to hide his coming. His plan was one in regard to
which he felt some guilty qualms. But he consoled himself with the
thought that whatever harm he might be doing to the little citizens of
the pond would be more than compensated by the protection he was
giving them. He was going to make a break in the dam, for the sake of
seeing just how the beavers would mend it.

On reaching the dam, however, it occurred to him that if he made the
break now the beavers might regard the matter as too urgent to be left
till nightfall. They might steal a march on him by mending the damage
little by little, surreptitiously, through the day. He had no way of
knowing just how they would take so serious a danger as a break in
their dam. He decided, therefore, to postpone his purpose till the
afternoon, so that the beavers would not come to the rescue too early.
In the meantime, he would explore the stream above the pond, and see
if there were other communities to study.

Skirting the hither side of the pond to near its head, he crossed the
little meadow and the canal, and reached the brook again about fifty
yards beyond. Here he found it flowing swift and narrow, over a rocky
bottom, between high banks; and this was its character for nearly half
a mile, as he judged. Then, emerging once more upon lower ground, he
came upon a small dam. This structure was not much over eighteen
inches in height, and the pond above it, small and shallow, showed no
signs of being occupied. There was no beaver house to be seen, either
in the water or on shore; and the water did not seem to be anywhere
more than a foot and a half in depth. As he puzzled over this--for he
did not think the beavers were likely to build a dam for nothing--he
observed a second and much larger dam far away across the head of the
pond.

Hastening to investigate this upper dam, he found it fully three feet
high, and very massive. Above it was a narrow but deep pond, between
comparatively steep shores; and along these shores he counted three
low-roofed houses. Out in the middle of the pond there was not one
dwelling; and he came presently to the conclusion that here, between
the narrow banks, the current would be heavy in time of freshet. The
lower dam, pretty obviously, was intended to reinforce the upper, by
backing a foot and a half of water against it and taking off just that
much of the pressure. He decided that the reason for locating the
three houses along the shore was that the