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 (ons [Dutch]) The ons is a Dutch unit of weight or mass, now used as a metric unit equal to the hectogram (100 grams, or about 3.5274 ounces).
Weight/Mass 
