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the infusible nature of the earths; H. Davy charged himself with the the strong affinity of their bases for inquiry; and presented its results oxygen made it unavailing to act in a paper, which was read before upon them in solution in water; the society on the 22d of January, and the only methods that proved 1824, and which was continued in successful, were those of operating another communication dated 17th upon them by electricity in some of June, 1824, and concluded in a of the combinations, or of combin. third, read 9th of June, 13:25. ing them at the moment of their We shall endeavour briefly to decomposition by electricity, in state the principal facts elicited metallic alloys, so as to obtain evi. by this inquiry. We have already dences of their nature and proper stated, that Davy had advanced the ties. It is impossible to follow the hypothesis, that chemical and elec. philosopher through all the intri. trical changes were identical, or cate paths of this investigation: dependant upon the same property suffice it to say, that, although he of matter; and that he had shown was unable to produce the metallic that chemical attractions may be bases of the earths in the same un. exalted, modified, or destroyed, by equivocal forn as he produced changes in the electrical states of those of the alkalies, he furnished bodies; that substances will only sufficient evidence of their being combine when they are in differ. metallic oxides.

ent electrical states ; and that, by Sir Humphrey Davy's Bakerian bringing a body, naturally positive, Lecture of 1808, entitled, “ An Ac. artificially into a negative state, its count of some new Analytical Re, usual powers of combination are searches on the Nature of certain altogether destroyed : it was, in Bodies, particularly the Alkalics, short, by an application of this ve• Phosphorus, Sulphur, Carbona. ry principle that he decomposed ceous Matter, and the Acids hith. the alkalies; and it was froin the erto undecomposed; with some same cnergetic instrumentality that general Observations on CHEMICAL he now sought a remedy for the ra. THEORY,” abounds in elaborate ex. pid corrosion of copper sheathing. periments with the Voltaic appara. When a piece of polished copper io tus, made with the hope of extend. suffered to remain in sea-water, the ing our knowledge of the principles first effects are, a yellow tarnish of bodies, by the new powers and upon the surface, and a cloudiness methods arising from the applica. in the water, which take place in tion of electricity.

two or three hours: the hue of the Shortly after the closc of the war, cloudiness is at first white, and it the commissioners of the navy, gradually becomes green. In less fully impressed with the evil ari. than a day a bluish-green precipitate sing from the destructive influence appears in the bottom of the vessel, of sea-water upon the copper which constantly accumulates; this sheathing of his majesty's ships of green matter appears principally war, applied to the council of the to consist of an insoluble compound Royal Society, in the hope that some of copper (a sub-muriate) and by. plan might be suggested for arrest. drate of magnesia. Reasoning up. ing, if not for preventing, the de. on these phenomena, Davy arrived cay of so expensive an article. Sir at the conclusion that copper could

act upon sea-water only when in a periments should be conducted on positive state ; and since that metal a large scale. The lords commis. is only weakly positive in the elec. sioners of the navy, accordingly tro.chemical scale, he considered gave Sir Humphry permission to that, if it could be only rendered ascertain the practical value of his slightly negative, the corroding ac. discovery, by trials upon ships of tion of sea-water upon it would be war; and the results, to use his own null.

expression, even surpassed his most A piece of zinc, as large as a pea, sanguine expectations. Sheets of on the point of a small iron nail, copper, defended by from 1-40th to was found fully adequate to pre- 1-1000th part of their surface of serve forty or fifty square inches of zinc, malleable and cast iron, were copper; and this, wherever it was exposed, for many weeks, in the placed, whether at the top, bottom, flow of the tide, in Portsmouth har. or in the middle of the sheet of bour, their weights having been copper, and whether the copper ascertained before and after the was straight or bent, or made into experiment. When the metallic coils. And where the connexion protector was from 1-40 to 1-110, between the different pieces of cop. there was no corrosion por decay per was completed by wires, or of the copper; with small quanti. thin filaments of the fortieth or fif. ties it underwent a loss of weight. tieth of an inch in diameter, the ef. The sheathing of boats and ships, fect was the same; every side, eve- protected by the contact of zinc, ry surface, every particle of the cast and malleable iron, in different 'copper remained bright, whilst the proportions, compared with that of iron, or the zinc, was slowly cor. similar boats and sides of ships un. roded. A piece of thick sheet cop. protected, exhibited bright sur. per, containing, on both sides, about faces, whilst the unprotected cop. sixty square inches, was cut in such per underwent rapid corrosion, be. a manner as to form seven divi. coming first red, then green, and sions, connected only by the small. losing a part of its substance in est filaments that could be left, and scales. In overcoming one evil, a mass of zinc, of the fifth of an another, however, has been creinch in diameter, was soldered to ated; by protecting the copper, the upper division. The whole the accumulation of sea weeds and was plunged under sea-water; the marine insects has been favoured, copper remained perfectly polish. and the ships thus defended by ed. The same experiment was iron or zinc have become so foul, made with iron; and after the lapse as scarcely to continue navigable. of a month, in both instances, the This would seem to depend upon copper was found as bright as when several causes, especially upon the it was first introduced, whilst simi. deposition of saline and calcareous lar pieces of copper, undefended, matter, arising from the decompo. in the same sea.water, underwent sition of marine salts. Had Davy's considerable corrosion, and pro. health remained unimpaired, his duced a large quantity of green genius would, without doubt, have deposite in the bottom of the ves. suggested a remedy ; but he unfor. sel. It remained only that the ex. tunately declined in health, at the

