OLD GEORGE STEPHENSON, who had served his articles of apprenticeship in a coal-mine, for many years working at the engines both above ground and below; ISAMBARD BRUNEL, whose principal experience had been acquired in the construction of the Thames Tunnel; JOSEPH LOCKE, a colliery-viewer, who had served his apprenticeship below ground; ROBERT STEPHENSON, brought up as a coal-miner, served his apprenticeship at Killingworth colliery; FRANK FORSTER had worked for seven years as an apprentice in a coal-mine; NICHOLAS WOOD, ditto; CHARLES LEAN, ditto; And a crowd of similar genii, all slaves of the same lamp, or “_Old Davy_,” as they term it. To such men the difficulties attendant upon the construction of a railway were trifling as compared with those against which all their lives they had been contending. For instance, he who along dark, intricate, subterranean passages, or “heavings,” as they are termed, often only three feet and a half high, and occasionally only two feet high, creeping and crawling through foul air, could with great speed, not only with unerring certainty find his way, but in such a secluded study could plan a variety of new cuttings, each forming part and parcel of a reticulated system of excavation which an unpractised mind would find it utterly impossible to comprehend, would, it may easily be conceived, experience but little difficulty, when walking erect in sunshine and in balmy air, to carry in his mind from, say Harrow to Watford, Watford to Tring, Tring to Wolverton, and Wolverton to Birmingham, those great leading features of the surrounding country which would enable him to exercise for the laying out of a railway the judgment and decision required. Again, what, it may justly be asked, are embankments, deep cuttings, and occasionally here and there a straight tunnel thirty feet broad, twenty-seven feet high, _usually forming by drainage its own adit_, in comparison with the overwhelming and intricate difficulties attendant upon-- 1st. The excavation of coal from strata of various characters, at various depths, each passage or “air-heaving” requiring perhaps a different system of support. 2nd. Encountering at various depths quicksands. 3rd. The great as well as minute arrangements necessary for wheeling carriages and raising the coals. 4th. The organization and management of a subterranean army of men and horses. 5th, and lastly. Lifting by steam-power from various depths, by night and by day, streams, floods, and occasionally almost rivers of water?