Beitr\"age zur Algebra und Geometrie Contributions to Algebra and Geometry Volume 36 (1995), No. 1 On the Radial Ratio in Dense Mixed Sphere Packings Luis G. De Luc\'\i a Packings of $\Bbb E^3$ are constructed with balls of two radii, $1$ and $r<1$, with density higher than the sphere lattice packing density ($\delta ^3_L ={\pi \over \sqrt{18}}$) for every $r$ in the interval $(0.482\ldots ,0.577\ldots ]$.