Rudolf Julius Emanuel Clausius (PL-DE) noted that heat is destructible, and examined how it can be converted to work with the flow of heat from a warm body to a cold one. He concluded that entropy, a concept he introduced, must inevitably increase in the universe (, ).
Bernard Courtois (FR) was the first to prepare iodine when he observed purple vapors rising from kelp ashes that he had acidified with sulfuric acid and heated. The purple vapors condensed on a cold surface, forming nearly black crystals (). : He actually performed this experiment in 1811.
Where do Rat Coat Colors Come From
Karl Georg Lucas Christian Bergmann (DE) and Joel Asaph Allen (US) independently proposed very similar rules in zoology. states that body weight tends to a minimum in warmer regions, increases to a certain threshold as temperature declines, and then falls off again as temperature falls further. Birds and mammals in cold regions have been observed to be bulkier than individuals of the same species in warm regions. It was proposed to account for an adaptive mechanism to conserve or to radiate body heat, depending on climate. states that animals adapted to cold have smaller and shorter limbs and other protruding body parts (, ).