hardened by many sledges and they covered sixty kilometres. But the next day, and for days afterwards, they were on new snow. The work was harder and they went slowly. Usually, Perrault went in front, on snowshoes, flattening the snow a little for the dogs Francois stayed by the sledge. the two men changed places, but there were Sometimes many small lakes and rivers, and Perrault understood ice better. He always knew when the ice across a river was very thin.