to replace whale oil used in lamps and essentially became a fuel commodity. This increased the importance of oil as a commodity, long before its eventual use as fuel for combustion engines. Diplomacy Although the Confederacy hoped that Britain and France would join them against the Union, this was never likely, and so they instead tried to bring the British and French governments in as mediators. The Union, under Lincoln and Secretary of State William H. Seward, worked to block this and threatened war if any country officially recognized the existence of the Confederate States of America. In 1861, Southerners voluntarily embargoed cotton shipments, hoping to start an economic depression in Europe that would force Britain to enter the war to get cotton, but this did not work. Worse, Europe turned to Egypt and India for cotton, which they found superior, hindering the South's recovery after the war. Cotton diplomacy proved a failure as Europe had a surplus of cotton, while the 1860–62 crop failures in Europe made the North's grain exports of critical importance. It also helped to turn European opinion further away from the Confederacy. It was said that "King Corn was more powerful than King Cotton", as U.S. grain went from a quarter of the British import trade to almost half. Meanwhile, the war created employment for arms makers, ironworkers, and ships to transport weapons. Lincoln's administration initially failed to appeal to European public opinion. At first, diplomats explained that the United States was not committed to the ending of slavery, and instead repeated legalistic arguments about the unconstitutionality of secession. Confederate representatives, on the other hand, started off much more successful, by ignoring slavery and instead focusing on their struggle for liberty, their commitment to free trade, and the essential role of cotton in the European economy. The European aristocracy was "absolutely gleeful in pronouncing the American debacle as proof that the entire experiment in popular government had failed. European government leaders welcomed the fragmentation of the ascendant American Republic." However, there was still a European public with liberal sensibilities, that the U.S. sought to appeal to by building connections with the international press. As early as 1861, many Union diplomats such as Carl Schurz realized emphasizing the war against slavery was the Union's most effective moral asset in the struggle for public opinion in Europe. Seward was concerned that an overly radical case for reunification