  We observe spin transfer within a non-degenerate heteronuclear spinor atomic
gas comprised of a small $^7$Li population admixed with a $^{87}$Rb bath, with
both elements in their $F=1$ hyperfine spin manifolds and at temperatures of
10's of $\mu$K. Prepared in a non-equilibrium initial state, the $^7$Li spin
distribution evolves through incoherent spin-changing collisions toward a
steady-state distribution. We identify and measure the cross-sections of all
three types of spin-dependent heteronuclear collisions, namely the
spin-exchange, spin-mixing, and quadrupole-exchange interactions, and find
agreement with predictions of heteronuclear $^7$Li-$^{87}$Rb interactions at
low energy. Moreover, we observe that the steady state of the $^7$Li spinor gas
can be controlled by varying the composition of the $^{87}$Rb spin bath with
which it interacts.
