42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 92 



takes place, and that the hirds sustain themselves on pinions which 

 are quite rigid and motionless, except for a rocking or balancing move- 

 ment involving little energy. 



" The writer desires to acknowledge his indebtedness to that most 

 conscientious observer, M. Mouillard,'^ who has described these ac- 

 tions of the soaring birds with incomparable vividness and minute- 

 ness, and who asserts that they, under certain circumstances, without 

 flapping their wings, rise and actually advance against the wind. 



" To the writer, who has himself been attracted from his earliest 

 years to the mystery which has surrounded this action of the soaring 

 bird, it has been a subject of continual surprise that it has attracted so 

 little attention from physicists. That nearly inert bodies, weighing 

 from 5 to 10, or even more, pounds, and many hundred times denser 

 than the air, should be visibly suspended in it above our heads, some- 

 times for hours at a time, and without falling — this, it might seem, 

 is, without misuse of language to be called a physical miracle ; and yet, 

 the fact that those whose province it is to investigate nature, have 

 hitherto seldom thought it deserving attention, is perhaps the greater 

 wonder. 



". . . . The common 'Turkey Buzzard' (Cathartcs 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 

 probably 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, undisturbed by any surface irregu- 

 larities 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 repeatedly, rising and fall- 

 ing 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 



^' L. P. Mouillard, L'Empire de I'Air, Paris : G. Masson. 



