2609

organ is made up of 2 parts, the true rima glottidis, at the upper part of the windpipe, and the bronchial larynx, which is furnished with a peculiarly tense membrane, performing the same duty as the reed in a clarinet.-The large proportionate development of the brain and of the nervous system of birds is another distinguishing feature of their organization. In many cases they exhibit an apparent superiority to the corresponding organs in mammalia of the same relative size and weight. Thus, for instance, while in man the size of the brain, in proportion to that of the whole body, varies from to part, that of the common canary bird is. There are, however, great variations in regard to the size of these organs in different families and even in different genera of the same families. Thus, while the brain of the goose is 380 of the entire body, that of the eagle is and that of the common European sparrow is. It differs chiefly from the same organ in mammalia, in the presence of certain tubercles corresponding to the corpora striata of other animals, and the absence of several parts found in the brains of the latter. -The senses of sight, smell, and hearing, are supposed to be most acute in a large proportion of the families of the class, much more so than that of taste, which is found well developed in only a few families, and still more than that of touch, which is presumed to be totally wanting. The organs of sight are of great proportionate magnitude, and occupy a large proportion of the cerebral developments. They are constructed with a wonderful contrivance not inaptly compared with so many peculiar kinds of "selfadjusting telescopes." They are also all provided with a very curious apparatus called the nictitating membrane. This is a fold of the tunica conjunctiva, so arranged as to be capable of being drawn out to cover the eye like a curtain, and to be withdrawn at will, enabling the possessor to meet the brightest rays of the sun undazzled by its brilliance, and protecting the organ from injuries.-With only a few exceptions birds have no external organs of hear ing corresponding to an ear. We find instead an aperture that is called meatus auditorius. The internal membranes of this organ are connected with each other by means of the aircells of the skull and have but a single auditory bone.-Among different authors there is much diversity of opinion in regard to the development of the sense of smell in birds. The experiments of Audubon and Bachman would seem to prove that, even in those families in which this sense is presumed to reach its highest point of perfection, the members are directed by sight rather than by smell to their prey. Still it is quite certain that they possess certain nervous developments corresponding to olfactory organs, which, if not designed for smell, possess no very apparent purpose. The sense of taste has a limited degree of development in a few families, such, for instance, as the divers, the waders in part, and

the several families of humming birds, honeysuckers, and a few others. As a general rule it is very imperfect, or even wholly wanting.The various contrivances and instinctive expedients, by means of which the entire class of aves develop the germs of their mature or perfect ora, are remarkable as well as distinguishing features in the economy of their propagation. They are peculiar to the class, and are without any known exceptions. They are shared with them by no other class of animals, with only occasional but remote approximations, apparent exceptions rather than real. Every individual of the entire class deposits the matured egg without any distinguishable development of the young bird. Lightness and buoyancy of body, whether for flight in the air, or for freedom of motion on land or in water, are essential pre-requisites in the animal econc my of all the various families of the class. So, to nearly the same extent, is also their abundant reproduction. The vast numbers of their enemies, and the many casualties to which they are exposed, render a large and constant propagation necessary for their preservation. It is quite evident that any habit at all corresponding with the gestation of viviparous animals would be inconsistent with both of these requirements. It would destroy lightness of body, prevent freedom of motion, expose to innumerable dangers from enemies, hinder from procuring food, and make fecundity an impossibility. Thus, the common quail or partridge (ortyx Virginiana) of the Atlantic states, has been known to have 36 eggs in a single nest. Before maturity the product of this nest exceeds in weight their parent at least 20 fold. To provide for these or but one of them, by internal organs of development, would be impossible. Yet how simply, how perfectly, and how beautifully are all these requirements met by means of external substitutes. The nests of birds correspond with them in their duties and uses, to the uterine organs of reproduction of mammalia, and yet more to the marsupial pouches of certain Australian quadrupeds. They serve as external organs indispensable to the development of the immature young, from the first appearance of the germ in the egg, to a maturity more or less advanced, and varying greatly with the family; from the ostrich that comes into the world able to shift for itself from the very shell, to the blind and naked offspring of other families that are utterly helpless when first hatched. For this development of the young birds there are two essentials-the external receptacle which, though not always with exactness, we call nests, and the application of a certain nearly fixed or uniform amount of caloric. In nearly all cases the latter is generated by contact with the bodies of the parent birds. In some it is aided by the heat of the sun. In a few instances this is effected by heat derived from vegetable decomposition, or from the sun's rays, without any parental intervention after the deposition of the egg.

