On the 8th April, 1812, he received the honour of knighthood from the Prince Regent, in testimony of his scientific merits. This was the more welcome, because he was on the eve of exchanging a life of professional labour for one, not of idleness, for he pursued his course of discovery with unabated zeal, but of affluence and independence. On the 11th of the same month, he married Mrs. Apreece, a lady possessed of ample fortune; previous to which he delivered his farewell lecture to the Royal Institution. At the same time he appears to have resigned the office of Secretary to the Royal Society, to which he had been appointed in 1807. Two months afterwards he published ‘Elements of Chemical Philosophy,’ which he dedicated to Lady Davy, “as a pledge that he should continue to pursue science with unabated ardour.” In March, 1813, appeared the ‘Elements of Agricultural Chemistry,’ containing the substance of a course of lectures delivered for ten successive seasons before the Board of Agriculture. That part of the Continent which was under French influence, being strictly closed against the English at this time, it is much to the credit of Napoleon, that he immediately assented to a wish expressed by Davy, and seconded by the Imperial Institute, that he might be allowed to visit the extinct volcanoes in Auvergne, and thence proceed to make observations on Vesuvius while in a state of action. He reached Paris, Oct. 27th, 1813. The French philosophers received him with enthusiasm: it is to be regretted that at the time of his departure their feelings were much less cordial. There was a coldness, and pride, or what seemed pride, in his manner, which disgusted a body of men too justly sensible of their own merit to brook slights; especially when, in spite of national jealousy, they had done most cordial and unhesitating justice to the transcendent achievements of the British philosopher. Nor was this the only ground for dissatisfaction. Iodine had been recently discovered in Paris, but its nature was still unknown. Davy obtained a portion, and proceeded to experiment upon it. This was thought by many an unfair interference with the fame and rights of the original investigators. Davy himself felt that some explanation at least was due, in a paper which he transmitted to the Royal Society; and as the passage in question contained what, though perhaps not meant to be such, might easily be construed into an insinuation, that but for him, the results communicated in that paper might not have been obtained, it was not likely to conciliate. There is probably much truth in the excuse offered by his biographer, for the superciliousness charged against him upon this, and other occasions, that it was merely the cloak of a perpetual and painful timidity.