Colin Gum and the discovery of the Gum nebula

The research of Colin Gum in the field of astronomy is reviewed. It includes a radio survey at 200 MHz, a photographic survey for HII regions in the Southern Milky Way from longitude 220 deg to 20 deg, and a catalogue of 85 physically separate regions. He suggested that certain faint nebulosities were part of a large, nearby H II region excited by gamma Velorum and zeta Puppis. He was also concerned with 21-cm studies.