Picture - Cosmic Polymath

88 DESIGN IN NATURE
PLATE LIV
that the lower limbs plait and o^'erlap slightly in walking : they in fact form complemental and opposite curves in each successive
step, as shown at Plate liii.. Figs. 2 and 4. A similar plaiting of the limbs occurs in the walking of the bird (Figs. 7 and 10 of this
Plate), and in the walking and running of quadrupeds, as for example the horse, &c. (Fig. 1 of this Plate).
Fig. 4.—Double, complemental, figure-of-8 spirals made by the wing of the bird in extension and flexion, as drawn by the Author
in 1867. The solid line and arrows indicate the double curve made by the wing in extension ; the interrupted line and arrows the
double curve made by the wing in flexion.
Fig. 5.—Shows the iigure-of-B movements made by the wing of the wasp in active flight, and also the angles made by the wing
with the horizon at every part of each stroke, as figured by the Author in 1867 and 1870. In tiie insect the direction of the .stroke is
more horizontal than in the bird and bat. The forward and backward stroke and figure-of-8 made by the tip of the left wing is seen
in the two upper figures at a, h, c, d, e, f, cj, and at g, h, i, j, k, I. The various angles made by the left wing with the horizon at successive
stages of the forward and backward stroke and when reversing are given in the two lower figures. The same letters in the upper and
lower figures represent the wing in the several phases through which it passes during the forward and backward stroke.
Fig. 6.—The cicada (C. septemdecim). Shows four typical wings. As the wings are transparent the venation and structure can be
seen to great advantage. The two right and the two left wings, when taken together, present a triangular outline; the roots of the
wings being thick and semi-rigid, the tips thin and elastic. The anterior margins, moreover, are thicker than the posterior ones. The
wings taper in two directions, namely, from the lOots to the tips, and from the anterior to the posterior margins. They are carefully
graduated structures and, as such, perfect organs for aerial locomotion. Wings so constructed inevitably fly forward during both the
down and up strokes when made to vibrate. Drawn by C. Berjeau from specimen in the Author's museum.
Fig. 7.—Photograph of the ostrich (Struthio camelus), as seen from behind, rnnning. Shows how the right leg {a) and left wing
and shoulder (6) move together to form a double diagonal curve (see darts) and one step ; and how the left leg (c) and right wing
and shoulder (d) move together to form a second and opposite double diagonal curve (see dart) and a second step. These movements
are repeated so long as the bird continues to run (the Author).
Fig. 8.—Diagram constructed by the Author in 1867 to show that the wing of the bird, contiary to prevailing belief and preconceived
notions, strikes downwards and /orjoarcfe during tlie down stroke. Prior to 1867 tlie wing was supposed to strike verticallj'
downwards or downwards and hachioards. The Author's view has been confirmed by instantaneous photography, and is now generally
accepted, x, Axis of body of bird ; d, root of wing ; a, a', double forward curve made by tip and posterior margin of wing during their
descent ;/,/', similar but opposite curve made by root and anterior margin of wing. The two margins make double and opposite
diagonal curves when the wing is in action. The wing, as a matter of fact, twists and untwists diagonally during the down and up
strol;es, and makes figure-of-8 movements similar to those made by the tails of fishes, the flippers of sea mammals, and the extremities
of quadrupeds and bipeds.
Fig. 9.—Photograph of vulture ( Vultur monachus), flying with the wings flexed as seen during the up stroke, and fully extended as
seen during the down stroke and in sailing flight. During the up stroke the wings are not only flexed or folded, but all the feathers
are separated so as to diminish to the utmost the resistance experienced from the superimposed air. During the down stroke the wino-
is fully opened out and extended, and the feathers, for the most part, tightly closed to seize and prevent the escape of the nether aiit
The right wing of the lower figure is twisted upon itself, and forms double figure-of-8 curves (the Author).
Fig. 10.—Photograph of the adjutant (Giconin alba) walking. This quaint bird walks precisely as a man does : thus it begins its
step by extending the toes of the right foot (1st figure, left side) ; it then folds and shortens the right leg (2nd figure) ; it then advances
the right leg and folds the right foot (3rd figure) ; it then straightens the right foot and somewhat straightens and advances the right
leg (4th figure) ; it then further straightens and advances the right leg and straightens and points the right foot downwards
(5th figure) ; it then still further straightens and advances the right leg and spreads out the toes of the right foot preparatory to
placing the right foot on the ground (6th figure). This completes one step. During the step the right leg and foot make a curve the
convexity of which is directed outwards or towards the spectator (see darts). The left leg and foot perform precisely similar movements
in making a second step, and make an opposite or complemental curve (the Author).
§ 10. Recapitulation.
The points which I have endeavoured to establish by the aid of the foregoing illustrations are :
1. That many crystals bear a strildng resemblance to plants and animals and parts thereof.
2. That crystals in many cases present radiating, branching, segmented, and concentric arrangements also found
in plants and animals.
3. That crystals form frost pictures and dendrites which resemble plants and animals and also electric sparks
and lightning flashes.
4. That crystals in some cases form spirals which resemble the fronds, tendrils, and other parts of plants,
and the bones, horns, teeth, and other parts of animals.
5. That plants and animals are composed, for the most part, of the same elements and have much in common
their constituent parts being, in the majority of cases, arranged in radiating, branching, and concentric lines, with
longitudinal and transverse cleavages in a more or less marked form.
6. That these cleavages also occur in inorganic matter, as in basaltic rock formations.
7. That the basaltic columns form pentagonal, hexagonal, and other prisms, which find their counterparts in
certain corals; these again resembhng the prisms found in the enamel of teeth, the fasciculi of muscles, and as
far as general outhne is concerned, the cells of the honeycomb, epidermic cells, pigment cells, &c.
8. That organic structures which are widely separated and which apparently have nothing in common do ne