Editing South-pointing chariot (section)

==Historical texts==

===Earliest sources===
[[File:指南車圖 (三才圖會).jpg|thumb|upright|An image of a south-pointing chariot from ''[[Sancai Tuhui]]'' (first published 1609)]]

The south-pointing chariot, a mechanical-geared, wheeled vehicle used to discern the southern cardinal direction (without magnetics), was given a brief description by Ma's contemporary [[Fu Xuan]].<ref name="needham volume 4 part 2 40">Needham, Volume 4, Part 2, 40.</ref> The contemporary 3rd century source of the ''[[Weilüe]]'', written by the East Han dynasty politician [[Yuan Huan]] also described the south-pointing chariot of belonging to the Chinese mechanical engineer and politician [[Ma Jun (mechanical engineer)|Ma Jun]].<ref name="needham volume 4 part 2 288" /> The [[Jin dynasty (266–420)]] era text of the ''Shu Zheng Ji'' (Records of Military Expeditions), written by Guo Yuansheng, recorded that south-pointing chariots were often stored in the northern [[gatehouse]] of the Government Workshops (Shang Fang) of the capital city.<ref name="needham volume 4 part 2 288" /> However, the later written ''[[Book of Song|Song Shu]]'' (''Book of Song'') (6th century) recorded the south-pointing chariot's design and use in further detail, as well as creating the background legend of the device's (supposed) use long before Ma's time, in the [[Western Zhou dynasty]] (1050–771 BC). The book also provided a description of the south-pointing chariot's re-invention and use in times after Ma Jun and the Three Kingdoms. The 6th century text, translated by the British scientist and historian [[Joseph Needham]], reads as follows (the south-pointing chariot is referred to as the south-pointing carriage):

{{blockquote|The south-pointing carriage was first constructed by the Duke of Zhou (beginning of the 1st millennium [[Before Common Era|BC]]) as a means of conducting homewards certain envoys who had arrived from a great distance beyond the frontiers. The country to be traversed was a boundless plain, in which people lost their bearings as to east and west, so (the Duke) caused this vehicle to be made in order that the ambassadors should be able to distinguish north and south. The ''Gui Gu Zi'' book says that the people of the [[Zheng (state)|State of Zheng]], when collecting jade, always carried with them a 'south-pointer', and by means of this were never in doubt (as to their position). During the [[Qin dynasty|Qin]] and [[Han dynasty|Former Han]] dynasties, however, nothing more was heard of the vehicle. In the [[Han dynasty|Later Han]] period, [[Zhang Heng]] re-invented it, but owing to the confusion and turmoil at the close of the dynasty it was not preserved.<ref name="needham volume 4 part 2 286">Needham, Volume 4, Part 2, 286.</ref>

In the State of Wei, (in the [[Three Kingdoms|San Guo]] period) Gaotong Long and Qin Lang were both famous scholars; they disputed about the south-pointing carriage before the court, saying that there was no such thing, and that the story was nonsense. But during the Qing-long reign period (233–237) the emperor Ming Di commissioned the scholar Ma Jun to construct one, and he duly succeeded. This again was lost during the troubles attending the establishment of the [[Jin dynasty (266–420)|Jin dynasty]].<ref name="needham volume 4 part 2 286 287">Needham, Volume 4, Part 2, 286&ndash;287.</ref>

Later on, [[Shi Hu]] (emperor of the [[Jie (ethnic group)|Jie]] [[Later Zhao]] dynasty) had one made by Xie Fei, and again Linghu Sheng made one for Yao Xing (emperor of the [[Later Qin]] dynasty). The latter was obtained by emperor An Di of the Jin in the 13th year of the Yi-xi reign-period (417), and it finally came into the hands of emperor [[Emperor Wu of Liu Song|Wu Di]] of the [[Liu Song dynasty]] when he took over the administration of [[Chang'an]]. Its appearance and construction was like that of a drum-carriage ([[odometer]]). A wooden figure of a man was placed at the top, with its arm raised and pointing to the south, (and the mechanism was arranged in such a way that) although the carriage turned round and round, the pointer-arm still indicated the south. In State processions, the south-pointing carriage led the way, accompanied by the imperial guard.<ref name="needham volume 4 part 2 287">Needham, Volume 4, Part 2, 287.</ref>

