observations. "What was
it this morning?"

"I'll see, sir," said Tom, and hurried into the house for his book on
wind observations, which he had kept faithfully, though, in all the five
months of the League's work, there had been no opportunity to make use
of them.

"It was south--a quarter--east this morning," he answered quite
importantly.

"And what is the present velocity?" came the next query.

Tom ran up the short ladder to the dial of his Robinson anemometer or
wind-measurer. This consisted of four cup-shaped pieces of metal
fastened to four arms at right angles to each other, and set
horizontally in a socket. The force of the wind on the open cup-shaped
sides was so much stronger than on the convex or rounded sides that the
anemometer whirled around quite rapidly.

"Say," said one of the boys as he watched Tom, "I didn't know he had all
this down so pat! It's great!"

"Fourteen miles an hour, sir," said Tom, as he ran down the ladder, "by
the anemometer dial."

"Well," the Forecaster replied, "fourteen miles an hour is a good enough
breeze for kite-flying. How about it, boys? Shall we try a flight
to-day?"

"Oh, let's!" the boys exclaimed.

"Very well," said the Forecaster, "we'll put the kites together. Have
any of you ever seen a weather kite?" he queried.

"I've seen a picture of one, sir," said Fred. "I saw it in one of the
Weather Bureau booklets. It looked like a box with the ends knocked out.
Are these like that?"

"Yes," the weather expert replied, "all over the world the Hargrave or
box kite is used. There's a little difference in the methods of bracing
the frames, but the principle of them all is the same."

"Are they the best kites for lifting, sir?" asked Anton. "I saw a
picture, once, of a man being carried along the ground by a kite, but it
didn't look like this. It was like a lot of little triangles all piled
one on top of the other."

"That's a different kind," the Forecaster answered, "it's called a
tetrahedral kite, and was invented by Dr. Alexander Graham Bell. They
will lift a man quite easily. Owing to the form of construction, they're
much heavier and harder to handle and they won't go up as high. The box
kites fly higher and more easily. They'll go up even in the lightest
wind, and that's quite important, boys, because you must remember that
sometimes there's quite a strong wind in the upper layers of the air
when there's only a zephyr below. As you see, boys, this kite