  We extend V. Arnold's theory of asymptotic linking for two volume preserving
flows on a domain in ${\mathbb R}^3$ and $S^3$ to volume preserving actions of
${\mathbb R}^k$ and ${\mathbb R}^\ell$ on certain domains in ${\mathbb R}^n$
and also to linking of a volume preserving action of ${\mathbb R}^k$ with a
closed oriented singular $\ell$-dimensional submanifold in ${\mathbb R}^n$,
where $n=k+\ell+1$. We also extend the Biot-Savart formula to higher
dimensions.
