Fig. 1 shows a single acting explosive machine comprising a cylinder a with an open top, a piston b, a double-acting pump, which serves both to supply atmospheric air (to form one portion of the explosive mixture), and to draw off from the cylinder, during the descent of the piston b, the products or any portion of the unconsumed gas which may remain after the explosion of the mixture has taken place. The air enters the lower part of the pump by the valve d during the ascent of the piston f; and upon the descent of the piston the air is forced through the valve g into the receiver A situated below the cylinder.

Figure 9, is s pump for supplying the hydrogen or other inflammable gas which forms the other portion of the explosive mixture. The gas enters the pump by the valve k, Figure 9, upon the ascent of the piston or plunger of the pump, and by the descent of the same is forced through a delivery valve (not seen in the Drawings) into the receiver h; l is the slide-valve case, communicating at the bottom with the receiver b, at the middle part, with the cylinder by the passage m, and at the top with the inlet valve n of the pump c, by means of the eduction pipe o; P is the delivery valve to the upper part of the pump opening into the waste pipe r; s is the slide valve, by the motion of which the internal portion of the cylinder, below the under side of the piston b, communicates alternately with the receiver it and the eduction pipe o; t is a gas burner, at which s small jet of gas is kept burning during the time the engine is in operation; c is the igniting cock for the purpose of igniting the explosive mixture, the mode of effecting which, and the construction of the cock, will be best understood by a description of Figures 8 and 4, which are drawn to an enlarged scale.

The Drawings, Figures 5 and 6, in the Sheet marked B, represent a double acting explosive engine. Figure 5 is a longitudinal section of the engine, and Figure 6 is an end elevation of the frame and pumps. a is the cylinder; b, the slide-valve case connected with the two receiving chambers c, c, into which the air and gases are forced by the three pumps d, e, and f; d is a double acting pump, which draws in air at the valves g and h, and forces it into the receivers through the valves i and k; e, Figure 6, is a pump open at top which draws in hydrogen or carburetted hydrogen at the valve l, and delivers it by another valve (not seen in the Drawings) into the same box as the valve i, whence it passes into the lower receiver c; f, Figure 6, is a pump open at bottom, the piston rod of which works through a stuffing box in the top of the pump. This pump draws in hydrogen or carburetted hydrogen at the valve m, and delivers it into the upper receiver c by the pipe n, which is connected to a valve fixed at the aperture o. These pumps, by means of the spur wheels y and q (indicated by red circles in Figure 5), make their ascending and descending strokes simultaneously with the ascending and descending strokes of the piston r. s is a pipe proceeding from the slide case to convey the products of the explosion, or any unconsumed portions of the explosive mixture from the cylinder, and having at its extremity a light hanging valve opening outwards; t, t, are two igniting cocks, the construction of which has been already explained. These cocks are placed over the gas burners v, v, in the position shewn in the Drawing. The cocks being open to the atmosphere, the gas within them is ignited by the flame from the burners v, v, and by turning the cock the flame communicates with the interior of the cylinder. x is the pipe which supplies the hydrogen or carburetted hydrogen gas to the pumps c and f.

The operation of this engine is as follows:— Let it be supposed that the lower receiver is charged with the explosive mixture, and that the slide valve be then moved so as to open the communication between the lower receiver and the cylinder at the under side of the piston, whilst the cylinder on upon the upper side of the piston communicates with the exit pipe S, the mixture in the lower receiver will immediately flow into the cylinder, and upon turning the lower igniting cock the mixture will ignite, and, by exploding, will expand and impel the piston to the top of its stroke, any air which may be above it being expelled through the eduction pipe S. During the ascent of the piston the pumps s and d are drawing in air and gas respectively, and the latter pump and the pump f are forcing air and gas respectively into the upper receiver c. Upon the piston reaching the top. of its stroke the slide is reversed, the explosive mixture is admitted above the piston, and upon the explosion taking place, the piston is driven to the bottom of its stroke.  If preferred, the eduction pipe may be connected to a double acting air pump, so as to exhaust the products of the explosion, or any unconsumed portion of the explosive mixture, from the cylinder on the eduction side of the piston.