Intelligence and Miscellaneous Articles. 311 



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Watt's system. There are other concurrent causes for the great 

 superiority, but that is the principal cause. 



In his specification of 1782, Mr. Watt proposed to use steam equal 

 to the atmosphere, with a far greater extent of expansive action than 

 he or his successors have been able to realize in practice ; and so Mr. 

 Woolf in his specification of 1 804 proposed to carry the expansion of 

 high-pressure steam to a far greater extent than has ever been exe- 

 cuted by himself or others*. 



When Mr. Woolf began, it was a common notion that mere varia- 

 tion in the elasticity of the steam employed could no way affect Mr. 

 Watt's invention of expansive working, and that the use of high- 

 pressure steam, as proposed by Mr. Woolf, could never be advan- 

 tageous. Such notions continued current, until he proved their fallacy 

 by the great performance of his engines : but he did not attain that 

 proof without exertion ; for the difficulties of carrying his invention 

 into effect were very great, and cost him some years of uninterrupted 

 labour and great expense to overcome them. He encountered much 

 active opposition from those who had made up their minds on his first 

 proposals ; and their unfavourable opinions prevented him from getting 

 orders for any large engines until 1813. 



The value of the improvement which Mr. Woolf made in the per- 

 formance of engines, before his system was adopted or countenanced 

 by other engineers, may be stated as follows. In 1814 the average 

 performance of the twenty-nine engines that were reported, was 

 20-37 millions, and their consumption of coals was 100,2563 bushels. 

 The price of coals being at that time \4~cl. per bushel, the cost of 

 coals was £60,570 per annum, or £2088 per annum for each engine,, 

 on an average. 



The average performance of Mr. Woolf's engines at Wheal Abra- 

 ham and Wheal Vor, during the three years and a half above cited, 

 was 42 - 08 millions, or more than double the average of all Mr. 

 Watt's engines in 1814 : hence if all those engines had been replaced 

 by engines such as Mr. Woolf had then made, more than half the ex- 

 pense of coals would have been avoided, being a saving of £29,300 

 per annum to the mine adventurers ; or at the rate of full £1000 per 

 annum saved in working each engine, on an average of the whole 

 number, each engine exerting about forty-horse power. 



The expense and complication of Mr. Woolf's engines with two 

 cylinders being found objectionable, he altered an old Watt's engine 

 at Wheal Abraham in 1816, to work by high-pressure steam, with an 

 increased extent of expansive action, in one cylinder ; and the im- 

 provement in its performance proved that two cylinders are not 



* If it is represented as a failure, that Mr. Woolf did not accomplish all 

 that he anticipated in 1804, still that is no reason for overlooking what he 

 did accomplish by himself in 1811 and 1815, or how much he then surpas- 

 sed all that had been done before : nor can any such imputation of failure 

 justify the omission of his name by those writers who undertake to state 

 the extension that has been given to Mr. Watt's discovery of expansive 

 working, by using high-pressure steam ; for that extension is not due to Mr. 

 Watt in any part, but to Mr. Woolf entirely. 



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