Wing, natural, when elevated and depressed must move forwards, [156]
Wing, angles formed by, when in action, [167]
Wing acts as true kite both during down and up strokes, [165]
Wing, traces of design in, [180]
Wing of bird not always opened up to same extent in up stroke, [182]
Wing, flexion of, necessary to flight of birds, [183]
Wing flexed and partly elevated by action of elastic ligaments, [191]
Wing, power of, to what owing, [194]
Wing, effective stroke of, why delivered downwards and forwards, [195]
Wing acts as an elevator, propeller, and sustainer both during extension and flexion, [197]