I'm going to guess that the wedge is how it was mounted, possibly to your house

Check out this online book: http://www.insulators.info/books/mpet/chap05.htm#para092

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I think Tricia560 has it. The wedge must have been the original support for the insulator. That's interesting because you don't usually see them mounted on anything these days. Did you find any other interesting things?

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That is it *exactly*! Right down to the screw holes in the exact same places as they appear on the wedge we found. I was surprised to see it attatched to anything, and never figured that was part of it's original function. Thinking maybe it was added to something later to serve some other purpose.
We also found a piece of tile that matches the tile surrounding our fireplace. The fireplace tiles are all in tact, so this may have been a broken piece during installation? There was also a brow glass bottle with stopper in place and a small blue bottle. THanks Tricia, that is it for sure!

Old glass insulators, especially ones with attractive colors like yours, have become collectors' items. I'm sure you could find some site online that would give you some idea of the value of this one.

As for the use... The service wire which ran from the street power line to individual houses were attached to insulators like ths one. The connection was then made from there to a heavy wire that connected with the fuse panel.

This type of insulator was intended to be used to support bare telegraph wires so it would probably have been attached to a pole. It's the more common threaded type so it was made after 1865.

There are books about the different types and collectors often meet for shows and swaps.

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Great resources, thank-you! I tried to do an on-line search, but didn't come up with anything this useful. THere is a patent date on it of 1893. Now to decide what to do with it. I would love to use it as a decoration somewhere in the house, along with a few other relecs that we have found. Thanks again for all of the great information!

Why not remount it on the house as a conversation piece. It belongs on the property it was part of the house at one time I think it'd be neat to put it back up.

It is not likely that a telegraph line would have been mounted on a house unless it was originally a train station.

I was a bit confused by the possibility of a telegraph line on a house; the home was originally owned by a doctor who, supposedly, ran his clinic out of the home for some time... For sure not a train station, though! So either the doctor had a lot of communication going on, or it landed in our yard by accident? Either way, it is a fun converstaion piece and I will find a place for it in our home decor. Thanks for the feedback!

Is there a railroad track near you?

Technically, there is a railroad track running to the lumber company that is across the street from our house. It is a single line used to deliver goods to the lumber yard. The actual track is approximately 1 block away. The main rail is about 3/4 of a mile away. We are also 1 block from what used to be a very large pickle factory.

The telegraph line would have run along the train right-of-way with telegraph stations at the railway stations. Your bracket appears to be intended for support of a single line on a pole. The insulator was designed to not only avoid grounding the line but to shed moisture from dew and rain.