of the Stcam-Engines in Cornwall. 10 1 



precisely similar to those which he before says* were " first 

 brouo-ht into use for high pressure steam by Mr. Trevithick 

 in 1804;" but in different arrangement of the flues f round 

 them; first introduced at Huel Hope, afterwards at Huel 

 Towan, and subsequently in many other mines (the Consoli- 

 dated, Huel Vor, &c.) ; in some degree by more attention to the 

 temperature of the hot well ; and in a great proportion by 

 carefully covering all the vessels containing dense steam with 

 bodies which transmit heat very slowly. 



That these originated with Capt. Grose, and were borrowed 

 from him (without acknowledgement) by Mr. Woolf and others, 

 will appear from the following extracts from Messrs. Lean's 

 monthly reports. 



Millions. 

 1827: average of all the pumping engines reported 31*9 



Huel Towan, Wilson's engine 58*1 



Consolidated Mines, 12 months' 7 ^q.-^ 



average of best engine j 



Woolfs engine^ 64'*4 



Huel Vor Trelawny's engine 4'7*2 



• Phil. Mag. and Annals, N.S. vol. viii. p. 313, note. 



f Hrcwster's Journal, vol. ix. j). 139. 



j Wilson's engine was at that time the best on Huel Towan. 



§ In the first nine months; the same engine was not every month ihc 

 best. 



II 'IVelawny's engine is the best on Huel Vor. 



H Woolfs engine was not reported until October 1827. 



♦• At an experiment made by some Cornish engineer* in this month the 

 duty waB 6I5'6 miliionii. 



1828. 