Attempts have been made, with some partial success, to classify the various architectural contrivances, or their substitutes to be found connected with the nesting and incubation of birds. The most recent and most nearly successful attempt to systematize the subject is that of Prof. James Rennie of King's college, London. To this the present article will nearly conform, giving, where practicable, indigenous representative examples and supplying the more noticeable deficiencies of that arrangement. In this system the entire class are ranged in 12 groups: miners, ground-builders, masons, carpenters, platform-builders, basket-makers, weavers, tailors, felt-makers, cementers, dome-builders, and parasites. The objections to this arrangement are, that it is imperfect in itself, and that it corresponds with none of the usual systems of ornithological classification. The large number of species which, without being miners or carpenters, invariably occupy for their nests corresponding sites, namely, holes in the earth or hollow trees, have no appropriate place. Some of these have been improperly classed as parasites. Nor is there a well-defined place for the large variety of species belonging to every order, which resort to the bare ground, making no perceptible nest, or for that remarkable family of Australian birds, the mound-builders, which combine something both of the miner and the ground-builder. It seldom if ever conforms, in a single family even, with any known classification. Thus, the hawks are platform-builders, ground-builders, occupants of hollow trees, &c. The swallows are miners, cementers, dome-builders, masons, &c., and so on. The mining birds compose a very large group, belonging to nearly every order, and having no other common peculiarity. They may be divided into 2 well-marked subdivisions: the true miners, which excavate holes for themselves, in which they construct their nests, and those which, without mining, occupy sites precisely similar. Of these a portion are supposed to be parasitic, availing themselves of the labors of others. Among the true miners may be named the common bank swallow, found nearly throughout the habitable globe, the bee-eaters of Europe and Asia, and the whole genus of thalassidromæ, better known as storm petrels or mother Carey's chickens; as also the several genera of puffins, king-fishers, penguins, &c. Among the other class, miners only by occupancy, may be named the wood wren and the winter wren of North America, the black guillemot, and the burrowing owls of North and South America. The last are parasitic miners, occupying invariably holes dug by other animals. The ground-builders include by far the largest group of birds of every order, and nearly of every family, and cannot be defined with exactness. In it must be classed many which build no nest, others that do, or do not construct nests, according to circumstances, those which build on the ground usually, but frequently elsewhere, some that are usually

ground-builders, but at times true miners, like the sky-lark of Europe, &c. The night-hawks and whip-poor-wills of America make no nest, the former depositing their eggs upon the bare earth, always selecting a site corresponding in color to their eggs, the latter selecting dried leaves as better suited to the same purposes of concealment. A very large proportion of the shore birds, waders, gulls, &c., make use of the bare sand with only a slight excavation for a nest. Others of the same species are more pains-taking, and construct well-formed nests. The herring gulls usually build a slight nest on the ground, but, after having been repeatedly robbed by eggers, the same birds are known to construct large and quite elaborate nests in trees or on precipitous cliffs. The mound-builders of Australia (see BRUSH TURKEY) Combine, in part, the habits of the miners with those of the ground-builders, in a manner peculiar to that remarkable family. Among the true groundbuilders may be cited nearly all the vultures, the entire sub-family of circida or hen-harriers, the zonotrichia or song sparrows of America, nearly all the waders, ducks, geese, swans, gulls, terns, &c., with more or less representatives in every order. The birds which, from their habits in nest-building, are classed as masons, are comparatively few in number of species. They are so called because they construct their nests, in whole or in part, with walls, coverings, barricades, &c., of mud or clay. Of this class the cliff swallow of North America is one of the most remarkable examples. The house swallows, both of Europe and America, the thrush and blackbird of Europe, the robin and the pewit flycatcher of North America, are among the most familiar examples. The species known among writers and travellers as the baker bird of South America may be given as the most skilful and remarkable of this class. This species constructs a nest in the most exposed situations, but at a considerable height, hemispherical, or in the form of a baker's oven, and hence its name. The opening of this nest is lateral, and is twice as high as it is wide, and the interior is divided into 2 chambers by a partition beginning at the entrance. The true carpenters are also a comparatively small group, consisting of those which excavate, by their own labor, holes for their nests in trees. Corresponding in the selection of the sites for their nests, but obtained without labor, are a yet larger number of species, that, for convenience, are grouped with them, some of which are also parasitic. The large and widely distributed family of picide or woodpeckers are the most familiar examples of the carpenter bird. With them are also classed the toucans of South America, the tomtits, the wrynecks, and the nut-hatches. Among the more common examples of the birds which, without being true carpenters, resort to similar places for their nests, may be mentioned the sparrow-hawk, the blue bird, the purple martin, the white-bellied swallow, and the house wren of North Ameri

