336 STEAM CARRIAGE stroke. It i9 said to have run 6 to 8 m. an hour. In 1786-7 Oliver Evans obtained from the Pennsylvania legislature the monopoly of his method of applying the steam engine in driving flour mills, and from Maryland a similar privilege in regard to propelling wag- s Steam Carriage, 1770. ons. In the same or the following year Wil- liam Symington constructed a working model of a steam carriage, which is now in the patent museum at South Kensington, London. In 1804 Oliver Evans completed a flat-bottomed boat to be used in dredging at the Philadel- phia docks, and, mounting it on wheels, drove it by its own steam engine to the river bank. Launching the craft, he propelled it down the river, -using its engine to drive its paddle wheels. Evans's "Oruktor Amphibolos," as he named the machine, was the first road loco- motive that we find described after Cugnot's time. In 1821 Julius Griffiths of London made a steam carriage to carry passengers on com- mon roads, which was probably the first ever constructed for that purpose only. During the succeeding 10 or 15 years, Messrs. Burstall and Hill and Bramah of London and Edinburgh, Sir Goldworthy Gurney, the Messrs. Seaward, Sir Charles Dance, W. H. James, Walter Han- cock, Ogle and Summers, and others in Great Britain, and Harrison Dyar, Joseph Dixon, Rufus Porter, and Mr. James in the United States, attacked this problem with varying success. Sir Charles Dance made several hun- dred trips between London and Cheltenham in 1831. Hancock ran between London and Stratford, and Scott Russell from Glasgow to Paisley. From May to October, 1836, Han- FIG. 2. Hancock's Steam Carriage. cock ran several carriages on the Paddington road. The general introduction of railroads, which took place immediately after the estab- lishment of steam locomotion on the Liverpool and Manchester railway in 1829, put an end to what had promised to become an important and successful method of transportation of passengers and light merchandise. In Decem- ber, 1833, more than 20 steam carriages were in use or under contract in and near London. It was proposed to substitute steam carriages, capable of travelling 12 or 15 m. an hour, for coaches drawn by horses on all mail routes. Hostile legislation procured by opposing inter- ests, and the rapid progress of steam locomo- tion onrailroads, caused an interruption of ex- periment, and almost nothing was done during the succeeding quarter of a century. It is only within a few years that any business has been founded upon the construction of road loco- motives, although the scheme seems to have been at no time entirely given up. J. Scott Russell, Boydell, and a few others in England, and Messrs. Roper, Dudgeon, Fawkes, Latta, and J. K. Fisher, in the United States, have all labored in this direction. The last named engineer designed his first steam carriage in 1840, and was at work upon the problem till his death in 1873. A few firms have succeed- ed within a few years in making a business of constructing road locomotives for hauling heavy loads, and in building steam road roll- FIG. 3. Fisher's Steam Carriage. ers ; but steam carriages of high speed, adapt- ed to the transportation of passengers, have not yet been successfully introduced. The great- est impediments seem to be the roughness and bad construction of the ordinary highway, the frightening of horses, the engineering difficul- ties of construction, and the limited power of the machine as it has usually been built. The capabilities of the road locomotive are readily determined by experiment, and the following is an abstract of the results of several series of trials. A trial of a road engine Was made by the well known French engineer H. Tresca, in presence of Prof. Fleeming Jenkin, and the report was submitted on Jan. 15, 1868. The results were as follows : 1. The coefficient of traction was about 0'25. on a good road with easy grades. 2. The consumption of coal was 4'4 Ibs. per horse power per hour. 3. The con- sumption of water was 132-2 gallons an hour with the ten-horse engine. 4. The coefficient of adherence, or of friction between the wheels and the soil, was 0-3. 5. A speed of 7 m. an hour caused no special difficulty in managing either the locomotive or its load. About this
