Convert from fotmal [lead] to nanogram

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 (nanogram)
The nanogram is a metric unit of mass equal to 10E-9 gram, or one millionth of a milligram.