Mathematics.- Castelli (Benedetto) Delle Misura dell'Acque Correnti, 2 parts in 1, first edition, engraved pictorial title, dedication to Urban VIII, second title with engraved arms of Taddeo Barberini (co-dedicatee), a few woodcut diagrams within text, woodcut head-pieces and decorative initials, repair to upper inner corner, with minor loss of printed area (supplied), water-stained, 18th century patterned-paper boards, [Bibliotheca Mechanica p.66; Riccardi I, 290 'Raro'], small 4to, Rome, Camerale, 1628.

⁂ First edition of 'one of the cornerstones of modern hydraulics', which discusses the speed of liquids in channels and their measurement. Castelli was a student of Galileo, and on his recommendation became professor of mathematics at Pisa in 1613. In 1626 he was invited by Pope Urban VIII to Rome to consult on the city's water supply.