C E Addams was chief surveyor at De Beers Consolidated Mines Ltd, Kimberley, during the early years of the twentieth century. He served on the board of management of the Alexander McGregor Memorial Museum (now the McGregor Museum), Kimberley, from its foundation in 1907 until 1911, when he moved from Kimberley to the Voorspoed diamond mine near Kroonstad. By 1906 he was a member of the South African Association for the Advancement of Science and that year served as joint secretary of its Section B (which included geology) at the association's meeting in Kimberley. His membership had lapsed a few years later.
Addams was an important collector of rocks and minerals for the McGreggor Museum from its inception. In 1908 he presented a collection of samples from various De Beers mines. During the next few years he contributed diamond bearing rocks from the Du Toit's Pan mine (1910), samples from other diamond mines (1911), and specimens from the Voorspoed mine and nearby Lace mine (1912).