164 THE REIGN OF LAW. 



from the first of the primary quills to the last and 

 feeblest of the tertiaries.* Now, the sharpness or 

 roundness of a wing at the tip depends on the 

 position which is given to the longest primary quill. 

 If the first or even the second primary is the 

 longest, and all that follow are considerably 

 shorter, the wing is necessarily a pointed wing, 

 because the tip of a single quill forms the end ; 

 but if the third or fourth primary quills are the 

 longest, and the next again on both sides are 

 only a little shorter, the wing becomes a round- 

 ended wing. Round-ended wings are also almost 

 always open-ended — that is to say, the tips of 

 the quills do not touch each other, but leave inter- 

 spaces at the end of the wing, through which, of 

 course, a good deal of air escapes. Since each 

 single quill is formed on the same principle as the 

 whole wing — that is, with the anterior margin 

 stiff and the posterior margin yielding — this 



* I owe to the accurate pencil of Mr J. Wolf the accompanying 

 engraving of the wing of the Golden Plover, a bird of powerful 

 flight. In this wing the gradation of the feathers is very perfect. 

 It will be observed that the first of the Secondaries, the eleventh 

 feather from the tip of the wing is marked by a slight variation in 

 he form of the margin. 



