. Our birds in their haunts [microform] : a popular treatise on the birds of eastern North America. Birds; Oiseaux. THE AMERICAN SWAN. 297 the skin, and supporting the main part. It is of a tough, horny material, and cylindrical in form, thus combining strength and lightness; for in no form is a gpiven amount of matter so strong to support a weight or a strain as in that of a tube or cylinder; and, of course, that is also the form most favorable to levity. Next comes the shaft supporting the vanes. This is somewhat four sided, to accommodate the vanes, and gradually diminishes toward the extre
. Our birds in their haunts [microform] : a popular treatise on the birds of eastern North America. Birds; Oiseaux. THE AMERICAN SWAN. 297 the skin, and supporting the main part. It is of a tough, horny material, and cylindrical in form, thus combining strength and lightness; for in no form is a gpiven amount of matter so strong to support a weight or a strain as in that of a tube or cylinder; and, of course, that is also the form most favorable to levity. Next comes the shaft supporting the vanes. This is somewhat four sided, to accommodate the vanes, and gradually diminishes toward the extremity. It is usually bent, thus rendering the feather much stronger and more convenient for its ordinary uses; and it is also made more firm by a light pith. The flat barbs, constituting the vane, join each other at their broad sides, thus striking the air edgewise, and so opposing the utmost resistance, just as a plank will sustain a greater weight when set on edge than when lying flat. These barbs are also broadest where they join the shaft, and taper to a point at the outer edge of the vane. The broad sides of these barbs are supplied with barbuleSy little hooks, so arranged as to hook or latch into each other, and so form the barbs of the vane into a continuous and firm sheet. At the base of the vane is generally more or less down, accord- ing to the nature of the bird, certain swimming birds, such as Ducks and Geese, being noted for their down. Some of the feathers of such species are down throughout, and are called down-feathers; while all birds have more or less feathers simply in the form of hairs. These last are particularly troublesome in dressing the common fowl, and are most conveniently cleaned by singeing. Again, the feath- ers of certain birds have a peculiar style of structure. Those of the Grebe are very open and loose, and of a glossy finish, giving them somewhat the appearance of an elegant kind of fur. " In the Owls the plumage is loose and soft; fila- m
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbirds, bookyear1884
