Lamp Electric Field Mark I

Lamp Electric Field Mark I
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The Lamp, Electric, Field, Mark I is a military signalling lamp used in the First World War. It consists of a rectangular metal housing and a fitting to allow its attachment to a tripod stand.

Description

Schematic of Lamp Electric Field Mark I

The lamp is rectangular in shape measuring approximately ??? wide, ??? tall and ??? long and weighing 12 lbs. 3 oz. It is carried in a leather case weighing 3 lbs. 7 oz. The lamp features three compartments, front, centre and rear. The sending key is enclosed in a watertight case and slides into a recess on the top of the lamp. It is connected to the lamp by eight feet of flexible lead to enable the key to be removed for working under cover. When not in use the lead is coiled up and carried in a recess beside the key. A sighting tub is fitted to the underside of the lamp for signalling purposes.^[1]

Front Compartment

The front compartment contains:

Three cells, electric, inert, "S," in series, carried in a compartment by themselves, with a drop door and catch.
The optical arrangement which consists of a 2 1/2-inch parabolic glass reflector, fitted in an aluminum tube. The electric bulb (3.5 volt) is held horizontally in a sliding carrier, which is clamped to an ebonite block on the outside of the tube by means of a milled clamping nut. The carrier is capable of movement for focusing purposes. The tube has, on the outside, a metal slide which fits into a dovetail and holds the tube in position.
A small terminal board of ebonite, with two terminals, and a brass tube which holds three spare lamp bulbs.
The sending key and leads.

Centre Compartment

The centre compartment contains:

Three cells, electric, inert, "S" (spare).

Rear Compartment

The rear compartment contains:

A small kerosene oil lamp for the use of the writer and caller. This lamp is detachable and has a drop cover with side pieces which act as a wind screen. The flame is protected by a mica window. A small quantity of oil is carried in a tin held in a recess on the right of the lamp.