. A history of British birds . Fig. 10. Fio. 11. hereby to be manifest. The principle on which the vocalorgans in Birds are framed is that which prevails in wind-instruments generally; the notes in the ascending scale beingproduced by a corresponding contraction of the diameter orthe length of the tube, and vice versa. 274 PASSERES. corvidj:. CORVID^. /^>/\

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Keywords: ., bookauthorsaun, bookcentury1800, bookdecade1870, booksubjectbirds