The mean curvature of a Lipschitz contiunuous manifold.

The connection between the mean curvature in a distributional sense and the mean curvature in a variational sense is discussed. It is shown that under suitable assumptions, for $U$ open in $\Bbb{R}^{n+1}$ and $E\subset U$, a mean curvature measure of $\partial E$ exists and that the mean curvature measure of $\partial E$ is given by the weak limit of the mean curvatures of a sequence of $n$-dimensional regular manifolds $M_j$ converging to $\partial E$ (where weak convergence is understood in the sense of measures). The manifolds $M_j$ are related to the level surfaces of the variational mean curvature of $E$.