vil FLIGHT 267 
damaged by the fact that Mr. Maxim’s flying machine, 
weighing 34 tons (a very heavy bird !), has actually 
risen from the ground. It is true that all the giant 
fossil birds that have been discovered seem to have 
been allies of the Ostrich and incapable of flight. 
Since, however, the geological record is not only 
imperfect but has, much of it, still to be read, we 
cannot say that giant flying birds never existed. 
Supposing that they once existed, they may have died 
out for reasons not connected with flight. Many large 
mammals and reptiles have become extinct, the 
smaller having some advantage in the race of life. 
When we come to compare the actual achievements 
of big and small birds, it will be found that the 
honours are divided. The small can rise with greater 
ease, the line of ascent being far nearer to the vertical. 
This may in many cases be due to the greater stiffness 
of the shoulder-joint in large birds, which prevents 
the wing turning its under surface backward, as it 
must turn for ascent up a steep incline (see above on 
upward flight). But in one of the big birds that I 
have examined, the Eagle,! this stiffness is not found. 
If we concede that small birds rise with less effort, 
on the other hand, the big are, I believe, even allowing 
for their greater bulk, better weight-carriers. An 
Eagle will carry a young lamb; for a House Sparrowa 
very small piece of bread is a heavy burden. 
In long-distance flight the two classes are about 
equally matched. 
Small birds never soar, and it is generally supposed 
1 It can rise with greater ease, I think, than many big sea- 
birds that are stiff at the shoulder. 
