Page:The Kinematics of Machinery.djvu/544

 never been any serious attempt made to analyse by it machines having any degree of complexity.

The view which our analyses have given iis of the action of the hand in the operation of the machine is remarkable. We see that it occasionally takes part in the directing and regulating gear, and less frequently in the main-train itself,—and also that as each machine develops into more perfect forms both its director and its regulator are made automatic. Looked at historically, from Humphrey Potter, who invented a primitive form of self-acting valve-gear to save himself the trouble of working the valves of Newcomen's engine, to the engineer of an American river steamer, whose business it is to control three polished levers in an elegantly-furnished cabin; from the turner of sixty years ago, whose hand was his tool-holder, to his successor of to-day whose machines, once set, can take five or six cuts off the work-piece simultaneously; we have one phenomenon only, developed in different degrees. This is the reduction of the direct action of the worker with his machine, or, if it be preferred, the increase of automatism in the machine. This process began with the very origin of the machine itself. For between the first timid attempt of men to constrain two external bodies to execute some determinate relative motion, and the most complex production of modern machine-industry, there is an unbroken connection; the lines of development are faintly marked, but are continually increasing in distinctness, while they have always followed and still follow the same fundamental laws.

Those machines must therefore be considered the most nearly perfect or complete in which (as already mentioned in Chap. VI.) human agency is required only to start the machinal process and to cause it to cease. In general the progress in this direction is quite visible, while in some cases existing machines appear to have already arrived fairly within sight of this ultimate perfection.

§ 137. The Relation of Machinery to Social Life.undefined

From the general point of view to which our special investigations have once more brought us, one question seems so