Explosion. Airborne detonation test of nitro- methane, an experimental mining explosive. Instruments around the fireball measure its thermal output. Explosives burn rapidly, creating large amounts of gas and heat to cause a sudden increase in pressure. Explosives need to be studied carefully to allow them to be stored and used safely. Photographed during research conducted by the Health and Safety Laboratory, Britain. CROWN COPYRIGHT UNDER LICENCE FROM THE HEALTH & SAFETY LABORATORY & CONTROLLER OF HER MAJESTY'S STATIONERY OFFICE & CONTROLLER OF HER MAJESTY'S STATIONERY OFFICE