Patt.23/23A Stage Arc Spot (1919 - 1945)
15/20A carbon arc stage spot, slide focus
1919 - 1929:
Patt.23 - 15/20A Carbon Arc movement or 500/1000W (E40) 'pip'-up lamptray, slide focus (similar to Pattern 22, but of lighter construction). Replaced c.1930 by Patt.23A and Patt.43.
1930 - 1945:
Patt.23A - Introduced in this form c.1930, discontinued c.1945. 6 x 9 inch plano convex lens, planished steel cased version of the Patt. 23.