Gunpowder was known in China as early as the 10th century and was probably first used in Europe in firearms during the 14th century. The use of gunpowder in blasting for construction and mining began in the 17th century. Gunpowder was the only practical explosive available until the middle of the 19th century, when nitrocellulose (gun-cotton) and other explosives were invented. Nitroglycerin, invented in 1847, was too dangerous for practical use until Alfred Nobel, a Swedish chemist, invented dynamite in 1866. Nobel also developed the use of mercury fulminate as a detonator. Several kinds of smokeless powders, including ballistite and cordite, were introduced in the late 1800's. Picric acid and TNT were important military explosives in World War I. PETN and RDX did not come into general use as military explosives until World War II. During the early 1900's dynamite became the most important explosive for blasting, but since the 1950's it has been largely-replaced by ANFO and slurry explosives.