The new standard was made of Baily's metal No. 4 consisting of 16 parts copper, parts tin, and 1 part zinc. It was 38 inches long and 1 inch square. The Weights and Measures Act of 1855 granted official recognition to the new standards. Between 1845 and 1855 forty yard standards were constructed, one of which was selected as the new Imperial standard. Four others, known as Parliamentary Copies, were distributed to The Royal Mint, The Royal Society of London, The Royal Observatory at Greenwich, and the New Palace at Westminster, commonly called the Houses of Parliament. The other 35 yard standards were distributed to the cities of London, Edinburgh, and Dublin, as well as the United States and other countries (although only the first five had official status). The imperial standard received by the United States is known as "Bronze Yard No. 11"