268 THE STRUCTURE AND LIFE OF BIRDS CHAP. 
that their weight is insufficient to give them momentum. 
This may be the true explanation. When we speak 
of a soaring bird as a kite, the momentum is the 
string, and the small bird with a spread of wing, for 
him, so large, may be like a kite whose string is too 
weak to hold it. Those who maintain the superiority of 
the small to the big, would perhaps say that they do 
not get the wind to help them, because they have no 
need of itshelp. - 
Velocity. 
Many and various are the methods by which 
attempts have been made to measure the velocity of 
birds’ flight. Audubon found rice in the crops of 
Pigeons which, judging by its condition, he estimated 
had been eaten six hours before. This rice they could 
only have obtained in Carolina, which was 300—400 
miles distant. These data give at the lowest estimate 
a velocity of fifty miles per hour. The Frigate Bird 
is often seen flying over mid-ocean, and it is said that 
he never travels at night, and never sleeps upon the 
sea. Hence, a very rough calculation of the pace of 
his flight may be made. 
Such methods, however ingenious and interesting, 
are most unsatisfying. We want indisputable 
measurements, and it is only in the case of one or 
two species that they are obtainable. The racing of 
Homing Pigeons is a popular amusement in England, 
Belgium, and other countries, and “times” are 
accurately taken. In 1892 a pigeon, according to 
the published record, accomplished a flight of 114 
miles at a rate of eighty miles per hour. This is so 
