44

HISTORY AND PROGRESS

modern date, the precise period of their firstadoption is involved in mystery.

A late anonymous author says, without ad-vancing his authority, Cf that, in 1738, cast-ironrails were first substituted for wooden ones ;but, owing to the old waggons continuing tobe employed, which were of too much weightfor the cast-iron, they did not completely suc-ceed in the first attempt. However, about1768, a simple contrivance was attempted,which was to make a number of smallerwaggons, and link them together, and by thusdiffusing the weight of one large waggon intomany, the principal cause of the failure in thefirst instance was removed, because the weightwas more divided upon the iron.” (Trans.Highland Society, vol. VI. p. 7.) It is some-what singular, when the failure of the attemptto introduce cast-iron arose from the want ofstrength in the rails, that it should requirethirty years to discover that, with a lighterload, they could be made to answer.

Mr. 11. Stephenson, whose enquiries intoRail-road conveyance have been pretty exten-sive, states, “ I some years since visited thegreat iron-works of Colebrook-dale, in Shrop-shire , where cast-iron was indisputably firstapplied to the construction of bridges, and,according to the information which I have been