Iranians invented squinches to cover a square-plan space with a dome. Filposh, a type of squinch first found in Sasanian architecture, is a conical vault constructed in the transition zone’s corners to transmit the dome’s forces and weight. This technique can be seen in three halls of the Sasanian palace of Ardeshir. In this paper, the geometry of the transition zone using filposh squinches between a spherical dome and the square supporting walls in Ardeshir Palace was re-examined. A historical descriptive method was employed to analyse the main drawings of the halls from the nineteenth century to the present, and two hypotheses concerning the geometry of the transition zone were modelled and evaluated. As a result, the hypothesis that the dome’s cross-section intersects the chamber’s square plan is rejected. Furthermore, the claim that the transition zone’s square plan circumscribes the dome’s cross-section was discussed and proven.
Hydraulic systems were built by ancient civilizations, notably the Persians and Romans, to deliver water to their residences where the water supply was scarce. Qanats were invented by the Persians to transfer water from aquifers to the surface, and aqueducts were built by the Romans to transport surface or underground water from its sources to distribution points in cities. Finding groundwater is a similarity between these two historical systems. This research compares ancient methods used by Persians and Romans to locate areas with abundant subsurface water. The oldest existing historical documents that recorded ancient ways of tracking groundwater, Al-Karaji’s treatise on qanats and Vitruvius’ treatise, were investigated with the qualitative content analysis method. As a result, historical means are divided into two categories in these two treatises including natural indications and practical tests. Natural indications consist of mountains and rocks, features of steppes, plants, vapours and dew, the whistles of the wind, and alluvial fans. An inverted container, a fleece of wool, an oil lamp, and a fire are instances of practical tests. Although these two treatises were authored over a ten-thousand-year interval and the structures of water systems differ, there are commonalities between ancient methods of tracing underground water.