Q. Why are salt and snow mixed together, colder than snow?
A. When salt is mixed with snow, it dissolves the crystals into a fluid; and whenever a solid is converted to a liquid, heat is absorbed, and the cold made more intense.
Q. Why does frost make the earth crack?
A. During the warm weather the earth absorbed abundance of moisture, which the winter freezes: and (as water expands by frost) the expanding water thrusts the particles of earth apart from each other, and leaves a chink or crack behind.
Q. Show the wisdom of God in this arrangement.
A. These cracks in the earth let in the air, the dew and rain, and many gases favourable to vegetation.
Q. Why does the earth crumble in spring?
A. In spring the ice of the clods dissolves, and the particles of earth (which had been held apart by the expanded ice) are left unsupported, and tumble into minute parts (because their cement is dissolved).
Q. Why does mortar crumble away in frost?