A form of ultraviolet microscope of the refracting type is described in which the source of radiation is a spark gap between fixed or rotating electrodes and the objectives are normally monochromats. The microscope is horizontal, thus avoiding the use of a mirror, and the fine motion mechanism responds to movements of 0.10 micron. Phase contrast may be used for visual scanning of the object and also for photography in the ultraviolet.The source of radiation can be supplied as a separate unit and used in conjunction with metallurgical microscopes of normal type to enable photographs of opaque objects to be taken in the ultraviolet.Some examples of microphotographs taken with the equipment described are appended, together with particulars.