A minute description of this ingenious apparatus, accom panied with drawings, will be found in the Transactions of the Society of Arts, vol. xli. p. 182.
Among the inventions for preserving lives at sea, we may enumerate: With a short eight inch mortar, the weight of which, and its bed, was 7 cwt. the elevation being unknown, 32 ounces of powder projected in one experiment 439 yards of deep sea line, and in another 479 yards ; while in a third experiment it projected 3367 yards of 21 inch patent Sun derland rope, which had strength enough to haul the largest boat from a beach.
As there is necessarily considerable practical difficulty in managing Captain Manby's apparatus, both front the snapping of the rope and the difficulty of adjusting the charge and elevation to the distance of the ship, it occurred to Mr. John Murray, lecturer on chemistry, that a musket Irt7I 1. The safety-buoy and life-boat of Mr. Boyce, consist ing of hollow canvass cylinders, painted and varnished, and connected with each other. Sec Transactions of the Societ! of Arts, vol. xxxii. p. 177. 1814.
2. The contrivance of Mr. G. Bray was, in 1818, of a boat filled with air-boxes, placed under the seats and along the sides. Id. vol. xxxv. p. 172.
3. Mr. Thomas Cook's life-buoy, for preserving the life of a person who falls overboard in the night. Id. vol. xxxvi.
p. 121.
Among the machines for saving persons in the act of drowning, we may mention a very ingenious one which has been used for some time at Duddingstone Loch, near Edinburgh, under the sanction of the Skating Club. As this loch is much resorted to, when frozen over, for the purpose of skating, several persons have been drowned, from the ice giving way in particular places. In order to give assistance to persons who have sunk in the ice, a rope is placed so as to surround the whole lake. This rope is at the command of any spectator, at any part of the circuit of the lake; and when any person needs assist ance, another, at the margin of the lake, has only to take hold of the rope, and drag it towards hint. The rope must necessarily pass over the spot where the person in danger has sunk; so that, by taking hold of it, he may be dragged on the ice, or be enabled to reascend.
Under our article Fine ESCAPES, we have given an ac count of various inventions for this purpose. To thc ma chines there described may be added Mr. Braby's fire escape, described in the Transactions of the Society of Arts, for 1816, vol. xxxix. p. 227. It consists of a car made to slide on a strip of plank, fixed to a pole, and directed by a rope.