hem. Only at the very apex of the mound there
was no mud, nothing but tangled sticks through which a breath of fresh
air found its way now and then. In spite of this feeble attempt at
ventilation I am obliged to admit that the atmosphere of the lodge was
often a good deal like that of the Black Hole of Calcutta, but beavers
are so constituted that they do not need much oxygen, and they did not
seem to mind it. In all other respects the house was neat and clean.
The floor was only two or three inches above the level of the water in
the angles, and would naturally have been a bed of mud; but they mixed
little twigs with it, and stamped and pounded it down till it was hard
and smooth. I think likely the Beaver's tail had something to do with
this part of the work, as well as with finishing off the dam, for he was
fond of slapping things with it, and it was just the right shape for
such use. In fact, I fear that if it had not been for the tail, and for
other tails like it, neither of the cities would ever have been as
complete as they were. With the ends of projecting sticks cut off to
leave the walls even and regular, and with long grass carried in to make
the beds, the lodge was finished and ready.

And now you might have seen the beavers coming home to rest after a
night's labor at felling timber--swimming across the pond toward the
island, with only the tops of their two little heads showing above the
water. In front of the lodge each tail-rudder gives a slap and a twist,
and they dive for the submarine door of one of the angles. In another
second they are swimming along the dark, narrow tunnel, making the water
surge around them. Suddenly the roof of the passage rises, and their
heads pop up into the air. A yard or two farther, and they enter the
chamber of the lodge, with its level floor and its low, arched roof. And
there in the darkness they lie down on their grass beds and go to sleep.
It is good to have a home of your own where you may take your ease when
the night's work is done.

Near the upper end of the pond, where the bank was higher, they dug a
long burrow, running back ten or fifteen feet into the ground. This was
to be the last resort if, by any possibility, the lodge should ever be
invaded. It was a weary task, digging that burrow, for its mouth was
deep under the water, and every few minutes they had to stop work and
come to the surface for breath. Night after night they scooped and
shovelled, rushing t