Jess (falconry) the bird, but the width is proportional to leg-length. Traditional jesses are made from a single length of leather, and slits are placed strategically along the jess to allow it to be looped through itself and around the ankle of the bird so that it fits comfortably but securely about and just above what would be the bird's ankle. With Aylmeri jesses, as created by Major Guy Aylmeri, the end of the jess is instead looped through itself repeatedly to form a "button", or knob at one end. The thin, pliable end of the jess is then threaded through an
Leather cannon especially if the terrain was uneven. Gustavus Adolphus' tactics were based on use of effective firepower. While heavy cannon were effective at the start of the battle, they could not be moved from the hill that they usually were deployed on (the guns themselves weighed from roughly 300 kilograms (660 pounds) to 3 tons). As such, the artillery could not respond effectively to developments in battle. In order to fill the gap, the so-called "leather cannon" was developed. A relatively thin copper tube was reinforced by heavy cords and finally clad in leather (alternatively clad in leather straps first and