HISTARCHers:



I'm looking for a citation for the end date of the use of manganese to

clarify glass in the United States. Dale Berge in his still relevant report

on the Simpson's Springs excavations in Utah tells us it was 1917, based on

a collector's book (Ferraro and Ferraro 1964). I have "known" for some

years now that the United States stopped importing manganese from Germany

as early as 1915 and that is a better end date for glass that solarizes

purple. I've used that date for some time now, but a reviewer on one of my

reports wants a citation (*&#!*#!!!). I've gone through all my standard

references and can't find anyone else who will back me up.



Anyone who can help?



Cathy





Catherine Holder Spude ¨ Archeologist ¨ Cultural Resources Management ¨

National Park Service – Intermountain Region ¨ 505.988.6831Voice ¨

505.988.6876 Fax

 The National Park Service cares for special places saved by the American

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