130 



ANIMAL LOCOMOTION, 



the mutilation took place. In this experiment, one wing was 

 operated upon before the other, in order to test the balancing- 

 power. The bird flew perfectly, either with one or with 

 both wings cut. 



Exp. 23. Detached the half of the secondary feathers and 

 a fourth of the primary ones of either pinion in the long axis 

 of the wing. Flight in no wise impaired. The bird, in this 

 instance, flew upwards of 30 yards, and, having risen a con- 

 siderable height, dropped into a neighbouring tree. 



Exp. 24. Detached nearly the half of the primary feathers 

 in the long axis of either pinion, the secondaries being left 

 intact. When one wing only was operated upon, flight was 

 perfect ; when both were tampered with, it was still perfect, 

 but slightly laboured. 



Exp. 25. Detached rather more than a third of both 

 primary and secondary feathers of either pinion in the long 

 axis of the wing. In this case the bird flew with evident 

 exertion, but was able, notwithstanding, to attain a very con- 

 siderable altitude. 



From experiments 1, 2, 7, 8, 10, 13, 16, 22, 23, 24, and 

 25, it would appear that great liberties may be taken with 

 the posterior or thin margin of the wing, and the dimensions 

 of the wing in this direction materially reduced, without 

 destroying, or even vitiating in a marked degree, the powers 

 of flight. This is no doubt owing to the fact indicated by 

 Sir George Cayley, and fully explained by Mr. Wenham, that 

 in all wings, particularly long narrow ones, the elevating 

 power is transferred to the anterior or front margin. These 

 experiments prove that the upward bending of the posterior 

 margins of the wings during the down stroke is not necessary 

 to flight. 



Exp. 26. Removed alternate primary and secondary feathers 

 from either wing, beginning with the flrst primary. The bird 

 flew upwards of fifty yards with very slight efl'ort, rose above 

 an adjoining fence, and wheeled over it a second time to settle 

 on a tree in the vicinity. When one wing only was oper- 

 ated upon, it flew irregularly and in a lopsided manner. 



Exp. 27. Eemoved alternate primary and secondary feathers 

 from either wing, beginning with the second primary. Flight, 



