XI. 



MASTER IMPERTINENCE. 



155 



Now compare the wing of the sparrow with the wing of 

 the swift. The former is short, broad, blunt and concave, 

 while the pinion of the swift is long, narrow, pointed and 

 relatively flat. Pluck the wings and there is not so much 

 to choose between them ; the difference is due to the 

 feathers. The great extension of the swift's wing is pro- 

 duced by the lengthening of the primary feathers that grow 

 on the man us or hand. An almost equally perfect wing, 

 but broader at the base and sharper at the point, is seen 



in the swift's companions in the summer air, the martin 

 and the swallow. These you might well suppose to be 

 first cousins of the swift. But external resemblances may 

 often be deceptive, and are so in this case. If you look at 

 their feet you will see that in this matter these birds are 

 very different. The four short toes of the swift are all 

 turned forward and bear thick but sharp claws. The toes 

 of the swallow are longer and more slender, and have more 

 delicate claws. The arrangement is similar to that in the 

 sparrow, the first toe projecting backwards while the other 



