Old and beat-up CD 126 Brookfield with early "slip" type wire tie. When constructing lines through forested areas, early line crews learned quickly that tying the line wire directly to the insulator usually resulted in the wire being broken, ripped from the tie, or yanking the pin off the tree, all due to wind, snow, or a toppled tree landing on the line. The slip tie with just a loose loop around the line wire allowed movement in the wind, or even the advantage of having the line wire pull off the insulator, rather than the wire snapping with a heavy pull. Depending on conditions, some telegraph circuits would actually still function with the wire laying on the ground for a few spans There have been insulators found where the lineman has turned the insulator into a "spool" by breaking the top off the dome and running the line wire through the pinhole. I'm sure a supply of the later-day "split-spool" tree insulators would have been a welcome item for those pioneer construction crews.