So that a man falling overboard at night is directed to the buoy by the blaze on the top of its pole or mast, and the boat sent to rescue him also knows in what direction to pull.

Even supposing, however, the man not to have gained the life-buoy, it is clear that, if above the surface at all, he must be somewhere in that neighbourhood; and if he shall have gone down, it is still some satisfaction, by recovering the buoy, to ascertain that the poor wretch is not left to perish by inches.
The method by which this excellent invention is attached to the ship, and dropped into the water in a single instant, is perhaps not the least ingenious part of the contrivance.

The buoy is generally fixed amidships over the stern, where it is held securely in its place by being strung, or threaded, as it were, on two strong perpendicular iron rods fixed to the taffrail, and inserted in holes piercing the framework of the buoy.

The apparatus is kept in its place by what is called a slip-stopper, a sort of catch-bolt or detent, which can be unlocked at pleasure, by merely pulling a trigger.

Upon withdrawing the stopper, the whole machine slips along the rods, and falls at once into the ship's wake.