,'304 ON AERIAL LOCOMOTION. 



would be required to balauce his exertious, makiug- uo allowauce for 

 weight beyoud liis own body. 



We have thus reasous for the failure of the iiiauy mis-directed at- 

 tempts that have from time to time been made to raise weights perpen- 

 dicularly in the air, by wings or descending surfaces. Though the flight 

 of a bird is maintained by a constant re-action or abutment against an 

 enormous weight of air in comparison with the weight of its own body, 

 yet, as will be subsequently shown, the support upon that weight is 

 not necessarily commanded by great extent of wing-surface, but by the 

 direction of motion. 



One of the first birds in the scale of flying magnitude is the pelican. 

 It is seen in the streams and estuaries of warm climates, fish being its 

 only food. On the Nile, after the inundation, it arrives in flocks of 

 many hundreds together, having migrated from long distances. A 

 specimen shot was found to weigh 21 pounds and measured 10 feet 

 across the wings from end to end. The pelican rises with much diffi- 

 culty, but once on the wing appears to fly with very little exertion, not- 

 withstanding its great weight. Their mode of progress is peculiar and 

 graceful. They fly after a leader in one single train. As he rises or 

 descends so his followers do the same in succession, imitating his move- 

 ments precisely. At a distance this gives them the appearance of a 

 long, undulating ribbon, glistening under the cloudless sun of an oriental 

 sky. During their flight they make about seventy strokes per minute 

 with their wing. This uncouth-looking bird is somewhat whimsical in 

 its habits. Groups of them may be seen far above the earth, at a dis- 

 tance from the river-side, soaring, apparently for their own pleasure. 

 With outstretched and motionless wings they float serenely high in the 

 atmosphere for more than an hour together, traversing the same locality 

 in circling movements. With head thrown back and enormous bills 

 resting on their breasts they almost seem asleep. A few easy strokes 

 of their wings each minute, as their momentum or velocity diminishes, 

 serves to keep them sustained at the same level. The effort required is 

 obviously slight and not confirmatory of the excessive amount of power 

 said to be requisite for maintaining the flight of a bird of this weight 

 and size. The pelican displays no symptom of being endowed with 

 great strength, for when only slightly wounded it is easily captured, 

 not having adequate power for effective resistance, but heavily flapping 

 the huge wings that should, as some imagine, give a stroke equal in 

 vigor to the kick of a horse. 



During a calm evening flocks of spoonbills take their flight directly 

 up the river's course, as if linked together in unison and moved by the 

 same impulse, they alter not their relative positions, but at less than 

 15 inches above the water's surface, they speed swiftly by with ease 

 and grace inimitable, a living sheet of spotless white. Let one cir- 

 cumstance be remarked,^though they have fleeted past at a rate of 

 near 30 miles an hour, so little do they disturb the element in which 



