A significant part of the “military revolution” that swept across early modern Europe was the “gunpowder revolution,” which rested to a significant extent on the supply of saltpeter. Saltpeter (potassium nitrate) was distilled from earth, well saturated with dung and urine—Cressy attributes its power to “the vitalizing power of urine and excrement, and the miracle of nitrous-rich soil” (174)—though it was also found in natural beds. It was the major ingredient in the explosive powder that played a major role in determining the outcome of battles and even the fate of kings and kingdoms.
Cressy follows the desperate search for those precious and vital nitrogenous earths, mostly in England but also with an eye on the American colonies at the Revolution, ending with a brief run into the nineteenth century. His story combines chemical and technological exploration, speculations about nature, the ever-growing needs of armies, the clash between the interests of monarchs and those of citizens displaced by the despised saltpetermen, and the woes of depending on imports. By 1500, guns had become the main weapon of warlike Europe, but the needs of a bellicose ruler like Henry VIII were but early chapters in the story of ever-larger armies and guns supplies, with the requisite salt-peter to sustain them. When Henry VIII laid siege to Boulogne in 1544, his army used thirty-two tons of saltpeter a day for 250 guns, whereas by mid-Victorian times, British fortresses and batteries at home could boast 1,664 guns, with 4,812 more of them scattered across the Empire. Only when cordite became the killer of choice did the saltpeter enterprise come to an end.
But the domestic search for saltpeter also had a contentious and political aspect. Since it gave carte blanche to saltpetermen to go where they chose, they showed no respect for private property; they dug under houses, churches, and public buildings. Young Christopher Wren saw his father’s pigeon house collapse because of such excavations, and many others had worse tales to tell. In Charles I’s day, the need to dig turned many a royalist and high-born property owner against the government’s policy. Those affected by cave-ins and ruined buildings, however, had little hope of recompense legally or financially; sometimes bribery was the only way to escape intrusion. The desperate search for adequate domestic supplies also spawned endless schemes for (cheaper) production, none of them ending in much more than bankruptcy, fraud, and failure. But for the king, the invasion of rights and boundaries was justified by a national crisis at a time when 80 percent of the military’s needs were covered by imports (from Europe and then, successfully, from the East Indies and India).
Cressy explores the foundations on which much military and political history rested. If an army marched on its stomach, it fired—as often as possible—by dipping into its stocks of saltpeter. Many short quotations from all sorts of interested parties help to ground the text, and the [End Page 383] twenty illustrations provide an idea of the distilling technology involved, the increasing size of the guns, and the ubiquitous “how to do it” books that made the creation of gunpowder accessible, at least in theory, to the naïve and the hopeful.