"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 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 a 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."[2]—The coal owners of the Tyne and Wear evinced their sense of the benefits resulting from this invention, by presenting Sir Humphry with a handsome service of plate worth nearly two thousand pounds, at a public dinner at Newcastle, October 11, 1817.
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 could occupy many pages with the interesting details of Sir Humphry Davy'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 Herculaneum manuscripts and to illustrate 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, in the remains of other palaces and baths of ancient Rome, and in the ruins of Pompeii. By the kindness of his friend Canova, who was charged with the care of the works connected with ancient art in Rome, he was enabled to select with his own hands specimens of the different pigments, that had been formed in vases discovered in the excavations, which had 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. 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 on artists 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 change of ages. He invented a composition for the solution of this substance, but he could not discover more than 100 out of 1,265 manuscripts, which presented any probability of success.
Sir Humphry returned to England in 1820, and in the same year his respected friend, Sir Joseph Banks, President of the Royal Society, died. Several discussions took place respecting a proper successor, when individuals of high and even very exalted rank were named as candidates. But science, very properly in this case, superseded rank. Amongst the philosophers whose labours had enriched the Transactions of the Royal Society, two were most generally adverted to, Sir Humphry Davy and Dr. Wollaston; but Dr. Wollaston very modestly declined being a candidate after his friend had been nominated, and received from the council of the Society the unanimous compliment of being placed in the chair of the Royal Society, till the election by the body in November. [3] A trifling opposition was made to Sir Humphry Davy's election, by some unknown persons, who proposed Lord Colchester, but Sir Humphry was placed in the chair by a majority of 200 to 13. For this honour no one could be more completely qualified. Sir Humphry retained his seat as President till the year 1827, when, in consequence of procrastinated ill health, in great measure brought on by injuries occasioned to his constitution by scientific experiments, he was induced, by medical advice, to retire to the continent. He accordingly resigned his seat as President of the Royal Society, the chair being filled, pro tem, by Davies Gilbert, Esq. who, at the Anniversary Meeting, Nov. 30, 1827, was unanimously elected President.
Since his retirement, Sir Humphry Davy resided principally at Rome, where a short time ago he had an alarming attack of a paralytic nature, but from which he was apparently, though slowly, recovering. Lady Davy, who had been detained in England by her own ill health, joined Sir Humphry, at Rome, on hearing of his alarming state. Thence he travelled by easy stages to Geneva, without feeling any particular inconvenience, and without any circumstances which denoted the approach of dissolution: but on Friday, May 29, 1829, the illustrious philosopher closed his mortal career, in the fifty-first year of his age, having only reached Geneva on the day previous. Lady Davy had the gratification of contributing, by her soothing care, to the comfort of his last days during their stay in Italy, and on their journey to Geneva, where they intended to pass the summer, and hoped to have derived benefit from the eminent practitioners of that city. Sir Humphry had also been joined by his brother, Dr. John Davy, physician to the forces in Malta, whence he came on receiving the intelligence of his brother's danger. But all human art and skill were of no avail. The last and fatal attack took place at half-past two on Friday morning, and the pulse ceased to beat shortly after. The event was no sooner known, than the afflicted widow received the condolence and affectionate offer of services from the most distinguished individuals of Geneva; amongst whom we must mention M. A. de Condolle, the eminent botanist, and M. Sismondi, the historian, both equally beloved for their amiable character, as illustrious throughout Europe for their works. M. de Condolle obligingly took charge of all the details of the interment of his illustrious colleague; and the governor of the Canton, the Academy of Geneva, the Consistory of the Geneva Church, the Society of Arts and of Natural Philosophy and History, together with nearly all the English resident there, accompanied the remains to the burial-ground, where the English service was performed by the Rev. Mr. John Magers of Queen's College, and the Rev. Mr. Burgess. The members of the Academy, in the absence of any relation of the deceased, took their place in the funeral procession; and the invitations to the syndicate, and to the learned bodies who accompanied it, were made by that body in the same character. The whole was conducted with much appropriate order and decency, and whilst every attention and respect were paid to the memory of the deceased, nothing was attempted beyond the unostentatious simplicity which the deceased had frequently declared to be his wish, whenever his mortal remains should be consigned to their last home; and which in accordance to that wish, had been expressly enjoined to her kind friends by the afflicted widow. In the procession, which followed the corporate bodies and the countrymen of the deceased, were many of the most eminent manufacturers of Geneva, and a large body of mechanics, who were anxious to pay this tribute of regard and gratitude to one whom they deservedly looked upon as a great benefactor to the arts, and promoter of sciences, by the application of which they earn their livelihood.[4]
During his retirement on the Continent, Sir Humphry continued to communicate the splendid results of his labours to the Royal Society, and at the anniversary meeting of the year 1827, the royal medal was awarded to him for a series of brilliant discoveries developing the relation between electricity and chemistry.[5] Upon this interesting occasion, Mr. Davies Gilbert spoke at some length, commencing as follows: "It is with feelings most gratifying to myself that I now approach to the award of a royal medal to Sir Humphry Davy; and I esteem it a most fortunate occurrence, that this award should have taken place during the short period of my having to discharge the duties attached to the office of president; having witnessed the whole progress of Sir Humphry Davy's advancement in science and in reputation, from his first attempts in his native town to vary some of Dr. Priestly's experiments on the extraction of oxygen from marine vegetables to the point of eminence which we all know him to have reached. It is not necessary for me more than to advert to his discovery of nitrous oxyde; to his investigation of the action of light on gases; on the nature of heat; to his successful discrimination of proximate vegetable elements; nor to his most scientific, ingenious, and useful invention, the safety-lamp,—an invention reasoned out from its principles, with all the accuracy and precision of mathematical deduction."
