  New millimeter-wavelength emission lines are reported for the Cloverleaf
(H1413+117), a gravitationally lensed quasar at redshift 2.56. High
signal-to-noise ratio spectra of four lines in CO (J=3-2, J=4-3, J=5-4, and
J=7-6) have been obtained and are modeled using an escape probability
formalism. The line brightness temperatures are flat or rising between CO(3-2)
and CO(4-3) and then drop to the CO(5-4) and CO(7-6) lines; this falloff
suggests that the optical depths in the CO lines are modest (tau_{4-3} < 3),
and that the gas is relatively warm (T ~ 100 K) and dense (n_H2 > 3 X 10^3
cm^{-3}). The neutral carbon fine structure line CI(3P1-3P0) was detected with
moderate SNR on two separate occasions, and appears secure. The HCN(4-3) line
is somewhat more tentative, as it was observed only once and detected with
moderate SNR. However, its brightness ratio of 0.25 relative to the CO(4-3)
line is very similar to the ratio seen in luminous infrared galaxies. The
detectability of the Cloverleaf in molecular and neutral atomic transitions is
largely due to high emissivity of the gas and magnification from gravitational
lensing, rather than an extremely large mass of gas.
