CHEMISTRY OF GASES. 275 



ments, that Cavendish is justly entitled to the he nor of this discovery, 

 which in his own time was never contested. The publication of his 

 Journals of Experiments 11 shows that he succeeded in establishing the 

 point in question in July, 1781. His experiments are referred to in an 

 abstract of a paper of Priestley's, made by Dr. Maty, the secretary of 

 the Royal Society, in June, 1783. In June, 1783, also, Dr. Blagden 

 communicated the result of Cavendish's experiments to Lavoisier, at 

 Paris. Watt's letter, containing his hypothesis that " water is com 

 posed of dephlogisticated air and phlogiston deprived of part of theii 

 latent or elementary heat ; and that phlogisticated or pure air is com- 

 posed of water deprived of its phlogiston and united to elementary heat 

 and light," was not read till Nov. 1783 ; and even if it could have sug- 

 gested such an experiment as Cavendish's (which does not appear 

 likely), is proved, by the dates, to have had no share in doing so. 



Mr. Cavendish's experiment was suggested by an experiment in 

 which Warltire, a lecturer on chemistry at Birmingham, exploded a 

 mixture of hydrogen and common air in a close vessel, in order to 

 determine whether heat were ponderable.] 



CHAPTER VI. 

 EPOCH OF THE THEORY OF OXYGEN. LAVOISIER. 



Sect. i. Prelude to the Theory. Its Publication. 



~\T7"E arrive now at a great epoch in the history of Chemistry. Few 

 revolutions in science have immediately excited so much general 

 notice as the introduction of the theory of oxygen. The simplicity 

 and symmetry of the modes of combination which it assumed; and, 

 above all, the construction and universal adoption of a nomenclature 

 which applied to all substances, and which seemed to reveal their 

 inmost constitution by their name, naturally gave it an almost irresis- 

 tible sway over men's minds. "We must, however, dispassionately 

 trace the course of 'ts introduction. 



11 Appendix to Mr. V. Harcourt's Address. 



