Picture essay. The Romans in Ulpia Noviomagus Batavorum (Nijmegen)
High Tech Romans
by Chloë Fonk
Accurate measuring equipment was vital for the construction of waterworks, streets and tunnels.
Surveyors used a hodometer to measure distances, a chorobates to measure height differences and a dioptra to measure vertical angles. The groma helped them mark out right angles and they had an advanced sort of abacus with which to make arithmetical calculations. Merchants weighed out goods on two kinds of scales: beam scales and steelyards. The largest unit in the Roman system of weights was the libra or pondus (327.45 grams) and the smallest was the uncia (27.29 grams).
In Great-Britain, ounces are still in use for weighing.
The first computer
A century ago, sponge divers found a 2,000-year-old analog ‘computer’ in the wreck of a ship off the Greek island of Antikythera. It has 30 bronze gear wheels, together forming a complex transmission. Until recently, nobody knew exactly what it was. Now, scientists think it was a calendar for determining the position of the sun, the constellations and the moon. It could be used to calculate the dates of lunar and solar eclipses and of the Olympic games. Roman sea captains probably also used devices of this kind.
The Romans planned every new town or military camp with a rectangular grid of streets. This was based on two main axes: one north-south (cardo maximus) and the other east-west (decumanus maximus). All the other streets were built parallel to these axes. To do this, Roman land surveyors used a surveying instrument called a groma. For that reason, the junction of the two main axes was also called the groma.
The Romans used ingenious cranes and lifting gear, both on building sites and to load and unload ships. This kind is called a tripastos: a crane with three pulleys. Operated by just two men, it could easily lift and move blocks of stone weighing up to 300 kilos. There were also cranes with more pulleys, enabling them to lift even heavier loads. The most powerful crane of all had a treadmill instead of a winch, in which slaves produced the needed force.
In the field of crafts the Romans focused on innovation and the development of new production methods.
Potteries were often industrial-scale enterprises in which crockery was produced by the thousands. This increased production was possible because of standardisation. For example, the use of moulds meant that luxury items in glass, earthenware and metal could be produced on a larger scale. Roman artisans were highly experienced in the use of natural pigments, leather, textiles, wood, stone, metal, glass and earthenware.
The woodworking joints used in buildings and furniture were so good that they are still in use today.
There were moulds for objects in earthenware, bronze or glass. First they made a model of the object. Then they pressed it into clay or plaster, so that it left a hollow impression. To make a lamp, they needed a two-part mould: one part for the top and one for the bottom. Lumps of clay were pressed into the moulds, then taken out and fitted together. Each mould could be used many times and the results were identical.
A real mosaic can contain up to 10,000 pieces (tesserae) per m². the Romans used various kinds of stone, coloured glass and ceramic to make the different colours. We think they had books of standard designs because some images have been found in several different places, like the dog and the words ‘‘Beware of the dog’’.
A computer screen works in the same way as a mosaic: it uses lots of small coloured dots (pixels) to make up the image. A screen uses around 400 pixels per cm² or 4 million per m².
Under floor heating
Floors which had to be heated rested on pillars made of round or square tiles. The warm air spread under the floor.
Rectangular hollow tubes, which were built into the walls, ensured that the warm air was removed and that the walls were heated.
Large tiles were placed on top of the pillars which had been joined together. A cement layer was then applied, onto which sometimes a mosaic floor was laid. The mosaic stones were made of stone, brick and glass.
A hole was made in a flat roof tile, and a chimney with holes was placed on top of this.
Food and drinks
The Romans imported their favourite food and drink: wine, olive oil, fish sauce, olives as well as preserved fruits.
Keys and locks
To supply their towns and cities with water the Romans built waterworks and aqueducts.
These carried fresh water from natural springs to distribution points on the edge of town. From there, pipes made of lead, ceramics or wood carried the water to bathhouses, public toilets, drinking fountains and affluent private households. Like us, the Romans drew their water from taps, usually made of bronze. Wastewater was removed by extensive sewer systems and discharged into rivers or the sea. The Romans improved on ancient Greek inventions like the Archimedes’ screw and the piston pump and made large-scale use of them.
To make their houses waterproof, the Romans used two kinds of roof tiles. The whole surface of the roof was covered with big, flat rectangular tiles with raised sides, called tegulae. The narrow, curved tiles, called imbrices, were used to waterproof the joints. Because Roman roofs were flatter than ours, the heavy tiles stayed in place and there was no chance of leaks. Roman roof tiles came in standard sizes and were turned out in huge batches by special tile works.
On the road
All the provinces in the empire were linked by an extended network of roads.
To speed up travel, the roads were built as straight as possible. Along the roads milestones were erected to indicate the distance to the next major town. Many modern highways follow the Roman trails.
Goods were transported by road on carts drawn by mules or oxen. Passenger vehicles even had springy suspension systems: leather straps supporting the body of the vehicle. On the rivers and at sea, fast wooden naval vessels guarded the navigational routes.
Along Roman roads, travellers would pass by milestones. These stated the distance to the nearest city, and honoured the emperor with an inscription. If a new emperor carried out maintenance work to the roads, new milestones were installed. However, the old milestones remained in situ out of respect for the emperor’s ancestors. And it is so that there are four milestones in one single location in the Netherlands. These milestones refer to Forum Hadriani, which is currently known as Voorburg. Here you see a cast of one of those milestones, honouring emperor Caracalla.
Hadrian’s Wall (15)
Hadrian’s Wall is in the north of England. It is 117 kilometres long and, until the middle of the 2nd century A.D., it marked the northern boundary of the Roman Empire. Surveyors used the groma and other measuring equipment to plot the line of the wall with its associated ditches, forts and gateways.
The Romans in the Netherlands
The pictures of this article are taken in the Valkhof Museum, Nijmegen (Holland). The text is based on the explanations of this museum by the exhibition High Tech Romans.