TIIK ri.l'MAGK AM) FLIGHT OV MUDS. 



9 



From these general iiiiuirks it is desirable to descend to some particulars; for while 

 the plumage of a bird demands admiration, it is also duo to the parts of which it is com- 

 posed. If a feather be carefully examined, it >> ill be foiuid composed of three primary- 

 parts : the quill, the shaft, and the vane. These, with the subordinate parts, are exhibited 

 in the adjouiinj;- figure. In (s) is exhibited the posterior surface of the solid stem, divided 

 into two jiarts by a longitudimxl grove, and from either side of which proceed a series of 

 laminir, composing Arith their fibrils what is tenued the vane (v). The lines, from 

 which the laminse arise, approach one another at the lower part of the stem, till they 

 meet at a point. Here the groove terminates, and there is a small orifice (o) leading 

 to the interior of the quill. From this part the transparent tubular portion of the 

 quill (t) commences ; and at its lower extremity (l) there exists a second or lower 

 oriticc. 



The separate pieces, or lamina-, of which the vane is composed, are called filaments, or 

 thi-eads. It will readily be remembered how mui'li stronger the vane shows itself to be 

 when pressed in a direction perpendicular to the plane, than when I'ubbed cither up or 

 down in the line of the stem. The reason of this is, that the lamincc, of which the vane 



FIG. J.— THE FEATHER. 



FIG. 0.— fibFlIls of a FEATHEK. 



FIG. ".— LAJIIX.E I.NTERLACED. 



is composed, are flat, and placed ^\-ith their flat sides towards each other, hence they 

 easily bend for the approaching of each other, as may bo perceived by drawing the 

 fingers ever so lightly upwards. But they are much harder to bend out of their plane, 

 as that is the direction in which they have to encounter the impulse and pressure of air, 

 and in which their strength is wanted and daily tasked. 



This one pecidiarity in the structure of a feather is worthy attention, but a second is 

 still more remarkable. For if a feather be examined, it will be observed that the laminae, 

 or tlu-eads, in their natural state unite ; that their union is something more than the 

 mere ojjposition of loose sm-faces ; that, though there is -no glutinous cohesion between 

 them, they are not parted without some degree of force ; that, therefore, by some 

 mechanical means or other, they catch or clasp among themselves, thereby giving to the 

 vane its closeness and compactness of texture. .Still further : when two lamina; which 

 have been separated by accident or force arc brought together again, they immediately 

 re-clasp ; the connexion, whatever it is, is perfectly recovered, and the vane of the feather 

 becomes as smooth and firm as if nothing had occurred. Let the finger be drawn down 

 the feather, which is against the grain, and probably the junction of some of the 



