56 THE ZOOLOGIST. 
both in shape and position. But they do precisely resemble a 
board so far as the exertion of motive power is concerned. For 
instance, if a bird floats in a wind of unvarying velocity over any 
fixed point on the earth, then if a board of the same shape and 
size and weight were put in its place it would remain there just 
as the bird does, as long as the conditions were unchanged. If 
the bird slightly changed the shape or position of its surfaces so 
as to vertically ascend indefinitely, the board would also ascend 
in the same way were it to be changed in a similar manner. 
This is seen in the performances of what I have termed 
“effigies.” They were surfaces of veneer or cardboard fastened 
to a frame and balanced by a weighted pendant. They would 
simulate the actions of “soaring” perfectly. I have made 
numbers of them. ‘They would leave the hand and travel against 
the wind for as much as 500 yards, remaining up for fifteen 
minutes. ‘They had no ability to automatically balance them- 
selves in unsteady currents of air, but they were good illustrations 
of ‘‘ soaring.” 
The first thing to be definitely ascertained was whether the 
wings of the soaring birds were in fact as motionless as they 
seemed. ‘To determine this point demanded close inspection, 
and although the creatures were not fearful of man in that 
remote country, they preferred a distance of thirty or forty feet 
away. ‘The captive bird was useless for any critical test. ’Tis 
true that a bird ten feet in alar dimensions, resting horizontally 
above one’s head thirty feet away, with the clear sky as a back- 
ground, could be pretty well examined; still a closer position 
was not only desirable but imperative, and a resort was had to 
the arts of mimicry with entire success. Procuring a few square 
yards of thin muslin fabric sufficient to completely envelope my 
person, it was covered with paint of the green and brown shades 
so as to resemble the tree tops of localities in the vicinity of 
either the breeding-places or the roosts of the soaring birds, and 
barring the unpleasant sensation one has when engaged in the 
arts of gross deception, I had everything pretty much my own 
way. Some trouble was experienced in striking the happy mean 
of scaring the great creatures enough to keep them from alighting 
on my face, and still not frighten them away, as they were totally 
oblivious of my presence. Wing movements could now be studied 
in every conceivable position at leisure, endwise, sidewise, from 
