One of the boys asked how sponges were obtained, and at what depths of water they were to be found.
HOW SPONGES ARE SPEARED.
The captain explained that they were found at all depths, from a few feet to two or three hundred. The most of them were taken from shoals and reefs, where they were ten or twenty feet below the surface, as they could not get a good supply of light in deeper water. In the East they are generally taken by diving, after the primitive fashion; while in the West Indies they are speared from boats.
"But we started out to talk about pearls," said Captain Johnson, "and we have wandered off to several other things. Suppose we go back to pearls, and see what we can ascertain about them."
The boys promptly agreed to this; and Frank was evidently determined to begin at the beginning, as he referred to the pearl which Cleopatra was said to have dissolved in vinegar, so that she might swallow a more costly drink than had ever been known to anybody else.
"That was more than eighteen hundred years ago," said Fred, "and perhaps the incident never happened."