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 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. 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 éloge (at the time of his death) before the Académie des Sciences, to describe him as "le père de la chimie modèrne qui ne voulait pas reconnaitre sa fille."

On 1st August 1774 Priestley discovered oxygen (dephlogisticated 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