  Sapphire and rubies (undoped and Cr-doped $\alpha$-Al$_2$O$_3$ single
crystals) have been deformed in compression at temperatures lower than those
previously used in studies of dislocations in the basal slip plane (see part
I). Above 1400$^\circ$C, several features associating stacking faults out of
the basal planes and partial dislocations (dissociation, faulted dipoles) have
been observed in previous transmission electron microscope investigations. The
formation of these features involves climb controlled by atomic diffusion.
Properties of climb dissociated dislocations are discussed in relation with
dislocation dynamics. TEM examination of dislocation structures at lower
deformation temperatures (1000-1100$^\circ$C) shows that similar features are
formed but that they often imply cross-slip. A new mechanism for the formation
of faulted dipole by glide is presented and an explanation for the 30{\deg}
Peierls valley orientation is proposed. The presence of chromium has a small
influence on stacking fault energies on planes perpendicular to the basal
plane.
