I found this book in my local library and found it most useful:

Tod, Jack H.
1977  A History of the Electrical Porcelain Industry in the United States.

It is published by the author out of Phoeniz AZ.

He has a short intro to the "electric age" and then goes into the types of
knobs, cleats, insulators, etc. made of porcelain and used in electricity.
Also has extensive info on the companies that made these artifacts, dates,
patent info, and lots of other data.

Mary Maniery
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