Page:A Voyage of Discovery and Research in the Southern and Antarctic Regions Vol 1.djvu/298

208 will, however, be difficult to get naturalists and philosophers to believe that these fragile creatures could possibly exist at the depth of nearly two thousand fathoms below the surface: yet as we know they can bear the pressure of one thousand fathoms, why may they not of two? We also know that several of the same species of creatures inhabit the Arctic, that we have fished up from great depths in the Antarctic, Seas. The only way they could have got from the one pole to the other must have been through the tropics; but the temperature of the sea in those regions is such that they could not exist in it, unless at a depth of nearly two thousand fathoms. At that depth they might pass from the Arctic to the Antarctic Ocean without a variation of five degrees of temperature; whilst any land animal, at the most favourable season, must experience a difference of fifty degrees, and, if in the winter, no less than one hundred and fifty degrees, of Fahrenheit's thermometer—a sufficient reason why there are neither quadrupeds, nor birds, nor land-insects common to both regions.