Chapter LI: Part IV: On the Usefulness of Mathematics

(1.) The Necessity of Mathematics in Human Things
(published separately as the _Specula Mathematica_).
(2.) The Necessity of Mathematics in Divine Things.--1°.
This study has occupied holy men: 2°. Geography: 3°.
Chronology: 4°. Cycles; the Golden Number, &c.: 5°.
Natural Phenomena, as the Rainbow: 6°. Arithmetic:
7°. Music.
(3.) The Necessity of Mathematics in Ecclesiastical
Things. 1°. The Certification of Faith: 2°. The
Correction of the Calendar.
(4.) The Necessity of Mathematics in the State.--1°. Of
Climates: 2°. Hydrography: 3°. Geography: 4°. Astrology.