Thoughts and purposes so incendiary as those I now cherished, could not agitate the mind long, without danger of making themselves manifest to scrutinizing and unfriendly beholders.
I had reason to fear that my sable face might prove altogether too transparent for the safe concealment of my hazardous enterprise.

Plans of greater moment have leaked through stone walls, and revealed their projectors.

But, here was no stone wall to hide my purpose.

I would have given my poor, tell tale face for the immoveable countenance of an Indian, for it was far from being proof against the daily, searching glances of those with whom I met.
It is the interest and business of slaveholders to study human nature, with a view to practical results, and many of them attain astonishing proficiency in discerning the thoughts and emotions of slaves.

They have to deal not with earth, wood, or stone, but with _men;_ and, by every regard they have for their safety and prosperity, they must study to know the material on which they are at work.