The development of sericulture led to more and better spinning machines. In the 1450s, Vicenza had eight shops of spinners. The number rose to ten in 1507, thirty-three in 1543, and over one hundred by 1596. Silk production in Verona underwent a similar expansion, rising from eight silk spinners in the 1420s to twelve in 1456, when Verona’s first hydraulic mill, on the Adige, was commissioned (Mola, 237). After that, the industry exploded; there were fifty spinners’ shops in 1543, seventy in 1549, and eighty-eight in 1559.
The raw silk and silk thread produced in the terra firma encouraged a new breed of entrepreneurs to buy silk. Many were financed by the Medicis. The Venetian government took a close interest in regulating the silk industry in its territory, issuing patents, which increased after the 1440s. In 1474, Venice published a general law of patents:
The decision has been made that, by the authority of this council, any person in this city who makes any new and ingenious contrivance, not made here before in our domains, shall, as soon as it is perfected so that it can be used and exercised, give notice of the same to the office of our Provveditori di Commune, it being forbidden up to ten years for any other person in any territory and place or ours to make a contrivance without the content and license of the author…. But our government will be free, at its complete discretion, to take and use for its needs any of the said contrivances and instruments, with this condition, however, that no one other than the inventors shall operate them.7
By these means, first Venice and Florence, then the whole of Italy came to dominate the raw-silk market of Europe—much as eastern Asia dominates the global market today.
Rice
Florence’s silk-based economic boom required more workers, and more workers required more food. As Braudel has pointed out, the yield from rice fields is some several times that of wheat.8
Rice had been known in the Mediterranean world since the Roman era, but it was used only for medicinal purposes. The first known reference to rice being grown in northern Italy is a letter of September 27, 1475, from the ruler of Milan, Galeazzo Sforza, to the duke of Ferrara concerning twelve sacks of Asian (Oryza Sativa) rice grown in the Po Valley.
Rice is the basic food of southern China. The Nung Shu included much advice from Wang Chen about wet rice cultivation, including how to husband and control water supplies from the great rivers that carry melted snow from the Mongolian plateau eastward to the sea.
Cultivators of rice build surface tanks and reservoirs to store water, and dykes and sluices to stop its flow (when necessary)…. The land is divided into small patches, and after ploughing and harrowing, water is let into the fields and the seeds sown. When the plants grow five or six inches tall, they are planted out. All farmers south of the river [Yangtze] now use this method. When the plants attain a height of seven or eight inches, the ground is hoed, and after hoeing the water is let go from the fields, so as to dry them. Then when the plants begin to flower and seed, water is again let in.
Chinese irrigation design.
The Nung Shu illustrates all manner of techniques for the vital task of regulating water supply to the rice fields—many types of bucket and chain pumps, locks and sluices, dams and conduit channels. Buckets, pallets, and chain pumps are a theme,9 as are bamboo “water palisades,” which acted as weirs.
As described in the previous chapter, Taccola and Francesco di Giorgio drew an array of pumps as well as dams and sluice gates.10 The chain pumps first shown in the drawings of Taccola are still in use today in northeastern Italy, where the local people call them “Tartar” pumps. Since Taccola and Francesco’s drawings of chain and bucket pumps were shown in chapter 16, in this chapter only piston pumps will be described.
Sheldon Shapiro in his article “The Origin of the Suction Pump” notes:
Not until the early fifteenth century does the first evidence of the valved piston appear. It turns up in a drawing (Fig. 4) by the Siennese engineer, Mariano Jacopo Taccola [in Munich Ms. 1435] whose still unpublished notebooks are of the greatest importance for the history of technology. In this drawing dating from about 1433, the valve in the piston is clear. Therefore, although a text and other details are lacking this drawing represents the first suction pump on record; it is unintelligible in any other terms.
