Final answer:
In the 19th century, Britain was required to use silver for its imports due to a trade deficit with China, the international preference for precious metals in trade, and practices rooted in mercantilism. The adoption of the gold standard and the importance of maintaining precious metal reserves for currency backing also contributed to this necessity.
Step-by-step explanation:
The question pertains to why the British had to use silver for their imports. This is tied to historical trade practices, particularly in the 19th Century when Britain had a substantial trade deficit with China because the British were importing vast quantities of tea.
At that time, silver was the common currency in international trade, especially with China, as there were few British products that the Chinese were interested in. Consequently, silver reserves in Britain dramatically decreased, forcing them to use silver to balance the trade.
Additionally, during the era of mercantilism, nations preferred to export more than they imported, accumulating gold and silver as a measure of wealth, which were preferred for international transactions over paper currency, reflecting a lack of demand for foreign paper money, such as the British currency.
This context places an emphasis on the need for precious metals - gold and silver - to conduct international trade.
In addition, the adoption of the gold standard by Britain and the United States made paper money backed by precious metals more trustworthy and valuable on the international stage.
However, this also meant that countries like Britain had to maintain adequate gold and silver reserves to support their currencies, thus necessitating the use of silver to pay for imports when their reserves of gold were in question or when trading partners demanded it.