Mixtures enter military practice
During Tang and Song times, knowledge involving sulphur, saltpetre and carbon-based materials entered incendiary devices. The military compilation Wujing zongyao, completed in 1044, preserved formulations and weapon descriptions. Material properties, supply and storage mattered, requiring makers and logistical support. Early devices differed from later firearms, using fire, smoke or explosive action in varied designs. Written organization made techniques teachable and reflected government efforts to assemble practical military knowledge.
Devices change with warfare
Incendiary arrows, balls and other devices combined substances with structures suited for delivery. Launchers, containers and ignition affected performance. Song-Jin conflicts encouraged continued changes, followed by fire lances and metal firearms. Moisture, danger and production consistency required attention and trained users. Designs developed within siege, naval and supply conditions. New devices altered some methods of attack and defence while increasing the demands of manufacture, transport and material storage.
Knowledge spreads through Eurasia
Gunpowder and weapon knowledge later moved across Eurasia, with regions adapting devices to materials, casting skills and military needs. Warfare and contact in the Mongol period helped move people and techniques, but diffusion was gradual. Formulations, containers and operating methods combined differently over time. Song records preserve early practice within this longer development. Expanding weapons production tied state manufacturing capacity and sustained supplies increasingly closely to the actions of armies.