The first detailed drawings of suction pumps date from the period 1475–1480; Francesco di Giorgio Martini in the last book of his Trattato di Architettura written about 1475 shows several suction pumps. In the most mechanically perfect pump the distance from the sump to the chamber seems only a foot or two, instead of the 32 feet possible, thus showing an imperfect understanding of the nature of this new type of pump.11
A Chinese chain pump used for irrigation purposes.
Clearly Franceso did not know how it worked; he must have copied a drawing.
As Needham points out, suction pumps in China are first described in the Wu Ching Tsung Yao (Collection of the most important military techniques, published in 1044). Here Needham describes the process:
For syringes (chi thung) one uses long pieces of (hollow) bamboo; opening a hole in the bottom (septum) and wrapping silk floss round a piston-rod (shui kan) inside (to form the piston). Then from the hole water may be shot forth…. In the 11th century…the military encyclopaedia just mentioned gives us elsewhere a very remarkable account of a flamethrower for naphtha which constituted a liquid piston pump of ingenious design.12
Di Giorgio’s piston pump is shown in the copy of his Trattato di architettura owned by Leonardo da Vinci, which is now in the Laurenzian Library in Florence. Leonardo improved upon di Giorgio’s drawings.
In many ways, the Po resembles a smaller version of the Yangtze. Both rivers carry melting snows from the mountains eastward to the sea. Both suffer from flash floods and are controlled by a network of canals, locks, sluices, and dams. The waters of both are used to form extensive rice fields. The exact date when the Po was first utilized for rice is not known. Clearly it predated the 1475 letter, but by how much? I suggest it was after 1435, when Taccola’s first drawings of pumps appear, and probably after 1438, when his drawings of lock and sluice gates first appear.
The combination of booming silk production in Florence and Venice and adequate food for the silk workers enabled “an extraordinary increase in silk production” between 1441 and 1461.13 By the 1480s silk had become “the main source of employment” for Florentine workers. The rise in silk production was mirrored by the rise in the Medici family’s wealth, which was largely a product of financing the export of fine silk cloth. Florence had acquired the port of Pisa in 1405 and Leghorn in 1421 and could thereafter export her cloths to northern Europe.
The Florentine Renaissance was fueled by wealth, especially that of the Medicis. The family was in exile when Pope Eugenius IV moved the pontificate from Rome to Florence in 1434, interceded with the opponents of the Medicis, and enabled the family to return to Florence. The Medicis once again became papal bankers and soon controlled Florence. As the future Pope Pius II said, “Political questions are settled at his [Cosimo’s] house. The man he chooses holds office…. He it is who decides peace and war and controls the laws…. he is king in everything but name.”14
Christopher Hibbert, in The House of Medici; Its Rise and Fall, writes of Cosimo de’ Medici: “Foreign rulers were advised to communicate with him personally and not to waste their time by approaching anyone else in Florence when any important decision was required. As the Florentine historian, Francesco Guicciardini, observed, ‘He had a reputation such as probably no private citizen has ever enjoyed from the fall of Rome to our own day.’”15
Cosimo was at the heart of western Christendom. When popes visited Florence, they stayed in Medici palaces, enjoyed Medici hospitality, accepted Medici loans, and, in return, granted highly valuable concessions. For example, in 1460 huge deposits of alum, an essential ingredient in fulling cloth, were found near Civitavecchia in the Papal States. In 1466 the Medicis signed an agreement with the papacy giving them and
their partners the sole right to mine alum and sell it abroad.
Hibbert wrote, “the French historian, Philippe de Commines, described the bank…as the greatest commercial house that had ever been anywhere. ‘The Medici name gave their servants and agents so much credit,’ Commines wrote, ‘that what I have seen in Flanders and England almost passes belief.’”16
By the 1450s, Florence had silk and food. The Medicis had derived unprecedented riches from the silk trade and had used their wealth to fund astronomers, mathematicians, engineers, sculptors, artists, explorers, cartographers, historians, librarians, archaeologists, and geographers. The Renaissance was in full flood—thanks in part to Chinese inventions and plants—use of machines powered by wind and water, Chinese rice, mulberry trees, and silkworms.
