Showing today are three mechanical pencils represented as a cluster of canon. All are different. Circa 1880. From the top they are made by: 1.) likely Sampson Mordan and unmarked, 2.) Sampson Mordan and 3.) Fairchild. All are made of sterling silver (except the inner workings). The top piece features a manual pull telescopic section/writing tip. With the middle piece, a telescopic section/tip is driven out to writing position via a stiff spring. The smallest and lowest pictured pencil extends by pulling the back ring away from the body This action simultaneously forces the working section/tip out to the writing position.. Generically, this pull/push style is referred to as a magic pencil. Internal gearing supplies the actual magic. The longest pencil is 2 3/8 inches long closed and 4 inches ready to write. The smallest of the bunch measures 1 7/8 inches compacted and 2 15/16 inches deployed. Measurements do not include the stirrups and rings. Boom! 😀