act upon sea-water only when in a positive state; and since that metal is only weakly positive in the elec. tro-chemical scale, he considered that, if it could be only rendered slightly negative, the corroding action of sea-water upon it would be null.

A piece of zinc, as large as a pea, on the point of a small iron nail, was found fully adequate to preserve forty or fifty square inches of copper; and this, wherever it was placed, whether at the top, bottom, or in the middle of the sheet of copper, and whether the copper was straight or bent, or made into coils. And where the connexion between the different pieces of copper was completed by wires, or thin filaments of the fortieth or fif. tieth of an inch in diameter, the ef. fect was the same; every side, every surface, every particle of the copper remained bright, whilst the iron, or the zinc, was slowly cor roded. A piece of thick sheet copper, containing, on both sides, about sixty square inches, was cut in such a manner as to form seven divisions, connected only by the small. est filaments that could be left, and a mass of zinc, of the fifth of an inch in diameter, was soldered to the upper division. The whole was plunged under sea-water; the copper remained perfectly polished. The same experiment was made with iron; and after the lapse of a month, in both instances, the copper was found as bright as when it was first introduced, whilst similar pieces of copper, undefended, in the same sea-water, underwent considerable corrosion, and produced a large quantity of green deposite in the bottom of the vessel. It remained only that the ex

periments should be conducted on a large scale. The lords commissioners of the navy, accordingly gave Sir Humphry permission to ascertain the practical value of his discovery, by trials upon ships of war; and the results, to use his own expression, even surpassed his most sanguine expectations. Sheets of copper, defended by from 1-40th to 1-1000th part of their surface of zinc, malleable and cast iron, were exposed, for many weeks, in the flow of the tide, in Portsmouth harbour, their weights having been ascertained before and after the experiment. When the metallic protector was from 1-40 to 1-110, there was no corrosion nor decay of the copper; with small quantities it underwent a loss of weight. The sheathing of boats and ships, protected by the contact of zinc, cast and malleable iron, in different proportions, compared with that of similar boats and sides of ships unprotected, exhibited bright surfaces, whilst the unprotected copper underwent rapid corrosion, becoming first red, then green, and losing a part of its substance in scales. In overcoming one evil, another, however, has been created; by protecting the copper, the accumulation of sea weeds and marine insects has been favoured, and the ships thus defended by iron or zinc have become so foul, as scarcely to continue navigable. This would seem to depend upon several causes, especially upon the deposition of saline and calcareous matter, arising from the decomposition of marine salts. Had Davy's health remained unimpaired, his genius would, without doubt, have suggested a remedy; but he unfortunately declined in health, at the

very moment his energies were most required. Future philosophers may propose successful expedients to obviate the evil, but the glory of the discovery will justly belong to him who first developed the principle. Whether or not that principle can be rendered subservient to the protection of copper sheathing, it must at least be admitted that the results obtained by him are of the most interesting description, and capable of various useful applications; several of which he has himself suggested, whilst others have been discovered by the ingenuity of contempory chemists. By introducing a piece of zinc, or tin, into the iron boiler of the steam engine, we may prevent the danger of explosion, which generally arises, especially where salt water is used, from the wear of one part of the boiler. Another important application is in the prevention of the wear of the paddles, or wheels, which are rapidly dissolved by salt water. Mr. Pepys has extended the principle, for the preservation of steel instruments, by guards of zinc; and razors and ancets have been thus defended with perfect success.

In 1812 Mr. Davy married. The object of his choice was Jane, daughter of Charles Kerr, of Kel. so, and widow of Shuckburgh Ashby A preece.

We now arrive at one of the most important results of Sir Humphrey Davy's labours, viz. the invention of the safety lamp for coal mines, which has been generally and successfully adopted throughout Europe.

