Chapter summary:
Like the Great Wall, the Grand Canal is the result of the obsession of many Emperors over thousands of years. The canal was started nearly two thousand five hundred years ago and greatly extended during the Sui Dynasty (581-618 AD). However, crossing so many rivers caused major engineering problems for the Grand Canal. The water level varied enormously depending on the time of year and other difficulties arose with the need to carry ships uphill as they neared Beijing. Boats could only move between lower and higher water levels in canals over double slipways
However, in 984 Ch’iao Wei-Yo invented the pound lock so that double slipways would not be needed. Pound locks made true summit canals possible. Water levels could differ by four of five feet at each lock without any problems at all. This made possible a vast extension of the canal network and freed hydraulic engineers from many awkward topographic restrictions. 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
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. The geography and climate of Lombardy, the region between the foothills of the Alps and the River Po, resembles that of eastern China. For centuries, the Po 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 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. Without locks, canals could not function. All of this was revolutionised about the year 1450. Chinese canal and lock building techniques had been imported into Lombardy through di Giorgio and the Nung Shu. An examination of the history of canals in Lombardy also illustrates the close connection between Taccola, di Giorgio, Leon Batista Alberti and Leonardo. 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. In other words, both di Giorgio and Alberti described the same locks which are also described on the Nung Shu. It is therefore incorrect to credit Leonardo da Vinci with the discovery of locks.
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 carried 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. The wonderful rich legacy based upon rice and silk, canals and steel is visible today.
Further reading:
The Triumph of Vulcan: Sculptors’ Tools, Porphyry, and the Prince in Ducal Florence
http://www.jstor.org/pss/2901977
Notes on Canal History and Engineering
http://mysite.du.edu/~jcalvert/tech/canhist.htm
Alex Keller ‘s review of Engineers and Engineering in the Renaissance by William Barclay Parsons http://www.jstor.org/pss/3102538
A history of canals
http://www.historyworld.net/wrldhis/PlainTextHistories.asp?historyid=aa19
The Grand Canal of China
http://www.chinapage.com/canal.html
