At the time James was building his two coaches, and after Blanchard had given up trying to interest Americans in his invention, a Frenchman named Pecqueur was experimenting on phases of the auto-carriage. He discovered the principle of the “differential,” the balance mechanism which enables one wheel to revolve faster than the other in turning corners. He invented a planet gearing in this connection, which was the origin of the idea of the differential, and applied it to a steam wagon which he built in 1828. The differential of today is based on the principle discovered by Pecqueur. While Pecqueur was evolving this invention, Goldsworthy Gurney in England made a car which was a practical failure in about everything except that it demonstrated that sufficient friction between the drive wheels and the road-bed could be created to produce propulsion. A trip of almost 200 miles from London and return was made in 1828 by Gurney in the second vehicle he built, in which the engine was concealed in the rear. His car made 12 miles an hour for part of the trip. From this time—1828 to 1840—the automobile really had a vogue in England. A number of them were made and run as passenger carriers. For four months a motor carriage made the nine mile trip from Gloucester to Cheltenham four times a day. The “Infant” built by Walter Hancock made trips between London and Stratford. The “Era,” also made by Hancock, ran from London to Greenwich. To such an extent did the auto-bus business develop, that speed of 30 miles an hour was claimed, and one conveyance in 1834 ran over 1,700 miles without repairs or readjustment. At least, that was the claim made, and as a claim it has a familiar sound. The twentieth century automobile manufacturers who claim a run of so many thousand miles without repairs to this and that, have here a precedent for it that is as old as the industry. But there was one feature about these early English motor busses that was their undoing. They weighed three tons and over, and the wheel rims were metal. The diameter of the wheels was six feet. The rubber tire was unthought of. The effect on roads of running a 3-ton, metal rimmed vehicle, carrying eleven to twenty passengers, was disastrous, and parliament, incited by horse owners and others, legislated them out of existence by making the toll charges prohibitive. Where the toll was $1 for horse drawn vehicles it was made $10 for steam auto buses. The consequence was that their manufacture and operation ceased about 1840. In 1878 Bollee built a steam omnibus which ran between Paris and Vienna, making 22 miles an hour. In this car was reached the highest efficiency the art had attained up to that time. Practically an identical car was built in 1880 by Bollee, which was entered by him 15 years later and won honors in the Paris-Bordeaux race. In 1879 the automobile development germ returned to America.