CONTENTS 
PART I 
FUNDAMENTAL FACTS AND PRINCIPLES 
I ’ The Quantum Theory : Preliminary Survey . . i 
1. Origin of the Quantum Theory i 
2. Photo-electricity ....... 4 
3. The Photo-chemical Equivalent .... 7 
4. The Quantum Theory of Spectral Series . . 8 
5. The Generalized Quantum Theory .... 9 
6. Molecular Rotations . . . . . .10 
7. The Quantum Theory of the Solid State of Matter . 11 
8. Nernst’s Heat Theorem . . . . .12 
9. Magnetism and the Quantum Theory . . .12 
10. Atomic Structure . . . . . . 13 
II Mathematical Introduction . . . . .16 
1. The Linear Harmonic Oscillator . . . .16 
2. The Fundamental Equations of Classical Dynamics 19 
3. The Quantum of Action ..... 20 
4. The Generalized Form of the Quantum Theory . 21 
5. Adiabatic Invariance . . . . . .25 
III Atomicity in Electricity and Magnetism ... 28 
1. The Electron Theory . . . . . .28 
2. Faraday Tubes of Electric Force . . . .30 
3. Theories of Magnetism . . . . . • 3 1 
4. The Magneton of Weiss . . . . -35 
5. The Magneton of Bohr ...... 36 
6. Other Suggestions as to the Magneton ... 38 
7. Quantum Magnetic Tubes ..... 40 
IV Line Spectra and the Quantum Theory ... 47 
1. Series of Lines in Spectra ..... 47 
2. The Theory of Ritz ...... 52 
3. The Quantum Theory of Line Spectra ... 52 
4. Energy Levels and Spectral Terms ... 60 
5. The Correspondence Principle .... 66 
V Atomic Structure and Complex Spectral Terms . 69 
1. Atomic Numbers ....... 69 
2. X-Rays and Atomic Structure .... 70 
3. The Arrangement of the Electrons in Space . . 73 
4. Complex Spectra and their Interpretation . . 78 
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