Radioactive elements concerned in mountain building, 125.
Radioactive layer, failure to account for deep-seated
temperatures, 127; assumed thickness of, 128; temperature at base
of, due to radioactivity, 129; in the upper crust of the Earth,
125; thickness of, 126-128.
Radioactive treatment, physical basis of, 251.
Radioactivity and heat emission from average igneous rock, 126;
rarity of, established by haloes, 241, 243.
Radium, chemical nature and transmutation of, 244-245; emanation
of, 245; rays from, 253, 254; table of family of, 253; period of,
253; small therapeutic value of, 254.
Radium C, therapeutic value of, 254; rays from. 254; generation
of, 254.
Rationality, conditions for development of, 163.
Rays, similarity in nature of gamma, X, and light rays, 248;
effects on living cell, 251; penetration of, 251.
Reade, T. Mellard, finding age of ocean by calcium sulphate, 13.