198 THE STRUCTURE AND LIFE OF BIRDS cuap. 
slower and stronger strokes, the rate of movement of 
the further end of the wing increasing enormously with 
increase. of length, and the resistance of the air in- 
creasing out of: all proportion to the increase .of 
velocity. Thus, in proportion to his weight and bulk, 
a big bird will require a firmer pivot, for his wing than 
asmall one. But the comparatively small inter-cora- 
coidal angle in the Pheasant (if I have estimated it 
correctly) shows ,that power of flight as well as size 
must be taken into consideration. 
The working of the passive machinery may be seen 
well in a dead bird. Only extend the arm, and the 
hand is extended! Only extend the hand, and all the 
large feathers are spread! The radius, as I have 
explained, slides back when the forearm is extended 
and pulls the hand with it, bringing it into line with 
the arm. Then follows the sudden expansion of the 
wing feathers like a fan, effected by means of elastic 
ligaments through which the primary and secondary 
feathers pass, and which are stretched directly the 
angle between the hand and forearm is widened. The 
system of ligaments is elaborate. If the skin is removed 
it will be seen that each of the great feathers is fastened 
to the bone by a stringy tendinous mass. Even in 
the dry skeleton they leave their mark. The elastic 
ligaments can be made out without any dissection, 
One, through which the quill of each feather passes, 
carr be clearly seen extending from the extremity of 
the handbone or. metacarpal to the armpit, including, 
therefore, all the secondaries, and, with the exception 
of those that spring from the fingers, all the primaries. 
It is in fact a continuation of a tendon connected with 
