The self-stratification of binary and ternary granular mixtures has been
experimentally investigated. Ternary mixtures lead to a particular ordering of
the strates which was not accounted for in former explanations. Bouncing grains
are found to have an important effect on strate formation. A complementary
mechanism for self-stratification of binary and ternary granular mixtures is
proposed.Comment: 4 pages, 5 figures. submitted for pubication, guess wher