The said vessels F are preferably made cylindrical with conical ends, and are provided with suitable insulating and water-tight packing boxes, as shown at F1 for the cable G to pass through at the stem and stern of each vessel.

The Lay Torpedo in Clearing Obstructions.—For this purpose the torpedo boat is provided with an apparatus, shown at [Fig. 134] and [135], in combination with the electric cable, whereby the said boat is controlled and guided, and there is arranged in the boat A a compartment A3, from which extends down into the water a line or rod U, provided at its outer end with a hook or claw U1, properly formed to take hold of any chain or bar with which it may come in contact. In the said compartment A3, and upon the upper end of the said line or rod U, is placed a small case or cylinder U2 containing a charge of dynamite or other explosive material and a cartridge or fulminating cap, or a bottle of sulphuric acid, surrounded with a certain quantity of chlorate of potash and sugar. This case or cylinder U2 is shown detached and drawn to an enlarged scale at [Fig. 135], and it will be seen that the said case is provided with a tube 1 containing a cartridge, or a phial filled with explosive substance at 2, and a ball or weight at 3. The said case is fitted to slide upon the said line or rod U, and when placed at the upper end thereof and not held or retained will slide to the lower end of the same. In the said compartment A3 is arranged at U4 an electro-magnetic apparatus, included in the circuit of the said cable, and connected with a bolt or catch which in its normal position holds the said explosive case and prevents its running down on the grappling line or rod U. This explosive case is also provided at its lower end with a grappling hook U5.

When the grappling hook U1, on the lower or outer end of the line or rod U, engages with any obstruction the boat will be stopped, and this stoppage will be indicated on the keyboard. The operator by this indication is apprised of the stoppage of the boat by an obstruction, and by sending a current through the cable by means of a switch provided for this purpose on the keyboard he can immediately release the explosive case U2, which runs down the line or rod U, and engages by its grappling hook U5 with the hook U1. The line or rod U is then disengaged from the boat A, and the explosive case U2 turns or falls over. As it turns over the ball or weight 3 contained in the tube 1 drops on the said phial 2, fractures it, and thereby allows the acid to mix with the explosive or fulminating charge and explode the case U2. This explosion will rupture or destroy the obstructing chain or bar, so that the ironclad ships or other vessels can pass freely and safely into the harbour or beyond the point where it was intended to stop them.

Used to clear away Mines and Electric Cables.—For this purpose there is an implement V provided, [Fig. 136], somewhat of an anchor form, but with four or any desired number of arms V2 extending outward at a suitable angle from its shank V1. In the neck of each of these arms are fitted two small plain or toothed discs V3, which are so arranged as to present their teeth to any object lying in the angle or corner formed by and between the arms V2 and shank V1 of the said implement, as shown at W.

In using this implement it may be attached to a line or cable coiled in the torpedo boat, which, in this case, is used without being charged with explosive material, and is sent in advance of any ship that has to enter or pass through the suspected water. This line must be arranged in combination with a detaching apparatus controlled by electro-magnetic apparatus included in the circuit of the cable which connects the torpedo boat with the keyboard at the operating station.

[LAY'S LOCOMOTIVE TORPEDO.]

By sending a current from the station the operator releases the said implement or its line from the detaching hook or holding device. The said implement then sinks to the bottom; then the said boat returns to the ship, paying out the said line as she so returns. The end of this line is then taken by a steam tug or other vessel, and the said grappling implement is thereby dragged along through the water over which the ships are to advance, thus breaking any wires or cables that may be in its course. This operation is shown at [Fig. 137], in which A is the towing boat, K the controlling cable, V the said implement, V* the line attached to the implement V, X X submerged mines, and X1 X1 are the mine cables.

In some instances it may not be practicable to reach the enemy's ship or other object of attack directly from the station to which the torpedo boat is connected, and from which it is controlled. In this case a small boat, &c., is used in addition, which should be so arranged as to present to the enemy's view as slight a surface as possible. This mode of attack is shown at [Fig. 138], where A is the torpedo boat, and N is the small auxiliary boat. This boat N is provided with a keyboard and battery like that described at [page 144], and the electric cable L, carried on and payed out from the torpedo boat A, is connected with the keyboard. The boat N is also attached to and towed by the torpedo boat A by the tow line O; and the torpedo boat is steered and guided by means of the said keyboard in the boat N. The auxiliary boat is designed to contain two men, who lie down, one at the bow, the other in any convenient position abaft him; the latter has control of the keyboard, while the former by the aid of a telescope keeps the torpedo boat in view, and transmits his orders to the man at the keyboard. On arriving at such a distance from the enemy as to render an attack practicable, the tow line O is disengaged, and the torpedo boat A, guided and controlled, and fired from the boat N. The torpedo boat being exploded, the auxiliary boat can be rowed back to the station or ship to which it belongs. By this means the range of action of the torpedo boat is greatly extended, and with comparatively slight danger to those employed in making the attack.