Book V of Kepler's The Harmony of the World
Book 5. Astronomical, on the causes of the periodic motions
Synopsis
- Prooemium (Preface)
- Kepler exults over his third law (see Ch.3 below)
- found 15 may 1618
- Ch.1. Regular polyhedra
- Orders them as: primary (cube, tetrahedron, dodecahedron)
and secondary (octahedron, icosahedron)
- Tetrahedron = unmarried
- cubic marriage = octa inside cube
- dodecahedric marriage = icosa inside dodeca
- Ch.2. Harmonic proportions
- Obtains sphere proportions as: tetra, 1:3
- cubic marriage, 1:sqrt(3)
- dodecahedric marriage, "ineffable" [1:sqrt(15-6*sqrt(5)]
- Ch.3. Astronomical theory
- 13 propositions, including the three laws
- Ch.4. The proper and extreme harmonies
- Tries various parameters
- Settles on the apsidal angular velocities
- Ch.5. The music of the planetary motions
- Transposes all planet ranges to Saturn's octave
- Ch.6. Heavenly modes
- Staff notations for all six planetary ranges
- Ch.7. Universal harmonies
- Six part polyphony, chords
- Ch.8. The four voices of celestial harmony
- Assigns planets to four choruses
- Ch.9. The causes of the eccentricities
- Very long (almost half of Book V)
- 9 axioms, 39 propositions, and a summary
- establishes that the world harmony model
- is more accurate than the platonic solids model
- Ch.10. Inhabitants of the Sun
- Speculates on the angels in the sun who
- watch and hear the world harmony
- influenced by Proclus?
Cf (Stephenson, 1994; ch 9).
Rev'd 14 apr 2003 by ralph abraham
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