Optical telegraph
device · 1792 · Industrial Revolution
Chappe’s semaphore line.
What it is made of
- Semaphore tower — has part. A tower with movable sails.
- Semaphore signal arms — has part. The positions of the arms encode characters.
- Telescope — has part. Operators read the neighbouring tower through a telescope.
Principles and materials it uses
- Lens — uses. Signals were read through telescopes.
- Wood — is made of. Chappe’s semaphore has wooden arms on a mast.
- Telescope — uses. Signals were read through a telescope.
- Lever — uses. The arms were moved by a system of levers and rods.
History: what it evolved from and what it influenced
- Electrical telegraph — evolved into. The electrical telegraph replaced semaphore lines.
- Railway semaphore — evolved into. The semaphore idea.
What it is a kind of
- Means of communication — is a kind of. A means of communication.