The execution by machinery of work ordinarily executed by hand-tools has been a gigantic stride in the path of material civilisation. The earliest phase of the great modern movement in this direction is represented, probably, by the sawmill. A sawmill was erected near London as long ago as 1663--by a foreigner--but was shortly abandoned in consequence of the determined hostility of the sawyers; and more than a century elapsed before another mill was put up. But the sawmill is comparatively a rude structure, and the material it operates upon is easily treated, even by the hand. When we come to deal, however, with such substances as iron and steel, the benefit of machinery becomes incalculable. Without our recent machine-tools, indeed, the stupendous iron creations of the present day would have been impossible at any cost; for no amount of hand-labour could ever attain that perfect exactitude of construction without which it would be idle to attempt fitting the component parts of these colossal structures together. The first impulse, however, to the improvement of machine-tools for ironwork was given by a difficulty born not of mass but of minuteness. Up to the end of the last century, the locks in common use among us were of the rudest description, and afforded scarcely any security against thieves. To meet this universal want, Joseph Bramah set his remarkable inventive faculties to work, and speedily contrived a lock so perfect, that it held its ground for many a day. But Bramah's locks are machines of the most delicate kind, depending for their efficiency upon the precision with which their component parts are finished; and, at that time, the attainment of this precision, at such a price as to render the lock an article of extensive commerce, seemed an insuperable difficulty. In his dilemma, Bramah's attention was directed to a youngster in the Woolwich Arsenal smithy, named Henry Maudsley, whose reputation for ingenuity was already great among his fellows. Bramah was at first almost ashamed to take such a mere lad into his counsels; but a preliminary conversation convinced him that his confidence would not be misplaced. He persuaded Maudsley to enter his employment, and the result was the invention, between them, of the planing-machine, applicable either to wood or metal, as also of certain improvements in the old lathe, more particularly of that known as the 'slide-rest.'