THE GROWTH OF THE STEAM-ENGINE. 



263 



Andrew Vivian in 1802. It is stated, by friends of Oliver Evans, 

 that be had, at an earlier date, sent Mr. John Sampson to England, 

 and, by him, had forwarded drawings and specifications, which 

 Trevithick and Vivian inspected, and to which, it is not improbable, 

 they may have been indebted for their plans. 



They used a non-condensing, return connecting-rod engine, and 

 carried as high as sixty to eighty pounds of steam. 



They built a locomotive-engine in 1804 (Fig. 29), for the railway 



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TT 



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Fig. 29. Trevithick's Locomotive, 1804. 



at Merthyr-Tydvil, in South Wales, which was quite successful, 

 although sometimes giving trouble by slipping its wheels. 



This engine had one steam-cylinder 4f inches diameter, and car- 

 ried forty pounds steam. 



In consequence of a fear of the wheel slipping, Blenkinsop em- 

 ployed, in 1811, a pinion on the locomotive shaft, gearing into a rack 

 on the road-bed. 



In 1813 Brunton, of Butterly, tried to introduce a locomotive-en- 

 gine propelled by levers, like an animal's legs, pushing behind ; and 

 just at this time mechanics, all over the world, seem to have become 

 very much interested in this problem. 



55. It is at about this period that we find evidence of the intelli- 

 gent labors of another of our countrymen one who, in consequence 

 of the unobtrusive manner in which his work was done, has never 

 received the full credit to which he is entitled. 



