Sterling Seiler’s Standard Glass Insulator Company Thomas-Houston Electric Company Thames Glass Works Twiggs Western Electric Manufacturing Company Western Glass Manufacturing Company Western Flint Glass Company Whitall Tatum Company Canada Diamond Dominion Hamilton Glass Works G.N.W.TEL. Co. International Agee (Australia) Isorex (France) Miva (Italy) Telgraficos Nacionales (Mexico) Zicme (South America) References External links National Insulator Association U.S. glass insulator reference site General Overview on Glass Insulators Overhead power lines Electric power distribution Ceramic engineering