I was just about to ask HN to come up with some communication devices using only ancient technology.
Although your rubber duck system would require less manpower than a system of signal fires, it would be MUCH slower, and probably even slower than the chains of horse riders that delivered messages Pony Express-style across the Roman Empire. In an emergency, a message could be transferred over 100 miles a day.
Although your rubber duck system would require less manpower than a system of signal fires, it would be MUCH slower, and probably even slower than the chains of horse riders that delivered messages Pony Express-style across the Roman Empire. In an emergency, a message could be transferred over 100 miles a day.
https://en.wikipedia.org/wiki/Cursus_publicus