El Camino Real, The Royal Road (a foot trail) connected the Spanish Mission plantations on the west coast of Mexico, now partly California. The natives were worked to death in exchange for salvation. In places, roads and state highways that parallel the path are called El Camino Real, or El Camino Real Highway. Bells about a mile apart served as a security measure. Someone who was injured, or attacked could attempt to reach the nearest bell and ring it to summon help. I don’t know if it ever really worked. It might have summoned more bandits. Travel was really dangerous before the railroads; armed guards were a good idea.
Bells unlike other instruments produce a lot of sound relative to the energy to activate them. There are other more practical applications. Sleigh bells, warn the bears that you are coming so you don’t startle and provoke them. Church bells call the faithful to prayer and can celebrate joyful events. They can also toll for the dead, with a different cadence. Town hall bells could provide some of those services and often served as the town’s clock striking as frequently as a quarter hour and tolling the hour count. Maybe that’s why we use a 12-hour clock, tolling 24 at midnight would be very annoying. Ships’ bells served two purposes. Strikes on the ship’s bell marked the progress of each watch, usually every four hours (8 bells). Continuous ringing warned other vessels of a ship’s presence in a fog. Harbor buoys had distinctive bells, gongs or whistles to alert sailors in fog or darkness and identify their location. The invention of steam engines with their boilers made steam whistles practical and potentially very loud. Some were big enough to be heard several miles. Factory whistles in many places served as a town clock that could be heard over a wide area.
The first mechanical siren was patented in 1799 and gradually became the default and ubiquitous warning device. All the others could be mistaken, but we have all learned that a siren is either a serious warning or a mythological singer. The first sirens were hand cranked but it was not long before ways were found to attach an engine or electric motor. During wartime sirens were used to warn large urban populations to take cover and air-raid-siren became a cliché.
In Hawaii Tsunami-warning-siren has become a cliché, belying the other purposes they might be put to. The siren now really means get more information, quickly. In the 50’s, it meant turn on your radio, the 60s TV or today, internet. Everyone should know that but why are we basically constrained by a nineteenth century technology with such a limited vocabulary? One idea is to have different tones for different emergencies or loud PA systems. That has been tried with limited success, unfortunately echoes can garble the message.
I wonder why we have a statewide system 400 gigantic expensive sirens in Hawaii that are miles apart. They have not been impressively reliable. Each siren is actually a multitude of individual machines on a single pole. Painfully loud if you are nearby, but limited in effectiveness as you move away, seldom useful farther than one mile. Adding more sirens at the same location makes it louder, but does not significantly improve the range so it has a diminishing benefit. Each warns about 3 square miles. Basically, it is an 18 th century technology hooked to 19 th century power via 20th century communication. Would thousands of smaller solar powered devices distributed on utility poles, activated by modern wireless electronics work better?
Mechanical sirens on vehicles that do not need to be heard as far away have been largely replaced with electronic devices that can have various situation specific voices. Wail, high-low, yip-yip or even spoken words.
Maybe we could do an even better job with a completely new system that can pre-empt all other communication within the affected area long enough to send a warning, and a link. There would have to be an opt out choice for special cases, and the operator would have to have the discipline to not let bad data drive out good data. Lives could be saved.