Although the Am stars have smaller true rotational velocities than the normal A stars (Abt & Moyd 1973), o Peg, 68 Tau, and 15 Vul being some of the most sharp-lined have one of their rotational poles pointed close to the line of sight. If photometric variability is due to different parts of the surface appearing in and disappearing from the observed hemisphere, this will only happen near the limb where limb darkening reduces the effect. If the changes in the surface composition and magnetic fields occur over a time long compared to the human life span as is thought based on various radiative diffusion scenarios, then these stars are among the worst cases to look for intrinsic variability among the Am stars. However, if this paradigm changes, then the lack of photometric variability for at least the sharp-lined Am stars acts as a constraint for alternative points-of-view.
Similar considerations apply to the HgMn stars. In both types of
stars, searches for photometric variability should be concentrated on those
stars with the largest values of 
. It is also desirable to work
with stars which have suitable photometric comparison stars.
Acknowledgements
This work was supported in part by NSF grant AST-9115114 to The Citadel and in part by grants from The Citadel Development Foundation. I appreciate the continuing efforts of Louis J. Boyd and Robert J. Dukes Jr., to keep the FCAPT operating properly.