Long-time reader and commenter Eon took a closer look at yesterday’s photo and recognized what I had not – it isn’t a line-throwing rifle, it’s a light mounted under the barrel. His comment in full:
The “can” definitely has an electrical connection at its bottom rear. The double-stranded line from it leads to a switch on the right side of the forearm just where the fingers of the shooter’s left hand would be placed.
The wire continues back from there, past the trigger guard. Note the “loops” hanging down, which can be mistaken for a lever-action loop (which the Lebel doesn’t have). The line goes on from there, my SWAG is to a 6V battery “off-camera”, as they would say in Hollywood.
The “can” is most likely from either a French or British Aldis lamp. It’s a light, not a line canister. Note the “bolts” top and bottom; they’re the pivot trunnions for its usual mount. It’s turned 90 degrees from its usual “up and down” orientation (like cannon trunnions).
The switch on the forearm would normally be on the lamp’s mount, behind it. A message would be “tapped out” in Morse, as on a telegraph.
This rig is intended for two jobs, I suspect;
1. “Jacklighting” German soldiers trying to creep up on the position after dark. An anti trench-raid weapon.
2. “Jacklighting” rats in the trench itself.
The light going on in the target’s face would blind them, and probably “freeze” them, for a split second, just long enough for a shot.
In each case, the procedure would literally be “Flash!- BANG!”