The Compass - a simple device that changed the world

Travellers would be lost without one!

A traditional magnetic compass. A gift from my colleagues when I retired in September 2022. Image: Roland’s Travels

The magnetic compass is a simple device. It can indeed be said that it changed the world. Without a compass, explorers of old would not have navigated around the world. Until modern times travel across oceans and continents depended on the magnetic compass. There are modern variations of the compass, but even the most sophisticated ship will have a magnetic compass as a backup.

The Chinese have been credited with the invention of the compass, way back in 206 B.C. They discovered lodestone, a naturally magnetised iron stone which would spin in a north-south direction.

The Chinese called it the ‘south-pointing fish’; today, we tend to say it points north, but of course, the opposite end of the needle points south. It was used for land travel from the 11^th century. Interestingly first mention of a needle was by the Chinese scientist and statesman Shen Kuo in 1088. The earliest needle compasses likely had the needle attached to a piece of wood or cork and floated in a dish of water. In principle, little has changed in the design. The 20th century saw the development of liquid-filled dials. The liquid prevents the needle from bouncing around so much and helps it settle in the direction it wants to point.

The Problems with a Magnetic Compass

We have to remember a couple of issues with the magnetic compass.

Firstly the compass points to the magnetic north and not the north pole. When following a map, that difference has to be taken into account. The magnetic pole also moves a little each year. A good map, such as those produced in the UK by Ordnance Survey, will show the difference and how to allow for the movement since the map was published. You need to remember that the longer the journey, the more the difference will be noticeable if you don’t make the necessary correction. You could find yourself many miles away from your intended destination.

The second issue with a magnetic compass is that the needle can be moved by outside magnetic forces and point in the wrong direction. Never use a compass near metal objects or electronic equipment like a mobile phone. These can attract the north of the needle to point towards or away from them. The magnetic compass on metal ships coupled with electronics was a problem as ships moved from wood to iron. There were ways to counteract this, but of course, along came gyroscopes and GPS, which are vital in ships and aircraft.

A baseplate magnetic compass is used by hikers to obtain the correct directions from a map. Image: Roland’s Travels

If you are lost when driving and decide to check your compass, get out of the car. Being in a metal box plus the electronics will play havoc with the needle.

If you like hiking, carrying a compass and a map is always a good idea. It could save your life, or at the very least, the embarrassment of getting lost. This simple device today is still relied upon by many. It doesn’t require batteries, a phone signal or a connection to a GPS satellite. Even if you use a modern method to navigate, it pays to take an inexpensive and reliable magnetic compass on your travels.

Enjoy your travels and may you always find your way!

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