Significados de extreme slightness en inglés

One instance will show the extreme slightness which characterizes many of the grounds of inculpation:-

Her body and limbs, notwithstanding her extreme slightness, were graceful, perhaps, but with the grace of the tigress.

The point to which I want to draw your attention is the extreme slightness and smallness of the revolver with which Mrs. Heredith was killed.