William S. Clark, American colonel and politician (d. 1886)
William Smith Clark (July 31, 1826 – March 9, 1886) was an American professor of chemistry, botany and zoology, a colonel during the American Civil War, and a leader in agricultural education. Raised and schooled in Easthampton, Massachusetts, Clark spent most of his adult life in Amherst, Massachusetts. He graduated from Amherst College in 1848 and obtained a doctorate in chemistry from Georgia Augusta University in Göttingen in 1852. He then served as professor of chemistry at Amherst College from 1852 to 1867. During the Civil War, he was granted leave from Amherst to serve with the 21st Regiment Massachusetts Volunteer Infantry, eventually achieving the rank of colonel and the command of that unit.In 1867, Clark became the third president of the Massachusetts Agricultural College (MAC), now the University of Massachusetts Amherst. He was the first to appoint a faculty and admit a class of students. Although initially successful, MAC was criticized by politicians and newspaper editors who felt it was a waste of funding in a state that was growing increasingly industrial. Farmers of western Massachusetts were slow to support the college. Despite these obstacles, Clark's success in organizing an innovative academic institution earned him international attention.

Japanese officials, striving to achieve rapid modernization of that country in the wake of the Meiji Restoration, were especially intrigued by Clark's work. In 1876, the Japanese government hired Clark as a foreign advisor to establish the Sapporo Agricultural College (SAC), now Hokkaido University. During his eight months in Sapporo, Clark successfully organized SAC, had a significant impact on the scientific and economic development of the island of Hokkaido, and made a lasting imprint on Japanese culture. Clark's visage overlooks Sapporo from several statues and his parting words to his Japanese students, "Boys, be ambitious!" (「少年よ大志を抱け Shōnen yo, taishi o idake」) have become a nationally known motto in Japan.After resigning the presidency of MAC in 1879, Clark left academia to become the president of a mining company, Clark & Bothwell. The company, in operation from 1881 to 1882, purchased several silver mines, mostly in Utah and California. Clark's partner, John R. Bothwell, proved to be corrupt and the company quickly folded, destroying Clark's reputation, his own finances and the fortunes of many of his friends and family. The subsequent scandal ruined Clark's health. He died of heart disease at his home in Amherst in 1886.