Page:Popular Science Monthly Volume 12.djvu/277

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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

PSM V12 D277 Trevitchick locomotive 1804.jpg
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 4¾ inches diameter, and carried forty pounds steam.

In consequence of a fear of the wheel slipping, Blenkinsop employed, 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-engine 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 intelligent 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.