Saltpeter in the context of "Cations"

The Bengal Subah (Bengali: সুবাহ বাংলা, Persian: صوبه بنگاله), also referred to as Mughal Bengal and Bengal State (after 1717), was the largest subdivision of the Mughal Empire encompassing much of the Bengal region, which includes modern-day Bangladesh, the Indian state of West Bengal, and some parts of the present-day Indian states of Bihar (from 1733), Jharkhand and Odisha between the 16th and 18th centuries. The province was established following the dissolution of the Bengal Sultanate, a major trading nation in the world, when the region was absorbed into the Mughal Empire. Bengal was the wealthiest region in the Indian subcontinent.

Aurangzeb (r. 1658–1707) described Bengal Subah as 'the paradise of Nations' and the "Golden Age of Bengal". It alone accounted for 40% of Dutch imports from Asia. The eastern part of Bengal was globally prominent in industries such as textile manufacturing and shipbuilding, and it was a major exporter of silk and cotton textiles, steel, saltpeter, and agricultural and industrial produce in the world. The region was also the basis of the Anglo-Bengal War.

The Wujing Zongyao (Chinese: 武經總要), sometimes rendered in English as the Complete Essentials for the Military Classics, is a Chinese military compendium written from around 1040 to 1044.

The book was compiled during the Northern Song dynasty by Zeng Gongliang (曾公亮), Ding Du (丁度) and Yang Weide (楊惟德), whose writing influenced many later Chinese military writers. The compendium was published under the auspices of Emperor Renzong of Song, who also authored the book's preface. The book covers a wide range of subjects, including everything from naval warships to different types of catapults. It contains the earliest known written chemical formulas for gunpowder, made from saltpeter, sulphur and charcoal along with many added ingredients. In addition to formulas for gunpowder, the compendium also contains details on various other gunpowder weapons such as fire arrows, incendiary bombs and projectiles, and grenades and smoke bombs. It also describes an early form of the compass (using thermoremanence), and has the oldest illustration of a Chinese flamethrower with a double-action dual-piston cylinder-pump capable of shooting a continuous blast of flame.

Bernard Courtois (French pronunciation: [bɛʁnaʁ kuʁtwa]), also spelled Barnard Courtois, (8 February 1777 – 27 September 1838) was a French chemist credited with first isolating iodine, making early photography possible.

By 1811 the Napoleonic Wars had made the government-controlled saltpeter business taper off since there was by then a shortage of wood ashes with which potassium nitrate was made. As an alternative, the needed potassium nitrate was derived from seaweed that was abundant on the Normandy and Brittany shores. The seaweed also had another, yet undiscovered, important chemical. One day towards the end of 1811 while Courtois was isolating sodium and potassium compounds from seaweed ash, he discovered iodine after he added sulfuric acid to the seaweed ash. He was investigating corrosion of his copper vessels when he noticed a vapor given off. It was in the form of an unusual purple vapor. Humphry Davy later records