Beddoes Mr. Davy resided for a considerable time, and was constantly occupied in new chemical investigations, being occasionally assisted by his friend Mr. W. Clayfield, a very respectable and amiable gentleman of Bristol, who was ardently attached to chemical pursuits. Here, he discovered the respirability of nitrous oxide, and made a number of laborious experiments on gaseous bodies, which he afterwards published in "Researches Chemical and Philosophical," a work that was universally well received by the chemical world, and created a high reputation for its author, at that time only twenty-one years of age. This led to his introduction to Count Rumford, and to his being elected Professor of Chemistry in the Royal Institution, established in Albemarle-street, for the purpose of diffusing knowledge, of facilitating the general introduction of useful mechanical inventions and improvements, and of teaching, by courses of philosophical lectures and experiments, the application of science to the common purposes of life. Among the beneficial effects of this Institution, it is not to be accounted the least that it proved the means of removing Mr. Davy to a station which afforded scope and opportunity for the exercise of his talents. On obtaining this appointment, Mr. Davy gave up all his views of the medical profession, and devoted himself entirely to chemistry, with what success the "Transactions of the Royal Society," his " Elements of Chemical Philosophy," of "Agricultural Chemistry," and his work of "Researches on Flame," and on the " Safety Lamp for Coal Mines," will best shew.

His first experiments in the capacity of Professor of Chemistry in the Royal Institution, were made on the substances employed in the process of tanning, with others to which similar properties were ascribed, in consequence of the discovery made by M. Seguier of Paris, of the peculiar vegetable matter, now called tannin; but after much investigation, Mr. Davy candidly declared, that practical experiments had already done so much for the art, that very little improvement could be expected from any known theory. He was, during the same period, frequently occupied in experiments on galvanism.

In 1802, he commenced his interesting course of lectures before the Board of Agriculture, which he continued for ten years. The dependence of agriculture upon chemical causes, had previously been noticed, but was first completely demonstrated in these lectures, which, at the same time, conveyed much practical information. But so rapid were the discoveries of the author, that, in preparing these discourses for publication a few years afterwards, he was under the necessity of making several alterations, to adapt them to the improved state of chemical knowledge, which his own labours had, in that short time, produced.

In 1803, he was elected F. R. S., and, in 1805, a Member of the Royal Irish Academy. He had already acquired, by his talents and urbanity, the friendship of most of the distinguished literary men and philosophers of the metropolis, and enumerated among his intimate friends, the late venerable President of the Royal Society, the celebrated philosophers Cavendish, Hatchett, Wollaston, Babington, Children, Tennant, and others equally eminent. At the same time he corresponded with the principal chemists of every part of Europe.

Being appointed in 1806 to deliver the Bakerian lecture of the Royal Society, he displayed some very interesting new agencies of electricity, by means of the well-known galvanic apparatus. Soon afterwards he made one of the most brilliant discoveries of modern times, in the decomposition of two fixed alkalies, which, in direct refutation of the hypothesis previously adopted, were found to consist of a peculiar metallic base united to a large quantity of oxygen. These alkalies were potash and soda, and the metals thus discovered were called potassium and sodium. Mr. Davy was equally successful in the application of galvanism to the decomposition of the earths. About this time he became secretary of the Royal Society.

In 1808 Mr. Davy received a prize from the French Institute, as a tribute to his indisputable merit, from which even national enmity could not withold the meed of admiration.

In pursuing his experiments on the application of electricity to chemistry, and on the alkalies, phosphorus, sulphur, carbonaceous matter, and the acids which had not been decomposed, he succeeded in proving the simplicity of the oxymuriatic acid. During the greater part of 1810, Mr. Davy was employed on the combinations of oxymuriatic gas and oxygen, and their chemical relations to inflammable bodies; and his experiments were confirmed by those of several French chemists, and by Berzelius of Stockholm. But the inferences, drawn by them from these experiments, differed in some instances from those deduced by Mr. Davy. The partizans of Lavoisier would not allow that oxygen is one of the principles of alkalies; they denied the metallism of potash and soda as metallic oxides; and maintained that they were simple bodies, which in combining with hydrogen formed hydrurets.

Towards the latter end of 1810, Mr. Davy delivered a course of lectures before the Dublin Society, and in December received from the provost and senior fellows of Trinity college Dublin, the honorary degree of LL.D.

In the following year, although we believe Mr. Davy made few discoveries of great public interest, there is reason to believe that he effected one of the greatest importance to his own happiness; and it may fairly be questioned whether the success of

any of his former experiments gave him half the pleasure, which he experienced on the first dawn of the hope that he had excited some interest in the bosom of his present amiable lady, then Mrs. Apreece, widow of Shuckburgh Ashby Apreece, esq. and daughter and heiress of the late Charles Kerr, of Kelso, esq. By his union with this lady, in 1812, Sir Humphry acquired not only a considerable fortune, but the inestimable treasure of an affectionate and exemplary wife, and a congenial friend and companion, capable of appreciating his character and attainments. A few days previously to his marriage, he received the honour of knighthood from his Majesty, then Prince Regent, being the first person on whom he conferred that dignity.

