Douglass says that Mr. Gore was cruel, artful, and obdurate. What are the examples that Douglass gives for each of these adjectives about Mr. Gore?

From the text:

He was cruel enough to inflict the severest punishment, artful enough to descend to the lowest trickery, and obdurate enough to be insensible to the voice of a reproving conscience. He was, of all the overseers, the most dreaded by the slaves.