Jess (falconry) Jess (falconry) A jess (plural "jesses") is a thin strap, traditionally made from leather, used to tether a hawk or falcon in falconry. Jesses allow a falconer to keep control of a bird while it is on the glove or in training, and allow a bird to be secured on a perch outside its aviary. Jesses come in various types: Jesses are generally made from strips of leather as thin as possible, for which purpose kangaroo leather has become increasingly popular over the years, as it is thin, light-weight and extremely durable with proper care. Jess size varies depending on
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