Thanks to all who responded.  I had never seen ghost
seams used for dating, but I wasn't aware it was
because they still appear today (yet another reason to
celebrate the centennial and sign up for your SHA
workshop!).

Best wishes,

Sarah

--- "George L. Miller" <[log in to unmask]>
wrote:
> Sarah,
>
> Ghost mold seams will be here past Christmas.  The
> are the lines left by a
> parison mold that shapes the glass before it is
> transferred to the blow
> mold.  If you look at any bottle of products that
> you are currently using
> you can generally see them.  The off-center circle
> on the bottom of bottles
> and jars is a ghost mold seam.  The bottle you have
> that is solarized was
> probably made on a semi-automatic bottle-blowing
> machine because manganese
> did not work well as a decolonizer in tank furnaces
> that were used to feed
> fully automatic bottle-blowing machines.  For
> further discussion of
> machine-made bottles see:
>
> George L. Miller and Catherine Sullivan
> 1984  Machine-Made Glass Containers and the End of
> Production for
> Mouth-Blown Bottles.  Historical Archaeology
> 18(2):83-96.
>
>       This has been reprinted Approaches to Material
> Culture Research for
> Historical Archaeologists compiled by David R.
> Brauner and is available
> from the Society for Historical Archaeology.  It
> contains 25 articles on
> material culture research and is a bargain at $25.00
> plus shipping.
>
>       I have a bibliography on machine-made bottles
> and a paper titled
> "Dates for Suction Scarred Bottoms: Chronological
> Changes in Owens
> Machine-made Bottles" by myself and Tony McNichol
> for anyone that is
> interested.
>
> George L. Miller
> URS Corporation
> =


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