very moment his energies were than dea:h. The general princimost required. Future philoso. ple of the discovery may be de. phers may propose successful ex. scribed as follows:pedients to obviate the evil, but the The common means formerly em. glory of the discovery will justly ployed for lighting the dangerous belong to him who first developed part of the mines consisted of a the principle. Whether or not that steel wheel revolving in contact principle can be rendered subser with flint, and affording a succes. vient to the protection of copper sion of sparks : but this apparatus sheathing, it must at least be ad. always required a person to work mitted that the results obtained by it, and was not entirely free from him are of the most interesting danger. The fire-damp was known description, and capable of various to be light carburetted hydrogen useful applications; several of gas; but its relations to combus. which he has himself suggested, tion had not been examined. It is whilst others have been discovered chiefly produced from what are by the ingenuity of contempory called blowers or fissures in the chemists. By introducing a piece broken strata, near dykes. Sir of zinc, or tin, into the iron boiler Humphrey made various experi. of the steam engine, we may pre- ments on its combustibility and exvent the danger of explosion, which plosive nature; and discovered, generally arises, especially where that the fire-damp requires a very salt water is used, from the wear of strong heat for its inflammation ; one part of the boiler. Another im. that azote and carbonic acid, even portant application is in the pre. in very small proportions, diminish. vention of the wear of the paddles, ed the velocity of the inflammation ; or wheels, which are rapidly dis. that mixtures of the gas would not solved by salt water. Mr. Pepys explode in metallic canals or has extended the principle, for the troughs, where their diameter was preservation of steel instruments, less than one seventh of an inch, by guards of zinc; and razors and and their depth considerable in lancets have been thus defended proportion to their diameter; and with perfect success.

that explosions could not be made In 1812 Mr. Davy married. The to pass through such canals, or object of his choice was Jane, through very fine wire sieves, or daughter of Charles Kerr, of Kel. wire gauze. The consideration of so, and widow of Shuckburgh Ash. these facts led Sir Humphrey to by 'A preece.

adopt a lamp, in which the flame, We now arrive at one of the most by being supplied with only a limit. important results of Sir Humphrey ed quantity of air, should produce Davy's labours, viz. the invention such a quantity of azote and carof the safety lamp for coal mines, bonic acid as to prevent the exwhich has been generally and suc. plosion of the fire-damp, and which, cessfully adopted throughout Eu by the nature of its apertures for rope. This invention has been the giving admittance and egress to means of preserving many valua. the air, should be rendered incapa. ble lives, and preventing horrible ble of communicating any explo. mutilations, more terrible even sion to the external air. These

