Submarine Telegraph Cables
From London's Ghost Acres
A speciality of the Silvertown Works, submarine telegraph cables were critical to the creation of a global telecommunications network. The cables themselves were a resource-intensive product, requiring several layers of gutta-percha, jute, iron wire, and tar wrapped around a core of copper wire. Caoutchouc (rubber) was used in the earliest production of cables, but was found to degrade on the seafloor much too quickly.