The ornamental design for a lampbase, substantially as shown and described.
FIG. 1 is a perspective view of the top, front and right side of a lamp
base showing my new design, a conventional shade being shown in phantom
lines and forming no part thereof;
FIG. 2 is a left side elevational view thereof on an enlarged scale;
FIG. 3 is a rear elevational view thereof on an enlarged scale;
FIG. 4 is a bottom plan view thereof on a reduced scale.