This 1954 fourth edition includes examples of typical aerial survey instruments, gravimeters and seismic reflexion methods.For many years, this book was the standard textbook on applied geophysics. It first appeared in 1928. This 1954 fourth edition includes examples of typical aerial survey instruments, gravimeters and seismic reflexion methods, and gives special attention to methods of locating radioactive ores.For many years, this book was the standard textbook on applied geophysics. It first appeared in 1928. This 1954 fourth edition includes examples of typical aerial survey instruments, gravimeters and seismic reflexion methods, and gives special attention to methods of locating radioactive ores.For many years, this book was the standard textbook on applied geophysics. It first appeared in 1928. This 1954 fourth edition was completely revised by Professor Keys to take into account additional developments. Examples of typical aerial survey instruments, gravimeters and seismic reflexion methods are included, and special attention is given to methods of locating radioactive ores. Some extra problems are also added.Preface; 1. Introduction; 2. Magnetic methods; 3. Electrical methods; 4. Electromagnetic methods; 5. Gravitational methods; 6. Seismic methods; 7. Radioactive methods; 8. Well-logging methods; 9. Other methods and applications; Appendices; Bibliography; Index.