The ornamental design for a lampbase, as shown and described.
FIG. 1 is a top plan view of a lamp base showing my new design;
FIG. 2 is a front elevational view thereof, the rear view being identical;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a fragmentary side elevational view thereof, the lower portion of
the base being omitted for convenience of illustration, the opposite side
of the upper portion being a mirror image of the side shown;
FIG. 5 is a cross-sectional view of the upper portion of the base as taken
along line 5--5 of FIG. 1.