This invention has been the means of preserving many valuable lives, and preventing horrible mutilations, more terrible even

than death. The general principle of the discovery may be described as follows:

The common means formerly em. ployed for lighting the dangerous part of the mines consisted of a steel wheel revolving in contact with flint, and affording a succes. sion of sparks but this apparatus always required a person to work it, and was not entirely free from danger. The fire-damp was known to be light carburetted hydrogen gas; but its relations to combus. tion had not been examined. It is chiefly produced from what are called blowers or fissures in the broken strata, near dykes. Sir Humphrey made various experiments on its combustibility and explosive nature; and discovered, that the fire-damp requires a very strong heat for its inflammation; that azote and carbonic acid, even in very small proportions, diminish. ed the velocity of the inflammation; that mixtures of the gas would not explode in metallic canals or troughs, where their diameter was less than one seventh of an inch, and their depth considerable in proportion to their diameter; and that explosions could not be made to pass through such canals, or through very fine wire sieves, or wire gauze. The consideration of these facts led Sir Humphrey to adopt a lamp, in which the flame, by being supplied with only a limited quantity of air, should produce such a quantity of azote and carbonic acid as to prevent the explosion of the fire-damp, and which, by the nature of its apertures for giving admittance and egress to the air, should be rendered incapa. ble of communicating any explosion to the external air. These

requisites were found to be afford. ed by air-tight lanterns, of various constructions, supplied with air from tubes or canals of small diameter, or from apertures covered with wire-gauze, placed below the flame, through which explosions cannot be communicated, and having a chimney at the upper part, for carrying off the foul air. Sir Humphrey soon afterwards found that a constant flame might be kept up from the explosive mixture is. suing from the apertures of a wiregauze seive. He introduced a very small lamp in a cylinder, made of wire-gauze, having six thousand four hundred apertures in the square inch. He closed all apertures except those of the gauze, and introduced the lamp, burning brightly within the cylinder, into a large jar, containing several quarts of the most explosive mixture of gas from the distillation of coal and air; the flame of the wick immediately disappeared, or rather was lost, for the whole of the interior of the cy. linder became filled with a feeble but steady flame of a green colour, which burnt for some minutes, till it had entirely destroyed the explosive power of the atmosphere. This discovery led to a most important improvement in the lamp, divested the fire-damp of all its terrors, and applied its powers, formerly so destructive, to the production of a useful light. The coal owners of the Tyne and Wear evinced their sense of the benefits resulting from this invention, by presenting Sir Humphrey with a handsome service of plate worth nearly 2000l., at a public dinner at Newcastle, October 11, 1817.

In 1813, Sir Humphrey was elect. ed a corresponding member of the Institute of France, and vice-presi.

dent of the Royal Institution. He was created a Baronet, October 20, 1818. In 1820, he was elect ed a foreign associate of the Royal Academy of Sciences at Paris, in the room of his countryman Watt; and in the course of a few years, most of the learned bodies in Europe enrolled him among their members.

Many pages might be occupied with the interesting details of Sir Humphrey Davy's travels in different parts of Europe for scientific purposes, particularly to investigate the causes of volcanic phenomena, to instruct the miner of the coal districts in the application of his safe. ty lamp, to examine the state of the Herculaneum manuscripts, and to illustrate the remains of the chemical arts of the ancients. The results of all these researches were published in the transactions of the Royal Society for 1815, and are extremely interesting. The concluding observations, in which he impresses the superior importance of permanency to brilliancy, in the colours used in painting, are especially worthy the attention of artists. On his examination of the Herculaneum manuscripts at Naples, in 1818-19, he was of opinion they had not been acted upon by fire, so as to be completely carbonized, but that their leaves were cemented together by a substance formed during the fermentation and chemical changes of ages. He invented a composition for the solu tion of this substance, but he could not discover more than 100 out of 1265 manuscripts, which presented any probability of success.

Sir Humphrey returned to England in 1820, and in the same year his respected friend, Sir Joseph Banks, President of the Royal So.

ciety, died, when he was elected his successor. Sir Humphrey retained his seat till the year 1827, when, in consequence of procrastinated ill health, he resigned his seat as President of the Royal Society.

Sir Humphrey Davy was, in every respect, an accomplished scholar, and was well acquainted with foreign languages. He always retained a strong taste for literary pleasures; and his philosophical works are written in a perspicuous and popular style, by which means he has contributed more to the diffusion of scientific knowledge than any other writer of his time. His

three principal works are, "Chemical and Philosophical Researches,' "Elements of Chemical Philosophy," and "Elements of Agricultural Chemistry," and the two last are excellently adapted for ele. mentary study.

The results of his investigations and experiments were not pent up in the laboratory or lecture-room where they were made, but by this valuable mode of communication, they have realized, what ought to be the highest aim of science, the improvement of the condition and comforts of every class of his fellow-creatures. Thus, beautiful theories were illustrated by inventions of immediate utility, as in the safety lamp for mitigating the dangers to which miners are exposed in their labours, and the application of a newly-discovered principle in preserving the life of the adven. turous mariner.

