n'l, you take the brush and whitewash a narrow line right
behind my hand as I move the string round."

Dan'l stooped down and rapidly painted in the circle, as the Forecaster
moved the string.

"Next," said the Weather Man, "we'll make another circle, a little
closer in."

"At any special distance, sir?" asked Anton.

"No," was the reply. "It doesn't matter. Any distance at all will do."

A second, and again a third circle was thus made.

"Tie a piece of rope around the pole," was the next direction, "as high
as you can reach."

This only took a minute.

"Now, boys," the Forecaster said, "all that you have to do is to watch
when the shadow of the rope crosses those three circles. Put in a peg
this evening when it crosses the inside one, then the middle and then
the outside. To-morrow morning, mark with pegs the place where the
shadow crosses the same circles on the other side, only, of course, it
will cross the outer one first."

"Then what shall we do, sir?" asked Anton.

"Have you a long straight board?" he asked in reply.

"Plenty of them," the younger lad answered.

"Good. Well then, to-morrow morning lay that board so that its edge
touches the two points where the shadow of the rope on the pole crossed
the outer circle and let Dan'l whitewash a straight line joining the two
points. Do the same with the second and with the inside circles."

"Yes?" queried the lad eagerly, "and then?"

"You'll have three parallel lines," the Forecaster said, "the outer one
longer and the next two shorter. Bisect those lines. Do you know how to
do that?"

The younger lad shook his head.

"Only by measuring with a bit of string and doubling the string," he
said.

The Forecaster took a pencil and an envelope out of his pocket.

"It's quite simple," he explained. "Fasten a string to the peg at one
end of the line you want to divide in half. Stretch the string along the
line till you come to the end of this line. Then make a circle. Do the
same thing from the other end of the line. That will give you two
circles crossing one another. With the board, draw a straight line
joining the points where the circles cross.

"To be exact, bisect the line on the middle and on the inner circles in
the same way. You'll find they all come out the same. The bisecting
line, reaching from the pole, and crossing the bisected lines is called
the plane of the meridian. If I were you, I'd make that line a permanent
mark by pressing int