A man builds himself a house from brick and lime. The bricks and the lime are burnt by wood. The wood has been prepared by the sun.

Everything that men need, that is for their use⁠—all that is prepared by the sun, and on all that goes much sun’s heat. The reason that men need bread is because the sun has produced it, and because there is much sun’s heat in it. Bread warms him who eats it.

The reason that wood and logs are needed is because there is much heat in them. He who buys wood for the winter, buys sun’s heat; and in the winter he burns the wood whenever he wants it, and lets the sun’s heat into his room.

When there is heat, there is motion. No matter what motion it may be⁠—it all comes from heat, either directly from the sun’s heat, or from the heat which the sun has prepared in the coal, the wood, the bread, and the grass.