Picture - Cosmic Polymath

§ 420. The Flight of Birds divisible into Four Kinds—Differences to be Noted between Flapping or Rowing
CONTENTS xix
Fhght, and Saihng or Swimming Flight ...1267
§ 421. The Eegular and Irregular in Flight ....
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PAGE
1270
The Wing Acts as a True Kite both during the Down and Up Strokes 1272
§§
§§
422-423. Analogy between the Wing and a Boy's Kite—Points of Difference to be Noted—The Angles formed
by the Wing with the Horizon during its Vibrations ... . . . 1272-1273
424-429. The Margins of the Wing thrown into Opposite Curves during Extension and Flexion—The Tip
of the Bird's and Bat's Wing describes an BlUpse—The Wing capable of Change of Form in all
its Parts—The Wing when made to Vibrate produces a Cross Pulsation—Compound Rotation of the
Wing—The Wing Oscillates unequally with Reference to a Given Line . . . 1275-1277
. ... 1277
431-432. Analysis of the Movements of Extension and Flexion in the Wing of the Gannet—The Angles of
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§ 430. The Flight of the Sea-GuU as witnessed on the West Coast of Scotland
§§
...... Flexion vary
Inclination which the Under Surfaces of the Gannet's Wing make with the Horizon in Extension and
MEASUREMENTS, WEIGHTS, &c., OF THE GANNET AND HERON
1278-1279
§ 433. Flight of the Gannet as witnessed at the Bass Rock, Firth of Forth, Scotland . . . 1280
§§
434-435. A Regulating Power necessary in Flight—The Wings at all Times thoroughly under Control 1281-1282
Analysis of the Down and Up Strokes of the Wing of the Bird in Flapping or Rowing Flight 1283
§ 436. The Body is made to Ascend when the Wings Descend and vice versd .
§ 437. The Natural Wing
...
when Elevated and Depressed must move Forwards 1286
§ 438. The Body and Wings move in Opposite Curves . . . 1287
. 1285
§ 439. Birds fly by causing their large, powerful Wings to act upon the Air as Kites ; the Air furnishing
a suitable Fulcrum for supporting and carrying them Upwards and Forwards—The Wings are Pro-
pelled by Voluntary well-directed Muscular Movements, aided by certain Elastic Structures which
contribute to the continued Vibrations of the Wings—In Fhght, Weight and Momentum play an
important Part . . . ... . . 1288
§ 440. Lifting Capacity of Birds 1288
§ 441. Mode of Ascending, Descending, Turning, &c. . 1289
THE WINGS OF BATS
§ 442. Where the Bat's Wing agrees with and differs from that of the Insect and Bird .
§ 443. The Bones of the Wing of the Bat—The Spiral Configuration of their Articular Surfaces .
§ 444. Extension and Flexion of the Wing of the Bat .... .
THE WINGS OF PTERODACTYLS {Extinct flying reptiles)
1291
1291
1291
§ 445. The Wings of Pterodactyls are Original Structures in the Sense that they formed part of the Animals
when Created ... 1293
§ 446. The Wings of Pterodactyls conform to the Requirements of Fhght, as witnessed in Insects, Birds, and
Bats
§ 447. The Wings of Pterodactyls afford Examples of Extreme Modification for a Special Purpose . , 1294
1294