On May 22, 2007, at 11:39 AM, McKee, Larry (Nashville,TN-US) wrote:
> Work on early 20th century sites commonly produces molded or extruded
> carbon rods of various sizes, generally identified as cores from
> zinc/carbon cells or batteries. Our recent excavation at a relatively
> isolated farmstead in Missouri produced one single oversized
> example out
> of a deposit datable to the first decade of the 20th century. The
> piece
> is 5.75 in long, cylindrical with flattened ridges along its length, 1
> in. in diameter, and with a hole at one end filled with corroded
> whitish
> material and what might be the remnants of a copper wire.
The large type of carbon rod with the wire and without were referred
to as battery cores by my father when they were found on our farm
when I was a kid in the 1950's. However, by that time, they were all
single artifact finds without any surrounding battery so I never saw
what they looked like when part of the whole.
They're a large variant on the dry-cell battery.
There's an interesting history of batteries at: http://
www.mpoweruk.com/history.htm
Quoted within it is:
1886 Carl Gassner of Mainz patented the carbon-zinc dry cell which
made batteries the convenient power source they are today. It used
the basic Leclanché (1868) cell chemistry with zinc as its primary
ingredient with the chemicals being encased in a sealed zinc
container which acted as the negative electrode. A carbon rod
immersed in a manganese dioxide/carbon black mixture served as the
positive electrode. Initially the electrolyte was ammonium chloride
soaked into the separator which was made of paper, but by adding zinc
chloride to the electrolyte the wasteful corrosion of zinc when the
cell was idle was reduced - adding considerably to the shelf life. A
bitumen seal prevented leakage. Although the technology has been
refined by over a century of development, the concepts and chemistry
are the same as Gassner's first cells.
>
>
Lyle Browning, RPA
>
> We haven't been able to track down much about specifics on these
> carbon
> rods, in terms of manufacturing dates and specific uses for different
> sizes and configurations. Any suggestions for such sources or
> references
> to archaeological studies with more information on these artifacts
> will
> be greatly appreciated.
>
>
>
> Larry McKee, Ph.D., RPA
>
> Program Manager and Senior Archaeologist
>
>
> TRC
>
> 1865 Air Lane Dr., Suite 9
>
> Nashville, TN, 37210
>
>
>
> 615.884.4430 phone
> 615.884.4431 fax
> 615.594.4675 cell
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>
> www.trcsolutions.com <http://www.trcsolutions.com>
>
>
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