"I can enlighten you on that too," replied the Doctor. "There are a great number of memorable winters, which appear to have come at intervals of about forty-one years. In 1364, the Rhone was frozen over as far as Arles; in 1408, the Danube was frozen throughout its entire extent, and the wolves crossed the Cattigut on firm ground; in 1509, the Adriatic and the Mediterranean were frozen at Venice and Marseilles, and the Baltic on the 10th of April; in 1608, all the cattle died in England from the cold; in 1789, the Thames was frozen as far as Gravesend; and the frightful winter of 1813 will long be remembered in France. The earliest and longest ever known in the present century was in 1829. So much for Europe." "But here, within the Polar circle, what is the lowest degree?" asked Altamont. "My word!" said the Doctor. "I think we have experienced the lowest ourselves, for one day the thermometer was 72 deg. below zero, and, if my memory serves me right, the lowest temperature mentioned hitherto by Arctic voyagers has been 61 deg. at Melville Island, 65 deg. at Port Felix, and 70 deg. at Fort Reliance." "Yes," said Hatteras, "it was the unusual severity of the winter that barred our progress, for it came on just at the worst time possible." "You were stopped, you say?" asked Altamont, looking fixedly at the captain. "Yes, in our voyage west," the Doctor hastened to reply. "Then the maximum and minimum temperatures," said Altamont, resuming the conversation, "are about 200 deg. apart. So you see, my friends, we may make ourselves easy." "But if the sun were suddenly extinguished," suggested Johnson, "would not the earth's temperature be far lower?" "There is no fear of such a catastrophe; but, even should it happen, the temperature would be scarcely any different." [Illustration: ] "That's curious." "It is; but Fourrier, a learned Frenchman, has proved the fact incontestably. If it were not the case, the difference between day and night would be far greater, as also the degree of cold at the Poles. But now I think, friends, we should be the better of a few hours' sleep. Who has charge of the stove?" "It is my turn to-night," said Bell. "Well, pray keep up a good fire, for it is a perishing night." "Trust me for that," said Bell. "But do look out, the sky is all in a blaze." "Ay! it is a magnificent aurora," replied the Doctor, going up to the window. "How beautiful! I never tire gazing at it." No more he ever did, though his companions had become so used to such displays that they hardly noticed them now. He soon followed the example of the others, however, and lay down on his bed beside the fire, leaving Bell to mount guard. CHAPTER X. WINTER PLEASURES It is a dreary affair to live at the Pole, for there is no going out for many long months, and nothing to break the weary monotony.