ca, several species of owls, and many others. The platform builders are a small but distinct class, whose architecture is well defined. In it are embraced most of the falconida or hawk tribe, the wood-pigeons, the cuckoos of America, &c. All the eagles are true platform builders, and many of them construct elaborate and remarkable nests. The nest of the white-headed eagle is a massive structure, sometimes forming an exact cube, each side of which is 5 feet square. The martial eagle of southern Africa also constructs a large platform, said to be able to support the largest man. These nests are perfectly flat, with no other security against the eggs rolling off than the ever small number of the latter and the constant presence of one of the parents. The common passenger pigeon, the turtle dove, and the yellow-billed cuckoo of North America, are the most familiar examples of this class, as also, in Europe, are the wood pigeons, the ringdoves, the herons, and the storks. Another larger class, whose architectural accomplishments are even more remarkable, are the basket-makers. Many of these exhibit an elaboration and an ingenuity beyond the power of human skill to imitate. The vireos of North America weave a cup-shaped basket nest, pendant from some convenient twig, the leaves of which conceal them from enemies. The European bullfinch, the American mocking bird, the red-winged blackbird, the yellowheaded troopials of North America, the ravens, crows, and magpies, and the cyanotis omnicolor of Chili, may be mentioned as among the more familiar or remarkable of this interesting group. The last-named bird attaches a nest of singular beauty and elaborateness to the stems of the large reeds of that country, constructed to resemble the ripened seed-vessels of the plant so closely as to deceive even the most wary. The locust-eating thrush of southern Africa builds a large basket fabric, containing many cells or separate nests, from 6 to 20 in number, the joint products of, and occupied by as many pairs. The pensile grosbeak swings its basket nest from a pendant twig over a running stream, and makes its entrance from the bottom. The sociable grosbeaks unite in the construction of a large, basket-like cluster of nests, sometimes containing 200 or 300 in a single structure. To describe all, or even a small portion of the varieties of this remarkable class, is beyond our present purpose or our limits. The weavers are closely allied to the preceding class, differing chiefly in their more pensile nests, and in the superior nicety of their structure. The weaver-oriole of Senegal is one of the most remarkable of this class. The Baltimore oriole of America, the Indian sparrow of southern Asia, the crested fly-catcher of southern Africa, and the yellowhammer of Europe, are among the more familiar and distinguishing instances of the weavers. Hardly distinguishable from the 2 preceding groups are the few species classed as tailors. The orchard oriole of America is hardly entitled to be so classed, though usually quoted as a

true tailor. The best known instance is that of the sylvia sutoria of the eastern continent, which sews a dead leaf to a living one, and between them constructs its tiny nest. The blue yellow-back warbler of America is another remarkable tailor, though its wonderful skill is as yet little known or appreciated. The feltmakers form quite a large and well-marked group of artificers among birds. These arrange the materials of their nests, though more loosely, in the same manner as that in which are put together the fibres of felt. These materials are, to all appearances, corded together. How this is done cannot be satisfactorily explained. The chaffinch of Europe, the goldfinch of America, the canary-bird, and the whole family of humming-birds, may be given as exemplifications of this peculiar and interesting group. The cementers compose a very small but well distinguished class, all the members of which, so far as is at present known, belong to the family of swallows. These birds secrete, from glands on each side of the head, a strongly adhesive glue, which is dissolved in their saliva, with which they unite the materials of their 'nests, and fasten them to their proposed sites. The chimney swallow of North America is the most familiar example of this group, while the esculent swallow of the East is the most remarkable. The dome-builders might without inconvenience be merged into the several ⚫ groups of weavers and basket-makers. They consist of a large number of species belonging to a great variety of families, who construct covered nests, which are entered by holes in the side. These nests are more common in tropical countries than in cold. The marshwrens, several of the sylvicola, among these the Maryland yellow-throat, the goldencrowned thrush or oven-bird, the meadowlark, and the quail, of North America, are among the most familiar representatives of this group on this continent. In Europe it embraces the common wren, the chiff-chaff, the hay-bird, the wood-wren, the sparrow, the magpie, and the bottle-tit, among its best known members. The last group is one which it is not easy to classify. The true parasites, those which, like the cuckoo of Europe, the cow-blackbirds of North America, and its congener of South America, never rear their own young, but intrude their offspring upon strangers, always laying their eggs in the nests of other species, are a small but well-marked class. The larger number, which resort to the chosen sites of other birds, but build their own nests and rear their own young, are less clearly defined, because they are not uniformly parasitic in their habits. Of this latter class the house-sparrow of Europe as often makes its own nest as it seizes upon that of another species. Nearly or quite all of this class, usually marked as parasites, are so only occasionally, and by force of circumstances. The true members of the group are not many, and, so far as is at present known, are confined to the two genera, cuculus or true

