of the Steam-Engines inCorn'wall. 103 



deeper, three additional ones have been erected, and the con- 

 sumption of fuel now stands as under, the mines being 20 

 fathoms deeper than in 182.5 : 



Job's engine (90-inch cylinder) about 2050 bushels. 



10,600 

 " The average duty of the six engines is now reported at 

 more than 50 millions." This difference I attribute entirely 

 to Capt. Grose's improvements. Mr. Farey has thought fit to 

 charge me* with keeping back the fact of our engines having 

 only one cylinder, and being worked with high-pressure steam, 

 acting expansively. If he will refer to Brewster's Journal, 

 vol. ix. p. 160, and vol. x. p. 42, he will find papers (which 

 although inaccui-ate in some minor details are substantially 

 correct) in which the elasticity of the steam employed is par- 

 ticularly mentioned. He has also said that I have, in quoting, 

 " altered " his expressions, so as to make them " veiy inde- 

 finite" ■\. I believe my quotations present his ideas in quite as 

 definite a form as that in which they stand in the original ; 

 and I do not base this assertion on my own opinion only. 



I may now be asked, in what respect Mr, Woolf has been 

 a benefactor to Cornwall? I reply, In introducing accurate 

 workmanship and some attention to proportion in the con- 

 struction of engines, both which disappeared on Messrs. Boul- 

 ton and Watt's removal. These I take to be the only benefits 

 he has conferred on the county ; but they are favours of no 

 mean order, as those who know the state of the engines in 

 Cornwall, before his arrival in the county, will readily admit. 



I pass over some points of minor importance on whicii 

 I could have desired to make a remark or two, as I fear I have 

 already trespassed too long on your patience, and I am half 

 ashamed that the discussion has assumed so unconnected a 

 form; but however much I may be disposed to enter further 

 upon it, I shalldeny myself the honour, unless the inquiry be 

 in luture directed to but one point at a time. Yours, &c. 



Penan Wl.aif, near Truro, Wm. J. IIknwoOU. 



April Jl, 18;J1. 



• Phil. Mag. and Annals, N.S. vol. vii. p. 423. t Ibid. p. 422. 



X. On 



