a large circle, rose level with the hill. Eound again he came, rising spirally—a spiral with a diameter varying from a furlong to a quarter of a mile, sometimes wider—and was now high overhead. Turn succeeded turn, up, up, and this without a single movement of the wings, which were held extended and rigid. The edge of the wing on the outer side was inclined to the horizon—one wing elevated, the other depressed—as the bird leaned inwards like a train going round a curve. The plane of the wings glided up the air as, with no apparent diminution of speed from friction, the bird swiftly ascended. Fourteen times the bird swept round, never so much as moving his wings, till now the gaze could no longer distinguish his manner of progress. The white body was still perceptible, but the wings were indistinct. Up to that height the gull had not assisted his ascent by flapping, or striking the air in any way. The original impulse, and some hitherto unexplained elasticity or property of air, had sufficed to raise him, in apparent defiance of the retardation of friction, and of the drag of gravitation. This power of soaring is the most wonderful of the various problems of flight being accomplished without effort; and yet, according to our preconceived ideas, there must be force somewhere to cause motion. There was a moderate air moving at the time, but it must be remembered that if a wind assists one way it retards the other.[1] Hawks can certainly soar in the calmest weather.
One day I saw a weasel cross a road in Hove, close to a terrace of houses.
- ↑ See the paper on "Birds Climbing the Air."
