50.0 MB (6.0 MB compressed)
4602 x 3797 pixels
38.9 x 32.3 cm ⏐ 15.3 x 12.7 in (300dpi)
SHEILA TERRY / SCIENCE PHOTO LIBRARY SHEILA TERRY / SCIENCE PHOTO LIBRARY
Depending on the requirements the combustible ingredients of gunpowder, i.e., charcoal, saltpetre and sulphur, need to be reduced to a high-quality powder of a particular particle size. This 19th century French pilon ( 'pestle') powder mill was driven by a waterwheel and had a mechanical system that caused the rise and fall of the two pestles in the mortars full of the mixture to produce the powder. A rate of 55-60 pestle strokes was maintained for several hours. An alternative to the pilon mill was the water cylinder mill.
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