We have also furnaces of great diversity, and that keep great diversity of heats: Fierce and quick; strong and constant; soft and mild; blown, quiet, dry, moist; and the like. But above all we have heats, in imitation of the suns and heavenly bodies’ heats that pass diverse inequalities, and (as it were) orbs, progresses, and returns whereby we produced admirable effects. Besides we have heats of dungs; and of bellies and maws of living creatures, and of their bloods, and bodies; and of hays and herbs laid up moist; of lime unquenched; and such like. Instruments also which generate heat only by motion. And further, places for strong insulations; and again places under the earth, which by nature, or art, yield heat. These diverse heats we use, as the nature of the operation, which we intend, requires.