The Mirror of Literature, Amusement, and Instruction | Page 9

arena where this brutal
ceremony was performed, is still distinguished by the name of the
"Bull-ring." The ancient stone and ring were removed about thirty years
since; but the chain is still in possession of the chamberlains, who pass
it annually to their successors; and it is sometimes applied to the
purpose of fastening up a gate, when a distress is made on a field
belonging to the corporation for rent; but its primitive use is wholly
superseded by the abolition of the amusement.
_Gentleman's Magazine._
* * * * *

NOTES OF A READER.
* * * * *
KNOWLEDGE FOR THE PEOPLE: OR, THE PLAIN WHY AND
BECAUSE.

Part IV.--_Zoology--Birds._
This portion illustrates the Economy of Birds, with a few of the most
attractive varieties, under European and British, and Foreign Birds. We
quote from the "General Economy;" premising that the present Part
contains about 250 such illustrations, or Why and Because.
Why are birds usually classed according to the forms of their bills and
feet? Because those parts are connected with their mode of life, food,
etc., and influence their total habit very materially. _Blumenbach._
Why have birds little power of suction?
Because of the narrowness and rigidity of their tongue; as may be seen
when they drink, having to hold up their heads, and depend upon the
weight of the water for transmitting it into the craw.--_Rennie._
Why are birds said to be "poised" in the air?
Because the centre of gravity of their bodies is always below the
insertion of their wings, to prevent them falling on their backs, but near
that point on which the body is, during flight, as it were, suspended.
The positions assumed by the head and feet are frequently calculated to
accomplish these ends, and give to the wings every assistance in
continuing the progressive motion. The tail also is of great use, in
regulating the rise and fall of birds, and even their lateral
movements.--_Fleming._
Why do birds fly?
Because they have the largest bones of all animals, in proportion to
their weight; and their bones are more hollow than those of animals that
do not fly. Air-vessels also enable them to blow out the hollow parts of
their bodies, when they wish to make their descent slower, rise more
swiftly, or float in the air. The muscles that move the wings of birds
downwards, in many instances, are a sixth part of the weight of the
whole body; whereas, those of a man are not in proportion

one-hundredth part so large.
Why are birds covered with feathers?
Because, by this addition to the non-conducting appendices of the skin,
birds are enabled to preserve the heat, generated in their bodies, from
being readily transmitted to the surrounding air, and carried off by its
motions and diminished temperature.--_Fleming._
Why are the strongest feathers of birds in the pinions and tail?
Because the pinion-feathers may form, when the wing is expanded, as it
were, broad fans, by which the bird is enabled to raise itself in the air
and fly; whilst its tail feathers direct its course.--_Blumenbach._
Why do birds moult?
Because they may be prepared for winter; this change being analogous
to the casting of hair in quadrupeds. During summer, the feathers of
birds are exposed to many accidents. Not a few spontaneously fall;
some of them are torn off during their amorous quarrels; others are
broken or damaged; whilst, in many species, they are pulled from their
bodies to line their nests. Hence, their summer dress becomes thin and
suitable. Previous to winter, however, and immediately after incubation
and rearing of the young is finished, the old feathers are pushed off in
succession by the new ones, and thus the greater part of the plumage of
the bird is renewed.--_Fleming._
Why do birds sing?
Because of the receptacles of air already mentioned but particularly by
the disposition of the larynx, which in birds is not, as in mammifera
and amphibia, placed wholly at the upper end of the windpipe; but, as it
were, separated into two parts, one placed at each extremity. Parrots,
ravens, starlings, bullfinches, &c., have been taught to imitate the
human voice, and to speak some words: singing birds also, in captivity,
readily adopt the song of others, learn tunes, and can even be made to
sing in company, so that it has been possible actually to give a little

concert by several bullfinches. In general, however, the song of birds in
the wild state appears to be formed by practice and
imitation.--_Blumenbach._
Why do the notes of different species of birds vary?
Because, probably, of the structure of the organs of each species
enabling them more easily to produce the notes of their own species,
than those of any other, and from the notes of their own