The Conservation of Fire

We arrive, thus, in the first half of the 18th century. In this period, in spite of some relevant to the science of heat work by Isaak Newton and Jean Bernoulli s son Daniel, the major contribution comes from Herman Boerhaave (1668-1738), professor of Medicine, Chemistry and Botany at 

Boerhaave was an excellent lecturer, that students from all over the civilized world came to listen to. His work was first published - in a pirated( ) edition - in 1727, and is described by Cardwell as follows (Cardwell, p.27)  

He sets out as an essential axiom the proposition that Fire is always conserved he argues that it cannot be created de novo, as claimed by certain English philosophers, and that in all changes the total quantity remains unaltered. Now this statement was perhaps crucial, for it is very difficult to see how a science of heat could have developed without a basic conservation principle such a principle was plainly essential for the formulation of the concepts of quantity of heat, of specific heat and of latent heat. (emphasis added.) 

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In addition to the fundamental axiom of the conservation of fire a second, but somewhat diffuse development, took place in the first half of the eighteenth century the notion of quantity of heat as a concept distinct from that of intensity or degree of heat was introduced. Cardwell comments (p.31) "Curiously, no one claimed to be the inventor of this concept. It seems that a number of scientists started using it independently, more or less simultaneously, and without any fiiss. It was a concept that led inevidently to the postulation of an absolute zero of temperature and, a little later on, to the discovery of specific and latent heats."... 

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