But the aqueducts of ancient Rome stand out thanks to their grand scale and breathtaking architecture, which often used elevated bridges to pass water across valleys and over urban areas. In fact, some carry water even now, some 2, years later. Aqueducts route water over long distances using gravity alone. For the concept to work, though, it needs to be built with staggering precision. Some Roman aqueducts slope just a foot or two per mile, according to the U.
Geological Survey. And while their stunning, arched stone architecture may have made aqueducts famous, the vast majority of Roman aqueducts were actually built underground. And as its military spread across the globe, Roman culture often replaced local traditions with its language, alphabet, calendar and technology. As a result, Roman aqueducts can still be visited across the ancient world. Roman builders constructed these monumental works of public infrastructure in far-off places like Great Britain and Morocco, where fast-growing civilizations also needed ample fresh water.
There are dozens of known examples found in Europe, Africa and Asia. In France, a first century A. In Spain, the Aqueduct of Segovia reaches nearly feet tall on its highest bridge and dates to around the second century A. It provided water to the city from a river roughly 10 miles away.
In Syria and Jordan, builders of the Roman empire spent more than a century constructing a monumental system of channels, tunnels and bridges called the Gadara Aqueduct.
Just one section was miles long. It carried water from a now-dry swamp to the booming league of 10 ancient cities called the Decapolis, creating an oasis in the desert. A people known for their military, political, and social institutions, the ancient Romans conquered vast amounts of land in Europe and northern Africa, built roads and aqueducts, and spread Latin, their language, far and wide. Use these classroom resources to teach middle schoolers about the empire of ancient Rome.
The ideas and culture of ancient Rome influence the art, architecture, science, technology, literature, language, and law of today. During his reign, Augustus restored peace and prosperity to the Roman state and changed nearly every aspect of Roman life. Julius Caesar was a Roman general and politician who named himself dictator of the Roman Empire, a rule that lasted less than one year before he was famously assassinated by political rivals in 44 B.
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Related Resources. Managing Resources. View Collection. Ancient Rome. Traces of Ancient Rome in the Modern World. View leveled Article. Writing about A. From the center of this plate rose a vertical pivot around which a toothed wheel was set so that it could revolve in a horizontal plane. A groove equal in width to the thickness of the toothed horizontal wheel ran the length of the screw, thus leaving a segment devoid of sections of the screw threads.
The screw could be turned to engage the teeth of the wheel and lock it in position. Or the screw may also have been employed to make very precise turnings of the wheel.
The elements described thus far formed the basic part of the dioptra. For taking the necessary readings Hero offered a choice of two attachments, each in the form of a column, either one of which could be set on the pivot and held by three vertical prongs fitting into slots in the toothed wheel surrounding the pivot.
One attachment included a water level, the other had a theodolite. In the case of the theodolite, two upright braces fastened to the top of the column held a vertical plate cut to the form of half a circle with teeth around the curved edge. This half plate revolved around a pivot passing through its thickness near the top horizontal edge, the pivot being secured in the upper ends of the braces.
Between the bottoms of the braces ran a horizontal screw engaging the teeth of the half plate. The alternate attachment, the water level, consisted of a Doric column to be set over the pivot of the lower section and locked in position by prongs fitting into the horizontal toothed wheel surrounding the pivot.
Atop this column was secured a long horizontal bronze bar or rod with a channel cut in its upper surface from one end to the other. A hollow bronze tube, with each end curved vertically upward, lay in this channel. From each upturned end of this tube projected a short length of glass tubing.
The knowledge that two connected bodies of water will rise to the same level was employed here in this water level. Each of these bronze plates was adjusted by a screw attached in its lower side and passing downward through the horizontal rod which projected slightly beyond the upturned tube. But with the sliding plates and the possible existence of calibrations on the plate supports it could also have been used for defining vertical angles.
In regard to both dioptra attachments it must be remembered that in Roman times there was no such thing as a telescopic sight. But the leveling rod used with the dioptra was much like that employed by surveyors today.
It had a vertical dove-tailed groove in its front face, in which was placed a sliding block with a flat disk or shield attached vertically to the front of it, the disk being painted black on one half and white on the other. To the back of the disk was also fastened a pointer which moved along a vertical scale marked on the side of the rod. The assistant holding such a leveling rod at a specified distance from the dioptra first made certain that it was in a vertical position on the ground.
