In managing these mines, Clark took an active role as President. He traveled thousands of miles, recommending improvements to mills and machinery and overseeing the improvements. Meeting initial success, the company's worth soon amounted to millions of dollars. The good fortune extended throughout the town of Amherst where, according to biographer John Maki, there was a "craze in mining stocks" as Clark's friends, family, and former academic colleagues became heavily invested in the company. There were also substantial investors in New York, Boston, Philadelphia and other cities.