Pound (mass) No standards of the Tower pound are known to have survived. The Tower pound was equivalent to about 350 grams. The merchants' pound ("mercantile pound", "libra mercantoria", or "commercial pound") was considered to be composed of 25 rather than 20 Tower shillings of 12 pence. It was equal to 9,600 wheat grains (15 tower ounces or 6,750 grains) and was used in England until the 14th century for goods other than money and medicine ("electuaries"). The London pound is that of the Hansa, as used in their various trading places. The London pound is based on 16 ounces, each ounce
Pound (mass) and for different applications, the pound (or its translation) has referred to broadly similar but not identical standards of mass or force. The libra (Latin for "scales / balance") is an ancient Roman unit of mass that was equivalent to approximately 328.9 grams. It was divided into 12 "unciae" (singular: "uncia"), or ounces. The "libra" is the origin of the abbreviation for pound, "lb". A number of different definitions of the pound have historically been used in Britain. Amongst these were the avoirdupois pound and the obsolete Tower, merchant's and London pounds. Troy pounds and ounces remain in use only