s two or three inches
thinner than elsewhere, which made them think that there was an inlet
there. They also showed me in another place what they thought was a
"leach-hole," through which the pond leaked out under a hill into a
neighboring meadow, pushing me out on a cake of ice to see it. It was a
small cavity under ten feet of water; but I think that I can warrant the
pond not to need soldering till they find a worse leak than that.
One has suggested, that if such a "leach-hole" should be found, its
connection with the meadow, if any existed, might be proved by conveying
some, colored powder or sawdust to the mouth of the hole, and then
putting a strainer over the spring in the meadow, which would catch some
of the particles carried through by the current.

While I was surveying, the ice, which was sixteen inches thick,
undulated under a slight wind like water. It is well known that a
level cannot be used on ice. At one rod from the shore its greatest
fluctuation, when observed by means of a level on land directed toward
a graduated staff on the ice, was three quarters of an inch, though the
ice appeared firmly attached to the shore. It was probably greater in
the middle. Who knows but if our instruments were delicate enough we
might detect an undulation in the crust of the earth? When two legs of
my level were on the shore and the third on the ice, and the sights
were directed over the latter, a rise or fall of the ice of an almost
infinitesimal amount made a difference of several feet on a tree across
the pond. When I began to cut holes for sounding there were three or
four inches of water on the ice under a deep snow which had sunk it
thus far; but the water began immediately to run into these holes, and
continued to run for two days in deep streams, which wore away the ice
on every side, and contributed essentially, if not mainly, to dry the
surface of the pond; for, as the water ran in, it raised and floated the
ice. This was somewhat like cutting a hole in the bottom of a ship to
let the water out. When such holes freeze, and a rain succeeds,
and finally a new freezing forms a fresh smooth ice over all, it is
beautifully mottled internally by dark figures, shaped somewhat like a
spider's web, what you may call ice rosettes, produced by the channels
worn by the water flowing from all sides to a centre. Sometimes, also,
when the ice was covered with shallow puddles, I saw a double shadow of
myself, one standing on