sufficiently solid and compact to sustain its bulk, they are yet so slender and delicate as to make but little addition to its weight. The quills of its feathers are firm, but very light, but by the firmness of them, it is enabled to cleave the Air with proper force: by their lightness it elevates itself at pleasure, and but for which it would sink downwards. All their Feathers are placed generally according to their length and strength; so that in flight, the longest and strongest feathers have the greatest share of Duty.

The feathers of the Bird would perpetually imbibe the moisture of the Atmosphere, and in every impetuous Shower would absorb so much wet, as would almost, if not wholly, impede its flight, had not the wise Economy of Nature obviated this by a most effectual Expedient. This Animal is furnish

bulk and strength, without adding to its Weight. The internal Structure of Birds is no less wisely adapted. The Lungs are placed close to the back-bone and ribs; the Air entering into them by a Canal from the Windpipe, passes through and is conveyed into a number of membranous Cells which lie upon the sides of the Pericordium, and communicate with those of the Sternum. In some Birds these Cells are continued down the Wings, and extend even to the Pinions, Thigh-bones, and other parts of the Body, which can be filled and distended with Air at the pleasure of the Animal. It seems to be evident that this general diffusion of Air † through the bodies of Birds is of infinite use in assisting Respiration in the rapidity of their Flights.

It has been asked, whether this universal dispersion of Air through their Bodies does not account for the superior heat of this Class of Animals? The separation of Oxygen from respirable Air, and its mixture with the Blood by means of the Lungs, is supposed by Dr. CRAWFORD to be the efficient cause of Animal Heat.

ed with a Gland at the Extremity of its body, containing a quantity of unctuous matter, which can be pressed out with its bill, and with which it lubricates and anoints its feathers at pleasure. The wisdom of Providence measures out to every class of Animal Nature a supply proportioned to its Necessities. Thus Birds that share, as it were, the habitations of Man, and live under covert, as they require a more slender supply of this Fluid, are not provided with so large a stock as those that rove and reside in the open Element. On this account it is that poultry, when wet, make so rumpled and scurvy a figure.

In considering and comparing the Senses of animals, we find that of Sight to be more piercing, extensive, and exact in Birds than in Quadrupeds; and this, from the conformation of the Eye, which is so organized as to render their Vision infinitely superior to that of all other Animals, and is much larger in proportion to the bulk of the head: nor is this superiority conferred upon them without a correspondent utility; it seems indispensable to their Safety and Subsistence: were this Organ dull and obtuse, Birds, from the rapidity with which they move, would be in danger of striking against every object in their way; the celerity of their motion, instead of being an advantage, would be an evil; their flight would be restrained by the danger resulting from it: were their Sight therefore defective, their Swiftness would avail them nothing. Indeed, we may consider the Velocity with which an Animal moves as a sure indication of the perfection of

its Vision: a Bird, for instance, that moves swiftly through the Air, must undoubtedly see better than one that slowly describes a waving tract; for its movement would be less rapid, were it not exempted from fear by a just confidence in the subtlety and Quickness of its Sight. Among the Quadrupeds the Sloth has its eyes enveloped, and its sight limited; but a Sparrow-hawk, while he hovers in the Air, espies a Lark sitting on a clod, though at twenty times the distance at which a Man or a Dog could perceive it. A Kite, soaring at an imperceptible height in the Clouds, yet distinguishes the small lizards, field-mice, birds, &c. and from this elevated station pounces upon them with astonishing swiftness and unerring aim. The Turkey-hen too sends forth a scream to warn her defenceless brood to make good their retreat from the Bird of prey, which she descries to be intent upon them from above, although at a Height which no human Eye could reach*.

* It were, however, injustice to dismiss the Eye as a piece of mechanism, without noticing that most exquisite of all contrivances, the Nictitating membrane, which is found in the Eyes of Birds and of many Quadrupeds. Its office is in the front of the eye; but its body is lodged in the back part of the Globe, where it is safe, and where it incumbers nothing. Its use is to sweep the Eye, which it does in an instant; to spread over it the lachrymal Humour; to defend it also from sudden injuries; yet not totally, when drawn upon the pupil, to shut out the light. The Commodiousness with which it is folded up in the upper corner of the Eye, ready for use and action, and the quickness with which it executes its purpose, are properties known and obvious to every Observer. The Membrane itself is an elastic Substance, capable of being drawn out by Force like a piece of elastie

In the faculty of Hearing, likewise, Birds hold a superiority over the fourfooted Race; encompassed, generally, when not on the wing, by the branches and leaves of Trees, which must greatly intercept their Sight, they would be the Victims of every attempt to destroy them, were they not admonished of approaching danger by their quick and distinct perception of Sound. The Sense of Smell, however, is less acute in Birds than among the Quadrupeds, as may readily be discovered on examining the structure of the Organ. Man is eminently superior to all animals in the Sense of Touch, and perhaps too in that of Taste; but he is inferior to most of them in the other three Senses. We may therefore say, Touch in Man, Smell in the Quadrupeds, and Sight in the Birds, are the three most perfect Senses, and which influence the general character.

BUFFON, to whose attentive Experiments and curious Researches the Science of Natural History is considerably indebted, seems of opinion, that the

Gum, and by its own elasticity returning when the force is removed to its former position. Such being its Nature, in order to fit it up for its Office it is connected by a Tendon or thread, with a Muscle in the back part of the Eye: this Tendon or thread, though strong, is so fine, as not to obstruct the Sight, even when it passes across it; and the Muscle itself being placed in the back part of the Eye, derives from its situation the advantage, not only of being secure, but of being out of the way. When the Muscle behind the Eye contracts, the Membrane, by means of the communicating thread, is instantly drawn over the fore part of it. When the muscular contraction (which is a positive, and most probably a voluntary effort) ceases to be exerted, the Elasticity alone of the Membrane brings it back again to its position.

Birds of Song owe not a little of their euphonic powers to their intermixture with the Human Species: "sweetness of voice and melody of song (says the celebrated French Naturalist) are qualities which, in Birds, are partly natural, partly acquired. Their great facility in catching and repeating sounds, enables them not only to borrow from each other, but often to copy the inflexions and tones of the human Voice*, and of our musical Instruments. Is it not singular (he asks) that in all populous and civilized Countries, most of the Birds chant delightful airs while in the extensive Deserts of Africa

It is imagined by some Philosophers, that Birds and Beasts (though without the Power of Articulation) understand one another by the Sounds they utter; and that Dogs and Cats have each a particular Language to themselves, like different Nations. Thus it may be supposed that the Nightingales of Italy have as fine an Ear for their native Wood-notes, as any Signor or Signora for an Italian Air; that the Boars of Westphalia gruntle as expressively through the Nose as the inhabitants of High Germany; and that the Frogs in the Dykes of Holland croak as intelligibly as the Natives jabber their low Dutch. However this may be, we may consider those whose Tongues hardly seem to be under the Influence of Reason, and do not keep up the proper Conversation of Human Creatures, as imitating the Language of different Animals. For instance, the Affinity between Chatterers and Monkeys, and Praters and Parrots, is too obvious not to occur at once: Grunters and Growlers may be justly compared to Hogs: Snarlers are Curs: and the Spitfire, Passionate, are a sort of wild Cats, that will not bear stroking, but will pur when they are pleased: Complainers are Screech Owls; and Story-tellers, always repeating the same dull note, are Cuckoos: Poets, that prick up their Ears, at their own hideous braying, are no better than Asses: Critics, in general, are venomous Serpents, that delight in hissing; and some of them, who have got by heart a few technical Terms, without knowing their Meaning, are no other than Magpies.