Ultra-violet microscopy

The paper describes experiences encountered in trials of various methods of ultra violet microscopy. The selection with the aid of the interferometer of the fused quartz for the objective; the arrangement of the illuminating systems; old and new methods of finding the ultraviolet focus; the mechanical requirements of the microscope; the control of the immersion fluid by the use of non-hygroscopic mixtures, and the investigation of the resolving power of ultra-violet systems, are among the subjects discussed.