Absolute Force of Gunpowder

Is measured by the pre ure it exerts on its environment when it exactly fills the space in which it is fired. Various attempts have been made to determine this force experimentally with widely different results. Robins estimated the pre ure on the square inch at 1000 atmospheres, Hutton at 1800, and Count Rumford as high as 100,000 atmospheres. While Rodman, by experiments upon strong cast-iron shells, verified the accuracy of Rumford’s formulas , he found that his estimate of the force was greatly in error. According to Rodman the pre ure is approximately 14,000 atmospheres. Dr. Wood bridge, another American philosopher and inventor, has shown that, fired in small quantities, the force of gunpowder does not exceed 6200 atmospheres. This agrees closely with the conclusion arrived at by the English “Committee on Explosives,” 1875, who found that even in large guns the force did not exceed 42 tons.