Page:A Treatise on Electricity and Magnetism - Volume 2.djvu/288

 Rh Rhand the tangential stresses disappear.

The stress in this case is therefore a hydrostatic pressure $$\frac{1}{8\pi}\mathfrak{H}^2$$, combined with a longitudinal tension $$\frac{1}{4\pi}\mathfrak{BH}$$ along the lines of force.

643.] When there is no magnetization, $$\mathfrak{B} = \mathfrak{H}$$, and the stress is still further simplified, being a tension along the lines of force equal to $$\frac{1}{8\pi}\mathfrak{H}^2$$, combined with a pressure in all directions at right angles to the lines of force, numerically equal also to $$\frac{1}{8\pi}\mathfrak{H^2}$$. The components of stress in this important case are

The force arising from these stresses on an element of the medium referred to unit of volume is

where $$m$$ is the density of austral magnetic matter referred to unit