Then, on signals given by the librator, he adjusted the disk up or down until the dividing line between the black and white sections fell in direct line with the sights of the dioptra. In Rome this obligation at first fell on the Censor but then Augustus created the post of curator aquarum to control all aqueduct details.
Any failure to live up to the contract could cause the forfeiture of this deposit. The first concern was to lay out the general course of the water channel from its source to the site where the main distribution reservoir would be located in the town.
For this purpose a librator or surveyor was secured. From the sample problems given by Hero for the use of his dioptra it appears most likely that this initial survey for the aqueduct line was actually begun on the outskirts of the town and run up into the hills to the source of the water. On this first survey the librator was able to calculate the height of the source above the delivery point. He accomplished this by sighting horizontally along sets of leveling rods, marking them at the level of his sights and recording the heights of these marks above the ground level.
This record was probably kept on sheets of papyrus. With these horizontal and vertical measurements he could determine the natural gradient of the line. Having decided upon the gradient for the first section. Thus the two rods were accurately located along the line which would lead down to the town.
Now he placed his dioptra between the rods so as to be in perfect alignment with them. A marking staff was set in the ground here and marked at the height of the disk. The dioptra then was moved downhill beyond the second leveling rod, adjusted to a horizontal level and sighted back to the second rod with the first leveling rod directly in line behind it.
The entire concept of surveying for the gradient was based on the theory of right-angle triangles, conceived in a vertical plane with the lengths of both arms provided by the surveying measurements. By altering the horizontal distance from one rod to the next or by changing the vertical height of a staff marker from the ground it was possible to create a different gradient. For measuring the distances necessary for these calculations Hero specifically indicated that measuring chains or cords were used.
In the case of very short spans a measuring stick or regula could be employed. This contrivance used toothed wheels geared in series to revolve one after the other. The wheels were of various proportionate sizes turning around axles in calculated ratios of revolution. Any discrepancy meant backtracking and correcting his established markers. A surveyor simply worked within understood limits. The gradients varied from one section to another and he understood that no section of the line could have a gradient so small that the water would move sluggishly, allowing sediment to settle and block the passage.
Yet short lengths of very steep inclination were indeed created and suggest that the Roman engineer was less fearful of their limited use than he was of a slope that was too shallow. Some confusion exists in the ancient Latin statements concerning the minimum gradient for an aqueduct channel. The Aqua Julia built for Rome in 33 B. The latter at one point, however, drops 5.
The city of Lyon in France had four aqueducts servicing it in Roman Imperial times. Later in its course it drops 90 meters over a length slightly less than three kilometers, for no apparent reason other than the slope of the land.
The Lyon aqueduct of Craponne, though not well-surveyed for such details, descends in great steps and probably offers similar indications of great variations. It would appear that these first three aqueducts of Lyon were constructed between 29 B. But then there is a fourth aqueduct, that of the Gier, which apparently dates to the period of Hadrian A. Obviously the channel of this aqueduct runs more consistently at gradients lower than those of the other three aqueducts.
While the improved dioptra may have played some role in the elimination of radical changes in level, the over-all gradient is related most directly to the long course of the Gier channel, amounting to 75 kilometers. According to one estimate it supplied Nimes with at least 20, cubic meters of water in 24 hours. The Appian aqueduct B. On the other hand, the Aqua Julia of 33 B. Yet nearly every Roman aqueduct in France, Spain, Italy, and elsewhere has by far its major portion laid below ground level.
Today, aqueduct arches too often give the impression that an aqueduct would look like this throughout its entire length. Charting the course of an aqueduct bridge across a valley was no difficulty for a Roman surveyor, and he marked a channel through a mountain using the same basic technique. Again, the theory was that of vertical right-angle triangles.
However, the channel would have to have a gradient. Once such surveying problems had been worked out and the proposed aqueduct line marked by posts, there was no further need for the professional librator.
It was now time for actual construction work to begin and any additional surveying requirements would be of such a nature that they involved only verifying adherence to the details defined by the librator. At this juncture the Contractors would have their Work crews already organized.
Towns of moderate size could also offer a certain number of more specialized workers skilled in various aspects of heavier construction work.
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