Here is a neat item -- is an early signal with a wire holder marked U.S. PAT JUN 30 14 -- Interestingly enough, this patent is not in the insulator.info data base. A google search found it:

M. G. KENNEDY patent for a CONDUCTOR CLAMP., APPLICATION FILED AUG. 22, 1910.

US Patent #1,101,802, Patented June 30,1914.

I believe the insulator was original with the attached clamp. Figure $25 plus postage.