64 Mr Russell on the Fallacies of the 



The study of the higher analysis cannot be too strongly re- 

 commended to those who wish to avoid errors in invention. 



In the reciprocating piston, therefore, acting through the 

 crank, the whole power is found by multiplying the stroke and 

 back-stroke, or twice the stroke of the piston, by the pressure 

 upon it, and this is equivalent to the whole effect produced in 

 the entire revolution of the crank ; the pressure of the steam, 

 and the space it moves through, are therefore the measure of 

 the power. 



In the revolving piston, the effect of the steam must be pre- 

 cisely the same, if the revolving piston be of the same size, and 

 moves through the same space as the reciprocating piston ; and 

 if the revolving piston have a pressure on it equal to the mean 

 pressure on the crank, and move through a circle equal to the 

 circle of the crank, the effect will be the same in both cases. 



Since there is no loss incurred by propagating the action of 

 the steam on a reciprocating piston through the crank of a re- 

 volving axle, and since it is not in the power of machinery of 

 any kind to augment the quantity of power given out by any 

 mover, but merely to arrange, dispose, and modify that power 

 to suit any given purpose, it follows that the rotatory piston 

 can have no purpose to accomplish, unless it excel the recipro- 

 cating one in simplicity and economy of construction, diminish- 

 ed bulk, durability and economy in operation, facility of re- 

 pair when deranged, diminished friction, or a peculiarity of 

 adaptation to some individual purpose, such as steam naviga- 

 tion or inland transport. 



I. As regards simplicity of parts, the engine with the rotatory 

 piston cannot excel the simplest forms of thereciprocating engine; 

 take, for example, that form which merely consists of a cylinder, 

 piston, and crank axle ; where the cylinder, mounted on an 

 axle, oscillates with the revolutions of the crank, which is imme- 

 diately attached to the end of the piston rod, and which requires 

 no moving valves of any kind, the steam being admitted and 

 emitted through ports in the axle of the cylinder, which open and 

 shut by the motion of the cylinder itself. Neither as regards fa- 

 cility and economy of construction does it possess superiority; for 

 it will be readily granted to me, that whether the piston and 

 channel in which it moves be rectangular or circular, they are 



