On the Sublime and Beautiful/Part III/Chapter 22
Gracefulness is an idea not very different from beauty; it consists of much the same things. Gracefulness is an idea belonging to posture and motion. In both these, to be graceful, it is requisite that there be no appearance of difficulty; there is required a small inflection of the body; and a composure of the parts in such a manner, as not to encumber each other, not to appear divided by sharp and sudden angles. In this ease, this roundness, this delicacy of attitude and motion, it is that all the magic of grace consists, and what is called its je ne sçai quoi; as will be obvious to any observer, who considers attentively the Venus de Medicis, the Antinous, or any statue generally allowed to be graceful in a high degree.