Page:Popular Science Monthly Volume 91.djvu/18

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The First Successful Fliers of Man and Nature

About seven million years ago the first bird began to fly. Flight was merely gliding, and clumsy gliding at that, which developed from the about-to-be birds instinctively spreading their limbs when falling from trees or jumping up in exuberance of spirits. Notice how closely the lines and movements of the first living flier resemble those of the pioneer motor-driven flier behind it