t gradually made its way,
and became an established tool in all the best mechanical workshops.
It was found alike capable of executing the most delicate and the most
ponderous pieces of machinery; and as slide-lathes could be
manufactured to any extent, machinery, steam-engines, and all kinds of
metal work could now be turned out in a quantity and at a price that,
but for its use, could never have been practicable. In course of time
various modifications of the machine were introduced--such as the
planing machine, the wheel-cutting machine, and other beautiful tools
on the slide-rest principle,--the result of which has been that
extraordinary development of mechanical production and power which is
so characteristic a feature of the age we live in.

"It is not, indeed, saying at all too much to state," says Mr.
Nasmyth,[12] a most competent judge in such a matter, "that its
influence in improving and extending the use of machinery has been as
great as that produced by the improvement of the steam-engine in
respect to perfecting manufactures and extending commerce, inasmuch as
without the aid of the vast accession to our power of producing perfect
mechanism which it at once supplied, we could never have worked out
into practical and profitable forms the conceptions of those master
minds who, during the last half century, have so successfully pioneered
the way for mankind. The steam-engine itself, which supplies us with
such unbounded power, owes its present perfection to this most
admirable means of giving to metallic objects the most precise and
perfect geometrical forms. How could we, for instance, have good
steam-engines if we had not the means of boring out a true cylinder, or
turning a true piston-rod, or planing a valve face? It is this alone
which has furnished us with the means of carrying into practice the
accumulated result's of scientific investigation on mechanical
subjects. It would be blamable indeed," continues Mr. Nasmyth, "after
having endeavoured to set forth the vast advantages which have been
conferred on the mechanical world, and therefore on mankind generally,
by the invention and introduction of the Slide Rest, were I to suppress
the name of that admirable individual to whom we are indebted for this
powerful agent towards the attainment of mechanical perfection. I
allude to Henry Maudslay, whose useful life was enthusiastically
devoted to the grand object of improving our means of producing per