Author: changabula

Chinese Inventions, Discoveries and Other Contributions   [Copy link] 中文

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Post time 2007-1-25 21:05:48 |Display all floors
Drive - Belt

The belt-drive or driving-belt transmits power from one wheel to another, and produces continuous rotary motion. It existed as early as the first century BC in China. It is attested by a passage in Yang Hsiung's book, Dictionary of Local Expressions, of 15 BC. It was developed for use in machines connected with silk manufacture, especially one called a quilling-machine, which wound the long silk fibers on to bobbins for the weavers' shuttles. These machines featured a large wheel and a driving-belt and small pulley. The machines are mentioned again in the book Enlargement of Literary Expositor compiled between 230 and 232 AD.

The Driving-belt was essential for the invention of the spinning-wheel. The belts could run not only round normal wheels with rims, whether grooved or not, but also round rimless wheels. A rimless spinning-wheel may sound a contradiction in terms, and the use of a driving-belt with rimless wheels might at first seem an impossible. But in fact a cat's cradle of fibers strung between wheel spokes which protrude slightly or exist in two sets placed in alternation can create an entirely adequate nexus for a belt.

Needham photographed just such an archaic spinning-wheel in use in Shensi in 1942. It is extraordinary to think that the spinning-wheel of 1270 survives unchanged into the modern era. Yet another Chinese technique of using a driving-belt with a rimless wheel is to mount grooved blocks at the ends of the spokes, and run the belt through the successive grooves.

A refinement of the driving-belt is the chain-drive, invented in China in 976 AD. A chain-drive is essentially a driving-belt which instead of being solid is a chain into the ilnks of which fit sprockets on the wheels around which it is wrapped.

The driving-belt was apparently imported to Europe as part of the technology of quilling-wheels and spinning-wheels introduced into Italy by travelers returning from China. The oldest actual representation of a driving-belt in remained extremely rare in Europe until the eighteenth and nineteenth centuries, indicating that Europeans did not appreciate the potential of this particular element of the Chinese texxtile machines for other purposesto any siginificant degree for mroe than three centuries. Flat belts and wire cables as driving-belts in Europe only began to be used in the nineteenth century.

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Post time 2007-1-25 21:10:54 |Display all floors
Matches

Every time we strike a match, we are using a Chinese invention. The first version of a match was invented in the year 577 AD by impoverished court ladies during a military siege, in the short-lived Chinese kingdom of the Northern Ch'i. Hard-pressed during the siege, they must have been so short of tinder that they could otherwise not start fires for cooking, heating, etc.

Early matches were made with sulfur. A description is found in a book entitled Records of the Unworldly and the Strange written about 950 by T'ao Ku:

If there occurs an emergency at night it may take some time to make a light to light a lamp. But an ingenious man devised the system of impregnating little sticks of pinewood with sulphur and storing them ready for use. At the slightest touch of fire they burst into flame. One gets a little flame like an ear of corn. This marvellous thing was formerly called a 'light-bringing slave', but afterwards when it became an article of commerce its name was changed to 'fire inch-stick'.

There is no evidence of matches in Europe before 1530. Therefore, the Chinese were using them for just short of a thousand years before they arrived in Europe. Matches could easily have been brought to Europe by one of the Europeans traveling to China at the time of Marco Polo, since we know for certain that they were being sold in the street markets of Hangchow in the year 1270 or thereabouts.

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A late-eighteenth century painting of a boy selling joss-sticks and matches:

[ Last edited by changabula at 2007-1-29 07:30 PM ]
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Post time 2007-1-25 21:13:38 |Display all floors
A Refined Value of Pi

The irrational number pi can be computed to an infinite number of decimal places. It expresses the ratio of the circumference of a circle to its diameter, a relationship which cannot be framed in terms of whole numbers. (Pi is needed to compute the area of a circle or volume of a sphere.) The value of pi was computed by Archimedes to three decimal places, and by Ptolemy to four decimal places. But after that, for 1450 years, no greater accuracy was achieved in the Western world. The Chinese, however, made great strides forward in computing pi.

One way in which the ancient mathematicians tried to approach an accurate value for pi was to inscribe polygons with more and more sides to them inside circles, so that the areas of the polygons(which could be computed) would more and more closely approach the area of the circle. Thus, they could try to find a value for pi, since the circle's area was found by using the formula containing it. (They could measure the diameter, and squeeze a polygon whose area they knew into the circle; the only unknown number would be pi, which could then be calculated.) Archimedes used a 96-sided polygon, and decided that pi had a value between 3.142 and 3.140.

