his uncommon mind, at this early age, it is worthy of mention, that Mr. Davy laid down for himself a plan of education, which embraced the circle of the sciences. By his eighteenth year he had acquired the rudiments of botany, anatomy, and physiology, the simpler mathematics, metaphysics, natural philosophy, and chemistry. But chemistry soon arrested his whole attention. Having made some experiments on the air disengaged by sea-weeds from the water of the ocean, which convinced him that these vegetables performed the same part in purifying the air dissolved in water which land-vegetables act in the atmosphere; he communicated them to Dr. Beddoes, who had at that time circulated proposals for publishing a journal of philosophical contributions from the West of England. This produced a correspondence between Dr. Beddoes and Mr. Davy, in which the Doctor proposed, that Mr. Davy, who was at this time only nineteen years of age, should suspend his plan of going to Edinburgh, and take a part in experiments which were then about to be instituted at Bristol, for investigating the medical powers of factitious airs; to this proposal Mr. Davy consented, on condition that he should have the uncontrolled superintendence of the expements. About this time he became acquainted with Davies Gilbert, Esq. M.P. a gentleman of high scientific attainments, (now President of the Royal Society), with whom he formed a friendship which has always continued; and to Mr. Gilbert's judicious advice may be attributed Mr. Davy's adoption of and perseverance in the study of chemistry. With Dr. Beddoes, Mr. Davy resided for a considerable time, and was constantly occupied in new chemical investigations. 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 to the Royal Institution in Albemarle-street. On obtaining this appointment Mr. Davy gave up all his views of the medical profession, and devoted himself entirely to chemistry.

Mr. Davy's first experiments as Professor of Chemistry in the Royal Institution, were made on the substance 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. He was, during the same period, frequently occupied in experiments on galvanism.

To the agriculturist, chemistry is of the first consideration. The dependence of agriculture upon chemical causes had been previously noticed, but it was first completely demonstrated in a course of lectures before the Board of Agriculture, which Mr. Davy commenced in the year 1802, and continued for ten years. This series of lectures contained much popular and practical information, and belongs to the most useful of Mr. Davy's scientific labours; for the application of chemistry to agriculture is one of its most important results; and 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 chosen a fellow of the Royal Society, and in 1805, a member of the Royal Irish Academy. He now enjoyed the friendship of most of the distinguished literary men and philosophers of the metropolis, and enumerated among his intimate friends, Sir Joseph Banks, Cavendish, Hatchett, Wollaston, Children, Tennant, and other eminent men. At the same time he corresponded with the principal chemists of every part of Europe. In 1806, he was appointed to deliver, before the Royal Society, the Bakerian lecture, in which he displayed some very interesting new agencies of electricity, by means of the celebrated galvanic apparatus ¹ 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 with 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. During the greater part of 1810, he was employed on the combinations of oxymuriatic gas and oxygen; and towards the close of the same year, he delivered a course of lectures before the Dublin Society, and received from Trinity College, Dublin, the honorary degree of LL. D.

In the year 1812, Mr. Davy married his 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, Mr. Davy 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.

We now arrive at the most important result of Sir Humphry 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; and were this Sir Humphry Davy's only invention, it would secure him an immortality in the annals of civilization and science. The general principle of this discovery may be described as follows:

"The frequency of 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