lesser gentry families from throughout the country. The civil examination system was later adopted by China's other East Asian neighbors Japan and Korea. The imperial examination system attracted much attention and greatly inspired political theorists in the Western World, and as a Chinese institution was one of the earliest to receive such foreign attention. The Chinese examination system was introduced to the Western world in reports by European missionaries and diplomats, and encouraged the British East India Company to use a similar method to select prospective employees. Following the initial success in that company, the British government adopted a similar testing system for screening civil servants in 1855. Other European nations, such as France and Germany, followed suit. Modeled after these previous adaptations, the United States established its own testing program for certain government jobs after 1883. Co-fusion steel process: Although British scientist, sinologist, and historian Joseph Needham speculates that it could have existed beforehand, the first clear written evidence of the fusion of wrought iron and cast iron to make steel comes from the 6th century AD in regards to the Daoist swordsmith Qiwu Huaiwen, who was put in charge of the arsenal of Northern Wei general Gao Huan from 543 to 550 AD. The Tang Dynasty (618–907) Newly Reorganized Pharmacopoeia of 659 also described this process of mixing and heating wrought iron and cast iron together, stating that the steel product was used to make sickles and Chinese sabers. In regards to the latter text, Su Song (1020–1101) made a similar description and noted the steel's use for making swords. Coke as fuel: By the 11th century, during the Song Dynasty (960–1279), the demands for charcoal used in the blast and cupola furnaces of the iron industry led to large amounts of deforestation of prime timberland; to avoid excessive deforestation, the Song Dynasty Chinese began using coke made from bituminous coal as fuel for their metallurgic furnaces instead of charcoal derived from wood. Color printing: By at least the Yuan Dynasty, China had invented color printing for paper. British art historian Michael Sullivan writes that "the earliest color printing known in China, and indeed in the whole world, is a two-color frontispiece to a Buddhist sutra scroll, dated 1346". Contour canal: After numerous conquests and consolidation of his empire, China's first emperor Qin Shi Huang (r. 221–210 BC) commissioned the engineer Shi Lu to build a new waterway