Approximately 2 1/2" high, 2 1/4" deep, 3 1/4" wide
The so-called glass blocks are one of the oldest known telegraph insulators dating to 1847. They were used in trees, crossarms & side brackets (see drawing on the next page) Most were found in the southeastern U.S. including a number of specimens which had never been used. Some styles were also made in porcelain. Many different colors and styles have been identified. The photo shows end, top, and side views of three different pieces.
Written Sunday, January 19, 1997; updated Tuesday, February 21, 2012