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.