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.
-- Hermann von Helmholtz
   
Hermann von Helmholtz   Name:
Hermann von Helmholtz
Type:
Physicist
Nationality:
German
Birth:
August 31, 1821
Death:
September 8, 1894
https://www.nutquote.com/quote/Hermann_von_Helmholtz