414 . PRIESTLEY. 



union of the gas and the metal which had changed 

 it. But nothing could overcome Priestley's repugnance 

 to give up phlogiston : he adhered to it while he lived ; 

 he never would believe that water was formed of the 

 two gaseous bodies whose combustion and disappear- 

 ance leaves a weight of liquid equal to their joint 

 weights ; he always imagined that water was held in 

 suspense by these gases and precipitated on their 

 disappearing. He never would believe that metals 

 owe their malleability and lustre to any cause other 

 than phlogiston, or lose their properties except by 

 combining with oxygen, which takes the phlogiston 

 from them. He never would believe that combustion 

 is anything but the phlogiston leaving the inflammable 

 body and joining the oxygen ; or that when an acid 

 is formed by the burning, that acid contains the 

 oxygen and the combustible base. That his obstinate 

 unbelief was perfectly disinterested no one can doubt. 

 The discoverer of oxygen, and of the true cause of re- 

 spiration, had, of all men, the strongest interest in 

 assenting to a theory which was wholly founded upon 

 his own discovery, and which made him the imme- 

 diate, as Black was the more remote, author of modern 

 chemical science made him the philosopher who had 

 raised the superstructure upon the foundation which 

 his predecessor had laid. 



The merit of Dr. Priestley, as a cultivator of science, 

 was the activity with which he made experiments the 

 watchful attention with which he observed every 

 phenomenon, following the minutest circumstances of 

 each process the versatility with which he prosecuted 

 each new idea that arose from his trials his diligence 



