Call of the Wild
Need a question answered for Call of the Wild
What are the contradictions in these sentences?
"Francois knew he was behind all the trouble, and Buck knew he knew; but Buck was too clever ever again to be caught red-handed. He worked faithfully in the harness, for the toil had become a delight to him; yet it was a greater delight slyly to precipitate a fight amongst his mates and tangle the traces."