After we pulled it from the dirt...These insulators were made by the R Thomas and Sons co in 1902 era. This was likely the first cemented multipart made by Thomas. The glaze and clay body characteristics appear similar to the Thomas "Boch "patent insulators of the same era. Most appear to have been made "twice fired" first an unglazed bisque firing and then a glaze firing. The inner skirts of some appear to be of dry process porcelain.