If the jar D be put behind the stand, and the cloud 2 removed, a vessel communicating by means of a wire with the outside of the jar may be swum in water under the remaining cloud; the mast being made of two pieces, and but slightly joined together, with a hollow space in one half of the mast, into which the ends of the conductor pass, but do not touch, leaving an interval of about a quarter of an inch between them. The hollow is then filled with gun-cotton, and closed with cork. When the cloud is passed over the vessel, the mast will be struck and shattered to pieces. A strip of tinfoil, arranged with pins over the hollow part of the mast, will show how a continuous conductor will convey the discharge safely away.
THE SPORTSMAN.
[This apparatus] is capable of affording much amusement. A is a stand of wood, B is a common Leyden jar, out of which proceed the wires H H—one terminating in ball F, the other in the ball D—to which are attached a number of pith birds by silken strings; E is a shelf for the birds to rest upon; C is the sportsman; G his gun.
To put this operation in motion the Leyden jar is to be charged with electricity by affixing a chain to the bottom part of it, and connecting it with an electrical machine in the usual manner, or by applying it to a prime conductor, when the birds will fly off the knob to which they are fixed in consequence of their being repelled. If the sportsman and gun be then turned, so that the end of his gun shall touch the knob F, an electric spark will pass from one to the other, a report will be heard, and the birds will fall down as if shot, in consequence of the electricity having been taken from the Leyden jar. There should be a communication between the sportsman and the jar formed of tinfoil, or some metal, as shown by the dotted line on the stand.
Such are a few of many numerous experiments which may be made by the young experimenter, who is fond of science and has any ingenuity; but should he like to amuse himself with an electrifying machine of little cost, he may warm a sheet of brown paper, and then rub it briskly on a teatray with india-rubber; on raising the paper in a dark room, he will see many pretty electrical sparks.
The back of a black tom cat is sometimes recommended as a cheap electrical machine; but as the wishes of the animal have to be consulted, perhaps it is wiser to leave the cat alone.