The invention of gunpowder was one of the most far-reaching events of all history. This terrific substance has not only revolutionized warfare, but has changed the current of human history itself. It is not known who invented gunpowder, or when it was first used. It is a compound of saltpetre, charcoal, and sulphur; the proportions in which these three ingredients are mixed vary in different countries and in different kinds of powders. It seems likely that powder was invented in the Far East, perhaps in China. Saltpetre comes, for the most part, from China and India, on whose vast plains it is found mixed with the soil. An ordinary wood fire kindled on ground containing saltpetre would bring the saltpetre into contact with charcoal, and thereby practically produce powder. It is probable that the discovery of the explosive occurred in this accidental way. Fireworks were used in China from a very early date, but it is doubtful if the Chinese, or any other nation of Asia, used gunpowder as a propelling force. It was left for the Western nations to develop and give practical value to the discovery of the Chinese. Our first knowledge of powder as an agency of war dates from about the year 700 A.D., when it was used by the Byzantine emperors in defending Constantinople against the Saracens. It was employed there, however, not as a propelling force, but in the form of rockets or a fiery liquid called Greek fire. Its first real use in Europe as a power for propulsion was in Spain, where the Moors and the Christians both used some kind of artillery as early as the twelfth century after Christ. Gunpowder was first introduced into England by Roger Bacon, a British scientist, who was born early in the thirteenth century. He probably did not discover its properties independently, but by reading ancient manuscripts. Owing to the crude and uncertain methods of making gunpowder, it did not attain much value until Berthold Schwarz, a German monk, at about 1320 A.D. introduced an improved method of manufacture. The improved powder thus made was first used in England by King Edward III in his war against the Scotch in 1327. It was perhaps used on the continent of Europe earlier than this, but the occasions are uncertain. The tubes from which the missiles were propelled were called "crakeys of war." Spenser called cannon "those devilish iron engines." They were probably used for the first time in field warfare by the English in the battle at Crécy, a small town in France, where on August 26, 1346, the English defeated the French. The artillery seemed to have been used in this battle merely to frighten the horses of the enemy, and the cannon were laughed at as ingenious toys.