Originally published in 1937, this book aims 'to develop the principles of quantum mechanics on the basis of a few standard observations'.Originally published in 1937, this book by renowned physicist Alfred Land? aims 'to develop the principles of quantum mechanics on the basis of a few standard observations'. Land? notes that, in contrast with classical mechanics, quantum mechanics is still a relatively young science with some way to go before it is internally consistent.Originally published in 1937, this book by renowned physicist Alfred Land? aims 'to develop the principles of quantum mechanics on the basis of a few standard observations'. Land? notes that, in contrast with classical mechanics, quantum mechanics is still a relatively young science with some way to go before it is internally consistent.Originally published in 1937, this book by renowned physicist Alfred Land? aims 'to develop the principles of quantum mechanics on the basis of a few standard observations'. Land? notes that, in contrast with classical mechanics, quantum mechanics is still a relatively young science with some way to go before it is internally consistent. This book will be of value to anyone with an interest in the history of physics and quantum mechanics.Preface; Introduction: 1. Observation and interpretation; 2. Difficulties of the classical theories; 3. The purpose of quantum theory; Part I. Elementary Theory of Observation (Principle of Complementarity): 4. Refraction in inhomogeneous media (force fields); 5. Scattering of charged rays; 6. Refraction and reflection at a plane; 7. Absolute values of momentum and wave length; 8. Double ray of matter diffracting light waves; 9. Double ray of matter diffracting photons; 10. Microscopic observation of ? (x) and ? (p); 11. Complementarity; 12. Mathematical relation between ? (x) and ? (p) for free particles; 13. General relation between ? (q) and ? (p); 14. Crystals; 15. Transition density and transition probability; 16. Resultant vallH