Memoir of James Watt, Esq. F.R.S. 443 



The steam-engine bad Ijeen for a century, or nearly about that 

 length of time, employed for drawing water ; and such was the 

 expense attending it, and the difficulty of keeping it in repair, 

 that it was never employed where wind, water, or animal force, 

 could answer the purpose. 



In this situation was that wonderful machine, when the model 

 was brought to Mr. Watt, of Glasgow, to be repaired, and put in 

 working order, for the instruction of students at the college there. 



Mr. Watt soon observed that there wa*; a great waste of heat, 

 and consequently consumption of fuel, occasioned by condensing 

 the steam in the cylinder in which the piston works. That cy- 

 linder being of cast-iron, was cooled by the same jet of water 

 that condensed the steam, so that when the fresh steam was ad- 

 mitted, a great quantity was consumed in again heating the cy- 

 linder ; for steam cannot exist in its rarified state, or, more pro- 

 perly speaking, cannot exist at all in a vessel that is not nearly 

 as hot as itself. 



Mr. Watt calculated that about two-thirds of the steam that 

 was introduced, was consumed or condensed by the coldness of 

 the vessel ; and his first expedient to prevent that Avaste of heat, 

 was to have a wooden cylinder, which, being a less powerful con- 

 ductor of heat or cold, would not be liable to rlie same disadvan- 

 tage in an equal degree. He was perfectly right; but he soon 

 found that wood was not a fit materia! in other respects. When 

 heated, and subject to continual friction, it was too rough; and 

 there were other inconveniences which made him ai)andon that 

 plan, but without, for a moment, abaudoniiig his endeavour to 

 improve the machine. 



It was then that his great genius exerted and developed itself, 

 and he was inspired with the happy idea of permitting t!ie steam 

 to pass into a separate vessel, there to be condensed; so that the 

 jet of cold water never being introduced into the cylinder wiiere the 

 steam was to be admitted for the next stroke of the engine, that 

 cylinder was never cooled, and consequently the fresh steam was 

 not three-fourths consumed in bringing it back to its proper heat. 



When this was dune, the grand improvement was made; but 

 the difficulties of tlie inventor were only beginning. He knew well 

 the value of his discovery, but to make others sensible of its value 

 and obtain the means of bringing it to perfection was the great 

 point. Mr. Watt was not only a modest, i)ut he was what is 

 termed a bashful man, and but few persons were capable of ap- 

 preciating his mci it *. 



• When his j^reat success — wlitn tiie works ho had [(I'ifoi'ined convinced 

 the world of his unconmiou merit and genius, this vory haslil'ulnes.s was in his 

 favour, and made hiui uioie highly esteenir-d ; but it was a sad inipcdiment 

 in his way at first. Men with ;^rcat pretensions and assurance obtain more 

 credit at first than they deserve, but modest or bashful men less. 



A gentleman 



