FEATHER. 496 FEATHER. ■ — especially a 'flight-feather,' as a wing-quill (remex) or a tail-quill (rectrix). Other kinds ■of feathers, as the soft and fluffy underlying downs, the hair-like, degenerate filoplumes, and scaly or wiry feathers, exhibit the absence of some or all of these connecting parts, or their modifica- tion. The purpose of the feathers is mainly protec- tion from cold and wef ; they are exceedingly warm because their substance ( resembling horn I is a. poor conductor of heat, cheeking radiation, and because of the air which they contain or entangle forming a blanket of dry air about the body. To -enable them the better to resist wet, most birds are provided with a store of grease in the oil- gla nd ( see Bird ) , with which they often anoint the plumage. Moreover, the skin of many birds, espe- cially aquatic species of cold climates, is covered with a thick coating of down feathers, each of. which is composed of a very small soft tube lying in the skin, from the interior of which arises a minute tuft of soft filaments, without any central shaft. This downy covering secures warmth without weight, like the soft fur at the base of the hair of Arctic mammals, and is an adaptive sur- vival of the earliest form of plumage. The embryo within the shell, and afterwards in the nest, is clothed with 'nestling down,' which consists,of short, incomplete, nearly colorless feath- ers, called neossoptiles, which in some birds grow only on limited spots, or. rarely, do not appear at all ; and sometimes they resemble hairs or bristles more than feathers. This first coat soon disap- pears, being pushed off in the first molt by the growth of the real plumage, which arises from Hie same places and areas as did the nestling down. Feather Tracts. Feathers do not grow uni- formly over the body as might be supposed, but ari' arranged in definite areas, called feather- tracts, or pterylse. These consist chiefly of con- tour feathers, but also hear many filoplumes, and sometimes true down. The arrange nt of the pterylse forms a special study in ornithology, known as pterylography. i See Bird and 1'terv- losis.i Feather- grow with great rapidity, and in »ome birds attain a length of more than three feet. They are almosi always renewed nt least once, and in some cases partially or wholly twice, annually: hence it may readily he con- ceived how much vital energy mu-t be exhibited in their development, and how critical tin- period of molting must be. The plumage is generally changed several times before it attain- the stale characteristic of the adult bird; these change may occupy a period ranging from one to live year-.: hut some birds attain their adult plu- ge v. iih the first molt. (See Molting.) When the exi I Hi- i 111 r, lor, as they frequent ly do, the young birds resemble the duller colored sex, generally the female. When the male in breed ing plumage is brighter colored than the female, he usually dons a eoat similar to hers after the breeding season i- over. Colors of Plumage. The coloi Eeathers, which birds owe their distinctive appearance and beauty, may lie due to pigments lodged in the i of tie- feather, or it may be the ondition of the complete reflection of light. To Hie due tho metallic sheen of the n in" Mid i he eyes of a peacock's (ail. the 'livelier iris' of the burnished dove-. It is. in fact, an iridescence. Notwithstanding their ex- travascular nature, feathers undergo a change ol color after they are completely formed, but such changes obviously cannot In- due to any new de- posits of pigment in the feather, for it is actually dead tissue. No subject connected with orni- thology has been more earnestly discussed in the last few years' than the method of color-change in birds. Those who hold that birds can change color by some unexplained changes in the feat ; i, rs are losing ground, however, and those who have given the subject most careful study are agreed in rejecting this theory of aptosochromatism, as it is called. It is well known now that most remarkable changes in color are produced merely by the wearing away or abrasion of the tips of the feathers, and this process, combined with the ordinary changes in the molt, is thought to be sufficient to account for all possible color-changes. Feathers vary in form in different parts of the body, and afford important zoological characters for the distinction of species. For those of the wings and tail, and their service in flying, see Bird; Flight. I'ses of Feathers. The chief uses to which feathers are applied in the arts are three — pens, due to the peculiar elasticity of the barrels; bed- feathers, due to the combined softness and elas- ticity of the barbs; and ornament, due to the graceful forms and delicate tints of the whole feather. The mode of preparing the barrel- for pens is described under Quill. Bed- feathers were used in England in the time of Henry VII.; but it is not known how much earlier. At the present day, goose-feathers are preferred, the white rather than the gray. What are called poultry feathers, such as those of the turkey, duck, and fowl, are less esteemed, on account of their deficient elasticity. Wild-duck feathers are soft and elastic, but contain an oil difficult to remove. The following is one among several modes of preparing feathers for beds: clean water is saturated with quicklime; the feathers are put into a tub. and lime wain Is added to the depth of a few inches; the feathers are well steeped and stirred for three or four days; they are taken out, drained, washed in clean water, dried upon nets, shaken occasionally while drying, and finally beaten to expel any dust. The larger establishments, however, now prepare bed-feathers by steaming, which is found to be a more profitable and efficient process. The down, which is of so light and exquisite a texture as to have become tin' symbol of softness, is mostly taken from the breasts of birds, and forms a warm and delicate stuffing for beds, pillows, and coverlets. The most valuable is that ob- tained from the eider-duck, described under ElDEB. Feal hers used for head-dresses, or other purposes of ornament, are selected according to the forms and colors which they display. The ostrich, a . ' i valuable hind of feather, may he taken as an example of the way in which ornamental feathers generally are prepared by the pluma* sier. The mode of catching the bird its,. If is noticed under OSTRIcn; it suffices here to slate that l la- hunici - endea or to u oid injuri feathers by blood or blows. When brought In market, the feathers are assorted according In quality: ilios,. from the bach and above the wings in- i he best, i he wing feathers nexl best, ami the thers least valued. The feathers of the
