68 AGRICULTURAL ENGINES. 



but the stroke was reduced from 4 feet 6 inches to 3 feet 

 4 inches, being very nearly the same as the Newcastle 

 locomotive. The cross-head, side rods, and boiler were 

 very similar to the Welsh stationary engines of that 

 date. This engine remained in use more than fifty years. 



The engines specially referred to in this chapter fully 

 prove, from their length of service, the practical cha- 

 racter of Trevithick's inventions, and of his having 

 persevered with his high-pressure portables until their 

 usefulness as locomotives and as agricultural helps had 

 been established ; but the ploughing, though fully de- 

 signed, and probably put into practice, was not followed 

 up to the same approach to perfection, or the record of 

 its progress has been lost. 



Since the foregoing was written, the following has 

 been received : 



" DEAR SlR, " TEEWITHEN, PROBUS, May 17th, 1872. 



" The engine you refer to is still occasionally used here ; 

 when first erected there was a large quantity of corn thrashed 

 by it, but of late years it has not been much used except for 

 chaffing, bruising, &c. 



" I remain, dear Sir, 



"Yours truly, 



"WM. TRETHNOY. 

 "F. TREVITHICK, Esq." 



Trevithick's Trewithen engine, which sixty years ago 

 was more manageable than horses going momentarily 

 faster or slower at the will of a common labourer, 1 re- 

 mains in use unchanged. 



His preparations for South America, and application 

 of high steam in the large Cornish pumping engines, 

 interfered with the perfecting the smaller agricultural 

 work. 



1 See vol. ii., p. 38. 



