THE ROOSEVELT'S ESCAPE 173 



strong and stiff, with a cutting edge on one side and saw- 

 teeth on the other. The blocks of snow are of different 

 sizes, those for the bottom row being larger and heavier 

 than those for the upper rows, and all are curved on 

 the inner side, so that when set together they will form 

 a circle. The thickness of the walls depends upon the 

 hardness of the snow. If it is closely packed, the walls 

 may be only a few inches thick; if the snow is soft, the 

 blocks are thicker, that they may hold their shape. 

 The blocks for the bottom layer are sometimes two or 

 three feet long and two feet high ; but sometimes they 

 are much smaller, as there is no ironclad rule about it. 



When sufficient blocks have been cut to make an 

 igloo, an Eskimo takes his position on the spot (usually 

 a sloping bank of snow) which is to be the center of 

 the structure. Then the others bring the snow blocks 

 and place them end to end, on edge, to form an egg- 

 shaped ring about the man in the center, who deftly 

 joints and fits them with his snow knife. The second 

 row is placed on top of the first, but sloping slightly 

 inward; and the following rows are carried up in a 

 gradually ascending spiral, each successive layer lean- 

 ing inward a little more, and each block held in place 

 by the blocks on either side, until finally an aperture 

 is left in the top to be filled with one block. 



This block is then properly shaped by the man inside 

 the igloo; he pushes it up endwise through the aperture, 

 turns it over by reaching through the top, lowers it into 

 place, and chips off with his knife until it fits the hole 

 like the keystone of an arch, firmly keying the structure, 

 whose general proportions are not unlike those of 

 a beehive. 



