"What's that? Is the house coming down?" cried Mr. Borlase, the surgeon-apothecary of Penzance, jumping out of his cozy arm-chair, as a tremendous explosion shook the house from top to bottom, making a great jingle among the gallipots in the shop below, and rousing him from a comfortable nap.

"Please, sir," said Betty, the housemaid, putting her head into the room, "here's that boy Davy been a-blowing of hisself up agen. Drat him, he's always up to some trick or other! He'll be the death of all of us some day, that boy will, as sure as my name's Betty."

"Bring him here directly," replied her master, knitting his brow, and screwing his mild countenance into an elaborate imitation of that of a judge he once saw at the assizes, with the black cap on, sentencing some poor wretch to be hanged. "Really, this sort of thing won't do at all."

Only, it must be owned, Mr. Borlase had said that many times before, and put on the terrible judicial look too, and yet "that boy Davy" was at his tricks again as much as ever. "I'll bring as much as I can find of him, sir," said Betty, gathering up her apron, as if she fully expected to discover the object of her search in a fragmentary condition.

Presently there was heard a shuffling in the passage, and a somewhat ungainly youth, about sixteen years of age, was thrust into the room, with the due complement of legs, arms, and other members, and only somewhat the grimier about the face for the explosion. His fingers were all yellow with acids, and his clothes plentifully variegated with stains from the same compounds. At first sight he looked rather a dull, loutish boy, but his sharp, clear eyes somewhat redeemed his expression on a second glance.

"Here he is, sir," cried Betty triumphantly, as though she really had found him in pieces, and took credit for having put him cleverly together again.

"Well, Humphrey," said Mr. Borlase, "what have you been up to now? You'll never rest, I'm afraid, till you have the house on fire."

"Oh! if you please, sir, I was only experimenting in the garret, and there's no harm done."

"No harm done!" echoed Betty; "and if there isn't it's no fault of yours, you nasty monkey. I declare that blow up gave me such a turn you could ha' knocked me down with a feather, and there's a smell all over the house enough to pison any one."

"That'll do, Betty," said her master, finding the grim judicial countenance rather difficult to keep up, and anxious to pronounce sentence before it quite wore off. "I'll tell you what it is, young Davy, this sort of thing won't do at all. I must speak to Mr. Tonkine about you; and if I catch you at it again, you'll have to take yourself and your experiments somewhere else. So I warn you. You had much better attend to your work. It was only the other day you gave old Goody Jones a paperful of cayenne instead of cinnamon; and there's Joe Grimsly, the beadle, been here half a dozen times this day for those pills I told you to make up, and they're not ready yet. So just you take yourself off, mind your business, and don't let me have any more nonsense, or it'll be the worse for you."

And so the culprit gladly backed out of the room, not a whit abashed by the reprimand, for it was no novelty, to begin his experiments again and again, and one day, by way of compensation for keeping his master's household in constant terror of being blown up, to make his name familiar as a household word, by the invention of a little instrument that would save thousands and thousands from the fearful consequences of coal-pit explosions.

The Mr. Tonkine that his master referred to was the self-constituted protector of the Davy family. Old Davy had been a carver in the town, and dying, left his widow in very distressed circumstances, when this generous friend came forward and took upon himself the charge of the widow and her children. Young Humphrey, on leaving school, had been placed with Mr. Borlase to be brought up as an apothecary; but he was much fonder of rambling about the country, or experimenting in the garret which he had constituted his laboratory, than compounding drugs behind his master's counter. As a boy he was not particularly smart, although he was distinguished for the facility with which he gleaned the substance of any book that happened to take his fancy, and for an early predilection for poetry. As he grew up, the ardent, inquisitive turn of his mind displayed itself more strongly. He was very fond of spending what leisure time he had in strolling along the rocky coast searching for sea-drift and minerals, or reading some favourite book.

In after life he used often to tell how when tired he would sit down on the crags and exercise his fancy in anticipations of future renown, for already the ambition of distinguishing himself in his favourite science had seized him. "I have neither riches, nor power, nor birth," he wrote in his memorandum-book, "to recommend me; yet if I live, I trust I shall not be of less service to mankind and my friends than if I had been born with all these advantages." He read a great deal, and though without much method, managed, in a wonderfully short time, to master the rudiments of natural philosophy and chemistry, to say nothing of considerable acquaintance with botany, anatomy, and geometry; so that though the pestle and mortar might have a quieter time of it than suited his master's notions, Humphrey was busy enough in other ways.

