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ment thereof, the Wings. Which as they are principal Parts, fo are made with great Skill, and placed in the moft commodious Point of the Body (3), to give it an exact Equipoife in that fubtile Medium, the Air.

And here it is obfervable, with what incomparable Curiofity every Feather is made; the Shaft exceeding ftrong, but hollow below, for Strength and Lightnefs fake, and above, not much lefs ftrong, and filled with a Parenchyma or Pitb, both ftrong and light too. The Vanes as nicely gauged on each Side as made; broad on one Side, and narrower on the other; both which incomparably minifter to the progreffive, Motion of the Bird, as alfo to the Union and Clofenefs of the Wing (4).

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(3) In all Birds that fly much, or that have the most occafion for their Wings, it is manifeft that their Wings are placed in the very best part, to ballance their Body in the Air, and to give as fwift a Progreffion, as their Wings and Body are capable of: For otherwife we fhould perceive them to reel, and fl unfteadily; as we fee them to do, if we alter their Equipoife, by cutting the end of one of the Wings, or hanging a Weight at any of the extreme parts of the Body. But as for fuch Birds as have as much Occafion for Swimming as Flying, and whofe Wings are therefore fet a little out of the Center of the Bodies gravity, fee Ch. 3. Note 9. And for (uch as have more occafion for Diving than Flying, and whofe Legs are for that Reafon fer more backward, and their Wings more forward, fee Ch. 4. Note 9.

(4) The wife Author of Nature hath afforded an Exam'ple of the great Nicety in the Formation of Birds, by the Nicety obferved in a part no more confiderable than the Vanes of the Flag-feathers of the Wing. Among others, these two things are obfervable. 1. The Edges of the exterior or narrow Vanes bend downwards, but of the interior, wider Vanes upwards; by which means they catch, hold, and lie clofe to one another, when the Wing is spread fo that not one Feather may mifs its full Force and Impulfe

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And no lefs exquifite is the Textrine Art of the Plumage (5) alfo; which is fo curioufly wrought,

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upon the Air. 2. A yet leffer Nicety is obferved, and that is in the very floping the tips of the Flag-feathers: The interiour Vanes being neatly floped away to a Point, towards the outward part of the Wing; and the exteriour Vanes floped towards the Body, at leaft in many Birds and in the middle of the Wing, the Vanes being equal, are but little floped. So that the Wing, whether extended or fhut, is as neatly floped and formed, as if conftantly trimmed with a pair of Sciffors.

(5) Since no exact account that I know of, hath been gi ven of the Mechanism of the Vares or Webs of the Feathers, my Obfervations may not be unacceptable. The Vane confifts not of one continued Membrane, because if once broken, it would hardly be reparable: But of many Lamina, which are thin, ftiff, and somewhat of the nature of a thin Quill. Towards the Shaft of the Feather (especially in the Flag. feathers of the Wing) thofe Lamine are broad, &c. of a femicircular Form; which ferve for ftrength, and for the closer shutting of the Lamine to one another, when Impulfes are made upon the Air. Towards the outer part of the Vane, these Lamina grow flender and taper: On their under fide they are thin and fmooth, but their upper outer Edge is parted into two hairy Edges, each fide having a different fort of Hairs, laminated or broad at bottom, and flender and bearded above the other half. I have, as well as I could, reprefented the uppermoft Edge of one of thefe Lamina in Fig. 18. with fome of the Hairs on each fide, magnified with a Microfcope. These bearded Briftles or Hairs on one fide the Lamina, have ftrait Beards, as in Fig. 19 those on the other fide, have hooked Beards on one fide the flender part of the Briftle, and ftrait ones on the other, as in Fig 2o. Both these forts of Briftles magnified (only fcattering and not clofe) are reprefented as they grow upon the upper Edge of the Lamina f. 1. in Fig. 18. And in the Vane, the hooked Beards of one Lamina, always lie next the ftrait Beards of the next Lamina, and by that means lock and hold each other, and by a pretty Mechaniím, brace the Lamina clofe to one another. And if at a y time the Vane happens to be ruffled and difcompofed, it can by this pretty easy Mechanism, be reduced and repaired. V. Book 4. Ch. 12. at Note 12.

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Book VII. and fo artificially interwoven, that it cannot be viewed without Admiration, efpecially when the Eye is aflifted with Glaffes.

And as curioufly made, fo no lefs curioufly are the Feathers placed in the Wing, exactly according to their feveral Lengths and Strength: The Principals fet for Stay and Strength, and thefe again well lined, faced, and guarded with the Coའ vert and Secondary Feathers, to keep the Air from pailing through, whereby the ftronger Impulfes are made thereupon

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And lastly, to fay no more of this Part, that deferves more to be faid of it, what an admirable Apparatus is there of Bones, very ftrong, but withal light and incomparably wrought? of Foynts, which open, fhut, and every way move, accor ding to the Occafions either of extending it in Flight, or withdrawing the Wing again to the Body? and of various Mufcles; among which the peculiar Strength of the Pectoral Mufcles deferves efpecial Remark, by reafon they are much ftronger (6) in Birds, than in Man, or any other Animal, not made for Flying.

