In 1726 Dr. Hales had announced that a gas capable of burning, and giving light while burning, could be distilled from coal. This announcement created great interest, and led to a long series of scientific investigations as to the possibility of utilizing it for house and street illumination, especially by a Mr. Murdock in the latter decade of the century. In 1802 Mr. Murdock made a public display of the result of his labors, by illuminating a factory with gas. In the year 1803-1804 the Lyceum Theatre in London was so lighted, and a year later some extensive cotton mills in Manchester. Public interest was so roused that investigations on a larger scale ensued, which resulted in lighting Westminster Bridge with gas in 1813, and the town of Westminster the following year. In 1816 street lighting by gas was common in London. The lighting of houses by gas followed later, but very slowly. It is a little difficult to see that there was much invention of an original or brilliant kind involved in the gradual development of the art of illuminating by gas; but it cannot reasonably be denied that a considerable amount of invention must have been done in the aggregate, for the reason that a wholly novel art was created. If it was not invented, how was it brought into being? The best answer probably is that the art was not the result of one brilliant invention followed by others that improved upon it, but was rather the aggregate work of a number of minor inventions, each one of which carried the art forward, but by only one short step. Other minor inventions produced the locomotive and the railroad. The first steam engines were stationary; but portable engines, now called locomotives, gradually came into being. They were engines mounted on platforms resting on wheels that, in turn, rested on the ground; the revolutions of the engines turning the wheels, and causing the advancement of the whole. In 1807 a wagon-way was laid down on which cars were run to and from a colliery, and this wagon-way passed close in front of a house in which lived a poor family named Stephenson, a member of which was a boy whose Christian name was George. In the following year, the wooden parts were taken up and replaced by a single line of iron rails with sidings. In 1811 a portable engine was constructed for running on these rails, and this was followed by another in the following year. George Stephenson made a locomotive for running on rails in 1814, and followed it by another in 1816, both for hauling coal. It was now so obvious that locomotives could haul other things than coal, that a railroad was laid down between Manchester and Liverpool, and a prize of £500 was offered for the best engine. On October 6, 1829, the competition was held, though only three engines appeared. The prize was won by Stephenson's locomotive, the _Rocket_, which attained a speed of 29 miles per hour.