In his walk along the beach, the nature of the air contained in the bladders of sea-weed was a constant subject of speculation with him; and he used to sigh over the limited laboratory at his command, which prevented him from thoroughly investigating the matter. But one day, as good luck would have it, the waves threw up a case of surgical instruments from some wrecked vessel, somewhat rusty and sand clogged, but in Davy's ingenious hands capable of being turned to good account. Out of an old syringe, which was contained in the case, he managed to construct a very tolerable air pump; and with an old shade lamp, and a couple of small metal tubes, he set himself to work to discover the causes of the diffusion of heat. At first sight the want of proper instruments for carrying on his researches might appear rather a hindrance to his progress in the paths of scientific discovery; but, in truth, his subsequent success as an experimentalist has been very properly attributed, in no small degree, to that necessity which is the parent of invention, and which forced him to exercise his skill and ingenuity in making the most of the scanty materials at his command. "Had he," says one of his biographers, "in the commencement of his career been furnished with all those appliances which he enjoyed at a later period, it is more than probable that he might never have acquired that wonderful tact of manipulation, that ability of suggesting expedients, and of contriving apparatus, so as to meet and surmount the difficulties which must constantly arise during the progress of the philosopher through the unbeaten track and unexplored regions of science!"

While Davy was thus busily engaged qualifying himself for the distinguished career that awaited him, Gregory Watt, the son of the celebrated James Watt, being in delicate health, came to Penzance for change of air, and lodged with Mrs. Davy. At first he and Humphrey did not get on very well together, for the latter had just been reading some metaphysical works, and was very fond of indulging in crude and flippant speculations on such subjects, which rather displeased the shy invalid. But one day some chance remark of Davy's gave token of his extensive knowledge of natural history and chemistry, and thenceforth a close intimacy sprang up between them, greatly to the lad's advantage, for Watt's scientific knowledge set him in a more systematic groove of study, and encouraged him to concentrate his energies on his favourite pursuit.

Another useful friend Davy also found in Mr. Gilbert, afterwards President of the Royal Society. Passing along one day, Mr. Gilbert observed a youth making strange contortions of face as he hung over the hutch gate of Borlase's house; and being told by a companion that he was "the son of Davy the carver," and very fond of making chemical experiments, he had a talk with the lad, and discovering his talents, was ever afterwards his staunch friend and patron.

Through his two friends, Mr. Gilbert and Mr. Watt, Davy formed the acquaintance of Dr. Beddoes, who was just setting up at Bristol, under the title of Pneumatic Institution, an establishment for investigating the medical properties of different gases; and who, appreciating his abilities, gave him the superintendence of the new institution.

Although only twenty years of age at this time, Davy was well abreast of the science of the day, and soon applied his vigorous and searching intellect to several successful investigations. His first scientific discovery was the detection of siliceous earth in the outer coating of reeds and grasses. A child was rubbing two pieces of bonnet cane together, and he noticed that a faint light was emitted; and on striking them sharply together, vivid sparks were produced just as if they had been flint and steel. The fact that when the outer skin was peeled off this property was destroyed, showed that it was confined to the skin, and on subjecting it to analysis silex was obtained, and still more in reeds and grasses. As superintendent of Dr. Beddoe's institution, his attention was, of course, chiefly directed to the subject of gases, and with the enthusiasm of youth, he applied himself ardently to the investigation of their elements and effects, attempting several very dangerous experiments in breathing gases, and more than once nearly sacrificing his life. In the course of these experiments he found out the peculiar properties of nitrous oxide, or, as it has since been popularly called, "laughing gas," which impels any one who inhales it to go through some characteristic action,—a droll fellow to laugh, a dismal one to weep and sigh, a pugnacious man to fight and wrestle, or a musical one to sing.

At twenty-two years of age, such was the reputation he had acquired, that he got the appointment of lecturer at the Royal Institution, which was just then established, and found himself in a little while not only a man of mark in the scientific, but a "lion" in the fashionable world. Natural philosophy and chemistry had begun to attract a good deal of attention at that time; and Davy's enthusiasm, his clear and vivid explanations of the mysteries of science, and the poetry and imagination with which he invested the dry bones of scientific facts, caught the popular taste exactly. His lecture-room became a fashionable lounge, and was crowded with all sorts of distinguished people. The young lecturer became quite the rage, and was petted and feted as the lion of the day. It was only six years back that he was the druggist's boy in a little country town, alarming and annoying the household with his indefatigable experiments. He could hardly have imagined, as one of his day-dreams at the sea-side, that his fame would be acquired so quickly.

In spite of all the flatteries and attentions which were showered upon him, Davy stuck manfully to his profession; and if his reputation was somewhat artificial and exaggerated at the commencement, he amply earned and consolidated it by his valuable contributions to science during the rest of his career.

