. Animals of land and sea. Zoology; Insects; Zoology. io6 ANIMALS OF LAND AND SEA weight there is a wing area of 4 square yards, 6 square feet and 105 square inches; in a butterfly of average size each pound of body weight represents a wing area of 3 square yards, 8 square feet, and 87 square inches; in the swallow this is reduced to only 4 square feet and 18 square inches, in the pigeon to i square foot and 14 square inches, and in the stork to only 122 square inches. Not only do the small birds have larger wings than big- ger ones, but they move them much more rapidly. The wings of the small
. Animals of land and sea. Zoology; Insects; Zoology. io6 ANIMALS OF LAND AND SEA weight there is a wing area of 4 square yards, 6 square feet and 105 square inches; in a butterfly of average size each pound of body weight represents a wing area of 3 square yards, 8 square feet, and 87 square inches; in the swallow this is reduced to only 4 square feet and 18 square inches, in the pigeon to i square foot and 14 square inches, and in the stork to only 122 square inches. Not only do the small birds have larger wings than big- ger ones, but they move them much more rapidly. The wings of the smaller humming-birds vi- brate so fast that it is difficult for the eye to follow them. The wing beats of the sparrow are 780 per minute, of the duck 540, of the pigeon 480, and of the crow about 120. It was the necessity of finding answers to these questions, why do small birds have to have larger wings than big ones, and why do they have to move their larger w ings more rapidly, that made the develop- ment of the flying-machine so diflicult. The wings of many of. Figs. 194-201. Some destructive, and some pre- daceous Beetles. For explanations of the figures see p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Clark, Austin Hobart, b. 1880. New York, D. Van Nostrand company
Size: 1258px × 1987px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecti, booksubjectzoology
