The third harmonic of the O [Single Bond] H band in formaldoxime vapor has been found to lie at lambda9572 (10,444.1 cm^—1) and under high dispersion has been resolved and found to resemble a parallel band of a symmetric rotator. Owing to the weakness of the lines near the center of the band a definitely unique rotational analysis could not be made but the harmonic mean of the two larger moments of inertia appears to lie between the limits 73.3 and 76.6×10^—40 g cm^2. The hydroxyl hydrogen does not rotate freely and indeed its torsional oscillation appears not to have a very low frequency. It is not possible to locate this hydrogen uniquely until other parameters of the molecule have been determined by electron diffraction. The possible effect of resonance on the O [Single Bond] H frequency is discussed
