Estienne apparatus
The Estienne apparatus is a telegraph from the 19th century .
functionality
The Estienne apparatus is a writing telegraph comparable to the Morse apparatus . The Estienne apparatus has two nibs in place of the writing wheel, which take paint from a paint container by capillary action and transfer it to a strip of paper. The nibs are set in motion by the two prongs of a fork-shaped lever that moves to the right or left under the influence of the current.
The writing surface of one nib is twice as wide as that of the other; the former is used to represent the lines, the latter to generate the points. The fork shaft has an iron tongue on the back of the device, the upper end of which protrudes between the pole pieces of an electromagnet. The lower end is magnetically polarized by the movable pole piece of a steel magnet mounted below the apparatus, so that currents in different directions deflect the tongue in opposite directions. Alternating currents are used to operate the device, which are sent using a double button.