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.

The largest canal of this system was called the Naviglio Grande (Grand Canal). It was small, of varying depth, depending on the amount of water coming from the mountains. It had no locks and therefore navigation was hazardous and seasonal. All of this was revolutionized around the year 1450.

This time, the impetus came from Francesco Sforza, a determined and clever leader who seized the throne from Filippo Visconti on his death in 1447. Sforza cut the Naviglio Grande, which promptly deprived Milan of its drinking water. Moreover, the mills alongside the canal lost their power supply so they could no longer grind grain. Milan capitulated and Francesco entered the city as conqueror in 1450. He was proclaimed Duke and created the house of Sforza.

Sforza set about providing Milan with continuous supplies of drinking water, hydropower, and the ability to transfer goods and food throughout the year. Sforza had inherited a canal in the west that connected Milan to Lake Maggiore, but it had no locks and depended on the variable height of water from the mountains. It was useless for navigation. He decided to equip it with locks and transform it into an all-season, all-weather canal.

He planned to build the Bereguardo Canal in the south, in order to link Milan with Pavia, and in the north a link between Milan and the River Adda, which flowed out of Lake Como. This grand scheme would create a waterway from Lake Maggiore in the west all the way to Lake Como in the east, which could provide water for Milan and serve as a navigation system linking the Adriatic with Lombardy. The problem, of course, was that in 1452 when the plan was conceived, Italians had no method of building locks. Without locks, canals could not function—especially not the Bereguardo Canal, which had a fall of eighty-two feet and spring weather that brought melted snow in abundance down from the mountains.

There are no prizes for guessing who provided the design for the locks: it was our old friends, Taccola,9 Francesco di Giorgio, and Leon Battista Alberti. Francesco, as described in chapter 16, copied and improved upon Taccola’s work. We presume he, like Taccola, had access to and copied from the Nung Shu. In chapter 16 we described di Giorgio’s Trattato di Architettura, notably the copy marked Codex Laurenziano, which was owned by Leonardo da Vinci and is now found in the Laurenzian Library in Florence. Also deposited with that document is di Giorgio’s Trattato dei Pondi Leve e Tirari.10 One of the last descriptions in the Laurenziana Codex, no. 361, concerns a series of lock gates:

If along a river…. we wish to conduct boats, when due to little water and an incline it might be impossible to navigate, it is necessary to determine the fall…. Let us suppose that the first part of the river has a drop of thirty piede: construct at that point a high door in the manner of a portcullis…. with windlasses to raise it, and in this manner lay off the entire length of the river and all its falls with such doors. After the boat enters, and the door is closed, the boat will soon rise…and will be able to enter the second chamber…and so step by step you will be able to take the boat to wherever you wish. Should you desire to return down, by opening each door, the boat with the water will be led to the next door, and so from one to the other it will be possible to return to the sea. All boats should be made with flat bottoms, so that they will float on little water.11

This description is accompanied by a picture showing a lock system with no fewer than four locks. The date of the picture, from the Hans Lee Laurenziana Codex,12 is about 1450—a date fixed by the description of the destruction of central Ragusa (Dubrovnik).

Sforza and his architect, Bertola de Novale, now had illustrations of how to build locks. At first they found them puzzling. Here is William Parsons’s13 description: “But the details of the locks were not understood and the contractors refused to move. So Berenzo de Passaro wrote further urgent requests to the Duke to send Bertola with the necessary explanations.”14

Parsons continues:

By 1461 the canal was completed as is shown by another letter by Lorenzo, in which he complains of defects in the locks and asks again that Bertola be sent to remedy the troubles. In this letter he writes of the locks being two braccia deeper than the bottom of the canal [which must refer to the height of fall]. The defects were said to be in the gates: their hinges were weak and the gates themselves could not withstand the water pressure.15

After 1461, locks were built on the canal between Milan and the Adda River, which was later called the Martesana. Bertola was engaged in the construction of at least five canals of major navigable importance, all requiring locks. He constructed no fewer than eighteen locks on the Bereguardo Canal and five more near Parma. Chinese canal-and lock-building techniques had been imported into Lombardy through Taccola Francesco di Giorgio and the Nung Shu.

An examination of the history of canals in Lombardy also illustrates the close connection between Taccola, Francesco di Giorgio, Leon Battista Alberti, and Leonardo da Vinci. Alberti, who was the notary to Pope Eugenius IV and would have likely attended the meeting between Eugenius and the Chinese ambassador, also designed locks. William Parsons said of Alberti:

The year 1446 saw him re-established in Rome, a friend of Nicholas V, and started on his engineering work—an attempt to recover the sunken galley in Lake Nemi [Alberti used a drawing virtually identical to that of Taccola and Francesco], which only lately has been accomplished…. This was followed by the work on which his fame depends, De re aedificatoria (written about 1452). From several references to it by other writers, it is certain that the contents were made available to scholars then or soon after. This fact is important because it fixes the date when the canal lock was first described…. Leon Batista continued thus: “Also, if you wish you can make two gates cutting the river in two places…that a boat can lie for its full length between the two: and if the said boat desires to ascend when it arrives at the place, close the lower barrier and open the upper one, and conversely, when it is descending, close the upper and open the lower one. Thus the said boat shall have enough water to float it easily to the main canal, because the closing of the upper gate restrains the water from pushing it too violently, with fear of grounding.”…We are sure that Bastista’s Aedificatoria was written about 1452, and that its contents were known to many engineers.16

In other words, both Francesco and Alberti have described the same lock systems that are described in the Nung Shu.

