sentences:  Four years later, William A. Clark, who had made a fortune in mining and commercial ventures in Montana, bought the United Verde properties and, among other improvements, enlarged the smelter.He ordered construction of a narrow gauge railway, the United Verde & Pacific, to Jerome Junction, a railway transfer point to the west.As mining of the ore expanded, Jerome's population grew from 250 in 1890 to more than 2,500 by 1900.