Reference edition:

Fluminis varatio, Limitis repositio: introduction, text, translation and commentary, ed. by Jelle Wietze Bouma, Studien zur Klassischen Philologie 77, Frankfurt 1993, 45-46.

The short text Fluminis varatio, received under the name of the gromatician Nipsus in the Corpus agrimensorum Romanorum, was perhaps part of a larger work, as the words preceding it in the manuscripts seem to indicate: incipit Marci Iunii Nypsi liber secundus feliciter. The content is mathematical and provides informations on how to calculate the width of a river from one bank to the other without a physical measurement, through tools (groma, ferramentum) and trigonometric operations, tracing two identical right-angled triangles on the ground. The problem is addressed other times in the tradition of Greek and Latin texts (Julius Africanus, Frontinus, Balbus). The illustrations present in the codes, intended to clarify the procedure, have been subject to corruption which has made them difficult to read and of little use. [R. Tabacco]