18
GRAND CANALS: CHINA AND LOMBARDY
On New Year’s Day 1991, it was savagely cold in Beijing. Marcella and I had spent the night watching sensuous Tang dynasty dancers in their shimmering peacock-blue dresses—a memorable display. I had a bad headache, for obvious reasons, and found the cold that froze my nostrils a pleasant sensation. In those days there were few cars; Beijing streets were a tangled mass of bicycles, their riders swathed in baggy blue jackets and head scarves angled against the biting wind. The trees—stubby pines for the most part—stooped before the wind and glinted with ice crystals. We drove to the southwest of Beijing to board a huge military aircraft that would take us down to Xian.
By the time we took off, the sun was rising in the east, sparkling on the frozen Grand Canal. We flew south over the silver pencil of the canal on our way down to the Yellow River, then turned to the southwest above the river to Xian.
What a prodigious undertaking this Grand Canal was—dug, according to popular fable, “by a million people with teaspoons.” That is probably a serious underestimate: the workforce is likely to have been nearer five million. Like the Great Wall, the Grand Canal is the result of the obsession of many emperors over thousands of years. They dug in sections, gradually extending, deepening, and widening the canal so that it now links the rice lands of the south with Beijing via the Yangtze, Huang He, and Yellow Rivers.
The canal was started nearly 2,500 years ago and greatly extended during the Sui dynasty (A.D. 581–618),1 when Emperor Yang enslaved his people to link his new capital of Luoyang to Xian (in those days called Changan).2 Over two decades, he extended the canal down to Hangzhou, enabling Yangtze junks to travel up the canal to ports along the Yellow River. The canal crossed major rivers, traveling from the Tibetan highlands to the sea.
By the Tang dynasty (A.D. 618–907), 100,000 tons of grain were transported northward each year. Kublai Khan extended the canal to Beijing in the north and built a number of locks—there are more than thirty today—rising to 130 feet above sea level.3 Marco Polo was much impressed by the flat canal barges being towed by horses: “This magnificent work is deserving of admiration and not so much from the manner in which it is conducted through the country, or its vast extent, as from its utility and the benefit it produces to those cities which lie on its course.”4
Crossing so many rivers, particularly the Yellow, entailed major engineering challenges. The water level varied enormously depending on the time of year and the amount of snow that had melted in the mountains of Tibet and was carried down the rivers to the sea. Other difficulties arose with the need to carry ships uphill as they neared Beijing. In The Genius of China, Robert Temple outlines the problem and the response:5
The canal pound lock was invented in China in 984 A.D. The inventor was Ch’iao Wei-Yo, who in 983 was appointed Assistant Commissioner of Transport for Huainan. The impetus for his invention was concern over the enormous amounts of grain which were being stolen during canal transport at that time. Grain was the normal tax payment throughout China’s history. Movement of the grain to central repositories and warehouses was the lifeblood of the Empire, and any substantial interruption of this process was a very serious social and political problem.
Until 984, boats could only move between lower and higher water levels in canals over double slipways. Chinese boats had no keels and were nearly flat-bottomed. A form of portage had been developed in China, therefore, whereby spillways originally designed to regulate water flow were elongated in gentle ramps both front and back, leading into the water. A boat would come along and be attached to ropes turned by ox-powered capstans. Within two or three minutes, the boat would be hauled up a ramp to the higher level and for a moment would balance precariously in the air. Then it would shoot forward like an arrow out of a bow and scud along the canal to a level several feet higher than it had started. Passengers and crew had to lash themselves tightly to the boat to avoid being hurled into the air and injured. The great disadvantage of this ingenious technique was that boats often split apart or were seriously damaged by the wear and tear of being dragged up the stone ramps. Whenever a boat broke up on a ramp, the contents would promptly be stolen by organised gangs—including corrupt officials—who waited for just such an occurrence. Sometimes apparently the ships were roughly handled on purpose, or were artificially weakened or had even been chosen for their weaknesses so that an “accident” of this kind could be brought about intentionally.
