Convert from libra [Italy] to fother [lead]

Unit Definition (libra [Italy])
The libra [Italy] is a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The traditional Italian libbra was often of similar size, but a wide variety of libbras were used in Italian markets over the centuries. The word "libra" is sometimes used now for the kilogram, a much larger unit.

Unit Definition (fother [lead])
The fother is a traditional English unit of weight for lead. The fother, equal to 30 fotmals, was always a little smaller than a (long) ton. The original version seems to have been equivalent to 2160 avoirdupois pounds, and the version still being used in the nineteenth century was equal to 19.5 hundredweight or 2184 pounds.