He's up to something.

Don't you remember the captain told us he was a bad-tempered fellow ?" "What did he do ?" asked Corny, looking back at the Indian, who now stood in the road, a short distance from the wall, regarding us very earnestly.
"Well, he never did anything, much," I said.

"He seemed to be angry, once, because we would not buy some of his things, and the captain said he'd have him told not to worry us.

That may have made him madder yet." "He don't look mad," said Corny.
"Don't you trust him," said Rectus.
"I believe all these Indians are perfectly gentle, now," said Corny, "and father thinks so, too.

He's been over here a good deal, and talked to some of them.