round channel."

"How far do you think the cave goes in?"

"That is one of the impossible things to say. It may extend for miles.
Like yourselves, I am curious to know all about it, as soon as we can
make further investigations. In the meantime, don't forget about the
flag."

"I had forgotten that. I am willing to start on it in the morning. How
large should it be made?"

"We should make it a regulation flag, by all means."

"Let me see; how many stripes must we have?" said Harry.

"I know; thirteen."

"Yes; and they must be red and white."

"That is correct," responded the Professor; "but do you remember how
many of each?"

The boys were silent.

"The top and the bottom stripes are red, and the intervening ones white.
What do these stripes represent?"

"The original States."

"I see you have a pretty good recollection. I remember a class of over
forty boys, on one occasion, which had only three boys who recalled
that. Then we must have a field of another color, up in the corner."

"That is the blue field, with stars on it."

"Yes; but how many stars?"

"A star for each State."

"And how many States are there now?"

There was no response to this. How many boys or men, even, can tell
offhand the number at the present time?

"There were 48 before we sailed. How many, if any, were added since I do
not know."

The next day the boys were anxious to set to work on the flag. There was
plenty of the ramie cloth at hand, but it was quite yellow. George
noticed this, and said: "It seems to me we shall have to be content with
making the flag red, yellow and blue, that is, if we can get the red and
the blue."

"No," was the Professor's rejoinder; "we must make it red, white and
blue."

"But how can we make the ramie cloth white?"

"By bleaching it."

That was a new idea; to make white cloth.

"How can we do it?"

"Wet it and put it in the sun. If we want to hurry it up we can use some
chloride of lime."

"But where is the chloride of lime?"

"Do you remember that black ore we have in the laboratory, which is
called manganese? If we put some of the sulphuric acid on that a gas
will be formed, called chlorine, one of the most powerful bleaching
compounds known. We can use it in that form, or subject some of our lime
to the gases, and in that case make chloride of lime."

The decision was to make the flag sixteen feet long and nine feet nine
inches wide, so that each stripe would be nine inches