"We might do that," said the Professor, "or they might be salted down, 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.