422 Mr. Farey on the Origin of the Impivvemenis "which have 



statements injurious to some improvers and builders of steam- 

 engines ; and three passages, marked with inverted commas, 

 are put forth as the substance of the objectionable statement. 



In the evidence printed by the Committee, those passages 

 are in the following words, respecting Woolt's patent: 



" Mr. Woolfs invention of isoorking steam-engines by high 

 pressure steatn, acting expansively {either in one or in ttvo cy- 

 linders) ;" at your page 323, the words in parentheses are 

 omitted. Again, in the printed evidence, speaking of deep 

 mining in Cornwall, my words are, " The difference in cost, be- 

 tween the quantity of coals consumed by the engifies nolo ifi use 

 {which are all on Mr. JVoolf's system) aud by an equal force of 

 engines, such as were in use before he we?it into Cornwall in 

 1813, xwuld absorb the profit of all the deep mining that is now 

 carried, on in Cornwall," this passage is altered at your p. 323, 

 so as to become very indefinite. 



What your correspondent calls the substance of my state- 

 ment, is made the basis of an insinuation, — that in speaking to 

 the Committee, I ascribed to Mr. Woolf the invention of ex- 

 pansive working, although in writing my treatise on the steam- 

 engine, I had before ascribed it to ]\Ir. Watt. 



The true quotation, as above, shows what I really did 

 ascribe to Mr. Woolf as his invention, for which he had a 

 patent, four years after Mr. Watt had retired from business 

 altogether; and it was not until after having made my defini- 

 tion, as above, that I stated the engines now in use for deep 

 mining in Cornwall, to be all on Mr. Woolfs system. The 

 meaning of the words I used, admits of no mistake, and the 

 statement they convey is true and exact. If it be intended to 

 deny that Mr. Woolf was the first who invented the system of 

 working steam-engines by high pressure steam acting expan- 

 sively, either in one or in two cylinders *, or to deny that he 

 was the first person who put that system in execution, with 

 engines of both kinds, first in London for turning machinery, 

 and then in Cornwall for draining minesf , the origin of that 

 system, with particulars of the person, time and place, should 

 be stated by the objector. 



The engines now in use for deep mining in Cornwall, are 

 strictly within the terms of my definition of Mr, Woolfs in- 

 vention; for they are worked by high pressure steam, acting 

 expansively in one cylinder. The engines Mr. Woolf first made 

 in Cornwall, with two cylinders, have gone out of use, not to 

 resume Mr. Watt's system of working by low pressure steam 

 acting expansively, but because engines with one cylinder 



* See the specification of liis patent of 1804. Philosophical Magazine, 

 vol. xxiii. p. Xio. f Sec Phiiosojjhical Magazine, vol. xlvi. p. 46.3. 



worked 



