Internal Work of the Wind. 427 



ject are found. Even in Washington, however, where the 

 writer at present resides, scores of great birds may be seen at 

 times in the air together, gliding with and against the wind, 

 and ascending higher at pleasure, on nearly motionless -wings. 

 " Those who have not seen it," says M. Mouillard, " when they 

 are told of this ascension without the expenditure of energy, 

 are always ready to say, ( but there must have been move- 

 ments, though you did not see them;' : ' " and in fact," he adds, 

 6i the casual witness of a single instance, himself, on reflection, 

 feels almost a doubt as to the evidence of his senses, when 

 they testify to things so extraordinary/' 



Quite agreeing with this, the writer will not attempt any 

 general description of his own observations, but as an illus- 

 tration of what can sometimes be seen, will give a single one, 

 to whose exactness he can personally witness. The common 

 " Turkey Buzzard" (Cathartes aura) is so plentiful around the 

 environs of Washington that there is rarely a time when some 

 of them may not be seen in the sky, gliding in curves over 

 some attractive point, or, more rarely, moving in nearly straight 

 lines on rigid wings, if there be a moderate wind. On the 

 only occasion when the motion of one near at hand could 

 be studied in a very high wind, the author was crossing the 

 long " Aqueduct Bridge " over the Potomac, in an unusually 

 violent November gale, the velocity of the wind being prob- 

 ably over 35 miles an hour. About one third of the distance 

 from the right bank of the river, and immediately over the 

 right parapet of the bridge, at a height of not over 20 yards, 

 was one of these buzzards, which, for some object which was 

 not evident, chose to keep over this spot, where the gale, un- 

 disturbed by any surface irregularities, swept directly up the 

 river with unchecked violence. In this aerial torrent, and 

 apparently indifferent to it, the bird hung, gliding in the usual 

 manner of its species, round and round, in a small oval curve, 

 whose major axis (which seemed toward the wind) was not 

 longer than twice its height from the water. The bird was 

 therefore at all times in close view. It swung around repeat- 

 edly, rising and falling slightly in its course, while keeping, 

 as a whole, on one level, and over the same place, moving 

 with a slight swaying, both in front and lateral direction, but 

 in such an effortless way as suggested a lazy yielding of itself 

 to the rocking of some invisible wave. 



It may be asserted that there was not only no flap of the 

 wing, but not the quiver of a wing-feather visible to the 

 closest scrutiny, during the considerable time the bird was 

 under observation, and during which the gale continued. A 

 record of this time was not kept, but it at any rate lasted until 



2G2 



