The origin of such a floe dates back to a very remote period. That it was cradled in some deep recess of the land, and there remained until it had grown to such a thickness that no summer's sun or water's washing could wholly obliterate it before the winter cold came again, is most probable. After this it grows as the glacier grows, from above, and is, like the glacier, wholly composed of fresh ice,--that is, of frozen snow. It will be thus seen that the accumulation of ice upon the mountain tops is not different from the accumulation which takes place upon these floating fields, and each recurring year marks an addition to their depth. Vast as they are to the sight, and dwarfs as they are compared with the inland _mer de glace_, yet they are, in all that concerns their growth, truly glaciers--pigmy floating glaciers. That they can only grow to such great depth in this manner will be at once apparent, when it is borne in mind that ice soon reaches a maximum thickness by direct freezing, and that its growth is arrested by a natural law. [Sidenote: AVERAGE THICKNESS OF THE ICE.] This thickness is of course dependent upon the temperature of the locality; but the ice is itself the sea's protection. The cold air cannot soak away the warmth of the water through more than a certain thickness of ice, and to that thickness there comes a limit long before the winter has reached its end. The depth of ice formed on the first night is greater than on the second; the second greater than the third; the third greater than the fourth; and so on as the increase approaches nothing. The thickness of ice formed at Port Foulke was nine feet; and, although the coldest weather came in March, yet its depth was not increased more than two inches after the middle of February. In situations of greater cold, and where the current has less influence than at Port Foulke, the depth of the table will of course become greater. I have never seen an ice-table formed by direct freezing that exceeded eighteen feet. But for this all-wise provision of the Deity, the Arctic waters would, ages ago, have been solid seas of ice to their profoundest depths. The reader will, I trust, bear patiently with this long digression; but I thought it necessary, in order that he might have a clear understanding as well of our situation as of the character of these Arctic seas; in which I shall hope that I have inspired some interest. As for ourselves, we were struggling along through this apparently impassable labyrinth, striving to reach the coast which now began to loom up boldly before us, and thence stretching away into the unknown North, there receives the lashings of the Polar Sea. [Sidenote: SLOW PROGRESS.]