Bobby began chopping off as large pieces as he thought he could conveniently handle. The ice was exceedingly hard and brittle. It had frozen centuries before, under the extremely low temperatures of the Arctic regions. It had its beginning, perhaps, in snow deposited in some far-off Greenland valley. Other snows had come upon it, and still other snows, until a tremendous weight of snow pressed it, as it froze, into a glass-like hardness.