Animal life in the sea and on the land . Fi. 159.— The North-wind CHARACTERISTICS OF BIRDS. 245 4. The Wing of a Bird.—Still, for all this, the bird couldnot fly without wings. So it is the wing that charms usmost, and when we ^ee what a simple thing it is, we won-der at its power. The framework is formed of a set ofbones (Fig. 161) very similar to those of our arm andhand, but having onlyone perfect finger,which correspondsto our over thisframework there isa thin covering offlesh and muscle fromwhich grow the quillsand smaller feathers,and these,when spreadout,make up t
Animal life in the sea and on the land . Fi. 159.— The North-wind CHARACTERISTICS OF BIRDS. 245 4. The Wing of a Bird.—Still, for all this, the bird couldnot fly without wings. So it is the wing that charms usmost, and when we ^ee what a simple thing it is, we won-der at its power. The framework is formed of a set ofbones (Fig. 161) very similar to those of our arm andhand, but having onlyone perfect finger,which correspondsto our over thisframework there isa thin covering offlesh and muscle fromwhich grow the quillsand smaller feathers,and these,when spreadout,make up the broadwing. 5. When opened, theupper surface of thewing is rounded, andthe air can readilyslide from its edges asthe bird mounts up-ward, while, on thecontrary,the hollowedunder surface holds the air, as in an inverted cup, and enables. the bird topress upon the air thus confined. The movement ofthe wing in flying is somewhat like the stroke of anoar; the wing cuts the air with its sharp front edge,but presses back upon it with it
Size: 2100px × 1190px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1887
