"saucers full of Greek fire"

 Greek Fire is a term used to describe an incendiary weapon used by the Byzantine Empire.  Concocted from a recipe that was very soon lost in the passage of time, it was pumped through large bronze tubes, usually onto enemy ships during sea battles.  Thought to have been invented in the 7th Century, its flames could not be extinguished by water; it would coat surfaces, stick to them, and ignite upon contact.  Evidence suggests that the weapon was used rarely, but caused devastating results when it was.  In 678, for example, the Byzantines destroyed an entire Muslim fleet of 30,000 men; it would appear that Greek Fire was reserved for battles of high importance.  To this day, nobody has been able to recreate the formula.