The History, Function, and Significance of Semaphore Telegraph Towers – Update 1

     Over the past two weeks, I have consulted various sources concerning optical telegraph systems, ranging from technical diagrams and close-up photographs to philosophical analysis of communication and comparisons to ancient and modern technologies.

     Historians and enthusiasts employ a variety of terms when discussing optical telegraphs, so it will be useful to pin down the definitions of a few. “Telegraph” refers to any method for communication over distance which does not involve the physical movement of an object over that distance – flag semaphore counts, but sending a letter does not. “Optical telegraph” refers to any sight-based telegraph technology. A “semaphore telegraph” is a type of optical telegraph employing a system of signs carrying encoded messages, communicated through signaling apparatuses such as arms or shutters. A “semaphore line” refers to a series of semaphore telegraph towers, each of which repeats the message of the tower before it, transmitting the message from station to station and down the line.

     Most of the optical telegraph systems discussed in this paper are semaphore telegraphs, since they use movable elements to transmit encoded messages. While semaphore telegraph systems intended to transmit information across long distances employ semaphore lines, certain semaphore telegraph towers stand on their own, transmitting their message only to people who can see it, and not to other towers for further transmission. One such example of a solitary tower is the semaphore tower which gave name to San Francisco’s Telegraph Hill. This tower looked down over the harbor and signaled the nature of ships which entered – valuable information to investors and businessmen.

     The first (and arguably most iconic) practical optical telegraph system of the early industrial period originated in France, prompting other nations to adopt the French system or develop a competing system. Thus, the revolutionary French system is a source of French national pride, and much French-language scholarship exists, sometimes providing details or interpretations not found in English-language scholarship. For this reason, my knowledge of French proved very useful, allowing me to read through French articles and web pages as I would those in English, providing information from people who feel a greater connection to the technology.

     The optical telegraph is a relatively obscure topic compared to later analogues such as the electric telegraph, to the point where people who live near remaining optical telegraph towers (out of use for centuries, and nearly universally stripped of their signalling equipment) often do not know the purpose or history of these towers, inaccurately classifying them as guard towers or something similar. Additionally, scant documentation, disappearing structures, and general forgetting can mean that the paths of semaphore lines, and the locations of towers, are not entirely known, as is the case with the Nova Scotia network.

     A decent amount of scholarship exists on the history and implications of the semaphore telegraph, but scholars do not typically concern themselves with relating the exact locations or precise mechanics of towers. Thus, this task falls to amateur enthusiasts, who seek to trace semaphore lines, visit remaining towers, and document such endeavors on websites. These sites proved useful in supplementing scholarly writings, and providing a full picture of semaphore telegraph systems, addressing both the concrete and the abstract.

     I have begun writing my research paper, which will be one of the final products of this project. It will place optical telegraph systems of the late 18th and early 19th centuries in their historical context, addressing precursors as well as successors. The paper will also describe the locations and operation of towers and lines, in order to show their extent and significance. The other final product will be one to three scale models of optical telegraph equipment, focusing on signaling systems (i.e. arms and shutters). I believe these models will enhance my presentation by allowing viewers to see the physical characteristics and operation of the obscure technologies. At this point, I will continue writing my paper and planning the models, providing further details in subsequent updates.

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