S. P. Langley — Internal Work of the Wind. 43 



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, 

 " 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 illustra- 

 tion 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 plenty 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 serial 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 titnes 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 

 the writer, chilled by the cold blast, gave up watching and 

 moved away, leaving the bird, still floating about, at the same 

 height in the torrent of air, in nearly the same circle, and with 

 the same aspect of indolent repose. 



If the wind is such a body as it is commonly supposed to 

 be, it is absolutely impossible that this sustention could have 



