Brown powder or prismatic powder, sometimes referred as "cocoa powder" due to its color, was a propellant used in large artillery and ship's guns from the 1870s to the 1890s. While similar to black powder, it was chemically formulated and formed hydraulically into a specific grain shape to provide a slower burn rates with neutral or progressive burning, as opposed to the faster and regressive burn typical of randomly shaped grains of black powder produced by crushing and screening powder formed into sheets in a press box, as was typical for cannon powder previously. Characteristics For pure explosive damage, high burn rates or detonation speeds (and accompanying brisance) are generally preferable, but in guns and especially cannons, slower-burning powder decreases firing stresses. This allows for lighter, longer (and more accurate) barrels with associated decreases in production and maintenance costs. Further modifications of its burning rate were achieved by shaping the powder grains into prismatic shapes, typically single-perforated hexagonal or octagonal prisms. They became obsolete as a propellant due to the introduction of nitro-explosive propellants such as Poudre B, in France, and later by Nobel's ballistite and, in Britain, by cordite. These new propellants produced less smoke, particularly less black smoke. Composition The differences in burning rate were achieved by several means. Changes to formulation were altering ingredients relative percentage by weight and using differently processed charcoals for fuel than those of a standard 75:15:10 (potassium nitrate:charcoal:sulfur) black cannon powder. Typically, sulfur was either not used in brown powders, or sulfur content reduced to around 1% by weight from the usual 10%. The reduction or outright removal of sulfur slowed the burn rate, while replacement of higher molecular weight sulfur dioxide by carbon dioxide or monoxide in the propellant gas mixture gave a higher specific impulse. Differently processed charcoals were used. Fully carbonized charcoal (mostly composed of elemental carbon) in black powder provides its distinctive black color, while its replacement with an incompletely carbonized, brownish colored charcoal produces a dark brown appearance, hence the names "brown powder" or "cocoa powder". The less carbonized charcoal was more reactive than fully carbonized charcoal, somewhat making up for the easy ignition characteristics usually provided by sulfur. The brown charcoal also helped to produce sturdier grains and replaced sulfur in the role of a binder. Further modifications of burn rate were achieved by shaping the individual powder grains, often into prismatic shapes such as single-perforated