The course of Sir Humphry Davy to the highest rank as a chemical philosopher, was, after his appointment at the Royal Institution, rapid and brilliant; and if he was previously aided by as few of the advantages of fortune as any man living, he had then at his disposal whatever his industry and talents chose to command. We have given but a hasty outline of his labours; but it is possible that he may have left behind him much, not yet made public, for which, science will be still further indebted to him. His works, papers, and letters are numerous, and the greatest portion of them are contained in the Transactions of the Royal Society. One of the most popular and interesting of his recent papers is that on the Phenomena of Volcanoes. This contains a series of investigations of Vesuvius, made by the author during a residence at Naples in 1819-20, and bearing upon a previous hypothesis, "that metals of the alkalies and earth might exist in the interior of the globe, and on being exposed to the action of air and water, give rise to volcanic fires, and to the production of lavas, by the slow cooling of which basaltic and other crystalline rocks might subsequently be formed." We have not space for the details of these investigations, interesting as they would prove to an unscientific reader; but we give an abstract of the result of Sir Humphry's observations:
"The phenomena observed by the author afforded a sufficient refutation of all the ancient hypotheses, in which volcanic fires were ascribed to such chemical causes as the combustion of mineral coal, or the action of sulphur upon iron; and are perfectly consistent with the supposition of their depending upon the oxidation of the metals of the earths upon an extensive scale, in immense subterranean cavities, to which water or atmospheric air may occasionally have access. The subterranean thunder heard at great distances under Vesuvius, prior to an eruption, indicates the vast extent of these cavities; and the existence of a subterranean communication between the Solfattara and Vesuvius, is established by the fact that whenever the latter is in an active state, the former is comparatively tranquil. In confirmation of these views, the author remarks, that almost all the volcanoes of considerable magnitude in the old world, are in the vicinity of the sea; and in those where the sea is more distant, as in the volcanoes of South America, the water may be supplied from great subterranean lakes; for Humboldt states that some of them throw up quantities of fish. The author acknowledges, however, that the hypothesis of the nucleus of the globe being composed of matter liquefied by heat, offers a still more simple solution of the phenomena of volcanic fires."[6]
We have hitherto spoken of Sir Humphry Davy as a philosopher. He was, however, in every respect, an accomplished scholar, and was well acquainted with foreign languages. He always retained a strong taste for literary pleasures; and when his continued illness retarded his scientific pursuits, he made literature his recreation. In this manner he wrote Salmonia: or Days of Fly-fishing, in a series of conversations, we gather from the Preface:—"These pages formed the occupation of the Author during several months of severe and dangerous illness, when he was wholly incapable of attending to more useful studies, or of following more serious pursuits. They formed his amusement in many hours, which otherwise would have been unoccupied and tedious." "The conversational and discursive style were chosen as best suited to the state of the health of the author, who was incapable of considerable efforts and long continued exertion." The volume is dedicated to Dr. Babington, "in remembrance of some delightful days passed in his society, and in gratitude for an uninterrupted friendship of quarter of a century:" and the likeness of one of the characters in the conversations to that estimable physician abovenamed, has been considered well drawn, and easily recognisable by those who enjoy his acquaintance.
The philosophical works of Sir Humphry Davy are written in a clear and perspicuous 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, "Chemical and Philosophical Researches," "Elements of Chemical Philosophy," and "Elements of Agricultural Chemistry," are in a popular and familiar style, and the two last are excellently adapted for elementary study. His numerous pamphlets and contributions to the Transactions of the Royal Society have the same rare merit of conveying experimental knowledge in the most attractive form, and thus reducing abstract theory to the practice and purposes of life and society. The results of his investigations and experiments were not therefore 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 adventurous mariner. Yet splendid as were Sir Humphry's talents, and important as have been their application, he received the honours and homage of the scientific world with that becoming modesty which universally characterizes great genius.