English: Figure 4 illustrates a portable battery of twelve electro-photographic exposors; it consists of a rectangular box divided into compartments, open at the front and rear. In twelve of these compartments are arranged rollers, curtains, magnets, etc., as previously described, and a compartment through which a focusing lens is used. The two end compartments provide for the adjustment of the camera, which is supported in the box to the rear of the exposing arrangements. A cable of insulated wires for connecting the twelve magnets with the exposing motor, contains a wire for the return current. As seen in the engraving, seven of the magnets by the passage of their respective currents have completed their releasing operations. In the eighth compartment the two apertures in the exposing band are in the act of effecting an exposure. The remaining four magnets are awaiting their turn for action.