Saltpetre Cave

During the War of 1812 and the Civil War (1861-1865), earth from this cave was mined for the bird and bat droppings it contained to make gunpowder. The earth was saturated with cold water and left in hoppers for a day or two. Once boiled in iron kettles, the mixture of earth and water, called “soak,” was filtered through wood ashes, producing a clear solution named nitrate of potassium. Boiled for a second time, the liquid was converted into crystallized salts, or “saltpetre,” and used to make gunpowder. It took 18 bushels of soak and 10 bushels of elm ashes to make 100 pounds of good saltpetre.

Virginia · United States