Hermann von Helmholtz

The older view of the nature of heat was that it is a substance, very fine and imponderable indeed, but indestructible, and unchangeable in quantity, which is an essential fundamental property of all matter.

What appeared to the earlier physicists to be the constant quantity of heat is nothing more than the whole motive power of the motion of heat, which remains constant so long as it is not transformed into other forms of work, or results afresh from them.

I must be informed, that one of my great duties was, to obey the priests in all things; and this I soon learnt, to my utter astonishment and horror, was to live in the practice of criminal intercourse with them.