Life of Sir Humphry Davy. 581 



suggested upon the bottom of a sailing cutter, under his own super- 

 intendence. Models were also constructed and floated in sea-water 

 for several months. The experiment seemed conclusive, and the plan 

 was put into extensive practice. In the month of June, 1824, the 

 Comet steam-vessel was prepared, to afford him the means of per- 

 forming his experiments upon the best means of protection, in which 

 he made a voyage to Heligoland and the Naze of Norway. When 

 in Denmark, he visited Professor Oersted and Dr. Olbers ; and at 

 Stockholm he had a transient interview with Berzelius. In June, 

 1825, he read before the Royal Society his third paper on Cop- 

 per sheathing; and the subject was continued in his last Bakerian 

 Lecture, in June, 1826, * On the Relation of Electrical Changes/ 

 for which the royal medal was adjudged to him by the Royal 

 Society. At the conclusion of this lecture he says, * A great variety 

 of experiments, made in different parts of the world, have proved the 

 full efficacy of the electro-chemical means of preserving metals, 

 particularly the copper- sheathing of ships ; but a hope I had once in- 

 dulged, that the peculiar electrical state would prevent the adhesion 

 of weeds or insects, has not been realized and an absolute remedy 

 for adhesions is to be sought for by other more refined means of 

 protection, which appear to be indicated by these researches.' 



The vessels, which had their copper-sheathing protected upon the 

 plan proposed by Sir H. Davy, were found to have their bottoms 

 completely covered with sea-weed, shell-fish of various kinds, and 

 myriads of small marine insects, the copper near the protectors being 

 much more foul than at a distance from them ; and the incon- 

 venience attending this circumstance was so great, as to cause the 

 plan to be abandoned altogether, after long-continued trial, under 

 various circumstances, in 1828. 



Dr. Paris gives a detailed account of similar experiments made in 

 France, on La Constance frigate, which were attended with similar re- 

 sults ; and informs us, that further experiments are about to be tried 

 in the British navy, founded on the same principle. Sir H. Davy 

 experienced disappointment and chagrin at the failure of his plan, 

 wholly inconsistent with the merits of the question; but his health was 

 now declining, and this produced, no doubt, that morbid sensibility 

 and irritation which his friends witnessed with pain. At the close of 

 the year 1826, his indisposition increased: he complained of pal- 

 pitation of the heart, and an affection of the trachea, and was 

 unable to walk without fatigue. In January, 1827, he published 

 the Discourses which he had delivered before the Royal Society, on 

 awarding- the Copley Medals, to which was prefixed his Discourse 

 on taking the chair of the Royal Society for the first time, which 

 contains some passages of interest, prophetic of future discoveries. 

 "While on a visit to Lord Gage, at the close of 1826, he felt more 

 than usually unwell, and determined to return to London : while on 

 his journey, he was seized with an apoplectic attack at Mayersfield; 

 prompt and copious bleeding on the spot arrested the symptoms 



VOL. I. MAY, 1831. 2 Q 



