The shape of the aeroplane
The development of the aeroplane is traced chronologically, because that is the clearest way to explain how its shape has developed. It is almost like a family tree with the pioneers aeroplanes at the beginning, the pure vehicles built to fly and with no other purpose than to get into the air—in fact that was just about as much as they could do. Then, the tree begins to branch, first into civil and military types, again subdividing into scouts, bombers, seaplanes, and so on. Today, the branches of the tree are manifold and there are aeroplanes weighing five hundred pounds or a hundred tons, capable of carrying one man or two hundred; they may have a speed of under one hundred or over one thousand miles an hour.