 Complete the following phrase:  Gustavus Adolphus of Sweden emphasized the use of light cannon and mobility in his army, and created new formations and tactics that revolutionized artillery. He discontinued using all 12 pounderor heaviercannon as field artillery, preferring, instead, to use cannon that could be manned by only a few men. One gun, called the leatheren, could be serviced by only two persons, but was abandoned, replaced by 4 pounder and 9 pounder demi-culverins. These could be operated by three men, and pulled by only two horses. Also, Adolphuss army was the first to use a special cartridge that contained both powder and shot, which sped up loading, and therefore increased the rate of fire. Additionally, he pioneered the use of canister shot against infantry, which was essentially a can, filled with musket balls. At the time, for each thousand infantrymen, there was one cannon on the battlefield; Gustavus Adolphus increased the number of cannon in his army so dramatically, that there were six cannon for each one thousand infantry. Each regiment was assigned two pieces, though he often decided to arrange his artillery into batteries, instead. These were to decimate the enemys infantry, while his cavalry outflanked their heavy guns. At the 