BOOK IV.. The Philosophy of the Secondary Mechanical Sciences.

THE PHILOSOPHY OF THE SECONDARY MECHANICAL SCIENCES.

CHAP. I. OF THE IDEA OF A MEDIUM AS COMMONLY EMPLOYED 293

Art. 1. Of Primary and Secondary Qualities. 2. The Idea of Externality. 3. Sensation by a Medium. 4. Process of Perception of Secondary Qualities.

CHAP. II. ON PECULIARITIES IN THE PERCEPTIONS OF THE DIFFERENT SENSES 302

Art. 1. Difference of Senses.

Sect. I. Prerogatives of Sight. Art. 2. Position. 3. Distance. {xv} Sect. II. Prerogatives of Hearing. Art. 4. Musical Intervals. 5. Chords. 6. Rhythm.

Sect. III. The Paradoxes of Vision. Art. 7. First Paradox. 8. Second Paradox. 9. The same for near Objects. 10. Objections answered.

Sect. IV. The Perception of Visible Figures. Art. 11. Brown's Opinion.

CHAP. III. SUCCESSIVE ATTEMPTS AT THE SCIENTIFIC APPLICATION OF THE IDEA OF A MEDIUM 322

Art. 1. Introduction. 2. Sound. 3. Light. 4. Heat.

CHAP. IV. OF THE MEASURE OF SECONDARY QUALITIES 333

Sect. I. Scales of Qualities in General. Art. 1. Intensity. 2. Quantity and Quality.

Sect. II. The Musical Scale. Art. 3. Musical Relations. 4. Musical Standard.

Sect. III. Scales of Colour. Art. 5. The Prismatic Scale. 6. Newton's Scale. 7. Scales of Impure Colours. 8. Chromatometer.

Sect. IV. Scales of Light. Art. 9. Photometer. 10. Cyanometer.

Sect. V. Scales of Heat. Art. 11. Thermometers. 12. Their progress. 13. Fixed Points. 14. Concordance of Thermometers. 15. Natural Measure. 16. Law of Cooling. {xvi} 17. Theory of Exchanges. 18. Air Thermometer. 19. Theory of Heat. 20. Other Instruments.

Sect. VI. Scales of other Quantities. Art. 21. Tastes and Smells. 22. Quality of Sounds. 23. Articulate Sounds. 24. Transition.