cuckoos, and molothrus or cow-birds. (For the systematic classification of birds, and the history of the science, see ORNITHOLOGY.) BIRDS'-NESTS, EDIBLE, the nest of the seaswallow of the Malay archipelago, the lawit of Java, and salangane of the Philippines, hirundo esculenta of botanists. The bird is uniformly dark-colored, inclining to green on the back, and blue on the breast, has a short, strong bill, broad at the base, and is a little smaller than our swallow martin. It gathers from the coral rocks of the sea, a glutinous weed or marine fucus, which it swallows and afterward disgorges, and then applies this vomit, with its plastic bill, to the sides of deep caverns, both inland and on the sea-coast, to form its nest. When complete the nest is a hollow hemisphere, of the dimensions of an ordinary coffee-cup; when fresh made, is of waxy whiteness, and then esteemed most valuable; of second quality, when the bird has laid her eggs; and of third, when the young are fledged and flown. The lawit frequents mostly the deep, surf-beaten caves of the S. coast of Java, principally those of Karang Bollong (Hollow reefs), in the province of Baylen. These caves open at the base of a perpendicular face of rock, nearly 500 feet high, the mouths being from 18 to 25 feet in breadth, and 30 feet in height; within they continue to expand, until they attain the enormous dimensions of from 100 to 120 feet in width, and 450 feet in height, and for many hundred feet within the waves of the Indian ocean break with terrific fury. The collectors of the nests, like the Orkney gatherers of eider duck down, are lowered over fearful chasms, and move along a slippery foothold, at the risk of instant destruction. The collections take place in April, August, and December. The day previous to the descent into the caves, a bimbang or feast is given, wayangs or games in masks are performed, buffaloes and goats are killed, the flesh of which is freely distributed, and a pretty young Javanese girl is dressed up in peculiar costume, and personifies Nyai Ratu Kidul (the lady queen of the south), an imaginary personage, to whom offerings are inade, whose assistance is invoked, and who must give permission that the collections shall commence, without which the collectors, though trained from infancy to the dangerous pursuit, cannot enter the caves. The Nyai is of course always favorable, when competent judges are assured that the right period for collection is at hand. These nests are also obtained in other parts of Java, and the islands eastward, on the coasts of Borneo, and in the limestone caves of the Philippines. The whole product of Java, and Netherlands India, in 1850, on account of the government, of which it is a monopoly, was 268 piculs, or 35,734 pounds, worth 560,334 florins, or about $250,000, selling according to quality, at from $5 to $20 a pound; some of the finer sorts selling in Chinese markets for twice their weight in silver. It is well known that the edible nest is a whimsical culinary fan

84

cy of the Chinese alone. They use it in the preparation of their most refined soups. Alone it has an insipid glutinous taste. A portion of the precious article is oftentimes, by way of ostentation on the part of a host, placed in a prepared dish of food already on the table, and in the view of the seated guests. The Chinese attribute to it peculiar strengthening qualities; but this sensual people chiefly prize it for its alleged properties as an aphrodisiac; and it is singular that this word is derived from the Greek word appos, "scum of the sea," which the gluten of this nest certainly is.

BIRKBECK, GEORGE, M. D., a social reformer and the founder of the first mechanics' institute in England, born at Settle, Yorkshire, Jan. 10, 1776, died in London, Dec. 1, 1841. He early displayed a love for scientific pursuits; studied medicine in Leeds, Edinburgh, and London; was intimate while at the Scottish capital with the founders of the "Edinburgh Review," and was elected professor of the Andersonian institute at Glasgow. In Nov. 1799 he gave his first course of lectures at Glasgow, on natural and experimental philosophy. As. there were no philosophical instrument-makers at Glasgow, he was obliged to have recourse to ordinary workmen to furnish his apparatus, and while explaining to them the uses of the instruments, he was struck with the idea of giving a gratuitous course of scientific lectures to the Glasgow mechanics. In 1801 he issued his prospectus for the establishment of a class solely for persons engaged in the practical exercise of the mechanical arts, men whose education in early life had precluded even the possibility of acquiring "the smallest portion of scientific knowledge." The first lecture was attended by 75, but so satisfactory was it to those who were present that at the 2d lecture the number was increased to 200, at the 3d to more than 300, and at the 4th to more than 500. In 1802 and 1803 the lectures were continued; in 1804 he resigned his professorship and quitted Glasgow; in 1806 he settled in London, where he obtained a good practice as physician. In 1820 he gave a gratuitous course of 17 lectures at the London institution. In 1823, a public meeting took place at the Crown and Anchor, at which he presided, and which Dr. Lushington, Jeremy Bentham, David Wilkie, and Mr. Cobbett, attended. The first officers of the "London Mechanics' Institu tion" were elected, and Dr. Birkbeck was chosen president. He continued his professional avocations, but to the last gave much time and labor to efforts for the education of the people.

BİRKENFELD, a principality of Oldenburg in Germany; lies on the left bank of the Rhine, in the valley of the Nahe, between Lichtenberg and the province of the lower Rhine; area, 143 sq. m.; pop. in 1855, 32,529. The soil is poor, though well cultivated wherever practicable. Its surface is covered with forests and mountains; it possesses iron mines and produces agates, chalcedony, &c., which are wrought for