in the form of spray plays on the tubes, T, and absorbing any residual heat.  The heat generated by compression in the cylinder, C, is absorbed by a spray of water from the pump, H, the vapor being carried along with the air through the pipe, R, to the chamber, Y, where it is separated, and falling to the bottom is circulated, as just described, by the pump, J. X is a small auxiliary air compressor, to obtain the necessary compression to start the engine, and is worked from the boiler, W. In future engines this compressor will be superseded by a specially designed injector, which will produce the necessary pressure at a considerable reduction in cost.  When once the engine is started, the fire of the auxiliary boiler can, of course, be drawn, as the main engine afterward makes its own steam.  The regenerator, E, has circular ends of fire clay perforated, the body being filled with fire clay spirals of the shape clearly shown in elevation in Fig. 2.  The injector valve for the creosote is shown to a larger scale in Fig. 3.  This valve has, however, been since considerably modified and improved.  The feed and exhaust valves, M, are actuated by cams keyed to a countershaft driven by bevel wheels from the main shaft.  The creosote pump, F, is also worked by a cam on the same shaft, but the pumps, G H J, are worked by eccentrics.  A stop valve, N, is fixed to the supply pipe, P, under which is place a back pressure valve to retain the pressure in the combustion chamber.  The engine is regulated by an ordinary Porter governor actuating the throttle valve, O. An engine, as described, has been constructed by Messrs. Adair & Co., engineers, Waterloo Road, Liverpool, and has been running most satisfactorily for several weeks, the results being clearly shown by the indicator diagrams (Figs. 5 and 6).  The results obtained by this motor are very remarkable, and are a long way in advance of any previous performance, as only a little over 1/2 lb. of fuel is used per i.h.p. per hour.  It may be mentioned that the temperature of the combustion chamber is calculated to be about 2,500 deg.F., and that of the exhaust gases does not exceed 180 deg.F.—­Industries.

[Illustration:  Diagram from cylinder—­25 in. diam, 18 in. stroke.  I.H.P., 63.  Scale, 1/30 in.  Mean pressure, 28.2 lb.  Fig. 5.]

[Illustration:  Diagram from air pump—­15 in. diam., 18 in. stroke.  I.H.P., 23.  Scale, 1/30 in—­Mean pressure, 28.5 lb.  Fig. 6.

Diagrams from cylinder and air pump.

Net indicated horse power, 40; revolutions per minute, 100; coal tar consumed per hour, 20.5 lb.; coal tar per I.H.P. per hour, 0.512 lb.]

* * * * *

AN INVESTIGATION INTO THE INTERNAL STRESSES OCCURRING IN CAST IRON AND STEEL.

By general Nicholas KALAKOUTZKY.

NO.  I.