38 INTRODUCTION. 



6. The primaries, or principal quills. These form the termi- 

 nation of the wings, and are the strongest feathers on the bird. 

 They rise from the hand, or that portion of the wings which is 

 below the wrist joint, and which, though it sometimes contains 

 three distinct bones in its length, is frequently called the first 

 (or third) bone of the wing. These feathers are numbered in 

 order ; the outer one, or that which is foremost in the expanded, 

 or lowest in the closed wing, is the first. Considerable differences 

 in the form of wings arise from the various lengths of the feathers ; 

 and these are accompanied by corresponding variations in the 

 style of flight. If the first or second of these feathers be the 

 longest in the wing, (and when the second is longest the first 

 comes underneath and supports it,) the bird can turn in the air 

 with greater ease than with any other form of wing. Birds 

 which hawk flying, or catch their prey while on the wing, whether 

 they catch other birds, as the Falcons, or insects as the Swallows, 

 have their wings of this construction. The Pigeons, which are 

 also birds of excellent wing, have the second feather longest ; but 

 the Lapwing, which is remarkable for the variety of its motions 

 in the air, has the longest feathers far into the wings. 



7. The secondaries, or second quills of the wing. They arise 

 from that part of the wing which is commonly called the second 

 bone, and which answers to the fore-arm in man. They come 

 from it towards the wrist joint, and admit of a folding of the 

 wing between them and the primaries, when the wing is closed. 

 When the wing is open they sometimes appear a continuation of 

 the same curve with the primaries, and at other times they form 

 a distinct curve of their own. 



8. The tertiaries, or third quills of the wing. They arise chiefly 

 from the same bones as the secondaries, but nearer to the elbow 

 joint. In some birds, especially those which are in the habit of 

 running very swiftly with the wings partially opened, the ter- 

 tiaries are often so long, and come so to a point, that the bird 

 appears as if it had four wings, or rather had a double wing on 

 each side. This form of wing answers some important purposes 

 in their economy. 



From the manner in which the several coverts support each 

 other and the quills, the wing is a finer combination of lightness, 

 strength, elasticity, and stiffness, than could be produced by any 

 other means. These coverts support, and admit of motion upon 

 each other, not unlike that which takes place in a coach-spring, 

 which is about the best of our mechanical contrivances for ren- 

 dering motion smooth and free from jolts, at the same time that 

 the compound spring is much less liable to be broken than if it 

 were formed of a single piece of metal. 



9. The rump-feathers and upper tail-coverts. The first of 



