course of their practical employment.

George Stephenson was not the first person to construct either a
locomotive or a tramway. Both were already in use, in more or less
rude forms, at several collieries. But he WAS the first person to
bring the two to such a pitch of perfection, that what had been at
first a mere clumsy mining contrivance, became developed into a
smooth and easy iron highway for the rapid and convenient
conveyance of goods and passengers over immense distances. Of
course, this great invention, like all other great inventions, was
not the work of one day or one man. Many previous heads had helped
to prepare the way for George Stephenson; and George Stephenson
himself had been working at the subject for many years before he
even reached the first stage of realized endeavour. As early as
1814 he constructed his first locomotive at Killingworth colliery;
it was not until 1822 that he laid the first rail of his first
large line, the Stockton and Darlington Railway.

Stephenson's earliest important improvement in the locomotive
consisted in his invention of what is called the steam-blast, by
which the steam is made to increase the draught of the fire, and
so largely add to the effectiveness of the engine. It was this
invention that enabled him at last to make the railway into the
great carrier of the world, and to begin the greatest social and
commercial upheaval that has ever occurred in the whole history of
the human race.

Meanwhile, however, George was not entirely occupied with the
consideration of his growing engine. He had the clocks and watches
to mend; he had Robert's schooling to look after; and he had