[ ELECTROMEDICAL APPARATUS-NAMELY, ] X-RAY TUBES [ AND APPARATUS INCLUDING AUTO-TRANSFORMERS FOR X-RAY TUBES, CONVERTERS FOR X-RAY TUBES, VIEWING LANTERNS FOR X-RAY TUBES, X-RAY TABLES, FILMHOLDERS AND SUPPORTS THEREFOR, X-RAY STANDS, X-RAY SCREENS AND HOLDERS THEREFOR, PHOTOGRAPHIC APPARATUS FOR X-RAY FILMS,X-RAY FILTERS, RECTIFIERS FOR SUPPLYING X-RAY TUBES WITH DIRECT CURRENT]