The Russellville Democrat., 1881-05-26
WING SPEED.
Some Interesting Facts About the Way That Birds Fly.
 Frazers Magazine.

Trazers Magazine.
 The speed at which some wings are driven is enormous. It is occasionally 80 great as to cause the pinions to emit 8 drumming sound. To this source the buzz of the fly, the drone of the bee and the boom of the beetle are to he refer red. When grouse, partridge or pheas- ant suddenly springs into the air, the sound produced by the whirring of its wings greatly resembles that produced by the contact of steel with the rapidly revolving stone of the knife-g grinder. It has been estimated that the common fly moves its wings 330 times per second, i. e. l9,S00 times per minute, and that the butterfly moves its wings nine times per second, or 540 times per minute. These movements represent an incredibly high spced even to the roots; but the speed is enormously increased at the tips of the wings, from the fact that the tips rotate upon the roots as centers. In reality, and as it has been already indicated, the speed at the tips of the wings increases in proportion as the tips are removed from the axes of rotation, and in propor- tion as the wings are long. This is ex- plained on the principle well understood in mechanics. If rod or wing hinged at one point be made to vibrate, the free end of the rod or wing always passes through very much greater space in a given tune than the part nearer the root of the wing. The progressive increase in the speed of the wings in proportion as the wings become larger explains why the wings of bats and birds are not driven at the extravagant speed of in- sect wings, and how the large and long wings of large bats and birds are driven more leisurely than the small and short wings of small bats and birds. That the wing is driven more slowly in proportion to its length is proved by experiment.; and by observing the flight of large and small birds of the same genius. Thus, large gulls fiap their wings much more slowly than small gulis; the confgura- tion and relative size of the wings to the body being the same in both. This IS hopeful feature in the construction of flying machines, as there can be no doubt that comparatively very slow movements will suffice for driving the long, powerful wings required to elevate and propel flying machines. The speed of the wing is in part regulated by the ampleture of the wing Thus, ifthe wing. be broad as well as long, the beats are necessarily reduced in frequency. This is especially true of the heron, which is one of the most picturesque, and, at the same time, one of the slowest flying birds we have. have timed the heron on several occasions, and find that in ordin- ary flight it's wings make exactly sixty up and sixty down strokes-i. e, 120 beats per minute. In the pterodactyl, the great extinct Saurian, the wing was enormouslv elongated, and in this par ticular instance probably from fifty to sixty beats of the wing per minute snfficed for fight. Fifty or sixty pulsa- tions of the wing per minute do not in volve much wear and tear of the work ing parts, and I am strongly of the opin- ion that artificial flight, if once achieved will become comparatively safe means of locomotion, as far as the machinery required is concerned.