  Previously unobserved nitrous oxide transitions around 2.5 $\mu$m are
measured by intracavity laser absorption spectroscopy (ICLAS) analyzed by
time-resolved Fourier transform (TRFT) spectrometer. With an accuracy of the
order of 10^-3 cm^-1, measured positions of 1637 assigned weak transitions are
provided. They belong to 42 vibrational transitions, among which 33 are
observed for the first time. These data are believed to be useful in particular
to monitoring atmosphere purposes.