It is therefore incorrect to credit Leonardo da Vinci with the invention of locks. As we know, his handwriting appears on the Laurenziano Codex of Francesco (as described in chapter 16). We also know that Leonardo learned much about waterways from his meeting in Pavia with di Giorgio. It is fair to say that Leonardo’s drawings of canals are the most elegant by far, but Leonardo did not invent locks, despite centuries of credit for the breakthrough.

Nevertheless, the introduction of locks, which enabled an all-weather, all-season system of navigable canals to be constructed in northern Italy, was of immense importance to the economic development of Lombardy. The introduction of Chinese rice, mulberry trees, and silk was all the more valuable once the rice could be carried downriver on the Po. Marble, too, could be transported from the mountains to the new cities of northern Italy. Italy now possessed an array of Chinese inventions—water-powered machines such as mills and pumps to grind corn and spin silk. After 1434, Italy was on her way to becoming Europe’s first industrial nation.

Europe’s First Industrial Nation

The wonderful rich legacy based on rice and silk, canals and steel, is visible today. During most summers of the past forty-two years Marcella and I have driven through Burgundy across the Col de Larche to her home in the Piedmont to stay with her family in the foothills of the Alps. We would drive eastward to Venice across the Po Valley through miles upon miles of golden rice fields irrigated by the famous canals fed by alpine snowmelt.

We would start our journey at dawn, the lanes full of puttering tractors. After four hours, Mantua would appear, a ghostly silhouette suspended from the sky, a light fog sitting on the lakes that surround the town. Medieval town builders exploited the loops of the Po and her tributary the Mincio to create a series of lakes that form Mantua’s defenses. Cremona, Pavia, Verona, and Milan were also built on loops of the Po tributaries that wound their way across the fields of Lombardy. Mantua’s historic town center is typical of these medieval cities. The Piazza Erbe is an ensemble of enchanting pastel buildings. It leads to the equally beautiful Mantegna and Sordello Squares, each more imposing than the last, each surrounded by superb medieval and Renaissance buildings. At the east side of Sordello Square stands the ducal palace of the Gonzagas,17 the princely family who ruled this town in the Middle Ages. One great hall leads to another, each covered from floor to ceiling with frescoes, fantastic Renaissance masterpieces—fables by Pisanello and Mantegna, portraits of the Gonzaga family, tapestries depicting the lives of the apostles. The most astonishing impact comes from differing styles being linked to form a harmonious single ensemble. The Gonzagas were clearly a family of enormous wealth and great discernment.

In Verona the Scaglieri18 ruling family, like the Gonzagas, patronized brilliant artists. This comes as a surprise, for Verona, Mantua, Milan, Urbino, and Ferrara had a different lifestyle than that of republican Florence and Venice. Instead of a wealthy mercantile class engaged in international trade, rulers and aristocracy in these northern cities lived on their wits, often acting as mercenaries to Venice. However, these ministates lay on trade routes. Milan and Verona controlled the approach to the principal alpine passes and were in a position to gather taxes and tolls from overland traffic between Venice and northern Europe. Each had a little army. The money the rulers lavished on Renaissance artists was undoubtedly part of their foreign policy—to appear wealthier and more important than they really were so as to impress their powerful neighbors, Venice and Florence. Today we are the beneficiaries of this largesse. These sumptuous Italian cities are stuffed with Renaissance masterpieces; one could spend a lifetime in each.19

The wealth of modern Italy remains visible in the houses of farmers and middle-class people—huge by the standards of northern Europe, and superbly finished. People wear expensive clothes, and the women exquisitely turned out, presenting the renowned bella figura.

To me, the wealth of northern Italy, particularly that of Piedmont, is epitomized in the food. One enters what appears to be a farmhouse; often no name discloses the restaurant within. The place is packed; there are no menus and no price lists—one just chooses a table and sits down. Our favorite is the Nonna, in the foothills of the Alps near Pian Fei. A bottle of slightly sparkling dry deep red wine made from Nebbiolo grapes is brought, together with a plate of Parma ham and salami. Then come crudités with bagna cauda, a sauce of garlic, anchovies, tuna, and olive oil, followed by pasta. Several courses—roast kid, guinea fowl, wild boar, suckling pig, and wild rabbit with chestnuts follow. Dessert is frequently the local raspberries and the famous chestnuts boiled with white vino and mixed with cream. One is handed the bill, usually about twenty euros a head for twelve courses.

To me there is no place on earth with a higher standard of living than the Piedmont with her huge houses, wonderful food, historic cities, good-natured and charming people—a life based upon natural wealth in a region whose advanced methods of farming and industrialization came six hundred years ago.

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