GAS AND OIL ENGINES 



ing of the entire gas. There is no reason whatever for 

 introducing the gasoline beyond this. Could a better 

 method of heating air be devised, the oil might be 

 entirely dispensed with, and the safety of the apparatus 

 enhanced, as well as the economy of operation. Efforts 

 have been made for fifty years to construct a hot-air 

 engine that would compete with steam successfully. 

 In the early fifties, as already noted, Ericsson showed the 

 feasibility of substituting hot air for steam, but although 

 he constructed large engines, their power was so slight 

 that he was obliged to give up the idea of competing 

 with steam, and to use his engines for pumping where 

 very small power was required. 



The great difficulty was that it was not found prac- 

 ticable to heat the air rapidly. All subsequent experi- 

 menters have met with the same difficulty until some- 

 what recently. It is now claimed, however, that a 

 means has been found of rapidly heating the air, and it 

 is even predicted that the hot-air engine will in due 

 course entirely supersede the steam engine. Mr. G. 

 Emil Hesse, in an article in The American Inventor, for 

 April 15, 1905, describes a Svea caloric engine as 

 having successfully solved the problem of rapidly 

 heating air. The methods consist in breaking up the 

 air into thin layers and passing it over hot plates, where 

 it rapidly absorbs heat. It passes from the heater to the 

 power cylinder which resembles the cylinder of a steam 

 engine; thence after expanding and doing its work it 

 is exhausted into the atmosphere. Large engines may 

 use the same air over and over again under pressure of 

 one hundred pounds per square inch, alternately heat- 



VOL. VI. 10 [ 145 ] 



