Apparatus for distinguishing japanese pearls with a mother-of-pearl core from real natural pearls

摘要

267,462. Nacken, R., (Assignee of Jaeger G.). March 9, 1926, [Convention date]. Addition to 254,307. Drawings to Specification. Inductances and capacities, measuring; magnetic tests. - Apparatus for distinguishing Japanese pearls with a mother-of-pearl core from natural pearls according to the method set forth in the parent Specification comprises two oscillatory circuits tuned somewhat in resonance with one another and in the electro-magnetic or electro-static field of one of which the pearl is relatively moved. Change in the interference note between the two circuits as distinguished by a telephone introduced into one of the circuits is heard only in the case of a Japanese pearl with mother-of-pearl core.