206 



NOTES TO BOOK XIV. 



(F.) p. 141. THOUGH the view of the mode in which 

 gaseous elements become f&ed in bodies and determine 

 their properties, had great additional light thrown upon it 

 by Dr. Black's discoveries, as stated in the text, the notion 

 that solid bodies involve such gaseous elements was not 

 new at that period. Mr. Vernon Harcourt has shown 

 (Phil. Mag. 1846,) that Newton and Boyle admitted into 

 their speculations airs of various kinds, capable of fixation 

 in bodies. I have, in the succeeding chapter, (Chap, vi.) 

 spoken of the views of Rey, Hooke and Mayow, connected 

 with the function of airs in chemistry, and forming a pre- 

 lude to the Oxygen Theory. 



(G.) p. 144. In the Philosophy (B. vi. C. 4,) I have 

 stated, with reference to recent attempts to deprive 

 Cavendish of the credit of his discovery of the composition 

 of water, and to transfer it to Watt, that Watt not only 

 did not anticipate, but did not fully appreciate the dis- 

 covery of Cavendish and Lavoisier ; and I have expressed 

 my concurrence with Mr. Vernon Harcourfs views, when 

 he says (Address to the British Association, 183 9,) that 

 " Cavendish pared off from the current hypotheses their 

 theory of combustion, and their affinities of imponderable 

 for ponderable matter, as complicating chemical with phy- 

 sical considerations ; and he then corrected and adjusted 

 them with admirable skill to the actual phenomena, not 

 binding the facts to the theory, but adapting the theory to 

 the facts." 



