Copy of the Imperial Standard Pound. Parliamentary Copy number 5 (P.C.5) of the Imperial Standard Pound, dated 1879. The imperial system of weights and measures was established in 1824 and refined by later acts of parliament, especially the Weights and Measures Act of 1878. The primary imperial pound was constructed in 1844, and is a platinum cylinder with a groove to allow it to be lifted. The relationship of this standard and its copies to the international pound and the kilogram was examined in the early 1960s by the UK's National Physical Laboratory (NPL). Photographed at the NPL in November 1969.