Convert from fotmal [lead] to myriagram

Unit Definition (fotmal [lead])
The fotmal is a traditional English unit of weight for lead. In medieval England the fotmal was equal to 70 "mercantile" pounds, which is equivalent to 72 avoirdupois pounds.

Unit Definition (myriagram)
The myriagram is a metric unit of mass equal to 10 000 grams or 10 kilograms (about 22.046 pounds). Although it is considered obsolete now, the myriagram was a useful unit comparable to the English quarter or Spanish arroba.