Ch’iao Wei-Yo determined to wipe out this practice. He therefore invented the pound lock so that double slipways would not be needed. Here is how the official history of the time relates the story: “Ch’iao Wei-Yo therefore first ordered the construction of two gates at the third dam along the west river (near Huai-Yin). The distance between the two gates was rather more than fifty paces [250 feet], and the whole space was covered over with a great roof like a shed. The gates were hanging gates: when they were closed the water accumulated like a tide until the required level was reached, and then when the time came it was allowed to flow out. He also built a horizontal bridge between the banks and added dykes of earth with stone revetments to protect their foundations. After this was done to all the double slipways the previous corruption was completely eliminated, and the passage of the boats went on without the slightest impediment.”
Pound locks made true summit canals possible. Water levels could differ by four of five feet at each lock without any problems at all. Over a stretch of territory, therefore, a canal could rise more than one hundred feet above sea level, as was the case with the Grand Canal, for instance (rising 138 feet above sea level). This made possible a vast extension of the canal network and freed hydraulic engineers from many awkward topographical restrictions.
The pound locks also conserved water, as Shen Kua relates in Dream Pool Essays of 1086:6
It was found that the work of five hundred labourers was saved each year, and miscellaneous expenditure amounting to one million two hundred and fifty thousand cash as well. With the old method of hauling the boats over, burdens of not more than twenty-one tons of rice per vessel could be transported, but after the double gates were completed, boats carrying twenty-eight tons were brought into use, and later on the cargo weights increased more and more. Nowadays [circa 1086] government boats carry up to forty-nine tons and private boats as much as eight hundred bags weighing one hundred and thirteen tons.
Not surprisingly, the Nung Shu, the Chinese agricultural treatise published in 1313, illustrated Chinese lock and sluice gates, which were essential to irrigating rice fields and controlling the water levels in canals. Needham states:
There is no doubt that throughout Chinese history the most typical form of sluice and lock gate was what is called the stop-log gate…two vertical grooves fashioned in wood or stone face each other across the waterway, and in them slide a series of logs or baulks let down or withdrawn as desired by ropes attached to each end. Windlasses or pulleys in wood or stone mountings like cranes on each bank helped to fit or remove the gate planks. This system was sometimes improved by fastening all baulks together to form a continuous surface and then raising or lowering it in the grooves by means of bolts….
The
oldest illustration of this kind we have found is in the Nung Shu Ch. 18, p 4b, the date of which (+1313) deprives Jacopo Mariano Taccola of the honour of having been the first to illustrate a dam with a sluice gate.7
So by the time Zheng He’s junks visited Venice in 1434 the Chinese had hundreds of years’ experience in building canals and locks and operating them in all kinds of conditions—dried-up rivers in summer and torrents in spring.
Lombardy
The geography and climate of Lombardy, the region between the foothills of the Alps and the River Po, resembles that of eastern China. The Po carries melted snow from the great lakes, especially Lake Maggiore, first southward, then east across the flat plain to the Po delta south of Venice. For centuries, the river has provided a means of transporting goods, including wood and marble, from the mountains to the cities of the plains, and her waters have produced fertile land.
Canals have played an important role in the development of commerce, agriculture, and industry in Lombardy. The impetus for Lombardy’s first major canal appears to have been the capture of Milan by the Holy Roman Emperor Barbarossa in 1161.8 Milan built substantial defenses, collecting water from local streams to form wide moats around the city. Milan also needed a secure supply of drinking water, and the best available was the River Ticino, which flowed from Lake Maggiore into the Po sixteen miles from Milan. This led to the first canal linking the Ticino with Milan—a huge undertaking for Europeans. The work was completed in about 1180, long before the Chinese arrived in 1434.
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