Humanities Simulation: Claude Chappe’s Telegraph

Thanks to the specter of professional obligation, a brief post detailing my work on simulation made it on to the UCLA Digital Humanities website.  I was very gratified for the opportunity to share what is (more or less) my personal work, and am very thankful to Miriam Posner for her signal-boosting retweet.

I thought I’d just take a second to dump some screenshots and explain the project in a bit more detail.  The thumbnail description is that I’m working on a simulation platform, used for the Chappe example, for discrete, agent-based modelling. More plainly, time advances in discrete steps, and each object modeled has a set of desires, goals etc. controlled at an individual level of granularity.

This is the base simulation.  On the left is the map of Chappe’s French network, circa about 1848 (it is geographically flattened). Each grey box is an originating station (the five in the Center make Paris. And aren’t they just as gran) and each black box is an interstitial station.  This is by Chappe’s own design — to keep codes secret, only higher-level functionaries at certain stations could commence transmissions.  Currently, all input is done from the console on the right.  The text displayed is the transition probability between spaces — since historical data concerning the transition probability from station to station exists, this can be used to simulate weather conditions.

Clicking on one of the initial stations allows you to enter the destination station on that line, as well as your message (all a bit crude right now, but emphasizing the discrete nature of writing, I suppose).

After you enter your message, press ‘S’ to step the simulation one time unit. Each station checks the station before it to see if it holds a new message. If it does, that station copies the message, and waits for the last station to display a new message before changing again.  This is also by Chappe’s design — a control regime that anticipates the development of information theory.

The messages are represented by the small white symbols that correspond to the arm positions of Chappe’s semaphore code.

Part of the joy of this system is it is already modular.  The network map is taken from a .csv file, as a sort of crude tilemap. This means you can make counterfactual maps to your heart’s delight, along with simulating the weather conditions that might impact transmission over certain inclement weather/geography areas (say, the Rocky Mountains).  With the addition of the (fortunately extant) data on average transmission speeds of Chappe’s original telegraph, you can even deduce the potential speed of these networks that never were.

Chappe is to be my starting point — I’m hoping to extend this to simulations of early American print culture.  Hopefully the time in which I can do that will eventually manifest!