Preface 5 I. The Need to Know 13 II. Atoms 18 III. Nuclei 26 IV. The Law of Radioactive Decay 37 V. Breakup of the Nucleus 41 VI. Reactions Between Nuclei 49 VII. Fission and the Chain Reaction 58 VIII. Action of Radiation on Matter 68 IX. The Test 80 X. The Radioactive Cloud 87 XI. From the Soil to Man 104 XII. Danger to the Individual 116 XIII. Danger to the Race 127 XIV. The Cobalt Bomb 134 XV. What About Future Tests? 137 XVI. Has Something Happened to the Weather? 146 XVII. Safety of Nuclear Reactors 152 XVIII. By-products of Nuclear Reactors 160 XIX. The Nuclear Age 168 Glossary 175 List of Illustrations A section of photographs will be found between pages 96 and 97. 1. A shallow underground explosion. 2. An atomic test tower. 3. A tower shot. 4. An air shot. 5. Leg bone of a rabbit after injection of Sr⁸⁹. 6. Leg bone of a woman dead of radium poisoning. 7. Capsules of cobalt⁶⁰. 8. Cobalt irradiation. 9. Smoke-ring cloud from the air-defense atomic weapon. 10. Wilful exposure—an experiment. 11. Condensation trails produced in a Wilson Cloud Chamber. 12. Closely-spaced tracks form a cloud. 13. Cutaway section of a nuclear reactor. OUR NUCLEAR FUTURE CHAPTER I The Need to Know Our world is changing, and the change is becoming more rapid. The moving force behind this change is scientific discovery. All of us are deeply affected by the consequences of science. At the same time, very few understand the highly technical foundations of our civilization. In this situation it is natural that scientific and technical progress should create uneasiness and alarm.