It is shown that the ultraviolet absorption bands reported previously do not belong to acetylene but to some impurity. In pure acetylene, bands are observed only below 2400A. These bands are arranged into three progressions and their interpretation is proposed using information from the work on the infrared absorption spectrum of acetylene.

• Received 26 December 1930

DOI:https://doi.org/10.1103/PhysRev.37.276