“_Volley fire_” is the usual fire employed by machine guns and corresponds to the volley fire of infantry. After the target and the elevation have been designated, the platoon commander directs that fire he opened by calling the name of the gun pointer who is to fire. A pause is made after every series of 20-30 shots, which is used to make necessary corrections. As soon as the proper elevation has been determined, “_rapid fire_” is opened. In this the _guns of a platoon fire alternately_. The fire is delivered in series of 100 rounds, and the time during which one of the guns is not firing is utilized by the non-commissioned officer with it to examine and oil the mechanism. The “_fire at will_” (continuous fire) of the machine guns corresponds to the magazine fire of the infantry. _All the guns fire simultaneously_ series of 50 to 100 rounds, interrupting the fire for a moment at the end of each series for the purpose of examining and oiling the mechanism; then they resume the fire with a new series of 50 to 100 rounds. On account of the great expenditure of ammunition entailed, and also in order to prevent the premature deterioration of the matériel, fire at will is used in exceptional cases only, for example, when danger is imminent, or when favorable opportunities offer. “_Progressive fire_” may be employed against narrow, deep targets, when the range could not be accurately determined. It may also be employed for searching an area 100-200 m. deep. =Austria= has begun to organize _cavalry and mountain machine gun batteries_ consisting of four guns each. The machine gun Model 7 (_Schwarzlose_), with pack animal equipment, has been adopted. The gun horse carries 500, and each of the two ammunition horses, 1500 rounds of ammunition. During mobilization two ammunition horses are to be added for each gun. Mountain machine gun batteries are similarly organized; each ammunition horse carries 2000 rounds of ammunition. On the gun itself, and on the gun frame, 44 belts, each holding 250 rounds, or a total of 11,000 rounds, are carried.[294] [294] The Schwarzlose machine gun weighs 18 kg. exclusive of frame and the water in the jacket. (The Maxim weighs 28 kg.). The formations employed by the cavalry machine gun batteries are the order in line (at close intervals), the combat order, and the route column.