Hearne, who travelled very high north and northwest on the continent of America, details various facts in his journal, which strongly corroborate Symmes's position. Some of the facts he attempts to explain agreeably to his own ideas, and others he considers inexplicable. Among a great collection of facts, he states, that large droves of _musk-oxen_ abound within the arctic circle, few of which ever come so far south as the Hudsons-Bay factories. He mentions seeing in the course of one day, several herds of those animals, of seventy or eighty in a herd, in about latitude sixty-eight degrees. He states that the polar white bears are very rarely found by any of the Indians in winter; and that their winter retreats appear to be unknown;[6] that they are sometimes seen retiring towards the sea on the ice in autumn; and appear again in great numbers in the latter end of March, bringing their young with them. Hearne also states, that the white or arctic foxes are, some years, remarkably plentiful; and always come from the north; that their numbers almost exceed credibility; that it is well known none of them ever migrate again to the northward; and that naturalists are at a loss to know where they originate.[7] He also mentions that all kinds of game, as well as fish, in those high latitudes, are at some seasons excessively plentiful, and at others extremely scarce. These facts strongly corroborate the doctrine of a hollow sphere: otherwise, why should the rein-deer, and other animals, migrate north instead of south; as our Buffalo on the plains of Missouri do, when pressed with snow and cold weather? Instinct generally leads animals to fruitful and productive, rather than unproductive, regions; why then proceed north on the approach of winter, unless in expectation of finding a warmer climate, or, at least, a more mild and plentiful country, beyond the icy circle? Independent of the immense droves of rein-deer, great numbers of musk-oxen, white bears, and white foxes, spend their winters towards the north; which tends to establish the fact, that a considerable extent of land must exist in that quarter of the earth. This, however, would infringe on the space necessary to accommodate the vast quantities of fish which appear to be propagated in that region, if the old system were true. If we were to judge of the internal surface of the sphere, by its animal productions,――admitting that those animals heretofore enumerated, are propagated there,――we should conclude that the internal region of the earth is as much more favourable to the support of animal life, as the rein-deer is larger than our deer, and the white bear larger than our bear; and, consequently, we must conclude that there are more salubrious climates and better countries within, than any we have yet discovered without.