Apart from the scientific value of Sir Humphrey's labours and researches, they are pervaded by a tone and temper, and an enthusias. tic love of nature, which are as admirably expressed as their influ

ence is excellent. We trace no mixture of science and scepticism.

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The same excellent feeling breathes throughout Salmonia, or Days of Fly-fishing," a volume published in 1828, and one of the most delightful labours of leisure ever seen. Not a few of the most beautiful phenomena of nature are here lucidly explained, yet the pages have none of the varnish of philosophical unbelief.

Sir Humphrey spent nearly the whole of the summer of 1828 in fowling and fishing in the neighbourhood of Laybach; and it has been related by a gentleman who accompanied him on a shooting excursion, that the relative weight of the various parts of each bird, the quantity of digested and undigested food, &c. were carefully noted down by the observant naturalist. It is believed that he was preparing for a large work on natural history.

The great philosopher closed his mortal career at Geneva. He had arrived in that city only the day before, namely, Friday, the 29th of May, 1829; having performed his journey from Rome by easy stages, without feeling any particular in. convenience, and without any cir cumstances which denoted so near an approach to the payment of the last debt of nature. During the night, however, he was attacked with apoplexy; and he expired at three o'clock on the morning of the 30th.

JOHN JAY.

May 17th, 1829. At Bedford, Westchester county, N. Y. John Jay, formerly Chief Justice of the United States, in the 85th year of his age.

Mr. Jay's ancestors were, origi. nally, from France. His grandfather, Augustus Jay, was the third son of Pierre Jay, an opulent mer. chant of Rochelle. Pierre was a Huguenot, who, on the revocation of the edict of Nantz, fled to Eng. land. Augustus Jay was educated in England, and was absent on a voyage when his famity were driven from France. Upon his return, he joined his father in England. Many of the French emigrants were, at this time, emigrating to South Carolina; and Augustus embarked for that part of the American conti. nent; but, disliking the climate of Carolina, he removed to New. York. In this province, he, for a while, established himself in business, at Esopus, on the Hudson. He afterwards removed to the city of New-York, where, in 1697, he married Anne Maria, daughter of Balthasar Bayard. He died, much respected, at the advanced age of 85, leaving three daughters, and one son, Peter, born in 1704, who in 1728, married Mary, daughter of Jacobus Van Cortlandt, of New. York. Peter, the father of John Jay, continued in New-York until about the year 1746, when he retired to his estate, at Rye. Here he remained, till the approach of the British army, at the commencement of the revolutionary war, forced him to remove. He died at Poughkeepsie, in the year 1782.

John Jay, the son of Peter, was born in the city of New-York, on the 12th day of December, 1745, old style. When eight years old, he was sent to a grammar school, kept by the Rev. Mr. Stoep, rector of the French Episcopal Church at New-Rochelle, where he commenced the study of the Latin language, and remained until 1756,

when he was taken home to receive instruction from a Mr. Murray, who was employed as a private tutor in the family. In the month of August, 1760, he entered King's, (now Columbia) College, then lately founded in the city of New-York. Dr. Johnson was, at that time, president of the college. Under his supervision, and that of his successor, Dr. Cooper, he became an excellent Latin scholar, and together with the late Richard Harison, read Grotius with Porfessor Cutting. He had, from his infancy, been unable to pronounce certain letters; and acquired, besides, a habit of reading in a hurried and unintelligible manner. By attention and perse. verance, he finally overcame these habits. After taking his bachelor's degree, May 15th, 1764, he entered the office of Benjamin Kissam, and, October 26th, 1768, was admitted to the bar.

The next year he was appointed secretary to the commissioners named by the king for settling the dispute in relation to the boundaries between the provinces of NewYork and New-Jersey.

In the year 1774, Mr. Jay mar. ried Sarah Livingston, the daughter of William Livingston, afterwards governor of New-Jersey. He had, by this time, acquired great reputation as a lawyer, and was employed in the most important causes, not only in New-York, but in the adjacent provinces of Connecticut and New-Jersey. He began, also, to be looked up to by his fellow-citizens, as one who was to direct and guide them through the contest which seemed to be approaching. The American revolution found him singularly well fitted for his country's service, by a rare union of the dignity and