Now your line from the peep-hole to the cross wires must be parallel to the axis of the gun.
Its most important feature is the total elimination of cross wires, struts and the like.
And the forward sight will be a ring with cross wires in it.
Place the eye-piece with cross wires in the telescope, with the cross in the shape of an X.
It was here that the field-telegraph of the Royal Engineers became a tangled spider's web of wires and cross wires.
It will be observed that the wires C, D are larger than the cross wires F.