In America, by means of electric contacts, clocks have been arranged to put gramophones into action. You will remember that it was pointed out that if a wire were dragged over a file a sound would be produced due to the little taps made as the wire clicked against the rough cuts on the file, and that the tone of the note depended on the fineness of the cuts, and hence the rapidity of the little taps. You can imagine that, if the roughnesses were properly arranged, we might get the tones to vary, and thus imitate speech. This is the principle of the gramophone. The roughnesses are produced by a tool, which, vibrating under the influence of human speech, makes small cuts in a soft material. This is hardened, and then, when another wire is dragged over the cuts, the voice is reproduced. In this way clocks are made to speak and tell the children when dinner is ready and when to go to bed. On this simple plan, too, dolls can be made to speak. The modern methods of clock and watch-making are very different from those in use in olden days. In former times the pivots were turned up by hand on small lathes, and even the teeth of the wheels were filed out. Each hole in the clock or watch frame was drilled out separately, and each wheel separately fitted in, so that the watch was gradually built up as one would build a house. Each wheel, of course, only fitted its own watch, and the parts of watches were not interchangeable. This has now all been altered. By means of elaborate machinery the whole of the work of cutting out every wheel and the making of every single part is done by tools moved independently of the will of the workman, whose only duty is to sit still and see the things made. He is, as it were, the slave of the machine, watching it and answering to its calls. Or shall we rather say that he is the machine’s employer and master? He has here a servant who never tires nor ever disobeys him. All the machine requires is that its cutting edges should be exactly true and sharp and microscopically perfect; then it will cut away and make wheel after wheel. It oils itself. It only wants the man to act as superintendent, and stop it if any cutting edge gets unduly worn. For this purpose he measures the work it is doing from time to time with a microscope to see that it is good and true and exact. When all the parts have thus been made you have perhaps a hundred boxes, each with a thousand watch parts in it, each part exactly like its fellows. You take one wheel or bit from each box indiscriminately, and you then have the materials for a watch, screws, fittings, pins, and all. All you have now got to do is simply to screw them all together, like putting together a puzzle. Everything fits; there is no snipping or filing. In such a watch if a bit gets broken you simply send for another bit of the same kind and fit it into its place.