which had been the cause of so many dreadful accidents. After various experiments, he effected three modes of lighting the mines in safety; these were, the blowing lamp, the piston lamp, and the safe lamp. The principle of safety consists in their being all extinguished when the air becomes so mixed with fire-damp as to be explosive; but their being thus extinguished was an inconvenience which it was highly necessary to remedy. He had already ascertained the important fact, that explosive mixtures could not be fired in metallic tubes whose diameters bore a certain proportion to their lengths. By an obvious deduction, it followed that, by lessening the diameter, he might shorten the tube; and that its length might thus be reduced to the thickness of an ordinary metallic plate; a number of perforations made in such a plate would be a collection of small tubes; the plate thus perforated would resemble wire-gauze. Wiregauze was tried, and Davy, with almost overpowering joy, beheld that, whilst Fght was still preserved, it was an impenetrable barrier to explosion. This little Hercules of science was introduced in the coal mines in 1816; and, in September, 1817, Sir Humphry Davy was invited, by a numerous body of coal-owners, to dine with them, at the Queen's Head, at Newcastle. Lambton presided on the occasion, and, after certain toasts had been drunk, he rose, and, in the name of the gentlemen assembled, presented to their distinguished guest a splendid service of plate, of the value of nearly £2000. This noble tribute had been richly earned. Davy had declined to take out a patent for the invention, by which he would, beyond doubt, have obtained from five to ten thousand a-year. When remonstrated with for thus neglecting his personal interest, he replied, "My sole object has been to serve the cause of humanity; and if I have succeeded, I am amply rewarded in the gratifying reflection of having done so. I have enough for all my views and purposes; more wealth might be troublesome, and distract my attention from those pursuits in which I delight; more wealth could not increase either my fame or my happiness. It might, undoubtedly, enable me to put four horses to my

Mr.

carriage, but what would it avail me to have it said that Sir Humphry drives his carriage and four ?"

Five papers relating to fire-damp in coal mines, and the combustion of explosive mixtures, were read before the Royal Society between the 4th of May, 1815, and the 23rd of January, 1817, for which Sir Humphry Davy was awarded the Rumford medal. He

afterwards received, from the Emperor Alexander of Russia, a superb silvergilt vase, of the value of £200; and, in 1818, he was created a baronet. In the same year, having made some experiments upon a few specimens of papyri from the ruins of Herculaneum, he was, at his own request, sent by government to Naples, for the purpose of unfolding these records. After two months unsuccessful trial, however, he returned to England, in 1820; and, on the 30th of November, was elected president of the Royal Society. In his address to the members upon taking the chair, he observed, "Although your good opinion has, as it were, honoured me with a rank similar to that of general, I shall always be happy to act as a private soldier in the ranks of science." Towards the latter part of this year, application was made to the president and council of the Royal Society, to furnish the government with advice relative to the best method of manufacturing sheet copper, so as to preserve it, when in

use

as sheathing on ships' bottoms, from the corrosive effects of oxidation. Sir Humphry singly undertook the inquiry. After a number of experiments connected with voltaic action, which appeared to him satisfactory and conclusive, he communicated to the government that he had fully succeeded in the required discovery of a remedy for the corrosion of copper sheathing. On putting, however, his plan into execution, for which purpose he made two voyages to sea, it was found a complete failure. This caused him much mental inquietude, from the sarcasms which were, in consequence, levelled against him, and a fit of apoplexy ensuing, he was recommended to revisit Italy. From hence, so unfavourable was the state of his health, that he sent a letter to the Royal Institution, resigning his presidentship.

He returned to London in the winter of

1827; but, in the spring of the following year, he was again advised to try the effect of Italian air; and he accordingly quitted England, never to return. On his arrival at Rome, he amused himself with writing his Consolations in Travel, or the Last Days of a Philosopher. These last days were now at hand whilst in a very weak state, from an attack of paralysis, he requested to be removed to Geneva, and there, in the presence of his brother and wife, he died, on the 29th of May, 1829. He left no children, and bequeathed the bulk of his property to Lady Davy and his brother, the share of the latter being nearly £10,000.

In Sir Humphry Davy were strikingly united a powerful imagination and a solid judgment: it has been said of him that, if he had not been the first chemist, he would have been the first poet of his age. Ile was eminently fertile in invention, and remarkably patient in investigation: "his mind was no less logical and precise than it was daring and comprehensive; nothing was too mighty for its grasp, nothing too minute for its observation; like the trunk of the elephant, it could tear up the oak of the forest, or gently pluck the acorn from its branch." It is, how ever, certain that, notwithstanding his own extraordinary powers, and the high station to which he had been elevated, he entertained an unworthy jealousy of the merits of others. The briliant reputation of Faraday, whom he had first introduced to public notice, gave him some inquietude; he felt there could not be two suns in the same system, and he knew he had passed the meridian of his glory. To the same unhappy temperament may possibly be attributed the circumstance of his opposing, with all his efforts, the election of Ampère as a foreign member of the Royal Society; although, as we have before stated, he had received from that distinguished individual the highest marks of attention during his visit to Paris, and had, for many years, held with him a friendly correspondence upon subjects of science.

