Convert from firkin [butter, soap] to scruple [troy]

Unit Definition (firkin [butter, soap])
The firkin [butter, soap] is a traditional unit of weight for butter and soap, equal to 4 stone or 56 pounds (about 25.40 kilograms).

Unit Definition (scruple [troy])
The scruple is a unit of weight in the traditional (troy) system used by English apothecaries, equal to 20 grains, 1/24 troy ounce or approximately 1.2960 gram.