A Figure standing firm on its Feet, makes an Equilibrium of all its Members, around the Central Line, on which it is sustain'd. A Figure therefore, thus steady, and thus balanced, stretching one of its Arms out from the Body, must at the same time shift so much of its weight to the opposite side, as is equal to that of the extended Arm: This must be understood of every part in general, sallying out beyond ordinary, from its whole.