DR. PETTIGREW ON THE MECHANISM OF FLIGHT. 271 



Fi°-. 31. The Red-legged Partridge (Perdix rubra) with wings fully extended aa in rapid flight, shows 



deeply concave form of the wings, how the primary and secondary feathers overlap and support 

 each other during extension, and how the anterior or thick margins of the wings are directed 

 upwards and backwards, the posterior or thin ones downwards and forwards. The wing in the 

 Partridge is wielded with immense velocity and power: and this is nec< ry because of its 



>ared with the great dimensions and weight of the 1 dy. 



the side. If a horizontal line be drawn across the i (a c) t ■ represent th 



com 

 rom 



horizon, and another from the tip of the tail (a) to the root of the wing (//), the ant 

 the wino- strikes the air is given. The wing in the Partridge is rounded and broad. 



{T. 



case the wmgs 



more 



s pointed and powerful as compared with the dimensions of the bird The Pigeon 

 expands its tail both in ascending and descending. The overlapping of the feathers of the wingi 



and tail can readily be seen in this figure. 



The Red-headed Pochard (Fuligula ferina, Linn.) in the act of dropping upon th or, the heai 



heme inclined forwards, the feet expanded, and the wings partially flc d. The feathers of the 



wing 



permil d 



»i i 



ii 



them. This is occasioned by the primary, secondary, and tertiary leathers not overlapping each 



other to any great extent. 



Fig. 35. The Curlew [N-, 



Here the body and win ^ rfch inclined 



at a decided angle upwards, the whole bird presenting a kite-like surface, 

 narrow, and pointed ; and the bird is a powerful flier. 



The 



Fig. 36. The Common Snipe {Scolopax gallinago) 



In this < ^e the direction of the 



inclined plane is reversed, the bird darting downwards like a boy's kite when stoopi. 



<* Tin win- 



b 



, Snipe are pointed, finely twisted upon themselves, ana very powemu. Their «n1 r i 

 margins are in the present instance directed downwards, their posterior or thm margin! 



with the tail, which is fully expanded, being directed upwards. 



Fig. 37. The Common 



cendin 



The wings in th 



& 



enormous 



mor 



Z Grey Heron (**. cinerea) immediately after rising In the Heron M M»^* 



i ui. ±Lo «i7P of the bird. The result i>, that tn< \ .ir< 



concave, and nnusnally large as compared «**«-££ lcavv , aD a aJ* ,.„, High 

 moved very leisnrely ; and every one u acqnamted with tire 1 





of the bird. The Heron figured 



Ol xne Dim. xne xierun iigm^ ff^* b - w „ 



greater than in the Wild Goose represented at fig. 42, wluch weighed over 9 lbs. 

 seonentlv more a auestion of power and weight than of buoyancy and .urfae, 



Plight is con- 



Common 



operating 



.rachuti 



/' 



being made nearly to touch each other both above and 

 is powerful, but by no means finely formed. 

 Fig. 42. The Wild Goose (Anser ferus, Linn.) as seen in" " 



ry great, the tips of the wings 

 p bodv. The wing of the Bool 



XI wings in 



moulded 



very compact and powerful. They are di tin 



pollers. Tl 



^ 



twisted upon themselves, and act with unu.ua. c , ^^ ^ . ^ ^ .^.^ ^ ]w _ 



of flight can be readily obtained by drawing a **™* f fc kft ^ trough 



rizon, and another through the left foot of the bud, along the 



the neck and head. 



2 oo 



- 



