Sholes and Glidden typewriter length. The redesigned platen also introduced the modern spacing functionality (horizontal and axial movement providing letter and line spacing, respectively). The cylindrical platen became "an indispensable part of every standard [typewriter]". By the end of 1872, the appearance and function of the typewriter had assumed the form that would become standard in the industry and remain largely unchanged for the next century. Although the machine possessed a cylindrical platen and what was essentially a QWERTY keyboard, two design elements that would later become essential were lacking: the ability to write in upper and lowercase letters and "visible" print. Although the
Typewriter 19th century, but the first machine known to be produced in series is the Cahill of 1900. Another electric typewriter was produced by the Blickensderfer Manufacturing Company, of Stamford, Connecticut, in 1902. Like the manual Blickensderfer typewriters, it used a cylindrical typewheel rather than individual typebars. The machine was produced in several variants but apparently it was not a commercial success, for reasons that are unclear. The next step in the development of the electric typewriter came in 1910, when Charles and Howard Krum filed a patent for the first practical teletypewriter. The Krums' machine, named the Morkrum Printing Telegraph,