THE MASTER WORKER 



by forming grooves in the sides of the revolving piston 

 and filling them with soft packing." 



Sundry other rotary engines, some of them actual 

 working models, are to be seen at the South Kensing- 

 ton Museum. There is, for example, one invented by the 

 Rev. Patrick Bell, a gentleman otherwise known to 

 fame as one of the earliest inventors of a practical reap- 

 ing machine. In this apparatus, "A metal disc is 

 secured to a horizontal axis carried in bearings, and the 

 lower half of the disc is enclosed by a chamber of 

 circular section having its axis a semi-circle. One end 

 of this chamber is closed and provided with a pipe 

 through which steam enters, the exhaust taking place 

 through the open end. The disc is provided with three 

 holes, each fitted with a circular plate turning on an 

 axis radial to the disc, and these plates when set at 

 right angles to the disc become pistons in the lower 

 enclosing chamber. Toothed gearing is arranged to 

 rotate these pistons into the plane of the disc on leaving 

 the cylinder and back again immediately after entering, 

 locking levers retaining them in position during the in- 

 tervals. The steam pressure upon these pistons forces 

 the disc round, but the engine is non-expansive, and al- 

 though some provision for packing has been made, the 

 leakage must have been considerable and the wear and 

 tear excessive." 



It is stated that almost the same arrangement was 

 proposed by Lord Armstrong in 1838 as a water motor, 

 and that a model subsequently constructed gave over 

 five horse-power at thirty revolutions per minute, with 

 an efficiency of ninety-five per cent. 



[121] 



