100 CAVENDISH. 



the speculations of chemists. He had a most happy 

 facility in reducing the knowledge cf scattered and 

 isolated facts to a system. His talent for generalization 

 has not often been surpassed ; and it led him, together 

 with his admirable freedom from preconceived preju- 

 dice, and his resolute boldness of investigation in un- 

 frequented paths, to make some of the most felicitous 

 inductions, well deserving the title of discoveries, that 

 have ever been made, although the materials of his in- 

 ferences were obtained from the experiments and ob- 

 servations of his predecessors, and his own experiments, 

 except on the nature of the diamond, led to no material 

 extension of our chemical knowledge. Stript of the 

 plumes in which he sought to array himself, repulsed 

 from the avenues by which he would fain have in- 

 truded himself among those whose experiments led at 

 once to great discoveries, he is now, on all hands, 

 allowed to have never made us acquainted with a single 

 new gas, or a new substance of any kind, or, except 

 as to carbon, with a single new combination of the old- 

 He did not, like Black, discover carbonic acid or latent 

 heat he did not, like Priestley, discover oxygen he 

 did not, like Scheele, discover chlorine he did not, 

 like Davy, discover the alkaline metals or like Caven- 

 dish, by direct experiment, show how water and nitrous 

 acid are constituted or, like Berthollet, explain of 

 what ammonia consists. But it is equally confessed 

 that, by sound and happy reasoning on the experiments 

 of others, he showed how the process of combustion 

 and of calcination takes place, and to him and his in- 

 dividual researches we owe the important discovery 

 that fixed air, however generated, whether by respira- 

 tion or by combustion or by fermentation (its three 

 great sources, as proved by Black), is the combination 

 of oxygen and carbon. Nor is it any derogation from 

 his claims to the title of a discoverer of physical truths 

 that his generalization pushed too far made him regard 

 oxygen as necessary to all combustion and all acidi- 



