"Roentgen" induction coils and other X-ray apparatus
A 1903 trade catalogue issued by the James G. Biddle Company of Philadelphia, listing Roentgen induction coils and X-ray apparatus for physicians, hospitals, and electrical suppliers. Line engravings and halftones show glass X-ray tubes with printed maker's lettering, spark-gap terminals, and coils on wooden bases with knobs and binding posts, useful as isolated equipment silhouettes and stippled metal-and-glass texture.
