ing as far down in the earth as they could get.
Nor were the German guns idle all this while. Far-away they lay in their coverts, hidden from the view of passing aviators by a generous use of tree branches and painted canvas. Monster shells were passing through the air at all times, and at great altitudes, since they were meant to fall miles and miles distant.
We-ee!
"Great Scott! What's that?" yelled Tom, but without being heard.
It was one of the great shells whistling past the plane in which Tom and the grizzled sergeant were seated. It came so close to them that the machine rocked violently. Tom felt cold at the thought of what would have happened had it by some mischance actually struck their plane.
"Some escape!" murmured the young aviator.
Here and there far down below him he saw spurts of flame bursting out from behind what he knew to be woods. Here there must be batteries in hiding, now taking part in deluging the German front with a hurricane of iron.
Meanwhile that wave of Frenchmen, their overcoats with the fronts fastened back so as to leave their knees clear, kept on advancing steadily. They would arrive at the enemy trenches presently, when those in hiding would
