FIG. 1 is a perspective view of a first part of the lamp showing my new design; FIG. 2 is a front elevational view of the lamp part shown in FIG. 1; FIG. 3 is a rear elevational view of the lamp part shown in FIG. 1; FIG. 4 is a left side elevational view of the lamp part shown in FIG. 1; FIG. 5 is a right side elevational view of the lamp part shown in FIG. 1; FIG. 6 is a top plan view of the lamp part shown in FIG. 1; and, FIG. 7 is a bottom plan view of the lamp part shown in FIG. 1. The broken lines shown are for illustrative purposes only and form no part of the claimed design.