To a man who does not understand the workings of a machine, it naturally seems, when he sees it in operation, that the most important part of the machine is the chip of wood that accidentally got into it and is tossed about in it, interfering with its working. A man who does not know the construction of the machine cannot understand that it is not this harmful and interfering chip of wood, but that little transmission gear turning noiselessly that is one of the most essential parts of the machine.
