AMONGST the various instruments which have been invented from time to time for rescuing persons from drowning, is the in- genious machine with the above title, a drawing and description of which we annex.

The Cliff-crane was invented in the year 1841, by JOHN JOHNSTON, Esq., of Brighton, for the purpose of affording aid to persons who might be wrecked at the foot of perpendicular cliffs. It is a light portable crane, on wheels, and with shafts fitted at the rear end, so that it may be transported by horse-power. The crane- beam is moveable, so that it may be pro- jected more or less over the brow of a cliff, according' to its nature. The crane-rope has a large basket or cradle of wicker-work at- tached at its outer end, of sufficient size to seat four persons, which is lowered or hauled up by an ordinary windlass, fitted in the framework of the machine. A box of bal- last is placed at the rear end of the frame, to counterbalance the weight of the basket with its contents, and pi-event the rear end from being lifted from the ground. An iron spar is fixed in either side of the frame, to penetrate the ground, and prevent the crane from being drawn too near the edge of the cliff; and hand-ropes are fitted for the same purpose.

Two of these cranes have been stationed for some years at the Portobello and Black- rock Coastguard Stations, on the coast of Sussex, between Brighton and Newhaven: that at the first-named place being the first that was constructed by Mr. JOHNSTON. It does not appear that many opportunities have occurred in that locality for their prac- tical use; but the crane at Black-rock, on one occasion, was the means of saving the life of a coastguardman, who had been precipitated with a falling portion of the cliff.

The other, at Portobello, was once the means of saving the greater part of a vessel's cargo, which was hoisted up the face of the cliff by the crane; but, unfortunately, it could not be conveyed to the spot in time to rescue the crew.

Two cranes, similar to those above described, or nearly so, have been placed on the pier at the Royal Harbour of Ramsgate, by the Harbour Commissioners; and they have, we believe, been the means, on more than one occasion, of saving lives. It is, indeed, in such positions that we think these portable cranes are most calculated to be of use. Wrecks take place so much more sel- dom at the base of perpendicular cliffs than on beaches, or at the entrance of pier harbours, that many years might elapse without the occurrence of one in any such positions where the Cliff-crane could be made avail- able ; but at many of our great trading ports which have pier entrances, such as Sunder- land and Hartlepool, scarcely a winter takes place that vessels do not get wrecked, and frequently their crews drowned, alongside their pier-walls. We remember two in- stances which occurred on the same day at Sunderland, in November 1852, at the I time we were ourselves in the neighbour- hood, when the English brig Napoleon and the French lugger Melancolie were both lost in a heavy gale within the entrance of the dock, and all on board them were drowned, almost alongside the pier-walls.

A cliff-crane, had there been one on the spot, might probably have been the means of saving the lives of several, if not all, of those unfortunate persons.

We are.not aware if any other ports are furnished with these cranes, but we think they would be a very proper and useful adjunct to the means for affording aid to wrecked persons at all the pier harbours in the kingdom.

We are indebted to Mr. JOHNSTON, who now resides at Ryde, for liberally supplying us with the plates of his cliff crane.