I've probably said this before but weights and measures in the medieval
period can be a real minefield. In checking through production levels for
English silver/lead mining operations in the late 13th / early 14th
centuries, and trying to make comparisons with modern production, I'm having
difficulty in relating the 'pound' weight used in quantifying lead
production to a modern, or any other, equivalent.
One of the benefits of using documentation generated for, or on behalf of,
the English Crown is that the weights and measures tend to be defined in the
accounts.
Silver production is accounted for in 'pondus cambii', the weights of the
exchange, i.e. the Tower pound of 5400 grains (350 grams), divided into 20
shillings of 12d.
Metallic lead production is accounted for in carreta (cartloads), with 24
feet of 70 pounds making up a carreta, and each 'pound' weighs 25 shillings
- et qualibet libra ponder' xxv. s.
If, as I understand the accounts, the weight of a 'pound' of lead is being
related to the Tower pound of 20 shillings, i.e. it is 25 percent heavier
than the Tower pound, then we have a 'pound' of 437.5 grams - heavier than a
Troy pound (373.24 grams) yet lighter than a modern avoirdupois pound (453.6
grams).
Has anyone come across such a 'pound' used in mining, metallurgy, or any
other industry, in the medieval or any other period.
Peter
________________________________________________________
Peter Claughton, Blaenpant Morfil, Rosebush, Clynderwen,
Pembrokshire, Wales SA66 7RE.
Tel. 01437 532578: Fax. 01437 532921: Mobile 07831 427599
University of Exeter - SHiPSS
(Centre for South Western Historical Studies)
Co-owner - mining-history e-mail discussion list
See http://www.jiscmail.ac.uk/files/mining-history/ for details
Mining History Pages - http://www.exeter.ac.uk/~pfclaugh/mhinf/
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