THE EMPIRE OF THE AIR. 421 



Pelicans on their travels arrange themselves m the form ol'u wedge, 

 wliieli from a distance simulates the point of an arrow. Tiiey move 

 with a curious sluggishness, and with the regularity of iron rolling- 

 mill macliines. These enormous palmiijedes sometimes afford a most 

 engrossing s})ectacle. I remember, one day upon the Nile, to have seen 

 a tlock of them come sailing out of the sky, dropping from a height 

 where first they seemed as swallows, alighting within liOO yards of my 

 boat, upon one of thos<' islands of gelatiuous nuid peculiar to that 

 river. 1 followed all tlieir ev(»lutions, through a telescojjc, and the 

 specta(de lasted half an hour, ft was astonishing! How beautiful were 

 these great birds in their wlieelin >s among the <'louds! From afar otf 

 one could hear the hissing of theii wings cleaving the air, their hoarse 

 cries, somewhat like the donkey's bray, and even the slap of their 

 great feet as they struck the liquid mud. 



Tlic three supports. — I*]aeli family of dying (•reatur(\s presents in the 

 air a particular aspect, w liicli it is intei'esting to stiuly. 



Tliere are birds with long arms and others witli short arms; some 

 lia\"e long |)rimary feathers and others liave them short. Some birds 

 have long nari'ow wings, otiiers ha\e them thin and short. Some 

 wings are round, sonu' are sipiare. terminating in five feathers of equal 

 length; others again run to a ]>oint in which either the third, the sec 

 ond, or e\en the first, priinar.x' featlu'r is th«' h>ngest. - For 



what ])articular kind (»f weather and for what si>ecial uses were these 

 wing forms intende<l .' 



When nature had to provide a large bird (and w<' need only con(;ern 

 ourselves with such) with wings for rapid flight, she made these wings 

 sumll and nariow. and ])ro\ided powerful pectoral mustdes, as witness 

 the ducks. When the bird's success in life reciiiired if to nH)ve in high 

 winds, like ocean storms, she in\ariabl.\' en(h)wed it with long and 

 narrov\' wings, to avcnd friction, as witness the gull, the mew, the gan 

 net, and the all)atross. When she determined, as in the case of the 

 eagle, to pro<luce a powerful creature, to create a great hunter, she then 

 endowed it with her best gifts; that is to say, with the a})fitu(le of sail 

 ing indefinitely without fatigue Avhile surveying the field. I^'or this she 

 gave it the wings of the sailing l)ird, and to these joined ]>owerful 

 motor musch's, so that it nught flap vigorously in case of need. AVhen 

 she determined only to i)rovide a biid with the faculty of remaining 

 in the sky without fatigue, she endowed if with two things: a large 

 mass and a large surface. 



As for other birds, her unfavored (diildren, the disinherited, she made 

 rowers of them, and they drag their bodies through the air by main 

 force, tlai»])ing and fatigue. 



Let us now impiire as to what i(dation there is between the mode of 

 flight ol' a bird and the length of the radius and of the ulna in propor- 

 tion to the liand. 



Before going further we should remark that the lengthening of the 



