Quote:Leveling the Ground: Water Levels and the Inclinometer
For much of their work, the Roman surveyors had to prepare flat surfaces or maintain an incline. For leveling ground, especially where it needed to be flat, the Roman surveyors used a rudimentary spirit level, which consisted of an elongated basin with a mark at either end to signify the level. There is little literary or archaeological evidence that they used this, but it was used by the Egyptians and the Greeks making it very likely that the Roman surveyors used it.