New, high-precision measurements of the R branches of the ν1 + 2ν2 + ν3 and 2ν1 + 3ν3 bands of CO2 in the Martian spectrum (1.05 and 1.038 μ) are reported. The resolved lines yield 75 to 77 m-atm for the abundance of CO2 and an effective atmospheric temperature of 199 ± 17°K. It is found that the observations are best satisfied by an atmosphere with a constant lapse rate, a maximum air temperature of 310°K at the surface, and 78 m atm of CO2. The lapse rate corresponds to the adiabatic lapse in a CO2 atmosphere. The surface temperature is in agreement with recent estimates based on radiometric observations of the planet. Our best estimate of the CO2 abundance is 78 ± 11 m atm (partial pressure 5.5 ± 0.8 mb). The surface pressure remains uncertain, its value lying between 5.7 and 10 mb. It is suggested that observations of the ν1 + ν3 band of CO2 at 12 µ would lead to the most reliable value for the surface pressure. An attempt was made to measure pressure differences between certain areas and thereby deduce the corresponding height differences. The results are negative, but the method is shown to have a height resolution of 2 km or better.