It will thus be observed that Stephenson had now much better opportunities for improving himself in mechanics than he had heretofore possessed. His practical knowledge of the steam-engine could not fail to prove of the greatest value to him. His shrewd insight, together with his intimate acquaintance with its mechanism, enabled him to apprehend, as if by intuition, its most abstruse and difficult combinations. The study which he had given to it when a workman, and the patient manner in which he had groped his way through all the details of the machine, gave him the power of a master in dealing with it as applied to colliery purposes. Sir Thomas Liddell was frequently about the works, and took pleasure in giving every encouragement to the engine-wright in his efforts after improvement. The subject of the locomotive engine was already occupying Stephenson's careful attention, although it was still regarded in the light of a curious and costly toy, of comparatively little real use. But he had at an early period recognized its practical value, and formed an adequate conception of the might which as yet slumbered within it, and he now proceeded to bend the whole faculties of his mind to the development of its powers. [Illustration: COLLIERS' COTTAGES AT LONG BENTON. [By R. P. Leitch.]] FOOTNOTES: [27] Speech at Newcastle, on the 18th of June, 1844, at the meeting held in celebration of the opening of the Newcastle and Darlington Railway. [28] At one part of the road he was once pulled off his donkey by some mischievous boys, and released by a young man named James Burnet. Many years after, Burnet was taken on as a workman at the Newcastle factory, probably owing his selection in some measure to the above circumstance. [29] Robert Stephenson was, perhaps, prouder of this little boyish experiment than he was of many of his subsequent achievements. Not having been quite accurately stated in the first edition of this book, Mr. Stephenson noted the correction for the second, and wrote to the author (Sept. 18th, 1857) as follows: "In the kite experiment, will you say that the copper wire was insulated by a few feet of silk cord; without this, the experiment can not be made." [30] Evidence given before the Select Committee on Accidents in Mines, 1835. CHAPTER V. THE LOCOMOTIVE ENGINE--GEORGE STEPHENSON BEGINS ITS IMPROVEMENT.