[Illustration: 5. Leg bone of a three-month-old rabbit killed ten minutes after injection of Sr⁸⁹. The darkened areas show where the strontium has been deposited. Sr⁹⁰ and normal Sr⁸⁸ would be deposited in the same places. It is an important fact that the deposition is fairly uniform in the calcified portions of the bone. _From a chapter by Vaughan, Tutt, and Kidman in the book_ Biological Hazards of Atomic Energy, _edited by Haddow, published by Oxford University Press, 1952_] [Illustration: 6. Leg bone of a woman who died of radium poisoning. The bright regions show where the radium has been deposited. Hot spots are clearly visible. _From an article, “The Late Effects of Internally Deposited Radioactive Materials in Man,” by Aub et al., in_ Medicine—_a professional journal, Vol. 31, No. 3, September, 1952_] [Illustration: _USAEC—Knolls Atomic Power Laboratory_ 7. Capsules of cobalt⁶⁰, shielded in a water tank. One hundred and thirty million dollars’ worth of radium, twice the world’s present supply, would be needed to equal the rays from this powerful gamma source.] [Illustration: _USAEC_ 8. Cobalt irradiation.] [Illustration: 1. The metallic element cobalt is machined into wafers slightly larger than a dime.] [Illustration: 2. The wafers are placed edge to edge in aluminum containers, then inserted into an atomic furnace, or reactor.] [Illustration: 3. Under bombardment of neutrons, the nuclei of the cobalt atoms become excited and emit radiation, or rays.] [Illustration: 4. After “cooking” in the reactor a certain time, the cobalt is removed and placed in shielded containers for shipment.] [Illustration: 5. The now radioactive cobalt goes from the Savannah River Plant to Oak Ridge for re-shipment to medical centers all over the country.] [Illustration: 6. At medical centers, it is placed in tele-therapy machines. Its powerful rays aid medical specialists in the fight against cancer.] [Illustration: _NTO—Lookout Mountain Laboratory Photo_ 9. The smoke-ring cloud from the air-defense atomic weapon.] [Illustration: _Wide World Photo_ 10.] [Illustration: _University of California Radiation Laboratory_ 11. The streaks are condensation trails produced by charged particles in a Wilson Cloud Chamber. They appear bright because the chamber is illuminated and the condensation trails reflect light just as an ordinary cloud does.] [Illustration: _University of California Radiation Laboratory_ 12. Another picture in the Wilson Cloud Chamber. A large number of closely-spaced tracks form a cloud. (The tracks are curved because of the presence of a magnetic field.)]