The Hemingray Glass Co. was based in Muncie
, and operated from the early 1850s, until the late 1960s, producing different telegraph insulator
s. The most popular insulator Hemingray made was the Hemingray 42 (CD 154) which was produced by the millions. Another was the Hemingray No. 9 (CD 106) which was produced by the millions, also, but was less popular. When the company started, threadless insulators, (insulators that did not have threads inside) were used, most notably on the Transcontinental Railroad
Then during the early 1870s, the style of the insulator changed to fit a threaded pin after the previous design failed. Hemingray issued a patent on December 19th, 1871 for a group of insulators including the CD 120, CD 125, and others. These are considered some of the earliest threaded insulators in the collection, and are worth money. The company kept manufacturing these until the 1880s when drip points (bead-like orbs on the base of the insulator, allowing water to drip off of it) were invented, and the CD 151 started using them. This lead to a whole new era of insulators including the CD 152, CD 154, and many others. These insulators were in service for years and years, until the 1930s when some styles were being put out of manufacturing, and only a few select styles were being produced. This worked well until the late 1960s when the modern porcelain power insulators were to be used, and almost all glass insulators were put out of service.