The ornamental design for a base for microscope, as shown and described.
FIG. 1 is a perspective view of the base for microscope of the present invention shown with a microscope;
FIG. 2 is a perspective view of the base for microscope of the present invention;
FIG. 3 is a top plan view of the base for microscope;
FIG. 4 is a bottom plan view of the base for microscope;
FIG. 5 is a front plan view of the base for microscope;
FIG. 6 is a rear plan view of the base for microscope;
FIG. 7 is a left side view of the base for microscope; and,
FIG. 8 is a right side view of the base for microscope.
The broken line showing of a microscope affixed to the base for microscope of the present invention in FIG. 1 is for illustrative purposes only and forms no part of the claimed design.