# hydraulic telegraph

> Semaphore systems using water-based mechanisms

**Wikidata**: [Q3556577](https://www.wikidata.org/wiki/Q3556577)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Hydraulic_telegraph)  
**Source**: https://4ort.xyz/entity/hydraulic-telegraph


## References

1. Freebase Data Dumps. 2013