1058 Lhe Problem of the Soaring Bird. [ November, 
easily climbed, and a little search was rewarded by the discovery 
of thick sturdy tops in which a secure lodgment could be had. 
The birds abounded in prodigious numbers, thousands occupying 
a single roosting ground. Not only was it seen that there was 
no motion of the wing as a whole, but that there was none of 
the individual feathers. There was no tremor, no slow nor fast 
waving ; the entire bird moved when the wing did. When the 
wing was flapped there was no doubt about it, and the flapping 
could be seen as far almost as the bird was visible. Both the 
“soaring” and flapping were discoverable when they occurred 
beyond any doubt whatever. To determine horizontality of the 
sea breezes of the coast, a radial arm, feathered and balanced 
level, was used. It is evident that somewhere in the interior of 
the peninsula there must be an upward trend of the meeting 
winds from the Atlantic and Gulf, but there is none discovera- 
ble on the western coast. The wind, twenty-five feet above tide, 
moves uniformly on level lines, and ten feet above the forest tree 
tops no upward flow can be found. The lantern of Egmont 
light, 150 feet high, at the entrance of Tampa bay, was frequently 
used for these atmospheric observations. 
There is a wide range in the relation between weight of bird 
and wing surface in the different species. It varies from less than 
one, to more than two feet for each pound weight. Uniformly 
the longer the wing to a given weight the greater the power of 
translation possessed by the bird, the man-of-war hawks in this 
respect surpassing all others. Wide, short wings were coupled 
with heavy bodies, as in the gannets, and these exhibited slower 
but steadier flight. The heavier the bird the steadier and easier 
seemed its movements, and a hungry vulture, which was very 
shaky in the breeze, could ride serenely when gorged with carrion. 
The only peculiarities discoverable in the atmospheric condi- 
tion required for soaring, was that the wind in all cases should 
move against the bird. The maximum velocity of this meeting 
of bird and air is unknown to me. I have timed the flight of. 
frigate birds through calm air on fixed wings at 100 miles per 
hour, and their velocity seems to depend on their wishes more 
than on any limitation of the powers of translation. The mini- 
mum speed, however, can be approximated. For the frigate bird 
. 
= it is about two miles per hour, three for the buzzards and five for 
_ the gannets. The heavier the bird the greater is the minimum | 
_ velocity required, and a gorged vulture cannot range itself with 
flock of hungry ones, which are sporting in their minimum, 
repeatedly flapping its 
> 
r its wings. 
(Zo be continued.) 