The Chinese tried to sneak up on pi in the same fashion, but they were better at it. Liu Hui in the third century AD started by inscribing a polygon of 192 sides in a circle, and then went on to inscribe one of 3072 sides which 'squeezed' even closer. He was thus able to calculate a value of pi of 3.14159. At this point, the Chinese overtook the Greeks.

But the real leap forward came in the fifth century AD, when truly advanced values for pi appeared in China. The mathematicians Tsu Ch'ung-Chih and Tsu Keng-Chih (father and son), by means of calculations which have been lost, obtained an 'accurate' value of pi to ten decimal places, as 3.1415929203. The circle used for the inscribing of the polygons is known to have been 10 feet across. This value for pi was recorded in historical records of the period, but the actual books of those mathematicians have vanished over the centuries. Nine hundred years later, the mathematician Chao Yu-Ch'in (about 1300 AD) Set himself to verify this value of pi. He inscribed polygons in a circle with the enormous number of 16,384 sides. By this means he confirmed the value given by the Tsu family. The Tsu family had a lead in the computation of pi of about 1200 years. Even by 1600 AD in Europe, the celebrated calculation of the value of pi by Adriaen Anthoniszoon and his son only gave 3.1415929, an approximate value extending to seven places, which still fell three short of the value found by the Tsu family.


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Note: Zu Chongzhi was a Chinese mathematician and astronomer. He introduced the approximation 355/113 to π which is correct to 6 decimal places.

[ Last edited by changabula at 2007-2-1 05:39 PM ]
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Post time 2007-1-25 21:19:47 |Display all floors
Pascal Triangle

Blaise Pascal gave his name to a triangular array of numbers. The Triangle is a wonderful time-saver, and one of the fundamental steps in getting mathematics really on its feet. But although it bears the name Pascal's Triangle, it was by no means invented by Pascal. He merely put it in a newer form in the year 1654.

In fact, this Triangle was invented in China. It may be seen depicted in a Chinese book of 1303 AD by Chu Shih-Chieh, entitled Precious Mirror of the Four Elements. Even here, it is called 'The Old Method'.

And old indeed it was,for it was known in China by 1100.The mathematician Chia Hsien expounded it at that time as 'the tabulation system for unlocking binomial coefficients'; but its first appearance is thought to have been in a book of that date, now lost, entitled Piling-up Powers and Unlocking Coefficients, by Liu Ju-Hsieh.

  The mathematician and poet Omar Khayyam discussed the Pascal Triangle somewhat indirectly about I 100. We do not know whether he got it from China or invented the elements of the system independently. But the first appearance of the Triangle in print in Europe was on the title page of the book on arithmetic of Petrus Apianus in 1527. Several succeeding mathematicians, such as Michael Stifel, considered it. And the Italian Nicolo Tartaglia, who was something of a scoundrel, claimed it as his own invention. But as far as we know, the inventor was indeed Liu Ju-Hsich, 427 years before the appearance of the 'Pascal' Triangle in Europe.

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[ Last edited by changabula at 2007-1-29 06:42 PM ]
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Post time 2007-1-25 21:22:54 |Display all floors
Using algebra in geometry

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Algebra and geometry developed independently. Today, we could not possibly do without their intimate partnership. To deprive ourselves of the use of them together would render modern technology impossible at once.

But the connection between algebra and geometry was not always obvious. Far from it, in fact. We now routinely use equations (algebra) to describe shapes (geometry). Everything from buildings to airplanes is constructed not just from blueprint drawings but from sets of equations describing the contours, surfaces, and structures. But the first people to do this sort of thing, expressing geometrical shapes by equations, were the Chinese.

A Chinese book of the third century AD called the Sea Island Mathematical Manual gives a series of geometrical propositions in algebraic form and describes geometrical figures by algebraic equations. Throughout Chinese history after that, if one wanted to consider geometry, algebra was regularly employed.

These techniques spread westward to the Arabs when the famous mathematician al-Khwdrizmi was sent by the Caliph to be ambassador to Khazaria during the years 842 to 847. (Khazaria lay on the main trade routes between China and the West.)

It is curious that the Chinese should have been a thousand years ahead with the basic idea!

