Pair of mica vanes suspended on a filament within a rectangular steel chamber. Filament broken. Chamber walls approximately 1.5 cm thick. Pierced with three circular windows covered by glass plates. Inverted glass cup with stop clock and lead to rubber tubing mounted on top of chamber. Chamber rotates on tribrach base with leveling screw feet. In use, air in chamber would have been evacuated until pressure reached about .02 mm Hg. For studying infrared absorption spectra.
