Stephenson’s first engine did not differ very materially from some of those which had preceded it. He was, so to speak, feeling his way. The machine had a round, wrought-iron boiler, eight feet long, with two upright cylinders placed on the top of it. At the end of the pistons from the cylinders were cross-rods connected with cogged wheels below by other rods. These cogged wheels gave motion to the wheels running on the rails by cogs not very far from the axles. Stephenson abandoned the cogged rail, and adopted smooth wheels and smooth rails; but he did not connect the driving-wheel direct with the piston, the intervening cogged wheels being thought necessary to unite the power of the two cylinders. In adopting the principle of smooth wheels on smooth rails, it is said that Stephenson proved by experiment that the arrangement would work satisfactorily. Mr. Smiles writes that Robert Stephenson informed him, “That his father caused a number of workmen to mount upon the wheels of a waggon moderately loaded, and throw their entire weight upon the spokes on one side, when he found that the waggon could thus be easily propelled forward without the wheels slipping. This, together with other experiments, satisfied him of the expediency of adopting smooth wheels on his engine, and it was so finished accordingly.” Thus it may be said that this obstacle—imaginary though it largely proved to be—was cleared away from Stephenson’s first engine. Ten months were occupied in building the machine, and at last came the day of its trial. This was the 25th of July, 1814. Would it work? Jolting and jerking along, it did work, hauling eight carriages at a speed of about four or six miles an hour—as fast as a brisk man could walk. Then came the question—Would it prove more economical than horse-power? Calculations therefore were made, and after a time it was found that “Blucher” as the engine was called, though we believe its real name was “My Lord,” was about as expensive as horse-power. The locomotive needed something more, some magic touch to render it less clumsy and more effective. What was it? Then came the first great practicable improvement after the smooth wheels on smooth rails. It was the steam-blast in the funnel, by which the draught in the furnace was greatly increased. Indeed, the faster the engine ran the more furiously the fire would burn, the more rapid would be the production of steam, and the greater the power of the engine. At first Stephenson had allowed his waste steam from the cylinders to blow off into the air. So great was the nuisance caused by this arrangement that a law-suit was threatened if it were not abated.