Electrical novelties : the ultra vacuum electrodes, X-ray tubes and stands, the multiple spark interrupter, spark lamp to produce violet rays, spark regulator for coil, electric heaters, X-ray plates
A 1903 trade catalogue issued by the Swett & Lewis Company of Boston to sell X-ray tubes, vacuum electrodes, spark interrupters and stands to physicians and electrotherapy practitioners. The plates mix halftone photographs with fine line engravings of blown-glass bulbs, slim tubular electrodes and cast-iron adjustable stands, numbered for ordering, giving designers isolated instrument silhouettes and hatched glass-and-metal textures on plain grounds.