In youth, his temper was mild and his disposition amiable; but as he advanced in years and reputation, he became occasionally captious and irascible. When a boy, his countenance was un

favourable, his voice unpleasant, and his figure awkward: as he became conscious of these imperfections, he became also soured that Nature had not been more bountiful in the exterior embellishments of his person. From the first moment of his success as a lecturer at the Royal Institution, he seemed ashamed of the simplicity of his character; because his audience consisted of noble personages, he felt abashed that he had not been born a duke. By some, he was accused of affectation in his public addresses; but it is not unlikely that much of this arose from a desire to disguise the discordancy of his voice. He could, unfortunately, derive but little assistance from his ear, which was most unmusical; he could never, in fact, catch the simple air of God Save the King. Whilst member of a volunteer corps, he could never keep step; and though he took private lessons of a serjeant, he still trod upon the heels of the forerank man. He was, it would appear, as little attached to painting as to music; for when taken to the Louvre, he passed hastily along the gallery without directing His attention to a single painting, simply observing to his companion, "What an extraordinary collection of fine frames!" The same apathy was shewn in the lower apartments, and not even the Apollo, the Laocoon, nor the Venus de Medicis, could extort an approving smile from him; but, upon observing a figure treated in the Egyptian style, and sculptured in alabaster, he enthusiastically exclaimed, "Gracious powers! what a beautiful stalactite!" He was, indeed, enthusiastic in everything that appertained to his own professional pursuits, or that fell in with his own habits or amusements: he gloried in Nelson, and would dwell upon his name with rapture; not because he won the battle of the Nile, but that, after he had lost his right arm, he used to fish with the left, a sport of which Davy was passionately fond.

Notwithstanding his respect for rank and fashion, as he increased in fame, it does not appear that he much altered either in the simplicity of his manners or dress. Volta, to whom he was introduced at Pavia, had attired himself in full dress to receive him, but is said to

have started back with astonishment on seeing the English philosopher make his appearance in a dress of which an English artisan would have been ashamed. The following anecdote is told of him:-Whilst staying for the night, at a small inn, in North Wales, with his friend, Mr. Purkis, a third traveller entered into conversation with both, and, as it happened, talked very learnedly about oxygen and hydrogen, and other matters relative to chemical science. When Davy, who had listened with great composure to all that had been said, retired to rest, Mr. Purkis asked the stranger what he thought of his friend who had just left him. "He appears," coolly replied the other, "rather a clever young man, with some general scientific knowledge:-pray |

what is his name?" 44 Humphry Davy, of the Royal Institution," as coolly answered the other. "Good heavens !" exclaimed the stranger; "was that really Davy?-how have I exposed my ignorance and presumption !"

Sir Humphry Davy's last communication to the Philosophical Transactions was entitled, Remarks on the Electricity of the Torpedo, in which he makes out that the electricity of the torpedo has no effect on the most delicate galvanometer. He is also known as the author of an interesting work on angling, called Salmonia; which, together with his Consolations in Travel, published posthumously, have procured him a high reputation as a writer, independently of his philosophical publications.

DAVID BREWSTER, one of the most learned natural philosophers of the present day, was born in Scotland, about the year 1785. The greater part of his numerous treatises are inserted in the Transactions of the Edinburgh Royal Society, of which he is secretary. He is principally celebrated as the inventor of the kaleidoscope, an instrument constructed for the purpose of creating and exhibiting an infinite variety of beautiful and perfectly symmetrical forms. The idea of the discovery first occurred to him in the year 1814, when he was engaged in experiments on the polarisation of light, by successive reflections between plates of glass; an account of which was published in the Philosophical Transactions, for 1815, and rewarded, by the Royal Society of London, with the Copley medal. The reflectors were, in some cases, inclined to each other; and he had occasion to remark the circular arrangement of the images of a candle round a centre, or the multiplication of the sectors, formed by the extremities of the glass plates. In repeating, at a subsequent period, the experiments of M. Biot, on the action of fluids upon light, Dr. Brewster placed the fluids in a trough, formed by two plates of glass,

cemented together at an angle; and, the eye being necessarily placed at one end, some of the cement, which had been pressed through between the plates, appeared to be arranged into a regular figure. The remarkable symmetry which it presented, led to Dr. Brewster's investigation of the cause of this phenomenon; and, in so doing, he discovered the leading principles of the kaleidoscope.

