GPT on Question 21, Sep 19

In the 18th century, black powder was manufactured in specialized powder mills from three ingredients: purified saltpeter (potassium nitrate), charcoal, and sulfur. Production generally followed these stages:

• 1.Refining the ingredients
• •Saltpeter was purified by dissolving it in hot water, filtering the solution, and recrystallizing it.
• •Sulfur was refined to remove mineral impurities.
• •Charcoal was produced under controlled, low-oxygen conditions, often from soft woods such as willow, alder, or dogwood. The wood and charring method strongly affected powder quality.

• 2.Grinding and mixing
  The ingredients were first reduced separately, then combined in an “incorporating mill.” Heavy wooden or stone wheels rolled over the damp mixture. Water was added to reduce dust and accidental ignition while helping distribute the ingredients uniformly.

• 3.Pressing
  The incorporated mixture was compressed into dense slabs or “press cake.” Greater density produced more consistent and generally more powerful powder than a loose mixture.

• 4.Corning
  The press cake was broken up and passed through sieves to create grains of controlled size. This was called corning. Different grain sizes were intended for pistols, muskets, cannon, blasting, or priming.

• 5.Glazing, drying, and grading
  Grains were sometimes tumbled in wooden barrels to smooth and strengthen them; graphite began to be used later as a surface treatment. The powder was then carefully dried, screened by grain size, tested, and packed in barrels.

Powder mills were deliberately built away from towns, with individual operations housed in separate, lightly constructed buildings. Machinery was often water-powered, and workers used non-sparking tools and avoided iron fittings where possible. Even so, explosions were frequent occupational hazards.

Earlier hand methods—such as grinding ingredients with mortars—continued in some places, but state arsenals and commercial mills increasingly relied on mechanized incorporation, pressing, and corning for uniform military powder. Modern reproduction is extremely hazardous and often legally regulated.