The inventions of the Chinese were extremely influential in creating the modern world. The Chinese magnetic compass joined gunpowder and many other developments in shaping history. Yet at first, its potential was not realized. By definition, a magnetic compass is a magnet that orients itself in a north to south line. How did this discovery impact the modern world?
Fig. 1 - A Magnetic Compass
Magnetic Compass Definition
Humans have always used the skies to make their way from place to place. At night, the North Star points the way northward. During the day, the rising, and setting of the sun displays the directions of east and west. These natural navigational tools allowed humans to explore and find their way back, but there is always room for improvement. That improvement came in the man made tool known as the compass.
How a Magnetic Compass Works
A magnetic compass works by using a magnetic material, which will align itself with the earth’s magnetic poles. When aligned, a magnet is oriented north and south. This allows not just discerning in what direction north lies, but finding more accurate bearings in all directions.
Magnetic Pole: Magnetic poles are the two points on which the Earth rotates. They are located at the northernmost and southernmost points of the earth. The rotation creates natural magnets.
This can be done by measuring the angle from north. The mathematical idea of a 360-degree circle goes back 6,000 years to the ancient world. When the circle is combined with the compass needle, 0 degrees is north, 90 degrees is east, 180 degrees is south, and 270 degrees is west. Using a circle in this manner allows a person to much more accurately create and navigate with maps.
The Magnet Compass through History
Through history, we find many great technological inventions that impacted on humanity at large. But there are a few that, even if today we deemed as simple as a piece of paper, changed and shaped our past and present. One of these remarkable inventions is the magnetic compass.
Chinese Magnetic Compass
Sometime between 950 and 1000, the Chinese began to use magnetic compasses. The first Chinese compasses were constructed using the naturally magnetic mineral lodestone. Initially, their use as a navigational tool was ignored. Instead, the compass took on more mystical uses. The earliest tasks for which the Chinese used the magnet compass were fortune telling and aligning buildings according to the principles of Feng Shui.
Feng Shui: Feng Shui is a Chinese system that attempts to put humans into alignment with an energy source that they call Qi. The idea is that practitioners gain knowledge of the flow of this energy and help others plan their living spaces in ways to receive beneficial Qi energy. Feng Shui is a belief system, not a science.
It was not until the Song Dynasty that the magnetic compass was first used as a navigational instrument. Like many scientific advances, it was first exploited by the military for land navigation around 1040. In 1111, it was finally being used for sea navigation.
Interestingly, this breakthrough device was originally only used as a backup to the traditional methods of celestial navigation. Zhu Yu’s writing in 1111 states that the compass was used when the weather blocked out the sun or stars to the point where they could not be used in navigation.
Fig. 2 - 16th Century Compass
European Magnetic Compass
The Chinese may have used the magnetic compass first, but by the late twelfth or early thirteenth century, European sailors were also navigating by the magnetic wonder. Like their Chinese counterparts, they initially used it only when poor weather impeded the use of the sun and stars for navigation. By the end of the thirteenth century, Europeans had expanded the devices use to study astronomy.
When the compass first made its way to Europe it was believed to be the work of the Devil! Lodestones had been considered to have magical properties, causing the Church to view the device as evil. The unseen force of magnetism was the root of superstition.
Middle Eastern Magnetic Compass
The thirteenth century also saw the introduction of the compass to the Middle East. Descriptions of designs indicate that the compass likely spread from China. Like the Chinese, they commonly used it for spiritual reasons. The magnetic compass was used to determine the directions of Mecca, towards which Muslims must pray. Later the compass was combined with a sundial to create a device that told both proper the time and direction for prayer.
The Compass Rose
A compass is an image on a map that aids the map reader in more clearly determining a specific direction. The image usually takes the form of a star with between 8 and 32 points. The star can be used to find degrees on a map, which can be used with either celestial bodies or a compass to very accurately navigate. This became popular with Arab navigators in the late tenth century before spreading throughout the Mediterranean and then to the rest of Europe.
Originally, a compass rose was just straight lines. The more famous ornate compass roses did not exist until the late fourteenth century.
Fig. 3 - A Compass Rose
Challenges of the Magnetic Compass
By the fifteenth century, the age of exploration was on. Portuguese sailors like Gonzalo Cabral and Ferdinand Magellan made their ways to distant lands. Sailors were increasingly reliant on the magnetic compass as they travelled exceptionally far from the sight of land. As sailors travelled further and further north, they began to discover that magnetic north was not quite the same as true north. It was English scientist William Gilbert who demonstrated that the Earth itself was a magnet, finally explaining the manner in which a magnetic compass operated.
Magnetic North: This is the central point in the earth's magnetic field where a magnet will point straight downward. It moves slightly over time with changes in the Earth's magnetic field.
True North: The location of the Earth's northernmost geographic center.
Fig. 4 - Edmund HalleyEdmund Halley
The country most interested in the development of the magnetic compass was Britain. The British invested in determining the variation of magnetic north as sailors travelled. Taking on the task was scientist Edmund Halley in 1698. Halley embarked upon many journeys through the Atlantic Ocean, measuring the distance between true and magnetic north. This information was published in a map by the Royal Navy in 1701.
Christopher Columbus is recorded to have noticed the divergence between true and magnetic north but was unable to make sense of what it meant.
Magnetic Compass - Key takeaways
- The earliest recorded use of the magnetic compass occurred in China between 950 and 1000
- Initially the device was used for spiritual purposes instead of navigation
- The device allowed navigation during poor weather that blocked the sun and stars
- By 1701 the British had solved the problem of determining the deviation between true north and magnetic north
Explanations 
Exams 
Magazine 
