The effect which this and his subsequent discoveries produced, in revolutionizing the theory of Chemistry, will form an interesting subject for discussion in a future part of the present work: I shall therefore only remark in passing, that the fact of oxygen, the acknowledged principle of acidity, existing in combination with a metallic base, and imparting to it the properties of an alkali, was no sooner announced, than its truth was strenuously denied. It was an attack upon opinions sanctioned by the general suffrage of the scientific world;--it was, in fact, storming the very citadel of their philosophy: no wonder, then, that the agitator should have been assailed with a full cry for his revolutionary plans.[75] M. Curadau read a paper before the French Institute, in which he endeavoured to prove, _first_, that the conversion of the alkalies into metals was not a deoxidation of those bodies, but a combination of them with new elements;--_secondly_, that the affinity of the alkaline metals for oxygen was merely a chemical illusion, occasioned by some body the presence of which had not been suspected;--_thirdly_, that carbon was one of the elements of the alkaline metals, since it could be separated from them at pleasure, or converted into carbonic acid;--and _fourthly_, that if the specific gravities of the new substances were less than that of water, it was because hydrogen was associated with carbon in the combination. [75] Many years afterwards, when Davy was travelling on the Continent, a distinguished person about a foreign court, enquired who and what he was; never having heard of his scientific fame. Upon being told that his discoveries had revolutionized Chemistry, the courtier promptly replied--"I hate all revolutionists--his presence will not be acceptable here."