nd making notes,
and trying to find out reasons. He was never satisfied with knowing a
thing; he must always find out _why_ it was. One day I heard him ask
the captain what it was that made the sea so green in some parts of
those seas. Our captain was an awfully stupid man. So long as he got
plenty of oil he didn't care two straws for the reason of anything. The
young doctor had been bothering him that morning with a good many
questions, so when he asked him what made the sea green, he answered
sharply, `I suppose it makes itself green, young man,' and then he
turned from him with a fling.

"The doctor laughed, and came forward among the men, and began to tell
us stories and ask questions. Ah! he was a real hearty fellow; he would
tell you all kinds of queer things, and would pump you dry of all you
knew in no time. Well, but the thing I was going to tell you was this.
One of the men said to him he had heard that the greenness of the
Greenland Sea, was caused by the little things like small bits of jelly,
on which the whales feed. As soon as he heard this he got a bucket and
hauled some sea-water aboard, and for the next ten days he was never
done working away with the sea-water; pouring it into tumblers and
glasses; looking through it by daylight and by lamplight; tasting it,
and boiling it, and examining it with a microscope."

"What's a microscope?" inquired one of the men.

"Don't you know?" said Tom Lokins, "why it's a glass that makes little
things seem big, when ye look through it. I've heerd say that beasts
that are so uncommon small that you can't see them at all are made to
come into sight, and look quite big, by means o' this glass. But I
can't myself say that it's true."

"But I can," said Fred, "for I have seen it with my own eyes. Well,
after a good while, I made bold to ask the young doctor what he had
found out.

"`I've found,' said he, `that the greenness of these seas is in truth
caused by uncountable numbers of medusae--'"

"Ha! that's the word," shouted Tom Lokins, "Medoosy, that's wot the
captain calls 'em. Heave ahead, Fred."

"Well, then," continued Fred, "the young doctor went on to tell me that
he had been counting the matter to himself very carefully, and he found
that in every square mile of sea-water there were living about eleven
quadrillions, nine hundred and ninety-nine trillions of these little
creatures!"

"Oh! hallo! come now!" we all cried, opening our eyes very w