The name of Humphrey Davy will always be best known from its association with the ingenious safety lamp which he invented, and which well entitles him to rank as one of the benefactors of mankind. It was in the year 1815 that Davy first turned his attention to this subject. Of frequent occurrence from the very first commencement of coal-mining, the number of accidents from fire-damp had been sadly multiplied by the increase of mining operations consequent on the introduction of the steam engine. The dreadful character of some of the explosions which occurred about this time, the appalling number of lives lost, and the wide-spread desolation in some of the colliery districts which they had occasioned, weighed heavily on the minds of all connected with such matters. Not merely were the feelings of humanity wounded by the terrible and constant danger to which the intrepid miners were exposed, but it began to be gravely questioned whether the high rate of wage which the collier required to pay him not only for his labour, but for the risk he ran, would admit of the mines being profitably worked. It was felt that some strenuous effort must be made to preserve the miners from their awful foe. Davy was then in the plenitude of his reputation, and a committee of coal-owners besought him to investigate the subject, and if possible provide some preventative against explosions. Davy at once went to the north of England, visited a number of the principal pits, obtained specimens of fire-damp, analyzed them carefully, and having discovered the peculiarities of this element of destruction, after numerous experiments devised the safety-lamp as its antagonist.

The principles upon which this contrivance rests, are the modification of the explosive tendencies of fire-damp (the inflammable gas in mines) when mixed with carbonic acid and nitrogen; and the obstacle presented to the passage of an explosion, if it should occur, through a hole less than the seventh of an inch in diameter; and accordingly, while the small oil lamp in burning itself mixes the surrounding gas with carbonic acid and nitrogen, the cylinder of wire-gauze which surrounds it prevents the escape of any explosion. It is curious that George Stephenson, the celebrated engineer, about the same time, hit on much the same expedient.

To control a "power that in its tremendous effects seems to emulate the lightning and the earthquake," and to enclose it in a net of the most slender texture, was indeed a grand achievement; and when we consider the many thousand lives which it has been the means of saving from a sudden and cruel death, it must be acknowledged to be one of the noblest triumphs, not only of science, but of humanity, which the world has ever seen. Honours were showered upon Davy, from the miners and coal-owners, from scientific associations, from crowned heads; but all must agree with Playfair in thinking that "it is little that the highest praise, and that even the voice of national gratitude when most strongly expressed, can add to the happiness of one who is conscious of having done such a service to his fellow-men." Davy himself said he "valued it more than anything he ever did." When urged by his friends to take out a patent for the invention, he replied,—"No, I never thought of such a thing. My sole object was to serve the cause of humanity, and if I have succeeded, I am amply rewarded by the gratifying reflection of having done so."

The honours of knighthood and baronetage were successively conferred on Davy as a reward for his scientific labours; and the esteem of his professional brethren was shown in his election to the President-ship of the Royal Institution, in which, oddly enough, he was succeeded by his old friend Mr. Gilbert, who had first taken him by the hand, and whom he had got ahead of in the race of life.

Davy died at Geneva before he had completed his fifty-first year, no doubt from over-exertion and the unhealthy character of the researches he prosecuted so recklessly. Assiduous as he was in his devotion to his favourite science, he found time also to master several continental languages; to keep himself well acquainted with, and also to contribute to the literature of the day; and to indulge his passion for fly-fishing, at which he was a keen and practised adept.

Eminent as were the talents of Sir Humphrey Davy, and valuable as his discovery of the safety-lamp has proved, it is but fair to own that his credit to the latter has been very openly denied. Two persons of scientific celebrity have been put forward as the real inventors of the safety-lamp—namely, Dr. Reid Clanny of Newcastle, and the great railway-engineer, George Stephenson. Of Clanny's safety-lamp a description appeared in the Philosophical Transactions in 1813—that is, ten years before Sir Humphrey made his communication to the Royal Society. However, it was a complicated affair, which required the whole attention of a boy to work it, and was based on the principle of forcing in air through water by the agency of bellows. Stephenson's was a very different apparatus. In its general principle it resembled Davy's, the chief difference being, that he inserted a glass cylinder inside the wire-gauze cylinder, and inside the top of the glass cylinder a perforated metallic chimney—the supply of air being kept up through a triple circle of small holes in the bottom.

Stephenson's claim has, of course, been disputed by the friends and admirers of Sir Humphrey Davy; but Mr. Smile has conclusively proved that his lamp, the "Geordy," was in use at the Killingworth collieries at the very time that Davy was conducting the experiments which led to his invention. It is not to be inferred, however, that Davy knew aught of what Stephenson had accomplished. It seems to be one of those rare cases in which two minds, working independently, and unknown each to the other, have both arrived simultaneously at the same result.