A Treatise on Painting/Chapter 62
Chap. LXII.—Of the Equipoise of Bodies, Plate V.
The balance or equipoise of parts in the human body is of two sorts, viz. simple, and complex. Simple, when a man stands upon his feet without motion: in that situation, if he extends his arms at different distances from the middle, or stoop, the centre of his weight will always be in a perpendicular line upon the centre of that foot which supports the body; and if he rests equally upon both feet, then the middle of the chest will be perpendicular to the middle of the line which measures the space between the centres of his feet.
The complex balance is, when a man carries a weight not his own, which he bears by different motions; as in the figure of Hercules stifling Anteus, by pressing him against his breast with his arms, after he has lifted him from the ground. He must have as much of his own weight thrown behind the central line of his feet, as the weight of Anteus adds before.