  In unified models of active galaxies the direct line of sight to the nucleus
is unobscured only within a certain cone of directions. An opening angle for
this cone is usually estimated by methods such as the overall ratio of Seyfert
1s to Seyfert2s, the latter assumed to be obscured versions of the former. Here
we shall show, as has often been suspected, that the opening angle of the cone
depends on the luminosity of the central source, with higher luminosities
corresponding to larger opening angles. This conclusion depends only on the
assumption that the width of the broad emission lines at a given luminosity is
a measure of inclination angle, an assumption that is supported by observation
in radio-loud systems. On the other hand we show that the scatter in X-ray
spectral index is not primarily an effect of viewing angle, in contrast to what
might be expected if the scatter on the spectral index versus luminosity
relation were a consequence of absorption in the obscuring material. The
observed correlation between linewidth and spectral index appears to be a
further consequence of the dependence of opening angle on luminosity.
