Rollo and Nathan measured with the reel and line, while Oliver planted a stake firmly in the snow at the four corners of the square.
According to Jonas's advice, the evening before, they had agreed to make their fortification twelve feet square, and the walls about one foot thick.
Rollo and Nathan held the cord, stretched from corner to corner, just along the surface of the snow, while Oliver, with the shovel, cut the snow square down to the ground, more than a foot and a half deep.
In this way they went round the whole enclosure, outside. They then went inside, and, by a similar process, cut away the snow so as to leave an unbroken line of snow wall about ten feet square and one foot wide.
"There," said Oliver, "there are the sills, as Jonas called them. It is what I call a good foundation."
After this, Oliver asked Rollo to bring in the measuring-board inside of the fort.
Oliver and Rollo remembered what Jonas had told them about "commanding and obeying," and agreed to take turns in being "director."
It was Oliver's turn for the first hour, and Rollo was to obey him. Nathan was to assist them both, when he was wanted.
Oliver, therefore, took the command, and directed where and how to cut out the snow, in the manner which Jonas had described.
They proceeded with the measuring-board, to mark off, and cut out by it, solid blocks of snow about four feet long, one foot wide, and one thick.