Wagon fort the square would usually be the cavalry. There were two principal stages of the battle using the wagon fort: defensive and counterattack. The defensive part would be a pounding of the enemy with artillery. The Hussite artillery was a primitive form of a howitzer, called in Czech a "houfnice", from which the English word howitzer comes. Also, they called their guns the Czech word "píšťala" (hand cannon), meaning that they were shaped like a pipe or a fife, from which the English word pistol is possibly derived. When the enemy would come close to the wagon fort, crossbowmen and hand-gunners
Field emission gun Field emission gun A field emission gun is a type of electron gun in which a sharply pointed Müller-type emitter is held at several kilovolts negative potential relative to a nearby electrode, so that there is sufficient potential gradient at the emitter surface to cause field electron emission. Emitters are either of cold-cathode type, usually made of single crystal tungsten sharpened to a tip radius of about 100 nm, or of the Schottky type, in which thermionic emission is enhanced by barrier lowering in the presence of a high electric field. Schottky emitters are made by coating a tungsten tip