An interesting book on the subject of telegraph networks is The Victorian Internet by Tom Standage [1]. As well as the technical and commercial drivers, it also describes how the telegraph forced people to confront concepts like simultaneity, information being distinct from its physical medium, privacy, early approaches to encryption, etc. A fascinating book. [1] https://en.wikipedia.org/wiki/The_Victorian_Internet
The GBP/USD currency pair is still known just as "the cable". Aside from all its other uses: the telegraph gave a way to synchronize clocks. And accurate time is accurate measurement of distance. > [...] The latest determination in 1892 is due to the cooperation of the McGill College Observatory at Montreal, Canada, with the Greenwich Observatory. [...] The final value for the longitude of the Harvard Observatory at…
This essentially doubled the capital intensity of international trade since the goods had to move in one direction but the money could be sent instantaneously in the other.