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 720 DAVY spiral will remain glowing in the midst of the explosive gas, and enable the miner to see as long as the air is fit for respiration. His atten- tion was first drawn to the subject in August, 1815, and in December his lamp was completed. Urged to take out a patent for his invention, he replied: "No, my good friend, I never thought of such a thing; my sole object was to serve the cause of humanity ; and if I have succeeded, I am amply rewarded in the grati- fying reflection of having done so." At the same time George Stephenson was engaged in a similar investigation, and invented a safety lamp embodying essentially the same principles as that of Davy. The two inventions appear to have been made almost simultaneously, each independently of the other. The priority was, however, awarded to Davy, to whom the mi- ning proprietors in 1817 presented a service of plate valued at 2,000, awarding 100 to Ste- phenson, who was then a mere mining opera- tive. A sharp controversy sprang up, and a further sum of 1,000 was raised and presented to Stephenson. The service of plate presented to Davy was bequeathed by his widow, who died in 1868, to the royal society, to be sold, and the proceeds applied to the encouragement of science. In May, 1818, Davy set out on a second continental journey, visiting Germany, Hungary, and Italy, and returning to England in June, 1819. On the death of Sir Joseph Banks in 1820, he was elected president of the royal society of London, and was annually re- elected for seven years. The last term of his scientific labors extends from 1823 to the sum- mer of 1826, during which time he communica- ted to the royal society three papers on the pres- ervation of metals by electro-chemical means, and the Bakerian lecture for 1826, "On the Relation of Electrical and Chemical Changes." As in the case of the safety lamps, these papers were intended to remedy a practical evil. His attention was directed by the commissioners of the navy to the corrosion of the copper sheath- ing of vessels by sea water ; he ascertained that the popular notion that impure copper is soonest corroded was an error, and that the corrosion is owing to the joint action of the air and the saline ingredients in the water ; he succeeded in preserving the copper sheathing from corro- sion by rendering it negatively electrical by small pieces of tin or zinc, or iron nails, these metals making a surface of copper from 200 to 300 times their own size so electrical as to have no action on sea water. The very per- fection of the protection rendered this method practically inapplicable, as shells and seaweeds adhered to the non-corroded surface ; but this principle of galvanic protection has been suc- cessfully applied to various important uses in the arts and sciences. In 1824 he made a journey to Norway, Sweden, Denmark, Hoi- stein, and Hanover, fishing and hunting, and communicating with their eminent men, among whom were Berzelius, Oersted, Gauss, Olbers, and Schumacher. In 1825 he began to expe- rience considerable indisposition, whitth ever after affected his ordinary elasticity of spirits, depressed also by the illness and death of his mother in 1826. He had suffered for more than a year with numbness and pain in his right arm, when toward the close of 1826 a paralytic at- tack affected his right side ; his mental facul- ties were not impaired, and while confined to his room he corrected the proof sheets of his " Discourses to the Royal Society," published in January, 1827. In this month he had so far re- covered as to start on a journey to the continent, going through France over Mont Cenis into Italy, where he occupied himself in hunting, fishing, and observations on natural history and chemi- cal science, for about three months; he' then journeyed through various parts of southern Germany and Switzerland, returning in Octo- ber, with health and strength slightly im- proved, to England, where he remained until March, 1828. " Salmonia, or Days of Fly Fish- ing," is a kind of dramatization of the most interesting parts of his journal in these last travels, rendered doubly valuable by his ob- servations in natural history. Finding no permanent improvement in his health, he left London again in March, 1828, for the Alpine regions of southern Austria, where he passed the summer, spending 'the winter in Italy ; during this journey he wrote " Consolations in Travel," his last writing, which Cuvier calls the work of a dying Plato. On Feb. 20, 1829, he experienced at Rome a sudden and severe paralytic attack, which ultimately proved fatal, though he so far improved as to quit Rome on the last of April for Geneva, where he arrived May 28. At 2 the following morn- ing he was taken alarmingly ill, and in a few moments expired; he was buried, in accord- ance with his expressed wish, where he died, in the city of Geneva, on June 1. His brother believed that the paralysis was caused by soft- ening of the brain, which, with some enlarge- ment of the heart, was the cause of his death. Sir Humphry Davy was of middle stature, 5 ft. 7 in. in height, well proportioned and muscu- lar, and able to endure considerable fatigue ; of sanguine temperament, warm in his feelings, of cheerful disposition, fond of company, per- severing and observing. He was chosen' a member of the French institute in 1817; he was also connected with most of the great academies of Europe, and was by universal consent considered without a superior, if he had an equal, among the chemists of his time. His memory is cherished at Geneva, where his widow founded a prize in his honor, to be given every two years for the most original and important discovery in chemical science. A statue, after the portrait by Lawrence, is to be erected to his memory at Penzance, at a cost of 6,000. Besides the life by his broth- er, there is one by John Ayrton Paris, M. D. (2 vols. 8vo, London, 1831). II. John, an Eng- lish physician, brother of the preceding, born at Penzance, May 24, 1791, died April 24,