These vehicles, constructed as they had been by barbarian ([[Qiang (historical people)|Qiang]]) workmen, did not function particularly well. Though called south-pointing carriages, they very often did not point true, and had to negotiate curves step by step, with the help of someone inside to adjust the machinery. The ingenious man from [[Fanyang]], Zi [[Zu Chongzhi]] frequently said, therefore, that a new (and properly automatic) south-pointing carriage ought to be constructed. So towards the close of the Sheng-Ming reign period (477–479) the emperor [[Emperor Shun of Liu Song|Shun Di]], during the premiership of the Prince of Qi, commissioned (Zi Zu Chongzhi) to make one, and when it was completed it was tested by Wang Seng-qian, military governor of Tanyang, and Liu Hsiu, president of the Board of Censors. The workmanship was excellent, and although the carriage was twisted and turned in a hundred directions, the hand never failed to point to the south. Under the Jin, moreover, there had also been a south-pointing ship.<ref name="needham volume 4 part 2 287" />}}

The last sentence of the passage is of great interest for navigation at sea, since the magnetic [[compass]] used for seafaring navigation was not used until the time of [[Shen Kuo]] (1031&ndash;1095). Although the ''Song Shu'' text describes earlier precedents of the south-pointing chariot before the time of Ma Jun, this is not entirely credible, as there are no pre-Han or Han dynasty era texts that describe the device.<ref name="needham volume 4 part 2 287 288">Needham, Volume 4, Part 2, 287–288.</ref> In fact, the first known source to describe stories of its legendary use during the Zhou period was the ''Gu Jin Zhu'' book of [[Cui Bao]] (c. 300), written soon after the Three Kingdoms era.<ref name="needham volume 4 part 2 288">Needham, Volume 4, Part 2, 288</ref> Cui Bao also wrote that the intricate details of construction for the device were once written in the ''Shang Fang Gu Shi'' (''Traditions of the Imperial Workshops''), but the book was lost by his time.<ref name="needham volume 4 part 2 288" />

===Japan===
[[File:The Chinese-children instruction vehicle of Expo 2005 Aichi Japan.jpg|Children's instructive toy chariot in Chinese display at [[Expo 2005]] in Japan|thumb]]

The invention of the south-pointing chariot also made its way to [[Japan]] by the 7th century. The ''[[Nihon Shoki]]'' (The Chronicles of Japan) of 720 described the earlier Chinese [[Buddhist]] [[monk]]s [[Zhi Yu]] and [[Zhi You]] constructing several south-pointing Chariots for [[Emperor Tenji]] of Japan in 658.<ref name="needham volume 4 part 2 289">Needham, Volume 4, Part 2, 289.</ref> This was followed up by several more chariot devices built in 666 as well.<ref name="needham volume 4 part 2 289" />

===''Song Shi''===

The south-pointing chariot was also combined with the earlier [[Han dynasty]] era invention of the [[odometer]], a mechanical device used to measure distance traveled, and found in all modern [[automobile]]s. It was mentioned in the [[Song dynasty]] (960&ndash;1279) historical text of the ''Song Shi'' (compiled in 1345) that the engineers [[Yan Su]] (in 1027) and [[Wu Deren]] (in 1107) both created south-pointing chariots, which it details as follows.<ref name="needham volume 4 part 2 291">Needham, Volume 4, Part 2, 291.</ref> (In Needham's translation, inches and feet (ft) are used as units of distance. 1 inch is 25.4 millimetres. 1&nbsp;ft is 12 inches or 304.8&nbsp;mm.)

{{blockquote|In the 5th year of the Tian-Sheng reign period of the [[Emperor Renzong of Song|emperor Renzong]] (1027), Yan Su, a Divisional Director in the Ministry of Works, made a south-pointing carriage. He memorialised the throne, saying, [after the usual historical introduction]: "Throughout the [[Five Dynasties and Ten Kingdoms|Five Dynasties]] and until the reigning dynasty there has been, so far as I know, no one who has been able to construct such a vehicle. But now I have invented a design myself and have succeeded in completing it".<ref name="needham volume 4 part 2 291" />

"The method involves using a carriage with a single pole (for two horses). Above the outside framework of the body of the carriage let there be a cover in two stories. Set a wooden image of a ''xian'' (immortal) at the top, stretching out its arm to indicate the south. Use 9 wheels, great and small, with a total of 120 teeth, i.e. 2 foot-wheels (i.e. road-wheels, on which the carriage runs) 6 ft. high and 18 ft. in circumference, attached to the foot wheels, 2 vertical subordinate wheels, 2.4 ft. in diameter and 7.2 ft. in circumference, each with 24 teeth, the teeth being at intervals of 3 inches apart.<ref name="needham volume 4 part 2 291" />

