.

"Now," Jack explained, "I am going to set this pail of water in your
kitchen window, by the sink. That will be our starting-point. Then I
want one of you boys to go, with a long-handled pitchfork, in the
direction of the spring, as far as you can and keep the pail in sight;
then set up your fork, and pin a piece of white paper on it just where I
tell you. As I raise my hand, you will slide the paper up; and, as I
lower my hand, you will slip it down."

Wad and Link both went with the fork, which they set up on the borders
of the woodland, back from the road. Then Wad, wrapping a piece of
newspaper about the handle, held it there as high as his head, with a
good strip of it visible above his hand.

Jack, standing in the kitchen, looked across the sights of his level
placed in the open window, and laughed.

"What do you think, Rufe? Is the paper high enough?"

"It ought to be a foot or two higher," was Rufe's judgment.

"_I_ say _a foot_ higher," remarked Lord Betterson, coming up behind.

"What do you say, Vinnie?"

"I think the paper is too high."

"Now look across the level," said Jack.

All were astonished; and Lord Betterson could hardly be convinced that
the level was constructed on sound principles. It showed that the top of
the paper should be just below Wad's knee.

"Now we will take our level," said Jack, after the paper was pinned in
its proper place, "and go forward and make another observation."

He chose a place at the top of the ridge beyond Wad, where, after
cutting a few bushes, he was able to look back and see the fork-handle,
and also to look forward and see the spring. There he set his pail on
the ground, waited for the water to become still, adjusted his level,
and caused a second strip of paper to be pinned to the fork-handle, in
range with the sights.

The boys then gathered around the fork, while Jack, taking a pocket-rule
from his coat, ascertained that the second paper was six feet and an
inch above the first.

"Which shows that our level is now six feet and an inch higher than it
stood on the kitchen window," said he. "Now let's see how much higher it
is than the spring."

Link was already on his hands and knees by the pail, turning the sights
in range with the spring on the farther side of the little ravine. He
suddenly flapped his arms and crowed.

"No need of setting the fork over there," he said. "The spring is
_almost_ as high as the pail!"

"Let's be exact," said J