Collectibles--General (Modern)/Brookfield insulator


I have one with these markings.  W Brookfield
         55 Fulton ST
On the bottom  ER    (3 marks I can't make out)  JAR
         Pat Feb 22 1870

Thanks for any help.

Sorry for the delay.  What you have is a CD 133 insulator made by the Brookfield glass company.  This is an early style made in the 1870's.  The back of the dome is marked Cauvet's patent July 25, 1865.  This was the patent for the process to thread glass - prior to that patent insulators were threadless.  The patent dates on the skirt are:

JAN, 25, 1870 & FEB 22, 1870 -- these are the reissue of the threading patent and a patent for an insulator press.

ER stands for the Erie Railway where this insulator was used.

This is a great piece of history that is around 130 years old!!  Brookfield made glass insulators from the early 1860's through 1922 and were based out of Brooklyn N.Y.   This insulator is very collectable and has a value in the $25-$30 range.

         Hope this helps,  Thanks, --Bob

Collectibles--General (Modern)

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Bob Berry


Questions related to collecting Glass Insulators and porcelain insulators - I can provide historical information as well as current collector values. I am also interested in purchasing insulators I need for my collection.


I have collected since the early 1970's and have much historical information, as well as knowledge of current insulator values.

National Insulator Association (

BS & MS in Electrical Engineering

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