Affectionately known as 'Cartwheels' because of their large size and weight, the 1oz copper penny coin produced at the end of the 18th century by George III is significant in being the first coin (along with the 2 oz copper twopence) to be produced using Matthew Boulton's steam powered coining press. The coins contained exactly one ounce of copper making them ideal as substitutes for weights in measuring produce, a task for which they were intentionally designed.