The compass is an instrument used to indicate directions with the help of magnetism. Formerly called "Sinan", compass was recorded in Master Han Fei in as early as the 3ra century. Later it was called "Sinan Ladle". Accord-ing to the records in Lun Heng by Wang Chong of the Eastern Han Dynasty, the Sinan Ladle was a ladle-shaped instrument made of natural magnets or magnetic material. Being round at bottom, the "ladle" could rotate freely, and the handle would always point southward when it stopped turning. Wu Jing Zong Yao, compiled mainly by Zeng Gongliang of the Song Dynasty, in-troduced a "Fish Compass" made of carbon steel. In Sketchbook of Dream Brook by Shen Kuo of the Song Dynasty, there are records about magnetically polished needles pointing south.

Shen Kuo arrived at the conclusion that "the compass often pointed a little east, not completely south. " Guang Lin Ji Shi written in the Yuan Dynasty also introduced a kind of "Tortoise Compass" carved out of wood. According to the historical records, the compass began to serve as an instrument for navigation in as early as the late 11th century and the early 12th century. In about 1180 the compass was brought into Europe via Arab.

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