The modern history of petroleum exploitation, in relation to extraction from seeps, began in the 19th century with the refining of kerosene from crude oil as early as 1823, and the process of refining kerosene from coal by Nova Scotian Abraham Pineo Gesner in 1846. It was only after Ignacy Łukasiewicz had improved Gesner's method to develop a means of refining kerosene from the more readily available "rock oil" ("petr-oleum") seeps in 1852 that the first rock oil mine was built near Krosno in central European Galicia (Poland/Ukraine) in 1853. In 1854, Benjamin Silliman, a science professor at Yale University, was the first American to fractionate petroleum by distillation. These discoveries rapidly spread around the world.