ts."

"I'd like to have a set, Ralph," said Ross promptly. "I hate to feel
like a dub and not know about the clouds. It's like not knowing any of
the stars."

"There certainly ought to be a set in the office of the _Review_,"
declared its editor-in-chief.

"I've been wondering," began Anton, "whether Mr. Levin wouldn't pick out
the best ones and tell us exactly what they are. I had an awful job
trying to get Ralph to bring his pictures to-day; he said he wanted to
wait until he had perfect ones."

"You'll wait a long time, my boy," the Forecaster put in, "if you wait
until you have a perfect set. I don't know of such a set anywhere in
the world. Clayden, in England, has got some fine examples--"

"It's his book I've got," interrupted Ralph.

"There are a few good pictures in that," the weather expert said.
"Loisel, in France, has some good examples and our own Weather Bureau
has done quite a little cloud work. But those I've seen of yours, Ralph,
are quite good. If you like, I'll go over them for you and pick out the
ones that are the most characteristic. Your plan to give a set to each
of the boys is quite worth while. Let's see the pictures, Ralph."

The "official photographer" pulled out, from a bulging inside pocket, a
large bundle of photographic prints and spread them on the table. The
collection included both the pictures Ralph had taken with his new lens
and some of the old ones intensified in the way that his visitor had
showed him. They made a striking contrast, in their vivid black and
white, to the cloud pictures, printed in a pale blue, issued by the
Weather Bureau.

"I think Ralph's pictures are away ahead of the Weather Bureau ones,"
declared Fred.

The Forecaster shook his head.

"Some of them are prettier pictures," he said, "but the Weather Bureau
sheet is chosen to help observers classify the clouds. If you notice
that blue sheet of cloud forms that Washington has issued, you'll notice
that they are very carefully selected and that you really can tell the
various types of cloud from them. At the same time, clouds are hard to
classify, because, at any given time, you're looking at a stretch of
sky--counting the separate layers of cloud--several hundred square miles
in extent, and, generally, there are many different types of cloud in
the sky at the same time."

"How many kinds of clouds does the Weather Bureau name?" asked Anton.

"Ten," was the reply. "There are lots of variations in th