INDEX—continued. 163 
Scapula, 69 
Shearwater, 133, 134, 139 
Snipe, 130 
Soaring, 141-153 
among Mountains, 144 
always over Land, 145 
over Plains, 146 
impossible for small Birds, 
143 
impossible 
wind, 152 
spiral Movement in, 148, 
151 
Sparrow-Hawk 
32 
in horizontal 
(see Pl. xiii), 
Starling, Prof., 73 
93 (Pl. xv) 
Stability, 23-37 
Pendulum, 25 
Starting, 48-58 (Pl. viii), 121- 
124 
Steering, 59-63 (Pl. ix) 
Sternum, 67-69 
Stork, 19, 20, 101 
Surface, Area of supporting, 18- 
22 
Swallow, 19, 20, 98, 106, 128 
Australian, 111 
Swift, 35, 48 
Tacking, Boat, 8, 26, 
Tail, use of, in Balancing, 31-34 
Soaring, 150 
Steering, 60 
Temperature, Regulation of, 
159 
Tern, 64, 94 
Thienemann, Dr., 107 
UlIna, 80 
Vane, Experiment with, 134 
Velocity, see Flight. 
Vertebre, 76 
Voluntary Adjustments, 29-37 
Vulture, 144 
Weight and Supporting Surface, 
19 
Wind and Flight, 107-109, 120- 
153 
Wind, at High Altitudes, 112- 
117 
—— Horizontal, 130, 152 
not Uniform in Velocity, 
122-124, 125 
having an upward Trend, 
130-153 
Wing (see Area, Surface, Sta- 
bility), Curve of, 15-18, 25, 
26 
—— Elasticity of, 27 
as Lever, 38-40 
Rotation of, 51-54 
——Shape of (see Pls. 
xv), 91-96 
—— Spreading of, 81-86 
—— Weight of, 75 
Wings, Whir of, 101 
Wing-strokes, Phases of (see Pls. 
iv.-vli.), 40-47, 84, 85 
Rate of, 50, 99, 144 
—— Short, 46 
Unequal (PI. ii), 30 
Witherby, Mr. H. F., 66 
Woodpecker, 55, 65 
Wright, Mr. Wilbur and Mr. 
Orville, 16, 153. 
xili- 
