French Saltpeter Caves in Minnesota
In 1700, the French fur-trader Pierre-Charles Le Sueur (1657-1704), while ascending the Mississippi River, described saltpeter caves along the west side of Lake Pepin, in Minnesota. This is the earliest record of cave saltpeter in America according to Shaw (1992, p. 52). Le Sueur’s Journal, under the dates September 10 to September 14, 1700, reports […]