Abstract
The infra-red absorption bands of hydrogen sulphide in the regions of 4.2, 5.6, and 8.0μ were investigated by means of a prism-grating spectrometer. A narrow, intense absorption band was observed at 4.2μ, but could not be resolved. The 5.6μ band observed by Coblentz was not found. Evidence is presented to show that the band observed by Coblentz might have been due to an impurity. Thirty-four lines of the band in the region of 8.0μ were observed.