60 AMID THE HIGH HILLS 
owing no doubt to its superior muscular power 
and driving force. 
In comparing the downward flight of the eagle 
and falcon it is also necessary to recollect the 
advantage which the former has by reason of its 
much greater weight. 
It is difficult to obtain thoroughly reliable 
records of the weights of the golden eagle and 
the different falcons ; but so far as I can ascertain, 
the weight of the eagle varies from 8 J to 12-o lb., 
that of the gyr-falcon from 3 to 3f lb., and that 
of the peregrine from 2 to 3 ounces under 2 lb. 
to 2 fib., in each case of course the female bird 
being heavier than the male. 
But for the resistance of the air, all bodies, 
light or heavy, small or large, would fall at the 
same rate. In fact, however, as velocity increases 
a notable air resistance is set up which increases 
rapidly. The velocity of a body falling freely in 
vacuo is over forty miles per hour at the end of 
two seconds, over sixty at the end of three 
seconds, and so on. 
We all know by experience the great force 
exerted by a wind of a velocity even as low as 
thirty miles an hour, which most people would 
call a hurricane. But it is not perhaps so generally 
