By having the fires made in the cellar, so that the air when heated, may ascend through pipes to the different parts of the building.
Is there any substance that does not contract by cold?
Yes; water, when near freezing, does not contract by cold.
What takes place with the water?
When it is reduced nearly to the freezing point, it begins to expand, and when it freezes, it expands still more.
How much does water expand by freezing?
It expands about one-seventh of its bulk. That is, seven gallons of water will make eight gallons of ice.
Does freezing water expand with much force?
Yes; it expands with great force.
Why are vessels containing water often broken during a cold night?