4. Next the Wings, the Tail is in Flight confiderable; greatly alifting in all Afcents and Defcents

(6) Pectorales Mufculi Homiris flellemes humeros, parti parum carnofi funt, non aquant 50am aut 7cam partem omnium Mufculorum Hominis. E contra in Avibus, Pectora Les Mufculi vaftiffimi funt, & æquant, imo excedunt, & magis pendent, quam reliqui omnes Mufculi ejufdem Avis fimul fumpi. Borell. de Mot. Animal. Vol. 1. Prop. 184.

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Mr. Willughby having made the like Obfervation, hath this Re féion on it, whence, if it be paffible for Man to fly, it is thought by them who have curiously weighed and confidered the matter, that be that would attempt fuch a thing with hopes of fuccefs, muft fo contrive and adapt his wings, that he may make use of his Legs, and not his Arms in managing them (becaufe the Mufcles of the Legs are fronger, as he observes.) Willugh, Ornith. E. 1. c. 1. §. 19.

Scents in the Air; as alfo ferving to steady (7) Flight, by keeping the Body upright in that fubtile and yielding Medium, by its readily turning and anfwering every Vacillation of the Body..

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And now to the Barts ferving to Flight, let us add the nice and compleat Manner of its Performance; all done according to the ftricteft Rules of Mechanifm (8). What Rower on the Waters, what Artift on the Land, what acuteft Mathematician could

exact Motion to the give a more agreeable and

Wings, than these untaught flying Artifts do theirs! ferving not only to bear their Bodies up in the Air, but alfo to waft them along therein, with a fpeedy progreffive Motion, as also to steer and turn them this Way and that Way, up and down, fafter or flower, as their Occafions require, or their Pleasure leads them.

5. Next to the Parts for Flight, let us view the Feet and Legs miniftering to their other Motiong Both made light, for eafier Tranfportation through the Air; and the former fpread, fome with Membranes for Swimming (9), fome without, for

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(7) Mr. Willu bby, Ry, and many others, imagine the principal ufe of the Tail to be to fteer, and turn the Body in the Air, as a Rudder. But Borelli hath put it beyond all doubt, that this is the leaft ue of it, and that it is chiefly to affift the Bird in its Afcents and Defcents in the Air, and to obviate the Vacillations of the Body and Wings. For as for turning to this or that file, it is perfo med by the Wings, and Inclination of the Body, and but very little by the help of the Tail.

(8) See Borelli ubi fupr. Prop. 182,

(9) It is confiderable in all Water-Fowl, how exactly their Legs and Feet correspond to that way of Life. For either their Legs are long, to enable them to wade in the Waters: In which cafe, their Legs are bare of Feathers a good way above the Knees, the more contealently for this 觉离 pute

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for fteady Going, for Perching, for Catching and Holding of Prey (10), or for Hanging by the Heels to gather their Food (11), or to fix thenfelves in their places of Retreat and Safety. And the latter, namely the Legs, all curved for their eafy Perching, Roofting, and Reft, as alfo to help them upon their Wings in taking their Flight, and to be therein commodiously tucked up to the Body, fo as not to obftruct their Flight. In fome long, for Wading and Searching the Waters; in fome of a moderate Length, anfwerable to their vulgar Occafions; and in others as remarkably fhort, to answer their efpecial Occafions and Manner of Life (12). To all which let us add the

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purpose. Their Toes alfo are all broad; and in fuch as bear the name of Mudfuckers, two of the Toes are somewhat joined, that they may not eafily fink in walking upon boggy Places. And as for fuch as are whole-footed, or whofe Toes are webbed together (excepting fome few) their Legs are generally fhort, which is the moft convenient fize for SwimIning. And 'tis pretty enough to fee how artificially they gather up their Toes and Feet when they withdraw their Legs, or go to take their Stroke, and as artificially again extend or open their whole Foot, when they press upon, or drive themselves forward in the Waters.

(10) Some of the Charecteriftics of Rapacious Birds, are to cave hooked, strong, and sharp-pointed Beaks and Talons, fitted for Rapine, and tearing of Flesh and strong and brawny Thigh for Ariking down their Prey. Willughby Ornith. L. z. c, 1. Rai Synopf. Av. Method. p. I.

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(11) Such Birds as climb, particularly thofe of the woodpecter kind, have for this purpofe (as Mr. Willughby obferves, L. 2. c. 4) 1. Strong and mufculous Thighs. 2. Short Legs and very ftrong 3. Toes ftanding two forwards, and two backwards. Their Toes alfo are clofe joined together, that they may more ftrongly and firmly lay hold on the Tree they climb upon. 4. All of them have a hard ftiff Tail bending alfo downwards, on which they lean, and fo bear up them felves in climbing.

(12) Swifts and Swallows have remarkably fhort Legs, efpecially the former, and their Toes grafp any thing very

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ftrong.

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