other the use of a smooth running surface to diminish friction.
Though these two principles are today combined, they were
originally absolutely distinct. In fact there were railroads long
before there were steam engines or locomotives. If we seek the
real predecessor of the modern railroad track, we must go back
three hundred years to the wooden rails on which were drawn the
little cars used in English collieries to carry the coal from the
mines to tidewater. The natural history of this invention is
clear enough. The driving of large coal wagons along the public
highway made deep ruts in the road, and some ingenious person
began repairing the damage by laying wooden planks in the
furrows. The coal wagons drove over this crude roadbed so
successfully that certain proprietors started constructing
special planked roadways from the mines to the river mouth. Logs,
forming what we now call "ties," were placed crosswise at
intervals of three or four feet, and upon these supports thin
"rails," likewise of wood, were laid lengthwise. So effectually
did this arrangement reduce friction that a single horse could
now draw a great wagon filled with coal--an operation which two
or three teams, lunging over muddy roads, formerly had great
difficulty in performing. In order to lengthen the life of the
road, a thin sheeting of iron was presently laid upon the wooden
rail. The next improvement was an attempt to increase the
durability of the wagons by making the wheels of iron. It was
not, however, until 1767, when the first rails were cast entirely
of iron with a flange at one side to keep the wheel steadily in
place, that the modern roadbed in all its fundamental principles
made its appearance. This, be it observed, was only two years
after Watt had patented his first steam engine, and it was nearly
fifty years before Stephenson built his first locomotive. The