AUDITIONING AN INSULATOR
Final inspection is being made by this engineer before an insulator is subjected to high voltage electricity in a static test at the Westinghouse Porcelain Works at Derry, Pa.
A copper-screened laboratory keeps out all electrical interference while a radio noise meter auditions insulators.
A special glaze coating is applied to high voltage insulators to eliminate sparking that might interfere with good radio reception.
Original Caption by Science Service