STEAM-LOCOMOTION ON RAILROADS. 181
conveyance,' Congress had entertained Colonel Stevens's
proposal, and, after verifying by actual experiment upon a
small scale the accuracy of his plan, had organized such a
'general system of internal communication and convey-
ance; who can begin to estimate the inappreciable bene-
fits that would have resulted therefrom to the comfort, the
wealth, the power, and, above all, to the absolutely impreg-
nable union of our great Republic and all its component
parts?
All this Colonel Stevens embraced in his views, for he was a statesman as well as an experimental philoso- pher; and whoever shall attentively read his pamphlet, will perceive that the political, financial, commercial, and mili- tary aspects of this great question were all present to his mind, and he felt that he was fulfilling a patriotic duty when he placed at the disposal of his native country these fruits of his genius."
WILLIAM HEDLEY, who has already been referred to, seems to have been the first to show, by carefully-conducted experiment, how far the adhesion of the wheels of the loco- motive-engine could be relied upon for hauling-power in the transportation of loads.
His employer, Blackett, had applied to Trevithick for a locomotive-engine to haul coal-trains at the Wylam collier- ies; but Trevithick was unable, or was disinclined, to build him one, and in October, 1812, Hedley was authorized to attempt the construction of an engine. It was at about this time that Blenkinsop (1811) was trying the toothed rail or rack, the Messrs. Chapman (December, 1812) were ex- perimenting with a towing-chain, and (May, 1813) Brunton with movable legs.
Hedley, who had known of the success met with in the experiments of Trevithick with smooth wheels hauling loads of considerable weight, in Cornwall, was confident that equal success might be expected in the north-country, and built a carriage to be moved by men stationed at four handles, by which its wheels were turned.
