I located these two Hemingrey glass insulators yesterday when we were excavting a sinkhole on our city sno-mobile trail. Turns out there were two old stone and mason structures underneath that were starting to fill in with dirt from the trail after a series of heavy rains. I managed to rescue them before we had to fill in the structures to prevent further damage to our trail. I located several types of Hemingrey insulators on the internet but none exactly this style. I am trying to determine their approximate age. Any help out there?? ken