Abstract :
The paper opens with a discussion of the causes leading up to the general adoption of electric mine lamps, and an account is given of the awards in the Home Office prize competition of 1911. The evolution of the alkaline mine-lamp accumulator is next considered, and the principles of construction of Edison, Jungner, and Wolf accumulator plates are described. The stages are traced in the development of the Wolf alkaline lamp from 1912 to 1919, and the successive changes in the design of filling-hole stoppers and tools for handling, automatic devices for electrolyte level testing and filling, and prevention of alkali leakage, are discussed. The evolution of the two-part lamp is next considered, and improvements in contact plates, locks, locking systems, bulbs, and cover glasses, are examined. Comparative polar curves and Russell diagrams are given showing the advances in lighting values, and illustrations of typical ¿Schedule A¿ type electric hand-lamps are included. Reference is made to the present position regarding electric mine lamps with firedamp indicators. The final section of the paper deals with the new statutory mine lighting regulations.
