The first section concerns bodies as they appear to us and as we perceive them directly by means of our eyes. By further research we have learnt that these bodies are built out of very small particles which we call atoms. Even though these atoms cannot be seen directly with the eye, yet we still have quite certain proofs of their existence and of many of their properties. The whole of our knowledge concerning the atomic structure of matter has been discussed in the second section. The work of the last few decades has allowed us to penetrate still further into the inner structure of matter. The structure of the atom itself is examined in the third section. Finally, there exists a whole series of phenomena, which have been explained on the assumption that, in addition to ponderable matters, there is something still else which fills all interstellar space, a medium which is called the aether. The phenomena which take place in this medium are discussed in the last section of the book.
Table of Contents
Part 1: The Material World 1. Fundamental Ideas Concerning Motion 2. The Motion of Bodies 3. Gravity and Gravitational Fields of Force 4. Elasticity 5. Impact 6. Waves 7. Acoustics Part 2: The Atomic Structure of Matter 1. The Classification of the Elements 2. The Gaseous State of Aggregation 3. The Fluid State 4. The Solid State 5. Temperature 6. Specific Heat 7. Heat and the Various States of Aggregation 8. The Laws of Thermodynamics 9. The Atom Part 3: The Structure of the Atom 1. Magnetism 2. Electrostatics 3. The Electric Current 4. Electromagnetics 5. Electrolysis 6. Ions and Electrons 7. Radioactivity 8. Electromagnetic Waves 9. The Structure of the Atom Part 4: The Physics of the Aether 1. The Undisturbed Propagation of Waves in the Aether 2. The Disturbed Propagation of Life 3. Interference and Diffraction 4. The Polarization of Light 5. Light and Colour 6. The Aether 7. The Aims of Modern Physics
Theordur Wulf taught physics at Valkenburg, a Jesuit University from 1904 to 1914 and 1918-1935. He designed and built an electrometer which could detect the presence of energetic charged particles (or electromagnetic waves). Since natural radiation sources on the ground were detected by his electrometer, he predicted that if he moved far enough away from those sources he would detect less radiation.