FIRST EDITION, 4to, pp. [xvi], 126, [2, blank]. Woodcut diagrams within the text. Contemporary English calf, boards ruled in blind. Some toning, edges a little browned at beginning and end. Rebacked in a different shade, red morocco label, boards scuffed and marked, edges worn.
A scarce and significant tract on the measurement of spirals using indivisibles, an important precursor of infinitesimal calculus. Stefano degli Angeli (1623-1697) was a Jesuat mathematician and pupil of Bonaventura Cavalieri, who had developed the method of indivisibles, and he spent much of the 1660s clashing with the Jesuits over the method - that conflict probably underlying Pope Clement IX's decision to abolish the Jesuati in 1668. In this work Angeli also generalises Archimedes's spiral.
Riccardi I 34.