. Animal flight; a record of observation . utline of outer part of wing of adjutant when circling with effort to gain height. A. Line on prolongation ofwhich is centre of effortof cambered part of thewing. B. Line on prolongation ofwhich is centre of liftingeffort of phalangeal quills. CJ. Carpal joint. MJ. Metacarpal joint. In fig. 31 I have represented the outline when thebird is in metacarpal descent. The wing-tip is shownretired by flexing at the metacarpal joint. The centreof effort of the cambered part of the wing is on theline A. The centre of effort of the wing-tip is on theline B. But
. Animal flight; a record of observation . utline of outer part of wing of adjutant when circling with effort to gain height. A. Line on prolongation ofwhich is centre of effortof cambered part of thewing. B. Line on prolongation ofwhich is centre of liftingeffort of phalangeal quills. CJ. Carpal joint. MJ. Metacarpal joint. In fig. 31 I have represented the outline when thebird is in metacarpal descent. The wing-tip is shownretired by flexing at the metacarpal joint. The centreof effort of the cambered part of the wing is on theline A. The centre of effort of the wing-tip is on theline B. But as this line by the retirement has beendisplaced backwards, instead of a couple tending to ANIMAL FLIGHT. 131 maintain the tilt of the wing, there is a couple tendingto decrease its tilt. That is to say, the new positionof the wing-tip results in a tendency to diminish theangle of the incidence of the cambered part of the wing. I think we mayregard it as a fact thatwhen the bird changesfrom ease-gliding orFig. 31. circling (fig. 32) to. Outline of outer part of a wing of an adjutant when in metacarpal descent. A. Line on prolongation ofwhich is centre of effortof cambered part of thewing. B. Line on prolongation ofwhich is centre of liftingeffort of phalangeal quills. metacarpal descent, it has changed from a mode offlight in which it takes energy from the air to a modeof flight in which it no longer takes energy from theair. The only known change in the disposition of thewings is the retire-ment of the wing-tips. If the wing nolonger takes energyfrom the air it isdifficult to imaginethat its angle of in-cidence is the same
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectan, booksubjectflight
