Military necessity mothered many metamorphoses of communication. The heliograph was one.
The month is February. The year is 1900. The battle is near Paardeberg. The problem is General Piet Cronje’s Boer force is surrounded. Cronje’s men are outnumbered more than 3:1 by a 15,000-man British force led by General Frederick Roberts. Cronje has blundered repeatedly into this current situation, but fellow Boer leader Christian De Wet is just miles away with a force of 1,500 giving the British forces fits. If De Wet and Cronje can get on the same page, De Wet can burst a secure a hole long enough in the British circle for Cronje’s beleaguered Boers to escape.
Obviously, a dispatch runner could be an answer here, but beyond the obvious danger of slipping through British lines, there is no efficient way to guarantee receipt of the message or a speedy reply. Terrain feels constant while weather can change on a dime. Both constantly present challenges and opportunities to the soldier, to the tactician. Terrain and weather make distance irrelevant or prohibitive. So can timing. For the past 100 years, most conventional armies have leaned on some form of the radio or telephone. But telephone landlines required time to lay and control of the land, and took much less time to cut. Walkie talkies were not yet widespread.
The two officers could use a system of shouting men to relay the message like the ancient Persians, but this would present at least four problems. This shouting relay team would risk garbling the message, would take longer greater depending on the distance, could be thwarted if the enemy was wedged between them, and would proportionately waste manpower based on the distance the message had to travel. Sending someone on horseback to relay the message could be an option, unless of course the enemy was already wedged between the general and the colonel.
If the message to the colonel were simpler, the general and colonel could communicate using flags much like the Egyptians or Chinese first did. Cretans four thousand years ago may have sent tactical messages using polished silver or bronze plates to flash messages, but these were likely simple as well. The Ponca tribe used reflective pieces of mica to communicate between hunting and war parties in the 1800s, but these were likely simple messages such as “enemy to your left” using say three flashes. Two men in the early 19th century would make waves felt by militaries for decades: Samuel B. Morse and Carl Friedrich Gauss. See part 2 for the rest of this story.
To learn more on your own see:
Evans, Nick. “THE BRITISH ARMY AND COMMUNICATIONS, 1899-1914.” Journal of the Society for Army Historical Research94, no. 379 (2016): 208-24. Accessed June 5, 2020. www.jstor.org/stable/44232704.
Nasson, Bill. The Boer War: The Struggle for South Africa. Stroud, United Kingdom: The History Press, 2011. P. 167-179.
Smith, Steven Trent. “Light Conversation: The Heliograph” https://www.historynet.com/light-conversation-heliograph.htm