Signatures: [*]² A-B² C-P⁴ Q².
In 4 pts. Pt. 1, 2, and 4 are studies by the hydro-engineers Andrea Chiesa and Bernardo Gambarini about the causes of flooding by the river Tiber, initiated by Pope Bendict XIV, and later republished in the 4th ed. of Raccolta d'autori che trattano de moto dell'acque. The 3d pt. is an earlier report by the professors Giovanni Bottari and Eustachio Manfredi, initiated by Pope Clemens XII, and republished 1770 in v.7 of the 2nd ed. of Raccolta d'autoris.