EARLY HISTORY The first rockets were probably made in China. When Mongol armies besieged the town of Kaifeng in ¥ 1232,
the townsfolk repulsed them with "arrows of flying fire." Tied to the shafts were tubes containing an early form of
gunpowder, which
produced a fiery exhaust. That these rockets were not purely incendiary devices is implied in an ancient manuscript that describes them as "making a noise like thunder" and "traveling a great distance." In the Middle East and Europe, the art of rocketry appeared soon afterward. In 1242 the English Franciscan monk Roger Bacon produced a secret formula for gunpowder, specifying 41.2 parts saltpeter, 29.4 parts charcoal, and 29.4 parts sulfur. He also succeeded in distilling saltpeterÑan oxygen-producing ingredientÑto achieve the faster rates of burning that would make rockets more practicable. In The Book of Fighting on Horseback and with War Engines, composed about 1280, the Syrian scholar al-Hassan-al-Rammah gave instructions for making gunpowder and rockets, which he called "Chinese arrows." Rockets are also mentioned in a German chronicle of 1258, and the Italian historian Muraroti describes how, during the siege of Chiozzia (near Venice) in 1379, a defending tower was set ablaze by a black powder rocket, thereby eliminating the last pocket of resistance. The British first encountered rocket warfare in India, to which the secret of rocket manufacture had probably been brought during the 17th century by Arab traders. Manuscripts suggest that the 18th-century Indian ruler Hyder Ali employed thousands of men for throwing rockets during warfare. Constructed of a thick stalk of bamboo 2.5 to 3 m (8 to 10 ft) long attached to a tube of iron weighing from 2.5 to 5.5 kg (6 to 12 lb) containing the fuse and powder, this rocket was said to be able to reach a distance of 2.5 km (1.5 mi). When the first examples of the Indian rockets reached England around 1770, Captain Thomas Desaguliers examined their structure at the Royal Laboratory at Woolwich, but he failed to reproduce their range or accuracy. The matter rested there until 1804, when inventor William Congreve took up the challenge and asked Woolwich to have several large rockets made to his specifications. Because a rocket has no recoil, Congreve thought that they might find application both at sea and on land. Within a year he had produced a 24-pounder with a range of about 1,800 m (6,000 ft). Congreve rockets were first used in battle during the Napoleonic Wars on the night of Oct. 8, 1806, when 18 rocket boats were quietly slipped from mother ships and rowed into Boulogne harbor (France) to enable officers and men of the Royal Marine Artillery to attack the French invasion fleet. The rocketsÑ32-pounders measuring 1.06 m (3.5 ft) long by 10 cm (4 in) in diameterÑhad balancing sticks 4.5 m (15 ft) long and a range of about 2,700 m (9,000 ft). Some of the warheads contained ball-shot to create a shrapnel effect; others had a liquid incendiary compound that squeezed out a flame from holes in the pointed nosecap and impaled wooden ships and buildings. The year 1810 saw the publication in London of W. Moore's treatise On the Motion of Rockets, which contained a mathematical study of rocket motors and trajectories. By 1844, the Englishman William Hale had invented spin-stabilized rockets, which eliminated the cumbersome guide sticks. These rockets were set into rotation by deflecting the exhaust through offset nozzles drilled in the baseplate, and, later, by restricting the expanding exhaust gases on one side of the nozzles by the use of semicircular vanes.