Armature: any part of an electric machine or device that vibrates under the influence of a magnetic field or within which an electromotive force is induced.

Armour: a protective covering

ATC: Atlantic Telegraph Company

Cable Line Indicator: a bell system that let the operator know which cable was calling. The small flags in the boxes indicated the source of the incoming messages.

Cable Relay: used to strengthen the signal received over the cable. Messages transmitted across the Atlantic became weakened and required this device.

Conductor: any material (e.g., copper) which allows an electrical charge to flow through it.

"CS": abbreviation for Commercial Cable Station.

Current: term used to describe electrical charges moving through a wire.

Electric telegraph: an electrically operated device or system for distant communication by means of visible or audible signals.

Electromagnet: works just like an ordinary magnet except that it only attracts while electricity is passing through its coil.

"Faraday": Siemens Brothers of London built the world's first ship designed specifically for laying cables. It was named after Michael Faraday, a pioneer of electrical technology.

Grapnel: an iron-clawed device attached to a rope and often used to retrieve an object.

"Great Eastern": during the Cable Expedition of 1865 only this ship would be big enough to carry the enormous weightof the cable. The Great Eastern weighed 18,000 tons and was 700 feet long and 85 feet wide. When converted into a cableship it had three enormous cable tanks.

Gutta Percha: a type of rubber obtained from the gutta percha tree, native ot Malaysia.

Hawser: a large rope or small cable.

Headphones: listening device used under varying circumstances to hear signals.

Inner sheathing: the inner sheathing of iron cables provided mechanical insulation, protecting the core from being damaged. For deep water, the breaking strain of the iron cables had to be around 100 tons per square inch.

Insulation: the insulating layer was invariably made from commercial gutta, a mixture of the gum gutta-percha (which was shipped in from the Far East), resin and water. Good-quality gutta was tough, water resistant and durable.

Insulator: any material (e.g., glass) which does not allow an electrical charge to flow through it.

Jute yarn: the yarn acted as a cushion between the cable core and the heavy iron wires that were used to protect it.

Leviathan: a very large ship.

Mirror Galvanometer: instrument consisting of a small but light steel magnet to which a tiny reflecting mirror is attached. It greatly improved the ability to receive messages. This instrument was capable of receiving 20 words per minute where as previous devices could only receive two.

Morse Code: code used by Samuel Morse to allow letters to be sent as short electrical signals (dots) and long electrical signals (dashes) was also called the "American" Morse Code.

Needle telegraph: device that required two or more lines to form a complete circuit.

Outer sheathing: the part of the cable that was out of the water at the Shore End was more prone to damage, so it was sheathed in a second layer of iron for added protection from the elements.

Relay: were used to detect the weak current in telegraph cables (10-20mA). The relay translates the signal on the telegraph line into an equivalent signal in a local circuit.

Resistance box: was used to put known values of resistance into circuits. These boxes came in several different, but equivalent, formats.

Semaphores: an apparatus for conveying information by means of visual signals, as with flags, etc.

Sounder: was a device for interpreting the signals coming off the telegraph cable. Every time a morse key was pressed, the sounder at the other end of the line made a corresponding 'click.'

Splice: to join two cables by interweaving the strands.

Submarine Cable: the submarine cable consisted of copper conductors insulated with India rubber and varnish. Jute Yarn which acted as a cushion between the cable core, the inner sheathing of iron cables, provided mechanical insulation. The inner sheathing was covered in two layers of conversely wrapped jute yarn, in order to keep the iron cables together. The part of the cable that was out of the water at the Shore End was more prone to damage, so it was sheathed in a second layer of iron for added protection from the elements. To keep the outer sheathing together, the iron cables were also wrapped in jute yarn.

Telecommunications: is the process of communicating over a long distance.

Telegram: a message sent by telegraph.

Telegraph: enables a detailed message to be sent instantaneously between two locations.

Telegraphy: comes from Greek. Tele meaning distant and graphein to write.

Telegraph key: used in sending out messages in code over the wires. Wires were stretched from one point to another and an electric current was either allowed to flow through the wires or broken by a switch called a telegraph key.

Transatlantic: crossing the Atlantic.