The thermal emission spectrums (7.0 to 13.5 μ) of six selected areas on the lunar surface were measured from an altitude of 32 km and their spectral emissivities calculated. All spectrums show departures from black- or gray-body emission. Emissivities in the 8.0- to 9.0-μ region of the spectrum are significantly higher than those for wavelengths greater than 10 μ. Differences are noted in the wavelengths of peak emissivity, particularly between the highland areas and the maria. The interpretation of the differences in terms of lunar composition is discussed in part 2.