The ice, often so very thick, is all crystal. And how beautiful it is when it is formed from clear water in a still place! There is one thing very singular about ice which I must mention. You know that it is lighter than water, for it swims on the top of it instead of sinking in it. This is rather strange. One would suppose that when the fluid water changed into a solid, it would be heavier, because the particles stick tighter together then; but somehow, although they stick together much more tightly, they are farther apart than they were before. It is this that makes the ice lighter. If they were closer together, of course it would be heavier.
We do not understand how God has made this to be so, but we can understand what reason he had for it. It would be very bad to have ice heavier than water. If it were heavier, there would be a great deal of ice on the bottom of our rivers, and ponds, and lakes in the winter. Then it would take a long time for the warm weather to melt this covered-up ice, and in some places it would not all be melted before another winter came. This would make bad work, and every year it would become worse, for there would be additions from year to year to the ice that is not melted. As it is now, the ice is all cleared out of the way in most parts of the world in the early spring, because the sun and the warm rains get at it, and thus the earth becomes ready in a very short time for the summer.
Regions of perpetual ice and snow.
With us the ice and the snow bear rule but a part of the year, but there are regions in the far north where they are always present. No summer comes there to melt them. You have heard of the icebergs in the seas of those regions. These piles of ice often rise like mountains, and many a noble ship has been crushed by them.
There are mountains, too, in some parts of the world so high that winter ever rules on their summits. The ice and the snow are ever there glistening in the sun, even while in the valleys below the golden harvests are ripening in all their beauty.
Questions.—What is said about the difference between snow and water? What is snow? Is the snow all alike? What is said about the beauty of snow-flakes? What are snow-flakes? Give the comparison between them and other crystals. What is true of the flakes of snow just as it is of leaves and flowers? What is said about the abundance of the crystals of snow? Tell about the tree covered with snow. What is said about God’s destroying the crystals of the snow? What is the frostwork on the windows in winter? What is said about the figures in it? What is ice? What is there very singular about it? What would happen if ice were heavier than water? Tell about the regions where there are always ice and snow. What is true of some mountains?
CHAPTER XXII.
HEAT AND COLD.
We do not know what heat is. Wise men have tried to find out what it is, but they have never been able to do it. But we know some things that heat comes from, and some things that it does, and these I will tell you about.