There are two patterns of aiming lamp in existence, the Mk. II (obsolescent) and the Mk. III which is the present service pattern. Both patterns are housed in wooden boxes which are stencilled with the appropriate designation.
The Mk. II aiming lamp consists of two lamps which are suitably housed in the box and connected to the batteries. A switch is provided which can be operated to illuminate either lamp separately or both lamps together, with an adjustable resistance to regulate the amount of light shown by the lamps. When in use the two lamps are fitted to the aiming posts, a length of cable housed on a drum in the lid of the box allowing electrical contact to be maintained when the box is positioned some distance from the post. The cable is wound by means of a folding handle on the side of the box.
The Mk. III aiming lamp has a hinged ground spike which folds against the box and is retained by a leather strap. The lamp is a proprietary electric cycle lamp, an amber celluloid disc being supplied to diffuse the light when necessary. Unlike the Mk. II, the box is left with the aiming post when in use, the lamp being operated by means of a 30 yards length of plaited fishing line. The line is connected to a switch rod which operates a ceiling type switch in the box which, in turn, is connected by flexible leads to the battery and lamp. A steel chain 30-in. long has one end secured to an eye in the box, the other end having a spring hook. The chain can be used for anchoring the box to any convenient post or object if the nature of the ground does not permit the use of the ground spike.
This lamp was used in conjuction with the bayonet for the .303-inch SMLE No. 1, Mk. III to create a basic aiming lamp. The war diaries of the Australian Machine Gun Battalions serving in the Far East record its use.
There are three patterns of aiming post in existence, the Mks. I and III being used in conjunction with the aiming lamps.The Mk. I (now obsolescent) is used with the Mk. II aiming lamp (also obsolescent) and consists of a telescopic stem which has at the bottom, a base plate with three ground spikes. The top portion of the stem slides in the lower portion and can be adjusted and secured at any convenient height. For day firing, a "U" bracket, having a disc fitted with a bulls-eye, is provided at the top of the stem, whilst for night firing the lamp is assembled to the bracket. A canvas cover, retained by a leather lace, is provided to cover the disc when the lamp is in use.
The Mk. II is used only by cavalry for day firing and consists of a stem constructed from two rectangular steel bars. The lower bar is pointed at the bottom to act as a ground spike, and has a stud at the top, whilst the upper bar is slotted to fit over the stud and clamped by means of a wing nut screwed on to the stud. It is fitted at the top with a white disc having a blank central disc 1-in. in diameter. The post can be folded in two for carrying purposes. No provision is made on this post for a lamp. The approximate weight is 8 ozs.
The Mk. III is designed for use with the Mk. III lamp; it has a triangular base with three ground spikes. The stem consists of two rectangular steel bars which are hinged by means of a stud and wing nut; a white aiming disc is riveted to the upper bar. A bracket riveted to the bottom of the bar allows the post to be used with the aiming disc in a lower position, this being possible by rotating the upper bar until it is at right angles with the lower bar and laying the post on its side, the bracket acting as a foot in conjuction with the side of the triangular base. The lamp is fitted at the extreme top of the post, and can be used with the post in the high or low positions. for storage the stem of the post is folded, a projecting bracket riveted on to the bottom of the stem protecting the aiming disc from damage during transit.
Specific source references can be provided if required.