speed and pressure. Preferably the water is here divided into two streams,
each driving a separate rotary motor or turbine, H, themselves driving
twin screws or propellers, I. The motors exhaust into the hollow shafts,
J, of the propellers, which are extended some distance beyond the
propellers, so that the remaining energy of the water may be utilized to
aid in propelling the torpedo on the well known principle of jet
propulsion. The torpedo is preferably steered by means of the twin screws.
A disk or other valve, A, is pivoted in an aperture in a diaphragm
dividing the outlet of the injector, and is operated by means hereafter
described, so as to diminish the stream of water on one side and increase
it on the other, so that one motor, and consequently the corresponding
propeller, is driven at a higher speed than the other, and so steers the
torpedo.

[Illustration: PAULSON'S SELF PROPELLING AND STEERING TORPEDO.]

The valve, A, is operated automatically by the following arrangement: A
mariner's compass, P, placed in the head of the torpedo has its needle
connected to one pole of a powerful battery, D. A dial of non-magnetic
material marked with the points of the compass is capable of being rotated
by the connections shown. This dial carries two insulated studs, _p_, each
electrically connected with one terminal of the coils of an electromagnet,
K, whose other terminal is connected to the other pole of the battery.
These two magnets are arranged on opposite sides of an armature fixed on a
lever operating the disk or valve, A. Before launching the torpedo the
dial is set, so that when the torpedo is steering direct for the object to
be struck, or other desired point, one end of the needle of the compass,
P, is between the steeds, _p_, but contact with neither, the needle of
course pointing to the magnetic north. Should the torpedo however deviate
from this course, the needle makes contact with one or other of the studs