S/K U'll.l.IAM .S7/-:.1//-:.Y\, l-.R.S. 6l 



of atmospheric air at equal temperature and pressure ; moreover 

 it was a far better conductor of heat, and both circumstances 

 qualified it for rapid respirative action. 



5. The fresh steam required for starting and sustaining the 

 power of the engine was generated by heat that would otherwise 

 be lost. No air-pumps, &c., were required, and the management 

 of the engine became as simple as that of an ordinary high- 

 pressure steam-engine. 



In conclusion, it was stated that at present there were several 

 regenerative engines in constant practical operation, in this 

 country (at the works of Messrs. Newall & Co., at Gateshead), in 

 France, and in Germany, varying from five to forty horse-power, 

 which had proved the practicability of the principle involved, 

 although they were still capable of improvement. Several other 

 engines were now in course of construction at establishments 

 celebrated for precision of execution, and with the advantage of 

 Mr. Siemens's increased experience in designing them. He had 

 been fortunate to meet with men of intelligence and enterprise, 

 lately joined together in a public company, whose co-operation 

 insured a more rapid development of his invention than indi- 

 vidual effort could produce. The benefit he had hoped to derive 

 from his discourse, incomplete as it necessarily was, would be 

 realized, if those men, eminent in science, whom he saw around 

 him, would accept his labours as an earnest towards the prac- 

 tical realization of the dynamical theory of heat, and hasten its 

 triumphs by their own researches. It was impossible to over- 

 estimate the benefits that mankind would derive from a motive 

 force at one-third or one-fourth part the cost and iucumbrancc 

 of the present steam-engine. The total consumption of coal would 

 certainly not diminish ; but our powers of locomotion and pro- 

 duction would be increased to an extent difficult to conceive, 

 tending to relieve men from every kind of bodily toil, and hasten 

 the advent of the hoped for period-of general enlightenment and 

 comfort. 



