In my pre-electricity world, fast communication is achieved by means of lighthouses, each being able to direct strong and precise beams of light towards distantly visible lighthouses.

However a problem is encountered whenever the weather turns. Many meteorological conditions, such as fog, rain, hail, snow, or various mirages, can interfere with these signals and prevent reliable communication.

Since such conditions, especially fog, are very common in certain areas, an alternative form of distant communication is required.

The usage of messengers is not a viable solution since certain lines of communication are disrupted to traffic on foot, e.g. one pair of signal towers signals to an island surrounded by strong currents.

The question is now, **what other techniques could be used to send messages?**

Edit: The messages sent function as the government 'internet'. As a result messages are often highly compressed (think of a [shorthand](https://en.wikipedia.org/wiki/Shorthand)-like correspondence), but there are large amounts of them.

Rural regions may get by with only emergency communications, but suburbs and more densely populated or important regions have a significantly higher bandwidth requirement.