Portion of an illuminating device

FIG. 1 is a front perspective view of a portion of an illuminating device showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The unshaded interior faces of the base form no part of the claimed design. The broken line showing of the interior elements of the base, the large circle on the exterior face of the base, the seven circles on the exterior face of the base, the circumferential line on the head, and the remainder of the illuminating device is for illustrative purposes only and forms no part of the claimed design.