PRIESTLEY 59 



be remarked en passant that he lived in a great age, 

 an age remarkable for great names, which recall to the 

 mind great ideas : Swift, Voltaire, Rousseau, Johnson, 

 Hume, Goldsmith, Gibbon, Goethe, Schiller, Burns 

 Chatterton, Franklin, Mirabeau, Pitt, Talleyrand, Napoleon, 

 Nelson, Washington, and a host of others more or less 

 great lived in the same age as Priestley ; and what 

 pictures these names conjure to the thinking reader ! 



Although many of his works will perish as time rolls 

 on, his chemical discoveries will remain for ever. 



Joseph Priestley's name will live as the discoverer of 

 OXYGEN. It is curious that Priestley himself was so 

 wedded to the doctrine of Stahl the phlogistic theory 

 which supposed the existence of a subtle principle, 

 phlogiston, that he did not appreciate the vast importance 

 of his own discovery, and his attitude led Cuvier when 

 pronouncing his loge (at the time of his death) before 

 the Academic des Sciences, to describe him as " le pere de 

 la chimie moderne qui ne voulait pas reconnaitre sa fille." 



On 1st August 1774 Priestley discovered oxygen (de- 

 phlogisticated air) from red precipitate (mercuric oxide), 

 which gave chemists a new gas of wonderful properties, 

 only to involve chemical processes into great confusion and 

 deeper mystery. The fire air (oxygen) of Scheele, recorded 

 in his Chemische Abhandlung von der Luft und dem Feuer, 

 brought some light into the chemistry of air ; but their 

 discoveries were enveloped in darkness the jargon of 



