324- Mr. Hen wood on the Stcam-Engines qfCornxcall. 



with propriety ascribed to Mr. Watt by every person, except- 

 ing Mr. Farey: and in another nJace^ even he has concurred 

 in this opinion; variation in the elasticity of the steam em- 

 ployed by no means affecting the invention. Moj-eover, the 

 evidence at present before the world, seems to preponderate 

 against the use of steam of very high tension. 



2ndly, With legard to tlie performance of steam-engines, it 

 has been stated f that Mr. Watt's projjosals ^vere. that his en- 

 gines should Hit 23'44' millions of pounds one foot high, by 

 the consumption of one bushel ( -- 81 pounds) of coal ; and 

 I am informed by Mr. Sims, an engineer vve'l 1- novvn in this 

 county, that the average duty of Watt's engines here, whilst 

 superintended by his own agents, was about 25' miU'ons; but 

 this will be seen more accurately stated in a paj)er recently 

 read before the Royal Society', by its illustrious Pies'dent. 

 Subsequently to Mr. Watt's relinquishing the superintendence 

 of the engines here, the average duty suliered a considerable 

 diminution. The following may be regarded as an approxi- 

 mation to the duty for some years. 



Average of all Average of 

 Cornwall. Wcolf's. 



1823 26-9 millions. 36- millions. 



1824 28- none at work. 

 1826 28-97 34-7 



1826 28-36 40-4 



1827 31-9 none at work. 



1828 37-2 



1829 (to June) 40-72 



Srdly, The construction of the Cornish steam-engines. 



I presume Mr. Farey follows many other writers, in ascri- 

 bing to Mr. Woolf the invention of an engine, all the mechanical 

 contrivances of which were made by M\\ Hornblower. But 

 the merit of invention apart, — t/itre is not one engine on this 

 construction ?ww at ivork in Corn-wall; the last, which was at 

 Kuel Alfred, having been stopped in 1826. Indeed, beside some 

 five or six rotatory engines, neither of which exceeded twenty- 

 eight inches cylinder, the only engines on Mr. Woolf 's plan 

 (or rather on Mr. Hornblower's, erected by Mr. Woolf) 

 worked on the mines of this county, were at 



Huel Vor 53 inches diameter of larger cylinder %. 



Huel Unity ... 60 § 



* Farey on the Steam-engine, p. 339. f l^'i<l- P- 337. 



\ The use of the smaller cylinder was discontinued soon after Mr. 

 Woolf's superintendence ceased. 



§ The small c}linder was not worked for some years, the engine at tho 

 time being under the supervision of Mr. Woolf. 



Huel 



