e
been at rest. His voluminous correspondence constantly reveals one
invention after another upon which he was engaged. A new micrometer, a
dividing screw, a new surveying-quadrant, problems for clearing the
observed distance of the moon from a star of the effects of refraction
and parallax, a drawing-machine, a copying-machine for sculpture--anything
and everything he used or saw seems immediately to have been subjected to
the question: "Cannot this be improved?" usually with a response in the
affirmative.

As we have read, he had long studied the question of a locomotive steam
carriage. In Muirhead's Biography, several pages are devoted to this. In
his seventh "new improvement," in his patent of 1784, he describes "the
principle and construction of steam engines which are applied to give
motion to wheel carriages for removing persons, goods, or other matter
from place to place, in which case the engines themselves must be
portable." Mr. Murdoch made a model of the engine here specified which
performed well, but nothing important came of all this until 1802, when
the problem was instantly changed by Watt's friend, Mr. Edgeworth,
writing him, "I have always thought that steam would become the
universal lord, and that we should in time scorn post-horses. _An iron
railroad would be a cheaper thing than a road of the common
construction._" Here lay in a few words the idea from which our railway
system has sprung. Surely Edgeworth deserves to be placed among the
immortals.[3] As in the case of the steamship, however, the
indispensable steam engine of Watt had to furnish the motive power. The
railroad is only the necessary smooth track upon which the steam engine
could perform its miracle. It is significant that steam power upon roads
required the abandonment of the usual highway. So we may believe is the
automobile to force new roads of its own, or to widen existing highways,
rendering those safe under certain rules for speed of twenty miles per
hour, or even more, when they were intended only for eight or ten.

The reading lamp of Watt's day was a poor affair, and as he never saw an
inefficient instrument without studying its improvement, he produced a
new lamp. He wrote Argand of the Argand burner upon the subject and for
a long time Watt lamps were made at the Soho works, which gave a light
surpassing in steadiness and brilliance anything of the kind that had
yet appeared. He gives four plans for lamps, "with the reserv