ester, in his little
book published in 1663, _A Century of the Names and Scantlings of
Inventions_, generally known as the _Century of Inventions_, gave an
account of one application of the power of steam to lift water which
he had worked out, probably on a scale large enough to have become of
practical service. Thomas Savery and Denis Papin, both of them men of
high attainments and great ingenuity, made important improvements
before the end of the seventeenth century.

Yet, if we refer to the question as to the proper age to which the
steam-engine as a useful invention is to be assigned, we shall
unhesitatingly speak of it as an eighteenth century invention, and
this notwithstanding the fact that Savery's patent for the first
pumping engine which came into practical use was dated 1698. The real
introduction of steam as a factor in man's daily work was effected
later on, partly by Savery himself and partly by Newcomen, and above
all by James Watt. The expiration of Watt's vital patent occurred in
1800, and he himself then retired from the active supervision of his
engineering business, having virtually finished his great life's work
on the last year of the century which he had marked for all time by
the efforts of his genius.

Similarly we may confidently characterise the locomotive engine as an
invention belonging to the first half of the nineteenth century,
although tramways on the one hand, and steam-engines on the other
hand, were ready for the application of steam transport, and the only
work that remained to be accomplished in the half century indicated
was the bringing of the two things together. The dynamo, as a factor
in human life--or, in other words, the electric current as a form of
energy producing power and light--is an invention of the second half
of the nineteenth century, although the main principles upon which it
was built were worked out prior to the year 1851.

It will be seen, in the course of the subsequent pages, that portable
electric power has as yet won its way only into very up-to-date
workshops and mines, and that the means by which it will be applied to
numerous useful purposes in the field, the road, and the house will be
distinctly inventions of the twentieth century. Similarly the
steam-engine has not really been placed upon the ordinary road,
although efforts have been made for more than a century to put it
there, the conception of a road locomotive being, in fact, an earlier
one tha