This resistance is due to the roughness of the surfaces; the minute projections upon each enter more or less into the minute depressions on the other, and when motion occurs these roughnesses must either be worn off, or continually lifted out of the hollows into which they have fallen, or both, the resistance to motion being in either case quite perceptible and measurable.
The frequent roughnesses of the traditional text suggest, however,that here and there marginal glosses may have crept in.
The shape and colour of these roughnesses depend on the nature of the underlying rock.
To the anatomist the roughnesses of the palm are of considerable interest.
How would you define roughnesses? Add your definition here.