Mother. I mean, my dear, that everything contains heat.
Daughter. Everything contains heat, mother, did you say? Why, then, is not everything warm? Some things, mother, are very cold; as ice, and snow, and that marble slab.
Mother. Yes, my child, everything contains heat, as I shall presently show you. When Alice goes to make a fire in a cold day, she does not carry the heat with her, and put it into the fire, nor into the wood, nor the coal, does she?
Daughter. Why, no, to be sure not, mother.
Mother. And the heat that comes from the fire, after it is made, does not come in at the windows, nor down the chimney, does it?
Daughter. Why, no, mother; it feels cold at the windows, and cold air comes down the chimney.
Mother. But, after the fire is made, we feel much heat coming from the fire, do we not?
Daughter. Why, yes, mother; that is what the fire is made for. We feel cold, and we want a fire to make us warm; and when the fire is made, it sends out heat, and makes us warm.
Mother. Well, now, where can the heat come from? You know what fire is made from, do you not?
Daughter. Certainly, mother; the fire is made of wood, or of coal.
Mother. But is the wood or the coal warm before the fire is made?
Daughter. No, mother, the wood and the coal come from the cold wood-house, or the cellar, and they are both very cold.
Mother. And yet, the wood and the coal become very hot when they are on fire.
Daughter. O yes, mother, so hot that we cannot touch them with our hands, and we have to take the shovel or the tongs to move them.
Mother. And do they burn the shovel and the tongs, my dear?
Daughter. Why, no, mother; if they did, the shovel and the tongs would be of little use in stirring the fire.
Mother. Can you think of any reason why they do not burn the shovel and the tongs?
Daughter. You told me, mother, that some things require a very little heat to set them on fire, and that other things require a great deal. I suppose that there was not heat enough to set them on fire; and if there had been, they would not burn, because they are made of iron.
Mother. You are partly right, my dear, and partly wrong. They would not burn, because there was not heat enough in the fire to burn them. But there are very few things, and in fact it may be doubted whether there is anything, which will not burn, when sufficient heat is applied. But let us return to the fire: you say the heat does not come from the windows nor from the chimney, and you say, also, that the wood and the coal are both cold. Now, where can the heat come from?
Daughter. I am sure I cannot tell, mother; will you please to tell me?
Mother. You recollect that I told you that the rubbing of the match on the sand-paper produces a little heat, which caused the match to burn. The match was then applied to the shavings, and, as it was burning, gave out heat enough to set the shavings on fire; the shavings produced heat enough to set the pine wood, or kindling, on fire, and then the pine wood, or kindling, produced more heat, and set the wood and coal on fire. Now, there was nothing to produce the heat but the match, the shavings, the wood and the coal; and the heat must have been in them. The fire only served to set it free, and let it come out of the match, the wood, and the coal.
Daughter. But, mother, how did the heat get into the wood and coal?
Mother. It is not known, my dear, how the heat got into the wood and coal, any more than how the fruit gets on to a tree. We say that it grows on the tree; but what growing is, and how it is caused, are among the secrets of God.
Daughter. If the heat is in the wood and the coal, mother, why do we not feel it in them? They both feel cold. I cannot perceive any heat in them.
Mother. The heat is in the wood and the coal, although you do not see it. Do you see any smoke in the wood and the coal, my dear?
Daughter. No, mother, I do not.
Mother. Did you never see a stick of wood fall on the hearth from the kitchen fire, and see the smoke coming from it?
Daughter. O yes, mother, very often; and the smoke goes all over the room, and into my eyes, and makes the tears come into my eyes.
Mother. And can you see the smoke in the wood before the wood is put on the fire?
Daughter. No, mother, I am sure I cannot.
Mother. But you are sure that the smoke comes from the wood, are you not?
Daughter. O yes, mother; I see it coming right out of the wood.
Mother. Then, my dear, I suppose you know that if there is something in the wood and coal, which you call smoke, although you cannot see it until it comes out, you can easily conceive how another thing, which we call heat, can be in the wood and coal, which we cannot perceive until it is made to come out.
Daughter. O yes, mother; how wonderful it is!
Mother. Yes, my dear, all the works of God are wonderful; and what is very surprising is, that many of his most wonderful works are so common, so continually before our eyes, that we do not deem them wonderful until we have been made to think much about them, by talking about them, as you and I have talked about the rain, and the clouds, and light, and its colors.
Daughter. I have been thinking, mother, about Alice and the fire. You told me that the fire did not make the heat, any more than I make the little mouse or the bird when I open the cage door and let them out. I see now how it is. Alice brings the wood and the coal into the kitchen fireplace, and the match lets the heat out of the shavings, and the shavings let it out of the wood and the coal, until we get heat enough to make us warm.
Mother. Yes, my dear; and there is no more heat in the room after the fire is made than there was before,—only, before the fire was made, the heat was hid, and we could not perceive it; but when the fire is made, it makes the heat come out, and makes it free, just as I make the little bird free, by opening his cage door.
