The South Pointing Chariot
The south-pointing chariot device was first invented by the Chinese mechanical engineer Ma Jun (c. 200-265 AD). It was a wheeled vehicle that incorporated an early use of differential gears to operate a fixed figurine that would constantly point south, hence enabling one to accurately measure their directional bearings. This effect was achieved not by magnetics (like in a compass), but through intricate mechanics, the same design that allows equal amounts of torque applied to wheels rotating at different speeds for the modern automobile. After the Three Kingdoms period, the device fell out of use temporarily. However, it was Zu Chongzhi who successfully re-invented it in 478 AD, as described in the texts of the Song Shu (c. 500 AD) and the Nan Chi Shu, with a passage from the latter below:
When Emperor Wu of Liu Song subdued Guanzhong he obtained the south-pointing carriage of Yao Xing, but it was only the shell with no machinery inside. Whenever it moved it had to have a man inside to turn (the figure). In the Sheng-Ming reign period, Gao Di commissioned Zi Zu Chongzhi to reconstruct it according to the ancient rules. He accordingly made new machinery of bronze, which would turn round about without a hitch and indicate the direction with uniformity. Since Ma Jun's time such a thing had not been.
Read more about this topic: Zu Chongzhi
Famous quotes containing the words south, pointing and/or chariot:
“We have heard all of our lives how, after the Civil War was over, the South went back to straighten itself out and make a living again. It was for many years a voiceless part of the government. The balance of power moved away from it—to the north and the east. The problems of the north and the east became the big problem of the country and nobody paid much attention to the economic unbalance the South had left as its only choice.”
—Lyndon Baines Johnson (1908–1973)
“Do you know what Agelisas said, when he was asked why the great city of Lacedomonie was not girded with walls? Because, pointing out the inhabitants and citizens of the city, so expert in military discipline and so strong and well armed: “Here,” he said, “are the walls of the city,” meaning that there is no wall but of bones, and that towns and cities can have no more secure nor stronger wall than the virtue of their citizens and inhabitants.”
—François Rabelais (1494–1553)
“Whose starward eye
Saw chariot “swing low”? And who was he
That breathed that comforting, melodic sigh,
“Nobody knows de trouble I see”?”
—James Weldon Johnson (1871–1938)