Richmond, VA c.1865 Civil War Afermath Threadless Hats
By Joe Maurath, Jr.; posted May 13, 2013 View Original: Click to zoom, then click to magnify (961 x 691) 240KB
Clearly this pole survived the blazing assault upon this city since (surprisingly!) this pole and its adjacent street lamp still remain.
The insulators appear to be dark colored glass threadless hats (upon close inspection of the original photo).