WILLIAM SIEMENS, F.R.S. l6l 



laritv in appearance between the two governors than really existed 

 in their modes of action ; and it was clear that the throttle-valve 

 ilfsi-i-ilicil in connection with the Allen governor must b'e 

 lookod upon as an essential part of the governor, the prompt 

 action of the governor depending upon the ease with which the 

 valve could be moved with a slight amount of force. Owing to 

 the irroat simplicity of this governor, and the careful manner in 

 which the mechanical details had been worked out, he had no 

 do'ibt it would meet with success in its application. 



II* 1 proposed a vote of thanks for the paper, which was passed, 

 to Mr. Ivitson, who he regretted was prevented by illness fro:n 

 bi-ing present at the meeting. 



fn the discussion of the Paper 



"ON WENHAM'S HEATED-AIR ENGINE," 

 By Mr. CONBAD W. COOKE, 



The PRESIDENT (MR. C. WILLIAM SIEMENS) * said that many 

 years ago he had given much attention to the question of obtain- 

 ing from heat a larger proportion of mechanical effect than had 

 previously been realised. 



With regard to the best medium to be employed for the purpose, 

 although on theoretical grounds this was immaterial so long as no 

 heat was thrown away, there were many important considerations 

 in favour of steam, which had a higher rate of expansion by heat 

 than air, and did not involve the employment of an air-pump for 

 producing a supply under pressure. By the application of the re- 

 generative principle he had obtained in small steam engines satis- 

 factory results upon the whole ; fifteen or sixteen engines altogether 

 had been made on that plan, of from 5 to 10 horse power, and had 

 worked for a series of years with very fair results. One of them 



* Excerpt Minutes of Proceedings of the Institution of Mechanical Engineers, 

 1873, pp. 82-85. 



VOL. i. M 



