Q: What does the common weight tell a buyer today?
Ola Senn: It gives every stall the same starting point. The difficulty is that a copper bar can be long and narrow or short and thick. The shared number is useful, but it does not describe the bar a buyer will carry away.
Q: Why do the guilds want certified weights of their own?
Senn: They say their makers need a measure that accounts for the shape of a bar. Buyers are right that more standards make comparison harder. A guild weight is only useful if its mark and method are public.
Q: The challenge book includes a notch where the old maker’s mark has worn away. Does that make the weight unsafe to use?
Senn: Not by itself. We still have its stamped weight and the record of its last inspection. The missing mark tells us the object needs a new chain of custody, not that every bar weighed with it is wrong.
Q: What would the paired test settle?
Senn: It can show whether the same bars receive repeatable readings under both systems. It cannot decide for buyers which system is easier to understand. That answer belongs on the board, in words as well as marks.
The assay table has not recommended a replacement. Senn says the test will be useful only if the challenge book records the bar, both weights, and the person who checked each reading.