The Problem of the Broken Bamboo, from Yang Hui's book Detailed Analysis of the Mathematical Rules in the 'Nine Chapters'and Their Reclassiftcation, published in 1261. Yang Hui was one of China's leading mathematicians, and in his works quadratic equations with negative coefficients appear for the first time. Here the broken bamboo, which forms a natural right- angled triangle, is discussed as an example of the properties of such triangles, their expression in algebra, and the use of such expressions for measuring heights and distances:

[ Last edited by changabula at 2007-1-29 08:17 PM ]
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Post time 2007-1-25 21:25:03 |Display all floors
First Law Of Motion

Isaac Newton formulated his First Law of Motion in the eighteenth century. It stated that "every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it."

  Needham's researches have now established "that this law was stated in China in the fourth or third century BC. We read in the Mo Ching: "The cessation of motion is due to the opposing force ... If there is no opposing force ... the motion will never stop. This is as true as that an ox is not a horse."

  The book Mo Ching is the collection of writings of a school of philosophers called Mohists, after their founder and sage Mo Ti (more commonly known as Mo Tzu, which means "Master Mo"). The Mohists disappeared completely from Chinese history after only a moderate time, and most of their writings remained unread and almost forgotten until recently. Their brilliant scientific insights were also largely lost, and made very little lasting impact on later Chinese history. The Mohists were also the only ancient Chinese to consider the subject of dynamics in the theoretical sense, though practical dynamics was continuously applied in the great strides made by Chinese technology and invention.

  Sadly, although Newton's First Law of Motion was anticipated two thousand years earlier by the Mohists, nothing seems to have come of it. It was only in 1962 that Needham, in the first proper study of Mohist scientific doctrines, published the fact that this great step had ever been taken - but it was a step in soft sand, quickly washed away by the advancing tide of history.

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Post time 2007-1-25 21:27:21 |Display all floors
Dial and pointer devices

The earliest Chinese compasses did not have needles. The 'pointers' were shaped as spoons, fish, or even sometimes as turtles. The introduction of a needle was a refinement which made possible a much greater precision of readings on the dials surrounding the pointer.

It was at this stage of develop- ment that we can say that the Chinese pioneered the world's first dial and pointer devices, which are absolutely fundamental to modern science. Needham says of this development: 'Probably by the seventh or eighth century AD the needle was replacing the lodestone, and pieces of iron of other shapes, on account of the much greater precision with which its readings could be taken.' Needles were also used as pointers on computing machines.

The use of a needle in a calculating device can be traced back to at least 570 AD in China; it seems to have been a form of abacus based on compass readings. A description of it survives in a book entitled Memoir on Some Traditions of Mathematical Art, and its accompanying Commentary by Chen Luan (flourished 570 AD). Chen Luan writes: 'In this kind of computing, the digits are indicated by the pointing of the sharp end of a needle. The first digit occupies the Li position, that is, pointing full south; second, or two, is K'un, south-west; the third, or three, is at Tui, full west. . . .' And so on. Chen Luan adds that a digit to be multiplied is indicated by the point of the needle, whereas a digit to be divided is indicated by the needle's (differently shaped) tail.

Needham says of this:

This technique, which would seem to have been a simple sort of abacus-like device, arising out of the old diviner's board, is elsewhere attributed to, or associated with, the name of Chao Ta, a famous diviner of the Three Kingdoms Period (221-65 Al)). But the remarkable thing is that a needle is said to be used as a pointer, and the series starts from full south. It seems hard to believe that this can have had no connection with the magnetic compass, and it must be at least of 570 AD if not earlier. Therefore, dial and pointer devices were in use in China by the sixth century at least, and quite possibly by the third century. Needham rightly points out that these Chinese devices were 'the most ancient of all pointer-readings, and ... the first step' on the road to all dials and self-registering meters.'

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The dial and pointer devices upon which we depend in the modern world had originated in China by the third century AD. They were geomantic compasses, used for consultation on such questions as to where a house should be built, or a city laid out. Of course, much was superstition, but at the basis of the practice was the phenomenon of the north-south alignment of the magnetized magnetic needle. The fantastic array of readings which were possible to a geomancer's compass may be seen here, though this is by no means the most complicated. Some are known with forty concentric circles of readings. The outermost circle here marks the twenty-eight lunar mansions. The next circle is marked in the'New Degrees' of 360' adopted for the'circle under Jesuit influence, indicating that this compass cannot be earlier than the seventeenth century. A full description of the readings is obviously impossible in the space available. (Science Museum, London

[ Last edited by changabula at 2007-1-29 08:29 PM ]
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