in. PRIME MOVERS. 389 



1945. Atmospheric Gas Engine. Otto Langen and Cross- 

 ley's joint patents. Actuated by the vacuum resulting from the 

 explosion of common coal gas and air. Crossley Brothers. 



In this engine, which works by the vacuum resulting from the explosion of 

 common coal gas and air, the piston is not, as is usual, connected with the 

 shaft on both up and down stroke, but on down stroke only. It is thus at 

 liberty to fly up freely from the force of the explosion, which takes place at 

 the bottom only, and by driving the piston before it empties the cylinder of 

 air through its open upper end. The return of the air on the down stroke 

 yields the driving power, and turns the shaft by means of a friction clutch, to 

 which the piston is geared by the rack. The vacuum beneath the piston in 

 equal to about 11 Ibs.per square inch for the greater part of the down stroke. 

 The governor does not act, as is usual, by increasing or decreasing the power 

 of each stroke, but by varying the number of strokes, each being of the same 

 power. This is done without materially changing the speed of the shaft. 

 Three or four explosions per minute are generally sufficient to turn the engine 

 itself, and as a maximum of 30 to 35 may be made, there is a balance of, say, 

 from 26 to 32 strokes or explosions per minute left to be applied to useful work 

 under the regulation of the governor. As this engine can be started and 

 stopped at a moment's notice, giving full power at once, and is free from the 

 risks of a boiler explosion, it is peculiarly suited for use as a motor in a 

 laboratory. The consumption of gas is seldom over 2s. 6<f. worth per week 

 for a 1-HP. engine. The engine as here exhibited contains many quite 

 recent and very important improvements. 



1946. Sectional Model of a Steam Engine, with expansion. 



Paul Lochmann, Zeitz, 



1947. Sectional Model of a Locomotive. 



Paul Lochmann, Zeitz. 



1948. Wall-diagrams illustrating the Hot-air Engine. 



Prof, von Gizycki, Aix la Chapelle. 



1949. Wall-diagrams illustrating the Gas Engine. 



Prof, von Gizycki, Aix la Chapelle. 



1950. Wall-diagram illustrating the Steam Engine, with 

 continuous expansion. Prof, von Gizycki, Aix la Chapelle. 



These diagrams are used in Prof, von Gizycki's lectures on description 

 and theory of machines. 



1951. Turbine to act as prime mover for physical laboratories. 

 Head of water necessary, 10-20 met. ; measure of water, 1 lit. per 

 sec. ; effective power about 10 meterkilo. 



Prof. Wiillmr, Aix la Chapelle. 



This turbine, with constant water pressure, is exceedingly steady in its 

 action, and thus is specially suited for apparatus that require a constant 

 velocity of rotation. With the fall of 1 8 metres available in air, and a water 

 supply of about one litre per second, the effect of the machine is equivalent 

 to one man's power. 



1952. Working Model, on a 1^ inch to 1 foot scale, of 

 a four wheel locomotive engine. Built at Alexandria in 1862 

 for service of Egyptian Railway between Alexandria and Suez. 

 Jeffrey Bey, C.E., Great George Street, Westminster. 



South Kensington Museum. 



