2008年12月12日星期五

De architectura


In summary
Probably written around 25 BC , it is the only contemporary source on classical architecture to have survived in its entirety. Divided into ten sections or "books", it covers almost every aspect of Roman architecture. The books break down as follows:
Town planning, architecture or Civil engineering in general, and the qualifications required of an architect or more modernly the civil engineer
Building materials
Temples and the orders of architecture;
continuation of book 3
Civil buildings
Domestic buildings
Pavements and decorative plasterwork
Water supplies and aqueducts
Sciences influencing architecture - geometry, mensuration, astronomy, sundial
Use and construction of machines - Roman siege engines, water mills, drainage machines, Roman technology, hoisting, pneumatics
Roman architects were significantly different from their modern counterparts, acting as engineers, architects, artists, and craftsmen combined. Vitruvius was very much of this type, a fact reflected in De architectura. He covers a wide variety of subjects which he saw as touching on architecture. This included many aspects which may seem irrelevant to modern eyes, ranging from mathematics to astronomy, meteorology and medicine. In the Roman conception, architecture needed to take into account everything touching on the physical and intellectual life of man and his surroundings.
Vitruvius thus deals with many theoretical issues concerning architecture. For instance, in Book 2 of De architectura, he advises architects working with bricks to familiarise themselves with pre-Socratic theories of matter so as to understand how their materials will behave. Book 9 relates the abstract geometry of Plato to the everyday work of the surveyor, while the mathematics. Astrology is cited for its insights into the organisation of human life, while astronomy is required for the understanding of sundials. Similarly, Vitruvius cites Ctesibius of Alexandria and Archimedes for their inventions, Aristoxenus (Aristotle's apprentice) for music, Agatharchus for theatre, and Varro for architecture.

Buildings

He sought to address the ethos of architecture, declaring that quality depends on the social relevance of the artist's work, not on the form or workmanship of the work itself. Perhaps the most famous declaration from De architectura is one still quoted by architects: "Well building hath three conditions: firmness, commodity, and delight." This quote is taken from Sir Henry Wotton's version of 1624, and is a plain and accurate translation of the passage in Vitruvius : but English has changed since then, especially in regard to the word "commodity", and the tag is usually misunderstood.
Vitruvius also studied human proportions (Book 3) and his canones were later encoded in a very famous drawing by Leonardo da Vinci (Homo Vitruvianus, "Vitruvian Man").

Roman technology

The work is important for its descriptions of many different machines used for engineering structures such as hoists, cranes and pulleys, as well as war machines such as catapaults, ballistae, and siege engines. He also describes the construction of sundials and water clocks.

Aqueducts and mills

Books 8, 9 and 10 form the basis of much of what we know about Roman technology, now augmented by archaeological studies of extant remains, such as the Pont du Gard in southern France. Numerous such massive structures occur across the former Empire, a testament to the power of Roman engineering. His description of aqueduct construction is short, but does mention key details especially for the way they were surveyed, and the careful choice of materials needed. His book would have been of assistance to Frontinus, a general who was appointed in the late first century AD to administer the many aqueducts of Rome. He discovered a discrepancy between the intake and supply of water caused by illegal pipes inserted into the channels to divert the water. They went far in exploiting water power, as the set of no less than 16 water mills at Barbegal in France demonstrates. The mills ground grain in a very efficient operation, and many other mills are now known.

Materials
Vitruvius describes many different construction materials used for a wide variety of different structures, as well as such details as stucco painting. Cement, concrete and lime receive in-depth descriptions, the longevity of many Roman structures being mute testimony to their skill in building materials and design.
It is worth noting that Vitruvius advises that lead should not be used to conduct drinking water, clay pipes being preferred. He comes to this conclusion in Book VIII of De Architectura after empirical observation of the apparent labourer illnesses in the plumbum foundries of his time. In 1986 the United States banned the use of lead in plumbing due to lead poisoning's neurological damage. However, much of the water used by Rome and many other cities was very hard, and coated the inner surfaces of the pipes, so lead poisoning was most unlikely.

Vitruvius gives us the famous story about Archimedes and his detection of adulterated gold in a royal crown. When Archimedes realised that the volume of the crown could be measured exactly by the displacement created in a bath of water, he ran into the street with the cry of "Eureka!", and the discovery enabled him to compare the density of the crown with pure gold. He showed that the crown had been alloyed with silver, and the king defrauded. We are not told what happened to the metal worker who crafted the crown, but no doubt he suffered a painful fate.

Dewatering machines

He describes the construction of Archimedes' screw in Chapter X, although doesn't mention Archimedes by name. It was a device widely used for raising water to irrigate fields and dewater mines. Other lifting machines he mentions include the endless chain of buckets and the reverse overshot water-wheel. Remains of the water wheels used for lifting water have been discovered in old mines such as those at Rio Tinto in Spain and Dolaucothi in west Wales. One of the wheels from Rio Tinto is now in the British Museum, and the latter in the National Museum of Wales. The remains were discovered when these mines were re-opened in modern mining attempts. They would have been used in a vertical sequence, with 16 such mills capable of raising water at least 96 feet above the water table. Each wheel would have been worked by a miner treading the device at the top of the wheel, by using cleats on the outer edge. That they were using such devices in mines clearly implies that they were entirely capable of using them as water wheels to develop power for a range of activities, not just for grinding corn, but also probably for sawing timber, crushing ores, fulling and so on.

