GPT on Question 21, Sep 16

In the 18th century, black powder was typically made in specialized powder mills rather than ordinary workshops because the process was extremely hazardous.

At a high level, manufacture involved:

• 1.Preparing the ingredients
  Craftsmen refined saltpeter (potassium nitrate), produced charcoal—often from light woods such as willow or alder—and obtained purified sulfur. Each material was dried and ground separately.

• 2.Mixing and “incorporating”
  The ingredients were blended and then worked together in a dampened state. Powder mills commonly used water-powered wooden or stone edge-runner wheels. Moistening reduced airborne dust and helped the materials combine, though accidental explosions remained common.

• 3.Pressing
  The incorporated mixture was compressed into dense cakes. This improved consistency and made the eventual grains stronger and more uniform.

• 4.Corning or granulating
  The cakes were broken into grains and passed through sieves. Different grain sizes were selected for muskets, cannon, pistols, mining, and other purposes.

• 5.Glazing and drying
  Grains might be tumbled in barrels to smooth and harden their surfaces, then carefully dried. Fine dust was removed or recycled because it burned differently and was especially dangerous to handle.

• 6.Testing and packing
  Finished powder was tested for consistency and strength, then stored in wooden barrels, often lined or constructed to minimize sparks.

Production was frequently regulated or monopolized by governments because saltpeter and gunpowder were strategically important. Mills were deliberately spread across separate, lightly built structures so that an explosion in one stage would not destroy the entire facility. Even with these precautions, powder-mill explosions were a recurring occupational hazard.