Insulators

Insulators were originally made to keep telegraph and telephone wires electrically insulated from wooden telephone poles (especially important in the rain). With the additional needs of rural electrification, there was a big insulator boom in the early 20th century, peaking from the 1920s through the 1940s, with production in the millions per year.

Made from glass or porcelain, in a dazzling array of shapes and colors (e.g. amber, cobalt blue, green, purple), they’re prized for color, beauty, and rarity. Collectors identify insulators by manufacturer (e.g. Hemingray) and by CD numbers, which are based on shape...