[Gk. mikros, small; and skopein, to see.] An instrument for viewing objects which are too small to be seen with the naked eye. A simple microscope consists of a tube having one convex lens, which magnifies the object; while a compound microscope has two convex lenses in a tube, one of which is called the object-glass, and the other one the eye-glass. In the compound microscope the thing looked at is first magnified by the object-glass, and this is again magnified by the eye-glass. The micro-scope is an interesting and wonderful instrument, and by its means many living things invisible to the naked eye are revealed. The microscope is also applied to the study of rock structure by grinding down the stone to thin sections. Preparations for the microscope are preserved on glass slips (3x1 in.) covered by very thin glass fastened by Canada balsam or shellac.