308 



Intelligence and Miscellaneous Articles* 



that time quite a new proposal, but the general opinion of engineers 

 was very unfavourable to it. 



In the course of four or five years, Mr. Woolf made a few small 

 rotative engines in London, some with two cylinders, others with one, 

 but he met with no encouragement, and lost much money ; until 1811, 

 when he had brought his small rotative engines, with two cylinders, to 

 such perfection, that on a well attested trial of a nine-horse engine 

 and corn-mill, it ground \7\ bushels of wheat by the consumption of 

 one bushel of coals ; and on a repetition of the trial, nearly 20^ 

 bushels. Mr. Watt's rotative engines of that power will not do 

 half so much. 



From that time there has been a demand for Mr. Woolf 's rotative 

 engines with two cylinders, and a great number have been made ; they 

 have answered very well, and on an average consume only half as 

 much fuel as the average of Mr. Watt's engines, exerting the same 

 power. About 1813 Mr. Woolf obtained encouragement in Corn- 

 wall, and went to reside there : his partner Mr. Edwards continued 

 the business by himself in London. In 1815 Mr. Edwards took out a 

 patent in France, and sent over some engines, which were so much ap- 

 proved that he was induced to remove to Paris, where he has since 

 made a great number of Mr. Woolf's engines. Also about the time 

 that Mr. Edwards went to France, Mr. Hall began making Mr. Woolf s 

 rotative engines with two cylinders, at Dartford, and has executed a 

 great many excellent engines ; most of them have been sent to France, 

 where Mr. Woolfs engines are very common, and are greatly pre- 

 ferred to any others. Mr. Hall continues the business on an extensive 

 scale. 



Mr. Woolf's first engines for pumping water from mines were set 

 up by him in 1814 at Wheal Abraham and at Wheal Vor mines in 

 Cornwall ; they had each two cylinders : their performance far ex- 

 ceeded that of any steam-engines ever made before. In the latter 

 half of 1815, the two engines raised on an average 48 million pounds 

 of water one foot high, for every bushel of coals they consumed. 

 Thus : 



Engines. 



Half of 1815. 



1816. 



1817- 



1818. 



Wheal Abraham* 

 Wheal Vor . . . 



48-63 

 4763 



49-71 

 44-23 



44-07 

 36-15 



36-91 

 29-33 



Average 



48-13 







46-97 



40-11 



33-12 



* Wheal Abraham engine raised 56 - 92 millions, on the average of all the 

 month of May 1816. In 1818, this engine was put. in order, and exact trials 

 of its performance were made by Mr. Farey, with the steam kept up to a 

 greater elasticity than usual, and acting with a greater extent of expansion 

 than usual ; it then raised 65-22 millions, on the average of two trials of 

 eight hours and six hours each : that was the greatest effect ever produced 

 by steam, until November 1827, when Woolf's engine at the Consolidated 

 mines raised 67" 10 millions, on the average of the month's working. 



The steam cases for the cylinders of these engines were exposed to the 



open 



