The men, hot under the July sun, threw aside their coats, and the officers, putting their own hands to the work, did likewise.

There was a continuous ring of axes, and the air resounded with the crash of trees falling in hundreds and thousands.
The tops and ends of the boughs were cut off the trees, the ends left thus were sharpened and the trees were piled upon one another with the sharp ends facing the enemy who was to come.
Robert watched as these bristling rows grew to a height of at least nine feet, and then he saw the men build on the inner side platforms on which they could stand and fire over the crest, without exposing anything except their heads.

In front of the abattis more trees with sharpened boughs were spread for a wide space, the whole field with its stumps and trees, looking as if a mighty hurricane had swept over it.
Robert was soldier enough to see what a formidable obstruction was being raised, but he thought the powerful artillery of the attacking army would sweep it away or level it.

He did not know that the big guns were being left behind.

In truth, Langy's first news that the cannon would not be embarked upon the lake was partly wrong.