$2 TRANSACTIONS OF THE [pEc. 19, 
and had never seen any indication of inverted primaries. He 
thought that the reversion of the imbrication could not possibly 
have escaped the notice of ornithologists if it were common in 
any class of birds. He had recently experimented on pigeons 
with primaries interlocked, and found that it rendered their 
flight impossible. 
Pror. TROWBRIDGE claimed that the experiments with pigeons 
were not a fair test, as the pigeon was not a soaring bird. He 
also claimed that the feathers could lock by a simple natural 
motion of the wing; that it was a natural position of the prima- 
ries, and that it was not a fair term to call it an “inversion of 
the wing.” 
Pror. ALLEN thought the wings shown by Prof. Trowbridge 
were so denuded and softened as to show too free movement of 
the parts, and an unnatural rotation. 
He had been unable, by dissection and experiment, to find any 
natural movement or rotation of the wing or primaries which 
could cause the latter to overlap in the reverse order or to inter- 
lock. He produced a freshly-killed hawk, and Mr. SENNETT 
asked ProF. TROWBRIDGE to make the primaries interlock by 
any motion of the wing. 
A spirited colloquy ensued. The ornithologists present claimed 
that Pror. TROWBRIDGE had not demonstrated the interlocking 
of the primaries. 
Dr. N. L. Britton referred to the momentary flight of birds, 
back downward, as he had observed in the evolutions of an aérial 
fight between a fish-hawk and turkey-buzzard. 
The PRESIDENT said the ornithologists should have charity for 
those who were not specialists in their line. The claim by Prof. 
‘Trowbridge that birds had the power to interlock their primaries 
must be settled by observation, not by assertion or ridicule. 
Being proposed by a student of animal mechanics, it deserved 
fair consideration. Instantaneous photography might, perhaps, 
‘ settle the question. The President said further that modern 
improvements in the arts had been simply copying from Nature. 
That the discovery of great inventions, for example the telegraph, 
