Mk 1 Electric Signal Lamp

This lamp does not appear in the 1911 reprint of the 1907 Signalling Manual, but has four pages (pp. 92-94) devoted to it in the 1915 (Provisional) signalling manual, and its own six-page chapter (Chapter XII, pp. 214-219) in the 1917 Signalling Manual.

The Mk 1 was replaced by the Lucas Lamp, invented in 1916 by O.L. Lucas.

The Mk I is not mentioned in the May 1919 "Signal Training, Part I. Visual Telegraphy" - rather there is an 8 page chapter (Chapter 4, pp 49-56) devoted to the Lucas Lamp ( "Lamp, Electric, Signalling, Daylight, or Lucas Lamp."). and has 3 1/4 pages devoted to it in the 1917 Signalling Manual (Appendix II, pp. 247-250) as "The 'O.L.' Daylight Signalling or 'Lucas' Lamp. (First Pattern.)'