Page:The Kinematics of Machinery.djvu/511

 MONTGOLFIERS RAM. 489

But all this is in direct contradiction to what our natural idea of completeness in a machine would be were we unhampered by theoretical definitions ; while the contrast which it presents to our simple direct idea of the machine makes us to a certain extent question the authority of the theoretical conception upon which (logically or not) this popular idea has based itself.

The doubt thus arising is strengthened by another question. If we look at a spinning-machine, we see the thread passing through certain motions which it could not receive were it not itself a transmitter of motion. Is the thread then here the body to be worked upon, or is it a transmitting part, or is it indeed itself the tool ? And where does it begin or end to be any one of the three ? Similar uncertainties exist in very many other machines. How is it that the spinning-machine, and with it indeed all other machines connected with the manufacture of textile fabrics, will not fit in to the theory ? Is it the fault of the machines, the excellence of which every one knows, or of the theory ? Let us take another example, the well-known hydraulic (Montgolfier's) ram. The water lifted by the machine is here a 'portion of the mass of water which works it. The machine is obviously com- plete, but which part is the receptor, which the tool, which the transmitter of motion ? Does the stream of water represent all three itself ? And if so, what are the other parts of the machine ? Or has Montgolfier bequeathed to us only a tantalising paradox, a machinal will-o'-the-wisp, instead of an orderly and respectable machine which can give a reason for its own existence?

Thus doubt arises upon doubt, question after question, so soon as we seriously attempt to apply the recognised theoretical classi- fication or subdivision to actual machines. But the question is not one to which one answer is as good as another, it concerns one of the most important factors in modern civilisation, a branch of human activity affecting almost every one more or less directly ; while the most strenuous exertions, intellectual and physical, have been made in order that it might be scientifically mastered. It is therefore not without good reason that we shall now commence the examination of the three popular subdivisions of machines.