<P> By 1850, some £ 94 million in sovereigns and half sovereigns had been struck and circulated widely, well beyond Britain's shores, a dispersion aided by the British government, who saw the sovereign's use as an auxiliary to their imperialist ambitions . Gold is a soft metal, and the hazards of circulation tended to make sovereigns lightweight over time . In 1838, when the legacy of James Smithson was converted into gold in preparation for transmission to the United States, American authorities requested recently - struck sovereigns, likely to maximise the quantity of gold when the sovereigns were melted after arrival in the United States . By the early 1840s, the Bank of England estimated that 20 per cent of the gold coins that came into its hands were lightweight . In part to boost the sovereign's reputation in trade, the Bank undertook a programme of recoinage, melting lightweight gold coins and using the gold for new, full - weight ones . Between 1842 and 1845, the Bank withdrew and had recoined some £ 14 million in lightweight gold, about one - third of the amount of that metal in circulation . This not only kept the sovereign to standard, it probably removed most of the remaining guineas still in commerce . The unlucky holder of a lightweight gold coin could only turn it in as bullion, would lose at least a penny because of the lightness and often had to pay an equal amount to cover the Bank of England's costs . There was also increased quality control within the Royal Mint; by 1866, every gold and silver coin was weighed individually . The result of these efforts was that the sovereign became, in Sir John Clapham's later phrase, the "chief coin of the world". </P> <P> The California Gold Rush and other discoveries of the 1840s and 1850s boosted the amount of available gold, and also the number of sovereigns struck, with £ 150 million in sovereigns and half sovereigns coined between 1850 and 1875 . The wear problem continued: it was estimated that on average, a sovereign became lightweight after fifteen years in circulation . The Coinage Act 1870 tightened standards at the Royal Mint, requiring sovereigns to be individually tested at the annual Trial of the Pyx rather than in bulk . These standards resulted in a high rejection rate for newly - coined sovereigns, though less than for the half sovereign, which sometimes exceeded 50 per cent . When the Royal Mint was rebuilt in 1882, a deciding factor in the decision to shut down production for renovation rather than transition to a new mint elsewhere was the Bank of England's report that there was an abnormally large stock of sovereigns, and that no harm would result if they could not be coined at London for a year . Advances in technology allowed sovereigns to be individually weighed by automated machines at the Bank of England by the 1890s, and efforts to keep the coin at full weight were aided by an 1889 Act of Parliament which allowed redemption of lightweight gold coin at full face value, with the loss from wear to fall upon the government . The Coinage Act 1889 also authorised the Bank of England to redeem worn gold coins from before Victoria's reign, but on 22 November 1890, all gold coins from before her reign were called in by Royal Proclamation and demonetised effective 28 February 1891 . Due to a continuing programme to melt and recoin lightweight pieces, estimates of sovereigns in trade weighing less than the legal minimum had fallen to about 4 per cent by 1900 . </P> <P> The sovereign was seen in fiction--in Dickens's Oliver Twist, Mrs Bumble is paid for her information with 25 sovereigns . Joseph Conrad, in his novels set in Latin America, refers several times to ship captains keeping sovereigns as a ready store of value . Although many sovereigns were melted down for recoining on reaching a foreign land (as were those for the Smithsonian), it was regarded as a circulating coin in dozens of British colonies and even in nations such as Brazil and Portugal . </P> <P> In 1871, the Deputy Master of the Mint, Sir Charles Fremantle, restored the Pistrucci George and Dragon design to the sovereign, as part of a drive to beautify the coinage . The return of Saint George was approved by the Queen, and authorised by an Order in Council dated 14 January 1871 . The two designs were struck side by side in London from 1871 to 1874, and at the Australian branch mints until 1887, after which the Pistrucci design alone was used . The saint returned to the rarely - struck two - and five - pound pieces in 1887, and was placed on the half - sovereign in 1893 . Wyon's "Young head" of Queen Victoria for the sovereign's obverse was struck from 1838 until 1887, when it was replaced by the "Jubilee head" by Sir Joseph Boehm . That obverse was criticised and was replaced in 1893 by the "Old head" by Sir Thomas Brock . Victoria's death in 1901 led to a new obverse for her son and successor, Edward VII by George William de Saulles, which began production in 1902; Edward's death in 1910 necessitated a new obverse for his son, George V by Bertram Mackennal . Pistrucci's George and Dragon design continued on the reverse . </P>

What's the difference between a half sovereign and a full sovereign