Now, the colonel, while a very indulgent father, had pronounced views on the subject of negroes, having studied them, as he often said, for a great many years, and, as he asserted oftener still, understanding them perfectly. It is scarcely worth while to say, either, that he valued more highly than if he had inherited them the slaves he had toiled and schemed for.
“I don’t think it safe to take Tom up North,” he declared, with promptness and decision. “He’s a good enough boy, but too smart to trust among those low-down abolitionists. I strongly suspect him of having learned to read, though I can’t imagine how. I saw him with a newspaper the other day, and while he pretended to be looking at a woodcut, I’m almost sure he was reading the paper. I think it by no means safe to take him.”
These lines occur when Dick suggests that his attendant, Tom, travel north with him. Dick knows that Tom will take the chance to escape, and since doing things the easy way suits Dick, Tom is the logical choice for a companion. The colonel, however, thinks himself an authority on the people he enslaves and has assessed Tom as “too smart” to risk letting him go north.
This assessment implies the colonel’s belief that Grandison isn’t smart. One of the story’s amusing ironies is that Grandison intelligently puts his weeks in northern cities to good use, patiently laying the groundwork for his family’s escape from slavery. Because the colonel is so sure about his “studied” grasp of the slaves he “schemed for,” it never occurs to him to suspect Grandison. Moreover, Tom and perhaps others have apparently learned to read, yet the colonel “can’t imagine” that such a thing is possible under his watchful eye.
"I want to warn you, though, Grandison,” continued the colonel impressively, “against these cussed abolitionists, who try to entice servants from their comfortable homes and their indulgent masters, from the blue skies, the green fields, and the warm sunlight of their southern home, and send them away off yonder to Canada, a dreary country, where the woods are full of wildcats and wolves and bears, where the snow lies up to the eaves of the houses for six months of the year, and the cold is so severe that it freezes your breath and curdles your blood."
The colonel dispenses this advice after interrogating Grandison to determine whether he is “abolitionist-proof” and can go north with Dick. Grandison’s replies have already pleased the colonel’s “feudal heart” and assured him that Grandison accepts the “wise subordination and loyal dependence” slaves have for their masters.
Yet the colonel still thinks it necessary to frighten Grandison with exaggerated threats about Canada, much as a fairy tale about witches and ogres in the forest might have once been told to scare children into staying close to home. When Grandison plays along, pretending to fear that abolitionists might try to “steal” him, the colonel assures him he’ll be protected. Then, like a parent sending a child off with a sweet treat, he grants Grandison the day off and gives him some of his own tobacco. The exchange reveals the colonel’s inability to think of Grandison as a mature man as well as his vulnerability to deception when sufficiently flattered.