The researches, which led to the invention of the safety-lamp for coal mines, which has been so generally and successfully adopted throughout Europe, may justly be considered as the most important of all Sir Humphry Davy's labours, since they enabled him to provide the means of preserving many valuable lives, and preventing horrible mutilations more dreadful even than death. The frequency of such accidents, arising from the explosion of the fire-damp, or inflammable gas of the coal mines, mixed with atmospherical air, occasioned the formation of a committee at Sunderland, for the purpose of investigating the causes of these calamities, and of endeavouring to discover and apply a preventive. Sir Humphry received an invitation, in 1815, from Dr. Gray, one of the members of the committee; in consequence of which he went to the North of England, and visiting some of the principal collieries in the neighbourhood of Newcastle, soon convinced himself that no improvement could be made in the mode of ventilation, but that the desired preventive must be sought in a new method of lighting the mines, free from danger, and which, by indicating the state of the air in the part of the mine where inflammable air was disengaged, so as to render the atmosphere explosive, should oblige the miners to retire till the workings were properly cleared. The common means then employed for lighting the dangerous part of the mines consisted of a steel wheel revolving in contact with flint, and affording a succession 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 combustion had not been examined. It is chiefly produced from what are called blowers or fissures in the broken strata, near dykes. Sir Humphry 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, diminished 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 Humphry 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 incapable of communicating any explosion to the external air. These requisites were found to be afforded 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 Humphry soon afterwards found that a constant flame might be kept up from the explosive mixture issuing from the apertures of a wire-gauze sieve. 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 cylinder 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 an useful light. Some minor improvements, originating in Sir Humphry's researches into the nature of flame, were afterwards effected. Experiments of the most satisfactory nature were speedily made, and the invention was soon generally adopted. Some attempts were made to dispute the honour of this discovery with its author, but his claims were confirmed by the investigations of the first philosophers of the age. The coal owners of the Tyne and Wear evinced their sense of the benefits resulting from this invention, by presenting Sir Humphry with a service of plate worth two thousand pounds.

In 1813, Sir Humphry was elected a corresponding member of the Institute of France, and vice-president of the Royal Institution; in 1817 one of the eight associates of the Royal Academy; in 1818 created a baronet, and during the last ten years he has been elected a member of most of the learned bodies of Europe. We regret that our limits preclude us from entering into the in

teresting details of Sir Humphry's travels in different parts of Europe for scientific purposes, particularly to investigate the causes of volcanic phenomena, to instruct the miners of the coal districts in the application of his safety-lamp, and to examine the state of the Herculanean manuscripts, and the remains of the chemical arts of the ancients. He analyzed the colours used in painting by the ancient Greek and Roman artists. His experiments were chiefly made on the paintings in the baths of, Titus, the ruins called the baths of Livia, and in the remains of other palaces and baths of ancient Rome, and the ruins of Pompeii. By the kindness of his friend Canova, who is charged with the care of the works connected with ancient art in Rome, he was enabled to select with his own hand specimens of the different pigments, that had been found in vases discovered in the excavations, which had then been lately made beneath the ruins of the palace of Titus, and to compare them with the colours fixed on the walls, or detached in fragments of stucco. His delicacy in selecting only minute portions of the colour, and from places where the loss was imperceptible, was so much approved, that Signor Nelli, proprietor of the celebrated Nozze Aldobrandini, liberally permitted him to make similar experiments on the colours employed in that valuable antique painting. The results of these researches were published in the Transactions of the Royal Society for 1815, and are highly interesting. The concluding observations, in which he impresses on artists the superior importance of permanency to brilliancy in the colours used in painting, are particularly judicious, aud worthy of atten

tion.

Towards the end of 1818, and in the beginning of 1819, he examined at Naples the Herculanean manuscripts, and soon declared his opinion, that 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 change produced in a long course of years. He invented a composition for the dissolution of this substance, but could not discover more than from 80 to 100 out of 1265 manuscripts, which presented any probability of success.

On his return to England in 1820, his respected friend, the late worthy professor of the Royal Society died. Many discussions took place amongst the members respecting a proper successor. Several individuals of high, and even very exalted rank, were named as candidates; but the scientific part of the society justly considered this honour, the highest that a scientific man can attain in Britain, not as a proper appendage to mere rank and fortune, but as a reward for scientific merit. Amongst the philosophers whose labours have enriched the Transactions of the Royal Society, two were most generally adverted to, Sir