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| 1. | Visible and Invisible Radiation | 1 |
| 2. | Origin and Character of Radiation. The Ether | 6 |
| 3. | The Atomic Theory in reference to the Ether | 11 |
| 4. | Absorption of Radiant Heat by Gases | 12 |
| 5. | Absorption by Iodine. Formation of Invisible Foci | 18 |
| 6. | Visible and Invisible Rays of the Electric Light | 21 |
| 7. | Combustion by Invisible Rays | 24 |
| 8. | Transmutation of Rays. Calorescence | 27 |
| 9. | Deadness of the Optic Nerve to the Calorific Rays | 30 |
| 10. | Persistence of Rays | 33 |
| 11. | Absorption of Radiant Heat by Vapours and Odours | 38 |
| 12. | Aqueous Vapour in relation to Terrestrial Temperatures | 41 |
| 13. | Liquids and their Vapours in relation to Radiant Heat | 45 |
| 14. | Reciprocity of Radiation and Absorption | 48 |
| 15. | Influence of Vibrating Period and Molecular Form. Physical Analysis of the Human Breath | 52 |
| 16. | Summary and Conclusion | 57 |
