144 THE PASSENGER PIGEON. 
conception." I know that the force of a tornado 
will break the trunk of a tree two feet in diameter, 
because its force acts horizontally against the up- 
right stem ; but how is it possible that a multitude 
of pigeons, alighting upon a tree^ could cause its 
upright bole, two feet in diameter, to break off at 
no great distance from the ground ? The branches 
of the tree, which took their lead diagonally from 
the bole, might possibly have given way under a 
heavy pressure, because they were inclined more 
or less from their perpendicular; but the upright 
bole itself would stand uninjured, and defy for ever 
any weight that could be brought to bear upon it 
from above. 
I now leave the assemblage of wild beasts, the 
solid masses of pigeons as large as hogsheads, and 
the broken trunk of the tree two feet in diameter, to 
the consideration of those British naturalists who 
have volunteered to support a foreigner in his exer- 
tions to teach Mr. Bull ornithology in the nineteenth 
century. 
The passages upon which I have just commented 
form part of " the facts'' on which R. B., in the 
Magazine of Natural History (vol. vi. p. 273.), 
tells us that the value of Mr. Audubon's Biography 
of Birds solely rests. No wonder that, ruit alto a 
culmine. By the way, I observe, at the end of that 
Biography^ a most laudatory notice by Mr. Swain- 
son, He tells us that Audubon contemplated Na- 
ture as she really is, not as she is represented in 
books : he sought her in her sanctuaries. Well, be 
it so ; I do not dispute his word ; still I suspect. 
