6.2 Compass

A compass is a navigational instrument that measures directions in a frame of reference that is stationary relative to the surface of the earth.

The invention of the navigational compass is credited by scholars to the Chinese, who began using it for navigation sometime between the 9th and 11th century, “some time before 1050, possibly as early as 850.” A common theory by historians,  suggests that the Arabs introduced the compass from China to Europe, although current textual evidence only supports the fact that Chinese use of the navigational compass preceded that of Europe and the Middle East.

The first compasses were made of lodestone, a naturally magnetized ore of iron. Ancient Chinese people found that if a lodestone was suspended so it could turn freely, it would always point in the same direction, toward the magnetic poles. Early compasses were used for geomancy “in the search for gems and the selection of sites for houses,” but were later adapted for navigation during the Song Dynasty in the 11th century. Later compasses were made of iron needles, magnetized by striking them with a lodestone.

The earliest Chinese literature reference to magnetism lies in the 4th century BC writings of Wang Xu: “The lodestone attracts iron.” The book also notes that the people of the state of Zheng always knew their position by means of a “south-pointer”; some authors suggest that this refers to early use of the compass.

6.3 Lighthouse

Before the development of clearly defined ports mariners were guided by fires built on hilltops. Since raising the fire would improve the visibility, placing the fire on a platform became a practice that led to the development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs and promontories, unlike many modern lighthouses.

Lighthouses existed since the Hellenistic period, but it is mainly the Roman ones which have survived. Ancient evidence exists in many forms. Written descriptions and drawings of the Pharos of Alexandria provide information about lighthouses, but the tower itself collapsed during an earthquake many centuries after its construction in the 3rd century BC by the Greeks. The intact Tower of Hercules at A Coruña and the ruins of the Dover lighthouse give insight into construction; other evidence about lighthouses exists in of depictions on coins and mosaics, of which many represent the lighthouse at Ostia. Coins from Alexandria, Ostia, and Laodicea in Syria exist.

The Pharos lighthouse in Alexandria which is very famous place for the tourist who come for travel to Alexandria , Egypt was a technological marvel of its times. Built in the 3rd century BC, the lighthouse was commissioned by Ptolemy Soter but was completed by his son. The Pharos lighthouse was the tallest man-made structure of its times, standing at an impressive height of 380+ feet. The structure had a mirror to reflect sunlight during the day and a fire was lit at night to warn travelers of a treacherous harbour.
The Pharos lighthouse was not just a lighthouse but more of a landmark. The structure was mentioned by many Arab travelers of the twelfth century in their travelogues. It was a place where people could actually climb above the limitations of gravity and look for miles around. It was a three storey structure with a mirror at the top to assist travelers and lost ships.

The structure had a square at the bottom which turned cylindrical towards the top, in the middle was an octagonal structure and the third storey finally ended in a circular top.
The Pharos lighthouse ignited the imagination of travelers to the city like little else did. Food was sold at the first storey and people would go to the lighthouse to picnic.
As with all wonders of the ancient world, the Pharos lighthouse too was surrounded in legends of its invincibility and its powers to cause grave damage. Some legends say that the Pharos lighthouse could burn enemy ships before they reached the shore as others talk of the light from the Pharos being seen at a distance of 35 miles. Apparently time dismissed such myths by sending out two earthquakes in 1303and 1323 which brought the structure to its knees. Whatever little remained of its base and foundation was taken up by the Sultan of Qaitbay to make his fort. Recent underwater explorations and satellite imaging of the shores of Alexandria have shown the remains of a structure that could well be the Pharos lighthouse of Alexandria and can be visited while on travel to Alexandria.

 One of the oldest lighthouses in North America must be in Tulum in Mexico. This aid to navigation guided ancient Mayan mariners from the Caribbean Sea through a dangerous reef passage and probably dates from the 13th century. Other ancient Mayan lighthouse sites have been identified on Cozumel and Isla Mujeres.

 Ruins of Tulum, Mexico

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