ed his _Systema Naturae_, our task
would have been easily accomplished. How far do you suppose our travels
need to have extended?"

"I don't quite comprehend you, Alexis. How far?"

"Why, simply into the courtyard of our palace. It would have been only
necessary to kill and skin one of the great bears chained by the gate,
and that would have fulfilled all the conditions papa has imposed upon
us."

"And yet, I don't understand you," rejoined Ivan, with a puzzled look.

"How obtuse you are, brother! Read the letter again; note well its
terms!"

"Well, I understand them. We are to travel on, and not come home again
till we have killed a bear of every variety known."

"There--just so. Of course papa means every variety known to
naturalists,--that is, to the `scientific world,' as it is termed. Now
you comprehend my meaning?"

"Oh, yes!" answered Ivan; "you mean that when Linnaeus published his
`System of Nature,' only our own brown bear of Europe was known to
naturalists?"

"Precisely so--only the _ursus arctos_; and consequently we should have
had but a very short journey to make, compared with what is before us
now. It is true that previous to his death, the Swedish naturalist had
made the acquaintance of the `Polar' bear (_ursus maritimus_); but,
strange enough, he regarded this as a mere variety of the _ursus
arctos_--an error that one may wonder Linnaeus could have made.

"Oh, they are very different. I could tell that myself. To say nothing
of the colour, they are unlike in shape; and, as everybody knows, their
habits are very dissimilar. Why, one lives in forests, and feeds
chiefly upon fruits; while the other dwells amidst fields of snow and
ice, and subsists almost exclusively on flesh, or fish. Variety,
indeed! no, they are surely different species."

"Undoubtedly," answered Alexis; "but we shall have an opportunity of
comparing them hereafter. For the present we must drop the subject, and
find out the route of travel which papa has traced out for us."

"But he has not indicated any route--has he? He gives us permission to
go where we please, so long as we get the bearskins, and do not return
upon our meridian. We are not to take the _backtrack_--ha! ha! ha!"

"Of course not; but you will find, to avoid doing this, we shall have to
go by a definite course, and can take no other."

"By my word! brother, I don't see what you mean. I shall trust all to
you: so take me where you please-