Force pump

Ctesibius is credited with the invention of the force pump which Vitruvius describes as being built from bronze with valves to allow a head of water to be formed above the machine. The device is also described by Hero of Alexandria in his "Pneumatica". The machine is operated by hand in moving a lever up and down. He mentions its use for supplying fountains above a reservoir, although a more mundane use might be as a simple fire-engine. One was found at Roman Silchester or Calleva Atrebatum in England, and another is on display at the British Museum. Their functions are not described but they are both made in bronze, just as Vitruvius specifies.
Vitruvius also mentions the several automatons that Ctesibius invented, and intended for amusement and pleasure rather than serving a useful function..

Central heating

He describes the many innovations made in building design to improve the living conditions of the inhabitants. Foremost among them is the development of the hypocaust, a type of central heating where hot air developed by a fire was channelled under the floor and inside the walls of public baths and villas. He gives explicit instructions how to design such buildings so that fuel efficiency is maximised, so that for example, the caldarium is next to the tepidarium followed by the frigidarium. He also advises on using a type of regulator to control the heat in the hot rooms, a bronze disc set into the roof under a circular aperture which could be raised or lowered by a pulley to adjust the ventilation. Although he does not suggest it himself, it is likely that his dewatering devices such as the reverse overshot water-wheel was used in the larger baths to lift water to header tanks at the top of the larger thermae, such as the Baths of Diocletian and the Baths of Caracalla.

Surveying instruments
That he must have been well practised in surveying is shown by his descriptions of surveying instruments, especially the water level or chorobates, which he compares favourably with the groma, a device using plumb lines. They were essential in all building operations, but especially in aqueduct construction, where a uniform gradient was important to provision of a regular supply of water without damage to the walls of the channel. He describes the hodometer, essentially a device for automatically measuring distances along roads, a machine essential for developing accurate itineraries, such as the Peutinger Table.

Sea Level Change
In Book IV Chapter 1 Subsection 4, there is a description of thirteen Athenian cities in Asia Minor, "the land of Caria", in present day Turkey. These cities are given as: Ephesus, Miletus, Myus, Priene, Samos, Teos, Colophon, Chius, Erythrae, Phocaea, Clazomenae, Lebedos, Melite and later a fourteenth, Smyrnaeans. Myus, the third city, is described as being "long ago engulfed by the water, and its sacred rites and suffrage". This sentence indicates that at the time of Vitruvius's writing it was known that sea-level change and/or land subsidence occurred. The layout of these cities is in general from South to North so that it appears that where Myrus should be located is inland. If this is the case then since the writing of De architectura the region has either experienced soil rebound or a sea-level fall. Though not indicative of sea-level change, nor speculation of such, many Roman ports suffered from silting. Roman salt works in Essex County, England today are located at the 5 meter contour implying this was the coastline. These observations only indicate the extent of silting and soil rebound affecting coastline change since the writing of De architectura.

Survival and rediscovery

Vitruvius' work is one of many examples of Latin texts that owe their survival to the palace scriptorium of Charlemagne in the early 9th century. (This activity of finding and recopying classical manuscripts is part of what is called the Carolingian Renaissance.) Many of the surviving manuscripts of Vitruvius' work derive from an existing manuscript that was written there, British Library manuscript Harley 2767. These texts were not just copied but also were known at the court of Charlemagne, since his historian, the bishop Einhard, asked for explanations of some technical terms at the visiting English churchman Alcuin.
Fifty-five copies of De architectura did exist in manuscript form during the Middle Ages but appear to have received little attention. Vitrivius' work was "rediscovered" in 1414 by the Florentine humanist Poggio Bracciolini, who found it in the Abbey of St Gallen, Switzerland. He publicised the manuscript to a receptive audience of Renaissance thinkers, just as interest in the classical cultural and scientific heritage was reviving.
The first printed edition, an incunabula version, was published by the Veronese scholar Fra Giovanni Sulpitius in 1486. The Dominican friar Fra Giovanni Giocondo produced the first version illustrated with woodcuts in Venice in 1511. It had a thorough philosophical approach and superb illustrations. Translations into Italian were in circulation by the 1520s, such as the translation by Cesare Cesariano in Como in 1521. It was rapidly translated into other European languages – the first German version was published in 1528 – though, curiously, English-speakers had to wait until 1771 for a full translation of the first five volumes and 1791 for the whole thing. Sir Henry Wotton's 1624 version, The Elements of Architecture, was more of a free adaptation than a literal translation, while a 1692 translation was much abbreviated.

Impact
The rediscovery of Vitruvius' work had a profound influence on architects of the Renaissance, prompting the rise of the Neo-Classical style. Renaissance architects, such as Niccoli, Brunelleschi and Leon Battista Alberti, found in "De Architectura" their rationale for raising their branch of knowledge to a scientific discipline as well as emphasising the skills of the artisan.
The English architect Inigo Jones and the Frenchman Salomon de Caus were among the first to re-evaluate and implement those disciplines that Vitruvius considered a necessary element of architecture: arts and sciences based upon number and proportion (architecture). The 16th century architect Palladio considered Vitrivius his master and guide, and made some drawings based on Vitruvius' work before conceiving his own architectural precepts.

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