ORIGIN OF COMPASS.

Timaru Herald, Volume CXXV, Issue 18501, 24 February 1930, Page 6

ORIGIN OF COMPASS.

CREDIT GOES TO ITALY. AGES-OLD INSTRUMENT. Discovery must precede every invention. In the case of the compass the invention was due to the finding of the magnet, or load-stone. But whereas the invention of the modern wireless aids to navigation, such as long-distance transmission, direction finders, and radio beacons, occupied the matter of a few after the discovery of electricity, the invention of the compass, following on the discovery of the load-stone, occupied thousands of years, writes F.N.J., in the “Melbourne Age.” During that time the compass had a most interesting and somewhat chequered career. Greek writers attribute the discovery of the magnet to a shepherd named

Magnes. We do not know whether or not Magnes was counting his woolly charges jumping over hurdles, but he fell asleep on Mount Ida, having left his crook lying against a big stone. When he woke and discovered his crook he found that the iron handle was stuck to the stone. He lost no time in communicating the fact to philosophers of the day, who subsequently held the stone to be of great value, because of its attractive influence for such physical defects as bow-legs and cross-eyes.

There is evidence, however, that the magnet was discovered by a much older civilisation tha nthat of the Greeks. Thousands of years before the birth of Christ, and before Magnes had his forty winks on Mount Ida, the Chinese were not merely acquainted with the load-stone, but had discovered its properties regarding polarity. Whenever they were on a long travel the Chinese took with them a small ornamental chariot, on which was pivoted a small doll in the guise of a priest. The doll had one arm, made of magnet, stretched out in a pointing

attitude. This little priest pointed to the Kibleh—due south—to which the Chinese always turned when making their devotions. Magnet as Compass. The first we hear of the Chinese using the magnet as a compass is in 2364 B.C. At that time China was troubled with a rebel named Tchiyeou. Emperor Hiuanyaun set out to quell Tchi-yeou, and met him on the plains of Tchou-lou. The rebel leader schemed to defeat Hiuanyaun’s army by the confusion of darkness, and made a thick smoke screen, which completely enveloped the Emperor’s army. The Emperor, however, consulted the priest on the chariot, and, having found the south, was able to work round to the rear of the rebels. Tchi-yeou was defeated, beheaded; peace restored till the next civil war, and the first compass was discovered.

It is not until 3000 years later, however, that we hear of the compass being used at sea. Even the Romans were unaware of its uses when they invaded Britain in 55 B.C. Their idea

of navigation was to sail and sail until a strange land was sighted, and then ask the oldest inhabitant what country it was. But records show that about 300 years A.D. a mariner’s compass, of a sort, was being used along the Chin°~e and along the Syrian coast, in the Mediterranean. A basin of

wuirj buncn lo a quiet corner of the ship, and a steel needle was polarised by being rubbed with magnet. The needle was then passed laterally through a straw to form a cross, and was placed carefully on the surface of the water. Supported by its straw float, the needle twisted until it pointed to north. This was quite serviceable in calm water, but when the wind freshened and the water became agitated the needle sank promptly to the bottom of the basin, and as the ships relied on the wind for propulsion; the compass was not of much use. Difficulty was experienced also in curing crews. Ever superstitious, sailors disliked sailing under such magical and uncanny influences.

This flimsy compass was persevered with until 1000 years later, when an

Italian named Flavio Gioia, living at Amalfi, designed a more stable instrument. In fact, it is to Gioia that we are most indebted for the wonderful instrument of to-day. Gioia discarded the water balance altogether and balanced the magnetic needle on a wooden pivot, enclosing it in a box. Around the needle he placed a card, on which was marked north, south, east, and west. These are the cardinal points, “cardinal” being derived from “carda—a pivot.” The compass box was then suspended and balanced on hoops, so that, however badly the ship rolled or dived, the compass maintained a horizontal position. A Grave “Defect.” Thus, in the fourteenth century, mariners were at last blessed with a satisfactory instrument as far as stability went. But it was not long before a grave “defect” in the compass itself was discovered. On September 13, 1492, when midway across the Atlantic on his historic voyage to America, Columbus was perturbed to find that the needle no longer pointed

directly to the north star, but varied about six degrees to the north-west. Knowing the alarm that would ensue if the sailors heard of the variation, he kept his own counsel until his pilots also discovered the phenomenon. They became very much frightened. All superstition of the compass had long been forgotten, but here they were now on a vast and trackless ocean, and, for all they knew, lost to the world. Columbus, however, cleverly put an end to their fears by stating that it was not the compass but the north star that was at fault. He explained that the north star had merely shifted from its original position, but would right itself on the next circuit of its orbit.

Since then scientific investigation has definitely established that the phenomenon noticed by Columbus was due to the magnetic pole not coinciding with the northern axis of the earth. Exploration trips all over the world have been made following on that discovery, and the deflection of the needle point according to longi-

tude reported. This is knowm as “tin variation of the compass.”

Another problem confronting navigators of comparatively recent years has been the remarkable effect that the displacement of stout oak by iron and steel in ship building has had on the compass. The influence of the metal in the ship has had such an influence on the needle that the compass plays all sorts of tricks.