  We show how the observed hydrogen Balmer and Lyman emission lines constrain
the modeling of quiescent solar prominences. We compare space observations of
Lyman lines with ground-based observations of Balmer lines for quiescent solar
prominences of comparable brightness defined by their H-beta emission. The
effective number densities of hydrogen atoms emitting from the same upper level
u deduced from the corresponding emerging Lyman and Balmer line emissions show
large differences that diminish with increasing level number and converge at
the highest level numbers. Hydrogen atoms excited in u=5 contribute 250 times
less, and those in u=8 still contribute 65 times less to the Lyman than to the
corresponding Balmer emission, supporting the idea of distinct spatial origin
of the emissions of both series. This is also indicated by the line widths. The
high optical thickness of all Lyman members allows the brightness temperature
T_b to be estimated from the spectral radiance at line center, where T_b is
found to be largely independent of the upper level number, in contrast to the
(known) behavior of the Balmer lines.
