LAVOISIER. 259 



paper printed seven years after by himself and M. de La 

 Place, on the nature of heat, a reference is distinctly 

 made to this doctrine of aeriform fluidity, as the theory of 

 M. Lavoisier*. We find this in the Memoirs for 1780f, 

 published 1784, but the paper was read June 18, 1783. 

 The theory of latent heat had been taught by Dr. Black 

 to large classes for above twenty years before that time, 

 and had been universally associated with his name in 

 every part of the world. 



But it may be supposed, that by some singular chance, 

 M. Lavoisier was unacquainted with that illustrious name. 

 I must therefore produce evidence to the contrary under 

 his own hand. In Oct., 1789, he writes to Dr. Black, 

 and professes himself to be " zele admirateur de la pro- 

 fondeur de votre genie, et des importantes revolutions 

 que vos decouvertes ont occasionnees dans la chimie." In 

 the following year, July 14, he tells him: " Accoutume 

 & vous regarder comme mon maitre, je ne serai content 

 jusqu'& ce que les circonstances permettent de vous aller 

 porter moi-mme le temoignage de mon admiration, et de 

 me ranger au nombre de vos disciples." Now after 

 writing these letters, M.Lavoisier published his 'Elements ;' 

 and while writing them he published, in the Memoirs of 

 the Academy, a paper in which the doctrine of latent 

 heat, as the cause of fluidity, is described, and described 



* Mem. 1780, p. 399. 



t See, too, vol. for 1777, p. 595. In the paper 1777 first cited, 

 the only thing ascribed to preceding philosophers is the belief in 

 the existence of an igneous fluid, or matter of heat in oui planet ; 

 and the experiments of Richman, Cullen, Mairan, and Baume on 

 the production of cold by evaporation. 



