they seemed about to actually enter the blue, till they were smaller in appearance than larks at their highest ascent, till the head had to be thrown right back to see them. This last circumstance shows how perpendicularly they ascend, winding round a line drawn straight up. At their very highest they are hardly visible, except when the under wing and breast passes and gleams in the light.
All this is accomplished with outstretched wings held at full length, without flap, or beat, or any apparent renewal of the original impetus. If you take a flat stone and throw it so that it will spin, it will go some way straight, then rise, turn aside, describe a half-circle, and fall. If the impetus kept in it, it would soar like the hawk, but this does not happen. A boomerang acts much in the same manner, only more perfectly: yet, however forcibly thrown, the impetus soon dies out of a boomerang. A skater gets up his utmost speed, suddenly stands on one foot, and describes several circles; but in two minutes comes to a standstill, unless he "screws," or works his skate, and so renews the impulse. Even at his best he only goes round, and does not raise his weight an inch from the ice. The velocity of a bullet rapidly decreases, and a ball shot from an express rifle, and driven by a heavy charge, soon begins to droop. When these facts are duly considered, it will soon be apparent what a remarkable feat soaring really is. The hawk does not always ascend in a spiral, but every now and then revolves in a circle—a flat circle—and suddenly shoots up with renewed rapidity. Whether this be merely sportive wantonness or whether it is a necessity, is
