Both may be developed in their greatest intensity by electricity.
They are both imponderable.
"When I consider thy heavens, the work of thy fingers, the moon and the stars which thou hast ordained:"
544. In what respects are light and heat dissimilar?
Heat frequently exists without light.
Light is usually attended with heat.
Light may be instantly extinguished, but Heat can only be more gradually reduced, by diffusion.
The solar rays deliver heat to the earth by day, and the heat remains with the earth when the light has departed.