n,
and that would not necessitate the receptacles, if we dried them."

The salted fish did not appeal to either of the boys, and it was
accordingly agreed to put up several packages for food.

"Will it be much trouble to preserve them by putting them in cans?"

"If proper precautions are taken they can be preserved. The difficulty
is that the air is not excluded, and the mischief is caused by the gases
which form, in that case, and when the pressure becomes too great the
receptacle bursts."

"Why are the fish, or other substances, so canned heated and put into
the cans while in that state?"

"When a can is filled with the material in a heated state it has been
expanded to its highest point, and after the package is sealed properly,
no air can enter it, so that it is prevented from changing its condition
by any chemical action. Our difficulty will be to get a proper metal for
the cans."

"What is the best to use?"

"Tin, for the reason that tin is not affected by any of the acids which
are formed by fish or by fruit, which may be put in them."

It has been stated that the boys were both musically inclined, and
George had taken several courses of lessons on the violin before he
joined the training ship. If there was anything more than another that
was missed, particularly in the evenings, it was the lack of musical
instruments, to which all had been accustomed. As a result, the boys had
for some time worked on a violin, which was now nearing completion, and
they hoped it could be finished before the start was made.

The Professor discovered the partly constructed violin, and at once
showed his appreciation of their enterprise. "Now that you have the
body, what are you going to do for strings?" and he laughed at the
bewildered look. They had forgotten the one essential thing.

Without a word, he left them, and when he returned, held in his hand a
dozen or more hard, bony-like and dried-up reeds. "Possibly these will
do for your purpose."

"What are they?"

"These are the intestines of the wildcat we shot about ten months ago."

"Well, aren't they as good as the intestines of the common cat?"

"Undoubtedly; but violin strings are not produced from that source."

"Aren't they known as catgut?"

"That is true; but it is a mistake. The strings of commerce are made
principally from the intestines of sheep, and, singularly, have been
always designated as 'catgut.' Other articles from the same source are
hatte