Gelignite is an explosive consisting of collodion-cotton (a type of nitrocellulose or gun cotton) dissolved in nitroglycerine and mixed with wood pulp and sodium or potassium nitrate. One of the cheapest explosives, it is mostly used for large-scale blasting in the construction and mining industries. Unlike gunpowder, it burns slowly and cannot explode without a detonator, so it can be stored safely. It was invented in 1875 by Alfred Nobel, who had earlier invented dynamite. Unlike dynamite, gelignite does not suffer from the dangerous problem of sweating, the leaking of unstable nitroglycerine from the solid matrix.