30 passengers at a cost of 1_s_. per mile, it was clear that the same engine, if applied to a railway, instead of conveying 20 or 30 people, would have conveyed 200 or 300 people, and instead of a speed of 10 or 12 miles an hour, a speed of at least 30 to 40 miles an hour would have been obtained." At this day it is difficult to understand how the sagacious and strong common-sense views of Stephenson on this subject failed to force themselves sooner upon the minds of those who were persisting in their vain though ingenious attempts to apply locomotive power to ordinary roads. For a long time they continued to hold with obstinate perseverance to the belief that for such purposes a soft road was better than a hard one--a road easily crushed better than one incapable of being crushed; and they held to this after it had been demonstrated in all parts of the mining districts that iron tram-ways were better than paved roads. But the fallacy that iron was incapable of adhesion upon iron continued to prevail, and the projectors of steam-traveling on common roads only shared in the common belief. They still considered that roughness of surface was essential to produce "bite," especially in surmounting acclivities; the truth being that they confounded roughness of surface with tenacity of surface and contact of parts, not perceiving that a yielding surface which would adapt itself to the tread of the wheel could never become an unyielding surface to form a fulcrum for its progression. Although Stephenson's locomotive engines were in daily use for many years on the Killingworth Railway, they excited comparatively little interest. They were no longer experimental, but had become an established tractive power. The experience of years had proved that they worked more steadily, drew heavier loads, and were, on the whole, considerably more economical than horses. Nevertheless, eight years passed before another locomotive railway was constructed and opened for the purposes of coal or other traffic. It is difficult to account for this early indifference on the part of the public to the merits of the greatest mechanical invention of the age. Steam-carriages were exciting much interest, and numerous and repeated experiments were made with them. The improvements effected by M'Adam in the mode of constructing turnpike roads were the subject of frequent discussions in the Legislature, on the grants of public money being proposed, which were from time to time made to him. Yet here at Killingworth, without the aid of a farthing of government money, a system of road locomotion had been in existence since 1814, which was destined, before many years, to revolutionize the internal communications of England and of the world, but of which the English public and the English government as yet knew nothing.