requisites were found to be afford. dent of the Royal Institution. He ed by air-tight lanterns, of various was created a Baronet, October constructions, supplied with air 20, 1818. In 1820, he was electfrom tubes or canals of small die ed a foreign associate of the Royal ameter, or from apertures covered Academy of Sciences at Paris, in with wire-gauze, placed below the the room of his countryman Watt; flame, through which explosions and in the course of a few years, cannot be communicated, and hay. most of the learned bodies in Eu. ing a chimney at the upper part, rope enrolled him among their mem. for carrying off the foul air. Sir bers. Humphrey soon afterwards found Many pages might be occupied that a constant fame might be kept with the interesting details of Sir up from the explosive mixture is. Humphrey Davy's travels in differ. suing from the apertures of a wire. ent parts of Europe for scientific gauze seive. He introduced a ve. purposes, particularly to investigate ry small lamp in a cylinder, made the causes of volcanic phenomena, of wire.gauze, having six thousand to instruct the miner of the coal dis. four hundred apertures in the square tricts in the application of his safe. inch. He closed all apertures ex. ty lamp, to examine the state of the cept those of the gauze, and intro- Herculaneum manuscripts, and to duced the lamp, burning brightly illustrate the remains of the chemi. within the cylinder, into a large cal arts of the ancients. The rejar, containing several quarts of sults of all these researches were the most explosive mixture of gas published in the transactions of the from the distillation of coal and air; Royal Society for 1815, and are the flame of the wick immediately extremely interesting. The con. disappeared, or rather was lost, for cluding observations, in which he the whole of the interior of the cy. impresses the superior importance linder became filled with a feeble of permanency to brilliancy, in the but steady flame of a green colour, colours used in painting, are espe. which burnt for some minutes, till cially worthy the attention of art. it had entirely destroyed the explo. ists. On his examination of the sive power of the atmosphere. This Herculaneum manuscripts at Na. discovery led to a most iinportant ples, in 1818-19, he was of opinion improvement in the lamp, divested ihey had not been acted upon by the fire-damp of all its terrors, and fire, so as to be completely car. applied its powers, formerly so de. bonized, but that their leaves were structive, to the production of a use. cemented together by a substance ful light. The coal owners of the formed during the fermentation and Tyne and Wear evinced their chemical changes of ages. He in. sense of the benefits resulting from vented a composition for the soluthis invention, by presenting Sir tion of this substance, but he could Humphrey with a handsome ser. not discover more than 100 out of vice of plate worth nearly 20001., 1265 manuscripts, which presented at a public dinner at Newcastle, any probability of success. October 11, 1817.

Sir Humphrey returned to Eng. In 1813, Sir Humphrey was elect. land in 1820, and in the same year ed a corresponding member of the his respected friend, Sir Joseph Institute of France, and vice-presi. Banks, President of the Royal So

ciety, died, when he was elected ence is excellent. We trace no his successor. Sir Humphrey re- mixture of science and scepticism. tained his seat till the year 1827, -The same excellent feeling when, in consequence of procras. breathes throughout “ Salmonia, tinated ill health, he resigned bis or Days of Fly-fishing," a volume seat as President of the Royal So. published in 1828, and one of the ciety.

most delightful labours of leisure Sir Humphrey Davy was, in eve. ever seen. Not a few of the most ry respect, an accomplished scho. beautiful phenomena of nature are lar, and was well acquainted with here lucidly explained, yet the foreign languages. He always re. pages have none of the varnish of tained a strong taste for literary philosophical unbelief. pleasures; and his philosophical Sir Humphrey spent nearly the works are written in a perspicuous whole of the summer of 1828 in and popular style, by which means fowling and fishing in the neigh: he has contributed more to the dif. bourhood of Laybach ; and it has fusion of scientific knowledge than been related by a gentleman who any other writer of his time. His accompanied him on a shooting ex. three principal works are, “ Chemi. cursion, that the relative weight of cal and Philosophical Researches,” the various parts of each bird, the “ Elements of Chemical Philoso. quantity of digested and undigested phy,” and “Elements of Agricul. food, &c. were carefully noted tural Chemistry," and the two last down by the observant naturalist. are excellently adapted for ele. It is believed that he was preparing mentary study.

for a large work on natural his. The results of his investigations tory. and experiments were not pent up The great philosopher closed his in the laboratory or lecture-room mortal career at Geneva. He had where they were made, but by this arrived in that city only the day valuable mode of communication, before, namely, Friday, the 29th of they have realized, what ought to May, 1829; having performed his be the highest aim of science, the journey from Rome by easy stages, improvement of the condition and without feeling any particular in. comforts of every class of his fel. convenience, and without any cir. low-creatures. Thus, beautiful the. cumstances which denoted so near ories were illustrated by inventions an approach to the payment of the of immediate utility, as in the safe. last debt of nature. During the ty lamp for mitigating the dangers night, however, he was attacked to which miners are exposed in with apoplexy; and he expired their labours, and the application at three o'clock on the morning of of a newly.discovered principle in the 30th. preserving the life of the adven. turous mariner. Apart from the scientific value of

JOHN JAY. Sir Humphrey's labours and re. May 17th, 1829. At Bedford, searches, they are pervaded by a Westchester county, N. Y. John tone and temper, and an enthusias. Jay, formerly Chief Justice of the tic love of nature, which are as ad. United States, in the 85th year of mirably expressed as their influ. bis age.

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