to create smoke screens to mask movements of friendly forces or disorient enemies, or to mark specific areas. The main types are bursting (using a payload powdered chemicals) and base ejection (delivering three or four smoke canisters which are deployed from the rear of the shell prior to impact, or a single canister containing submunitions distributed via a bursting charge). Base ejection shells are a type of carrier shell or cargo munition. Base ejection smoke is usually white, however, colored smoke has been used for marking purposes. The original canisters typically used hexachloroethane-zinc (HC), modern ones use red phosphorus because of its multi-spectral properties. However, other compounds have been used; in World War II, Germany used oleum (fuming sulfuric acid) and pumice. Due to the nature of their payload, powder smoke shells using white phosphorus in particular have a secondary effect as incendiary weapons, though they are not as effective in this role as dedicated weapons using thermite. Illumination Modern illuminating shells are a type of carrier shell or cargo munition. Those used in World War I were shrapnel pattern shells ejecting small burning "pots". A modern illumination shell has a time fuze that ejects a flare "package" through the base of the carrier shell at a standard height above ground (typically about 600 metres), from where it slowly falls beneath a non-flammable parachute, illuminating the area below. The ejection process also initiates a pyrotechnic flare emitting white or "black" infrared light. Typically illumination flares burn for about 60 seconds. These are also known as starshell or star shell. Infrared illumination is a more recent development used to enhance the performance of night-vision devices. Both white- and black-light illuminating shells may be used to provide continuous illumination over an area for a period of time and may use several dispersed aimpoints to illuminate a large area. Alternatively, firing single illuminating shells may be coordinated with the adjustment of HE shell fire onto a target. Colored flare shells have also been used for target marking and other signaling purposes. Carrier The carrier shell is simply a hollow carrier equipped with a fuze that ejects the contents at a calculated time. They are often filled with leaflets (see external links), but can be filled with anything that meets the weight restrictions and is able to withstand the shock of firing. Famously, on Christmas Day 1899 during the siege of Ladysmith, the Boers