Arts; but it was not till as late as 1846 that steps were taken to procure for him some public acknowledgment of his labours in the cause of humanity in connection with colliery explosions. An appeal having been made on his behalf, a purse of gold was collected, which together with a silver salver, was presented to him at the Athenæum, Sunderland, on the 3rd of February, 1848.

The invention of the safety-lamp was regarded by Dr. Gray as a sufficient reason for dissolving the Sunderland Society for the Prevention of Accidents in Mines.

The share which the Rev. J. Hodgson had had in the steps which led to the invention of the safety-lamp was no small one. It was he who, braving the displeasure of the affluent Brandlings, had vividly portrayed and laid before the public eye, in his little pamphlet on the Felling explosion, the awful spectacle presented by a colliery devastated by "whirlwinds of tempestuous fire," and aroused the attention of the humane to the perils to which the workers in fiery mines were exposed. The assistance he had given in forwarding the invention afforded him some solace even in his last illness.

Sir Humphry Davy in after life always dwelt with peculiar satisfaction and delight upon the invention of his safety-lamp. "I value it," he used to say, "more than anything I ever did. It was the result of a great deal of investigation and labour;

but, if my directions be only attended to, it will save the lives of thousands of poor labourers. I never was more affected than by a written address which I received from the working colliers, when I was in the North, thanking me, in behalf of themselves and their families, for the preservation of their lives." He used also to exhibit to his friends with great delight the service of plate which had been presented to him.

Not only has the safety-lamp been instrumental in saving thousands of lives, but it has also enabled untold millions of tons of coal to be rescued from the bowels of the earth, which without its aid would have been irrevocably lost. It rendered possible the entire removal of the pillars of coal, great part of which was formerly left underground in fiery mines. It led to the re-opening of many collieries which had been abandoned after having been worked out as far as was practicable by means of candles and steel mills. Walker Colliery, which had been abandoned in 1811, was re-opened in 1818 by the aid of the Davy lamp, and has continued working to this day. Great part of the formerly relinquished workings in Wallsend, Willington, Percy Main, Hebburn, Jarrow, Elswick, Benwell, &c., as well as several collieries on the river Wear, were recovered and resumed work by its aid.

The introduction of the safety-lamp did not put an end to colliery explosions; though few indeed are traceable to it, notwithstanding the many thousands

of wire-gauze lamps, of various forms, which subsequently came into daily use. Difficulties there are even with its aid; but, in the case of deep mining, what vastly greater, what insuperable difficulties would have existed, had science not armed the miners with the wonderful insulated lamp, which warns them of the presence of their invisible enemy, and protects them from its power.

The dates cited in the above narrative can, we think, be established beyond the possibility of controversy. It is perhaps almost unnecessary to remark that both Dr. Clanny and Mr. Stephenson subsequently adopted the Davy wire gauze in their lamps, but for which vital improvement they would long since have been laid aside.

"Soon shall thy arm, unconquer'd Steam! afar
Drag the slow barge, or drive the rapid car."
-DARWIN.

WE have seen that the chief use to which the steamengine was put for a long period subsequent to the date of its first invention was to draw water from coal and other mines; then it came to be applied indirectly to draw the coal out of the pits through the medium of the double water-wheel; and soon after the invention of the double-acting engine by Watt it began to come into general use applied directly to the shaft of the drum, or rope-roll, and quickly superseded the previous circuitous arrangement. The last of the double water-wheels employed drawing

coal in the North of England were were at Chopwell Colliery, and the A pit, Greenside, near Ryton; one of which was abandoned in 1800, and the other in 1808.

In the beginning of the present century a further extension of the use of the steam-engine began to be thought of. At this time the conveyance of coal on railways was performed entirely by horses, excepting in cases where conditions existed favourable to the employment of self-acting incline-planes, when the loaded waggons in descending were made to haul up the ascending empty ones. Hence the railways were made merely of sufficient strength to bear the weight of the loaded coal-waggons. On most of them wooden rails were still used, but the employment of cast-iron rails was making steady progress; and in a few cases light bars of malleable iron had been applied on the top of wooden rails with good results. An early railway of the latter description was constructed at Alloa Collieries, on the Frith of Forth, in 1785. The wooden foundation was of a substantial character, consisting of broad sleepers about a foot apart, to which were secured the rails, four inches square, in the form known as the "double-way," there being both an upper and an under rail employed. On the top of the upper rail a light bar of malleable iron was laid, 14ths of an inch in breadth, and ths of an inch in thickness. Light waggons were used, with cast-iron wheels,