Saltpeter

This is the story of saltpeter, the vital but mysterious substance craved by governments from the Tudors to the Victorians as an ''inestimable treasure.''National security depended on control of this organic material - that had both mystical and mineral properties. Derived from soil enriched with dung and urine, it provided the heart or ''mother'' of gunpowder, without which no musket or cannon co...