"...&nbsp;Then below the crossbar at the end of the pole, two small vertical wheels 3 inches in diameter and pierced by an iron axle, to the left 1 small horizontal wheel, 1.2 feet in diameter, with 12 teeth, to the right 1 small horizontal wheel, 1.2 ft. in diameter, with 12 teeth, in the middle 1 large horizontal wheel, of diameter 4.8 ft. and circumference 14.4 ft., with 48 teeth, the teeth at intervals of 3 inches apart; in the middle a vertical shaft piercing the center (of the large horizontal wheel) 8 ft. high and 3 inches in diameter; at the top carrying the wooden figure of the ''xian''.<ref name="needham volume 4 part 2 291" />

"When the carriage moves (southward) let the wooden figure point south. When it runs (and goes) eastwards, the (back end of the) pole is pushed to the right; the subordinate wheel attached to the right road-wheel will turn forward 12 teeth, drawing with it the right small horizontal wheel one revolution (and so) pushing the central large horizontal wheel to revolve a quarter turn to the left. When it has turned around 12 teeth, the carriage moves eastwards, and the wooden figure stands crosswise and points south. If (instead) it turns (and goes) westwards, the (back end of the) pole is pushed to the left; the subordinate wheel attached to the left road-wheel will turn forward with the road-wheel 12 teeth, drawing with it the left small horizontal wheel one revolution, and pushing the central large horizontal wheel to revolve a quarter turn to the right. When it has turned round 12 teeth, the carriage moves due west, but still the wooden figure stands crosswise and points south. If one wishes to travel northwards, the turning round, whether by east or west, is done in the same way."<ref name="needham volume 4 part 2 291 292">Needham, Volume 4, Part 2, 291&ndash;292.</ref>}}

After this initial description of Yan Su's device, the text continues to describe the work of Wu Deren, who crafted a wheeled device that would combine the odometer and south-pointing chariot:

{{blockquote|It was ordered that the method should be handed down to the (appropriate) officials so that the machine might be made. In the first year of the Da-Guan reign period (1107), the Chamberlain Wu Deren presented specifications of the south-pointing carriage and the carriage with the li-recording drum (odometer). The two vehicles were made, and were first used that year at the great ceremony of the ancestral sacrifice.<ref name="needham volume 4 part 2 292">Needham, Volume 4, Part 2, 292.</ref>

The body of the south-pointing carriage was 11.15 ft. (long), 9.5 ft. wide, and 10.9 ft. deep. The carriage wheels were 5.7 ft. in diameter, the [[carriage pole]] 10.5 ft. long, and the carriage body in two stories, upper and lower. In the middle was placed a partition. Above there stood a figure of a ''xian'' holding a rod, on the left and right were tortoises and cranes, one each on either side, and four figures of boys each holding a tassel. In the upper story there were at the four corners [[trip-mechanism]]s, and also 13 horizontal wheels, each 1.85 ft. in diameter, 5.55 ft. in circumference, with 32 teeth at intervals of 1.8 inches apart. A central shaft, mounted on the partition, pierced downwards.<ref name="needham volume 4 part 2 292" />

In the lower story were 13 wheels. In the middle was the largest horizontal wheel, 3.8 ft. in diameter, 11.4 ft. in circumference, and having 100 teeth at intervals of 2.1 inches apart. (On vertical axles) reaching to the top (of the compartment) left and right, were two small horizontal wheels which could rise and fall, having an iron weight (attached to) each. Each of these was 1.1 ft. in diameter and 3.3 ft. in circumference, with 17 teeth, at intervals of 1.9 inches apart. Again, to left and right, were attached wheels, one on each side, in diameter 1.55 ft., in circumference 4.65 ft., and having 24 teeth, at intervals of 2.1 inches.<ref name="needham volume 4 part 2 292" />

Left and right, too, were double gear-wheels (lit. tier-wheels), a pair on either side. Each of the lower component gears was 2.1 ft. in diameter and 6.3 ft. in circumference, with 32 teeth, at intervals of 2.1 inches apart. Each of the upper component gears was 1.2 ft. in diameter and 3.6 ft. in circumference, with 32 teeth, at intervals of 1.1 inches apart. On each of the road-wheels of the carriage, left and right, was a vertical wheel 2.2 ft. in diameter, 6.6 ft. in circumference, with 32 teeth at intervals of 2.25 inches apart. Both to left and right at the back end of the pole there were small wheels without teeth ([[pulley]]s), from which hung bamboo cords, and both were tied above the left and right (ends of the) axle (of the carriage) respectively.<ref name="needham volume 4 part 2 292" />

If the carriage turns to the right, it causes the small pulley to the left of the back end of the pole to let down the left-hand (small horizontal) wheel. If it turns to the left, it causes the small pulley to the right of the back end of the pole to let down the right (small horizontal) wheel. However, the carriage moves the xian and the boys stand crosswise and point south. The carriage is harnessed with two red horses, bearing frontlets of bronze.<ref name="needham volume 4 part 2 292" />}}