Chorobates

Isaac Moreno Gallo, a Technical Engineer of Public Works specialized in Ancient Rome's civil engineering, claims that the present-day representation of the chorobates (in a table-like shape) is mistaken due to a misinterpretation derived from an incorrect translation of the Latin term "ancones" used by Vitruvius.

"...ea habet ancones in capitibus extremis aequali modo perfectos inque regulae capitibus ad nomam coagmentatos..."

In this context, "ancones" could be translated as "limbs" (extremidades) or "arms", but also as "ménsulas" (brackets or corbels). According to Isaac Moreno, this vertical design is way more efficient when it comes to optical leveling and makes more sense from a topographer's point of view. Furthermore, it preserves the original length described by Vitruvius (20 feet or 5.92 meters) that the table-like chorobates versions persistently seem to ignore.

This "vertical" chorobates was indeed the predominant interpretation of the chorobates in the oldest representations recorded: 1547's engravings included in Jean Goujon's translation of Vitruvius works into French. Or 1582's Miguel de Urrea's first edition of Vitruvius works, this time in Spanish. And few years later, when Juan de Lastanosa published “The Twenty-One Books of Engineering and Machines" of Gianello della Torre”.

All three of them consistently represented the chorobates in a very similar way, until 1673 Claude Perrault's translations radically altered the vertically shaped stand with "ménsulas" and turned it into a horizontal table-like chorobates (with "legs" instead of "brackets") that has become the standard representation nowadays.

In his "Ars Mensoria" series, Isaac Moreno Gallo recreates practical demonstrations of Roman topographic instruments using his own replicas. Among them, the chorobates.