This folder contains correspondence relating to the business of Bergmann & Co. The company manufactured electric lighting fixtures, sockets, and other devices used with the Edison system of electric lighting, as well as equipment for the Edison phonoplex system of telegraphy. Most of the letters are by Joseph Hutchinson, secretary of the company, and Samuel Insull, general manager. Many pertain to the manufacturing and pricing of phonoplex devices and electric meters. Other correspondence concerns new types of insulating materials for electrical devices submitted to the laboratory for testing.

Approximately 30 percent of the documents have been selected. The following categories of documents have not been selected: routine correspondence relating to equipment orders and accounts; letters of transmittal.

Related material can be found in D-89-66 (Telegraph - Phonoplex) and in D-89-68 (West Orange Laboratory - General).