Research Division

Reprinted from "INSULATORS - Crown Jewels of the Wire", November 1976, page 34

Dear Dora:

Ref the insulator on page 32, Aug '76 CJ, here is the light you wanted shed on the marking.

The insulator is Patent #520,602, May 29, 1894, Henry H. Luscomb, Hartford, Conn. (As you state, this patent is shown in Brown's "Unique", page 27.)

Luscomb was an employee or officer of the Johns-Pratt Co., Hartford. He had other patents beside this one, some of which were assigned to Johns-Pratt.

My crystal ball therefore suggests the complete marking on Harold's specimen would read:

THE IRON CLAD POLE TOP 
MADE IN U.S.A. 
THE JOHNS-PRATT CO. 
HARTFORD, CONN.

The histories of the related companies (H. W. Johns Mfg. Co., H. W. Johns-Manville Co., Johns-Manville Co.) are briefly given on page 168 of my book.

The subsidiary Johns-Pratt Co. was organized in 1886 for the manufacture of products from Vulcabeston, and later Moulded Mica (of Gould & Watson Co.). Johns-Pratt (and later Johns-Manville) for many years sold an extensive line of pin type and strain insulators made of these materials.

It would be great if one or more collectors really worked at it to form specialized collections of all these "composition" insulators made by Johns-Pratt Co., Electrose Corp. and others. We have the company histories and catalogs. It would be a shame if the specimens got lost in the shuffle as time marches on.

Jack H. Tod

Is it a strain insulator? There is one hole with groove like it was meant for a wire, but the other hole looks as if it were meant for a post or something rather than a wire. Does anyone know about this?
Gerald Brown

Dear Dora,

Do Oakman (rim embossed) CABLE (embossed) CD 259's normally come with threads on the inside of outer skirt?
Thanks,
Chuck Moylan

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Yes, Chuck, to the best of my knowledge. Every one I have ever seen does.

Dora