kind of Springiess or Elasticity readily come together of themselves, and re-unite. Or
else by the Birds stroaking the Feather, or drawing it through its Bill, they all become
settled and woven into their former and natural Posture. In short, there are such an
infinite Company of hooked Tendrils ready to catch hold of the jointed Fibres, that
they must necessarily hang together whenever they come to meet ; and though the Square
Holes, which they form by crossing over one another, and which are visibly open and
pervious, appear by the Microscope to be more than half the Surface of the Feather, it
seems reasonable to believe, however extraordinary, that the Air does not pass through
them.
PLATE XIX. FIG. 3, 4, 5.
Parts of a Peacock's Feather
'TIS plain, by the naked Eye, that the Stem of each Feather in the Tail of a
Peacock,
sends out Multitudes of lateral Branches ; and that each of these
lateral Branches has innumerable little Sprigs, Threads or Hairs, issuing on either Side of
it, from End to End.
The Figure before us shews about the thirty-second Part of an Inch in Length of
one of these lateral Branches, as examined by the Microscope.
A, B. Point out the middle or stem-like Part cut off at both Ends.
CD, CD, CD, Represent the Hairs or Threads issuing therefrom, each of which ap-
pears to be a long Body, of some Breadth, with a Multitude of bright reflecting Parts,
whose Form and Shape cannot easily be determin'd, since they change continually, and
seem very different in different Positions to the Light : nay, only interposing one's Hand
between them and the Light, or even putting up or pulling down a Sash very much
changes their Appearance. However, by frequent Examinations, compared with one
another, 'tis hoped the true Figure is here determin'd.
These Threads are found, therefore, to consist of Rows of small Laminæ or Plates,
such as E E E E : each of which is shaped much like Fig. 4, a b c d : where the Part a c
being a Ridge or little Stem, and b, d, the Corners of two small thin Plates growing
from the said Stem in the Middle, make together a Kind of little Feather. These lit-
tle Plates or Feathers lie close to, and partly over one another, like a Number of sloping
ridge or gutter Tyles. They grow opposite to one another, on each Side of the Stem,
by two and two, from Bottom to Top ; the Tops of the lower covering the Roots of
the next above them, in the Manner represented Fig. 5.
Each of these laminated Bodies is on the under Side of a very opake Substance, that
suffers very few Rays to be reflected ; but their upper Sides, consisting of exceeding thin
Plates, lying close together, do thereby, like Mother of Pearl, not only reflect a very
bright Light, but tinge that Light in a most curious Manner ; and, by means of various
Positions in respect of the Light, they reflect back now one Colour, and then another,
and that most vividly. And hence we may account for all the gaudy and beauteous
Colours which adorn the Feathers of this and many other Birds : Namely, from the
exceeding Smallness and Fineness of the reflecting Parts.