Having thus brought the kaleidoscope to a state of perfection, he, by the advice of his friends, took out a patent for it; in the specification of which, he describes the kaleidoscope in two different forms. The instrument, however, having been shown to several opticians in London, became known before he could avail himself of the patent, and, being simple in principle, was at once largely manufactured. To countenance these piratical proceedings, it was asserted that Dr. Brewster had been anticipated in his invention, by Professor Wood, and Bradley, the astronomer; but it has been sufficiently shown, and has been certified by Professor Wood himself, Professor Playfair, and Mr. Pictet, of Geneva, that, of the kaleidoscope as at present made and used, Dr. Brewster is the original dis

coverer. "As to the effect," says Mr. Playfair, "the thing produced, by the kaleidoscope, is a series of figures, presented with the most perfect symmetry, so as always to compose a whole, in which nothing is wanting, and nothing redundant. It matters not what the object be, to which the instrument is directed, if it only be in its proper place, the effect just described is sure to take place, and with an endless variety. In these respects, the kaleidoscope appears to begin to be singular among optical instruments. Neither the instruments of Bradley, nor the experiment, or theorem in Wood's book, have any resemblance to this; they go no further than the multiplication of the figure." "Dr. Brewster's invention," he adds, "is quite singular among optical instruments; and it will be matter of sincere regret, if any imaginary or vague analogy, between it and other optical instruments, should be the means of depriving the doctor of any part of the reward to which his skill, ingenuity, and perseverance, entitle him

so well.'

It should be stated, however, in connexion with the history of the kaleidoscope, that Kircher and B. Porta have suggested a polygonal speculum; but, undoubtedly, the practical application of the principle to reflectors, inclined towards each other at small angles, was wholly a suggestion of Dr. Brewster's. The production of the kaleidoscope excited a singular sensation; and it is calculated that not less than two hundred thousand were sold in three months, in London and Paris together, though, out of this number, Dr. Brewster says, that not, perhaps, one thousand were constructed upon scientific principles, or capable of giving anything like a correct idea of the power of the kaleidoscope. Dr. Brewster is the editor of The Edinburgh Philosophical Journal, and of The Edinburgh Encyclopædia; and has published a variety of treatises, respecting polarisation of light. He is said to possess a great fund of general information, and is not more distinguished for his scientific attainments, than for the politeness of his

manners.

WILLIAM WYCHERLEY, the son of a gentleman of Cleve, in Shropshire, was born there about the year 1640. After having received a school education, he was sent to France, where, although only sixteen years of age, his fine person and engaging manners recommended him to the notice of Madam de Montausier, whose charms, it is said, induced him to adopt the Roman catholic faith. He returned home in that persuasion, a short time previously to the Restoration; and, in the year of that event, became a gentleman commoner of Queen's College, Oxford; but being never matriculated, he left the university without taking a degree, and entered himself a student of the Middle Temple, with a view of studying the law. This, however, he soon deserted for an occupation more congenial to his mind; and plays being then the rage, he produced his Love in a Wood, or St. James's Park, which brought him into notice among the first noblemen and wits of the day, and into favour with the Duchess of Cleveland, and Villiers, Duke of Buckingham, who gave him the commission of captainlieutenant in his own company. His talents also procured him the especial notice of King Charles the Second, who called upon him during an illness, recommended him to take a journey to Montpellier for the restoration of his health, and ordered the sum of £500 to be given to him to defray his expenses. Wycherley accordingly went to France; but, on his return, he lost the favour of the king, by his absence from court in the prosecution of his amour with Lady Drogheda, the commencement of which is thus related in Spence's Anecdotes:-" Wycherley was

in a bookseller's shop at Bath, or Tunbridge, when Lady Drogheda came in, and happened to inquire for The Plain Dealer, which he had then written, when a friend of Wycherley, who stood by him, pushed him towards her, and said, There's the plain dealer, madam, if you want him." Wycherley made bis excuses; and Lady Drogheda said, "that she loved plain dealing best." He afterwards visited the lady, and in some time married her; but her jealous disposition rendered his union a source of little happiness; and though on her death, a few years after, she settled her whole estate upon him, the title was disputed; and he became so much involved in his circumstances by law expenses and other incumbrances, that he was at length thrown into prison.

He remained in confinement for seven years, when King James the Second, going to see his comedy of The Plain Dealer, was so pleased with the entertainment, that he bestowed a pension of £200 upon the author, and ordered his debts to be paid. Not furnishing, however, a full account of the demands upon him, he still laboured under pecuniary difficulties for many years, until, in 1715, he married a young woman with £1,500, part of which he applied to the liquidation of his debts. He died eleven days after the celebration of his nuptials, making it his last request to his wife, that she would not take an old man for her second husband. In addition to the plays before-mentioned, he wrote The Gentleman Dancing Master, and The Country Wife; and his posthumous works were published by Theobald,

in 1728.