Lightning rod ?

[steelheadwill]

Hit this dead center with my shovel, otherwise would never have seen ductile copper core, brittle copper sheath, and what appears to be insulative material between.
pointed on one end, flattened on other, about 9" length.
compared with others on roofs, looks similar to ones on the early sections of the Wentworth/Coolidge Mansion, Portsmouth NH, the later parts of the building have what appear to be 3 piece units, anyone familiar with early lightning rods ??
Here's an interesting history of the mansion: http://www.seacoastnh.com/Places_&_Events/Historic_Tours/Wentworth-Coolidge_Mansion/
From Wiki :
Pointed-Tip LIghtning Rods
•The pointed-tip lightning rod (the American version of the blunt-tip lightning rod) was first proposed in 1749 in an experiment famously conducted by Benjamin Franklin. As the experiment played out, he observed that a rod built with a sharpened tip directed electricity away from a charged metal orb, which he believed provided better safety measures over the blunt-tip. His Franklin Rods were soon protecting colonial homes from Maine all the way down to Georgia.
no mention of the 'cored' design.

Thanks to all, & Great Digs, Herbie.

 

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[traderoftreasures]

most likely a grounding rod

 

[oldsledz]

The ground rods I have seen were a solid copper alloy they need to be strong enough to be drove into the ground with a hammer or post driver.

 

[steelheadwill]

This is clearly not a modern piece, dug in area that has yeilded many 18th & 19th century artifacts, the condition of exterior copper tells me it is quite old.
Thanks for your replies, still hoping for someone familiar with these old rods,
I don't want to climb that roof to confirm!

 

[Lucas]

Heating element?

 

[IronSpike]

Lightning rod would be my first guess too, but why the insulation? Is it ceramic?

Heating element or other electrical device

Come on Herbie climb the roof of that cool mansion

http://thedailyportsmouth.com/2010/05/02/the-wentworth-coolidge-mansion-2/

 

[oldsledz]

Maybe the stuff inside is not insulation, but something to make the thin copper rod stronger.

 

[steelheadwill]

Thanks for the help!!
The 'insulation' is just a powdery substance, no idea why it's there,
I looked at the older rods on the mansion with binoculars, they appear to be a match.
Will try to get there tomorrow with camera & 300mm Lens for a closeup to post.
Climb The Roof ?? i've done everything but that, thanks for posting the great pic of the mansion, that whole area is like my backyard, I lived just around the next bend in the river for a long time, had a little boat, there's half a dozen small islands there that were inhabited long ago, one of them, (Pest Island) was a quarantine station for immigrants, the area is LOADED with history and artifacts, we seem to be short of MD'ers, YoungunTher, Where Ya been?

 

[DigginThePast]

The pointed one looks like the ones used on my house and outbuildings that date back to 1780. There is just the rod without any ornamentation, which is attached to a grounding cable.

 

[IronSpike]

Thanks for the help!!
The 'insulation' is just a powdery substance, no idea why it's there,
I looked at the older rods on the mansion with binoculars, they appear to be a match.
Will try to get there tomorrow with camera & 300mm Lens for a closeup to post.
Climb The Roof ?? i've done everything but that, thanks for posting the great pic of the mansion, that whole area is like my backyard, I lived just around the next bend in the river for a long time, had a little boat, there's half a dozen small islands there that were inhabited long ago, one of them, (Pest Island) was a quarantine station for immigrants, the area is LOADED with history and artifacts, we seem to be short of MD'ers, YoungunTher, Where Ya been?

That looks like a very interesting place to Metal detect I like your determination to get this one solved Herbie Maybe also bring the piece with you and talk to the folks there.

 

[steelheadwill]

Here's some pix of the lightning rods on WC mansion,
they have a copper sheath, sealed with tar.
Gonna green check this one, the size & shape are pretty similar.
also got a pic of the anchor & boat slipway, bet there's a relic or two around there,
Unfortunately there are also LARGE signs prohibiting metal detecting, and live in caretakers. why leave important history buried ? quite frustrating

 

[DigginThePast]

Saw the green check but thought I'd follow up with a pic from here.

 

[Lucas]

Unfortunately there are also LARGE signs prohibiting metal detecting, and live in caretakers. why leave important history buried ? quite frustrating

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