  In the powerful, high redshift radio galaxies, it is believed that the
dominant source of ionization for the interstellar gas is the hard radiation
field associated with the active nucleus. The photon source is generally
external to the clouds being ionized and so the geometrical perspective from
which the gas is observed and the presence and distribution of dust must be
properly accounted for in the diagnostic process. In this paper, we examine the
formation of the three strong lines: CIV$\lambda$1549, Ly$\alpha$ and
CIII]$\lambda$1909 which are often observed in the nuclear and extended
emission from these sources. We find that the observed trends, in particular
the high CIV$\lambda$1549/Ly$\alpha$ ratio, are often better explained by
geometrical (viewing angle) effects than by the presence of large quantities of
dust either within or outside the excited clouds. We show that neutral
condensations along the line-of-sight, by reflecting photons near the
wavelength of Ly$\alpha$, can increase the observed CIV/Ly$\alpha$ ratio. The
existence of HI absorption clouds (i.e., mirrors) external to the emission
region leads also to the presence of large, diffuse haloes of what appears to
be pure, narrow Ly$\alpha$ emission.
