264 SCIENCE PROGRESS 



since, for the first time, combustion of the fuel was made to 

 take place within the engine itself, whilst the steam turbine 

 retains the boiler as an essential auxiliary. But from another 

 point of view the steam turbine, with its absence of all 

 reciprocating parts, such as piston, connecting rod and crank 

 shaft, bears less likeness to its progenitor than does the gas 

 or oil engine. Both were great and successful efforts to cast 

 off the trammels of " previous practice " and to revert to first 

 principles for a fresh start. Each of these two prime movers 

 is ousting the reciprocating steam engine from an increasing 

 portion of its domain and has added its quota to the solution 

 of the great problem. 



In the invention which promises to rival and finally to 

 surpass in importance the gas engine and steam turbine at 

 least in many fields of usefulness, Mr. Humphrey casts back 

 to first principles and starts out in a new direction. The prime 

 mover that can raise water or put it under pressure can be so 

 arranged that it will readily give up its energy in other forms. 

 The Humphrey pump combines the novel features of both 

 gas engine and turbine, in that, whilst the combustion of the 

 fuel takes place within the pump itself, it has also the advantage 

 that there are no reciprocating parts with the exception of the 

 water to be pumped and this swinging freely controls the cycle 

 of operation. 



The absence of solid pistons, fly-wheels, gearing bearings, 

 connecting rods and cranks, together with cooling jackets, 

 cams, shafts, etc., is an advantage of the Humphrey system 

 which all can appreciate ; the extent to which simplicity has 

 been carried can best be realised when it is known that a pump 

 can be made only with four moving parts, namely, the two 

 valves — one for admission and one for exhaust — one water valve 

 and one small paddle moved by the liquid to effect ignition. 



So far we have, we hope, made quite clear the principle 

 involved by reference to the simplest type of apparatus. The 

 importance of the invention has been indicated and a few 

 developments may now be considered. 



We will now describe the double-barrelled pump which is 

 diagrammatically illustrated in fig. 2, in which there are two com- 

 bustion chambers a and b in which explosion occurs alternately. 

 In each chamber the usual cycle is followed of compression, 

 expansion, exhaustion and the taking in of the new charge, 



