| Element | Atomic Weight | T (average time-period—half transformed) | Rays (given out in each decomposition) |
| Uranium I | 238 | 4.5 × 109 yrs. | Alpha |
| Uranium X1 | 234 | 23.8 days | Beta, Gamma |
| Uranium X2 | 234 | 1.15 min. | Beta, Gamma |
| Uranium II | 234 | About 2 × 106 yrs. | Alpha |
| Ionium | 230 | About 9 × 104 yrs. | Alpha |
| Radium | 226 | (+) 1700 yrs. | Alpha |
| Niton (Emanation) | 222 | 3.85 days | Alpha |
| Radium A | 218 | 3.05 min. (?) | Alpha |
| Radium B | 214 | 26.8 min. (?) | Beta, Gamma |
| Radium C | 214 | 19.5 min. (?) | Alpha, Beta, Gamma |
| Radium C′ | 214 | 10-6 sec. (?) | Alpha |
| Radium D | 210 | (+) 16 yrs. | Beta, Gamma |
| Radium E | 210 | (+) 4.85 days | Beta, Gamma |
| Radium F (Polonium) | 210 | (+) 136.5 days | Alpha |
| Radium G (End-product uranium-lead) | 206 | ............... | ............... |
URANIUM Y (ACTINIUM) SERIES
| Element | Atomic Weight | T (average time-period—half transformed) | Rays (given out in each decomposition) |
| Uranium Y | 234 | (+) 24.6 hrs. | Beta |
| (branching from Uranium II) | (2.2 days?) | ||
| Protoactinium | 230 | About 104 yrs. (?) | Alpha |
| Actinium | 226 | 20 yrs. | Beta |
| Radio-actinium | 226 | 19 days | Alpha |
| Actinium X | 222 | (+) 11.2 days | Alpha |
| Actinium (Emanation) | 218 | 3.92 sec. | Alpha |
| Actinium A | 214 | .002 sec. | Alpha |
| Actinium B | 210 | 36 min. (?) | Beta, Gamma |
| Actinium C | 210 | 2.16 min. (?) | Alpha |
| Actinium D | 206 | 4.76 min. | Beta, Gamma |
| Actinium E (End-product actinium-lead) | 206 | ............... | ............... |
THORIUM SERIES
| Element | Atomic Weight | T (average time-period—half transformed) | Rays (given out in each decomposition) |
| Thorium | 232.1 | 2.2 × 1010 yrs. | Alpha |
| Mesothorium I | 228 | 6.7 yrs. | Beta, Gamma |
| Mesothorium II | 228 | 6.2 hrs. (?) | Beta, Gamma |
| Radio-thorium | 228 | 1.90 yrs. (?) | Alpha |
| Thorium X | 224 | 3.64 days | Alpha |
| Thorium (Emanation) | 220 | 54 sec. (?) | Alpha |
| Thorium A | 216 | .14 sec. (?) | Alpha |
| Thorium B | 216 | 10.6 hrs. (?) | Beta, Gamma |
| Thorium C | 212 | 60 min. (?) | Alpha |
| Thorium D | 208 | 3.2 min. (?) | Beta, Gamma |
| Thorium E (End-product thorium-lead) | 208 | ............... | ............... |
Transcriber’s Notes
Punctuation, hyphenation, and spelling were made consistent when a predominant preference was found in the original book; otherwise they were not changed.
Simple typographical errors were corrected; unbalanced quotation marks were remedied when the change was obvious, and otherwise left unbalanced.
This book uses terminology that was current at the time of publication, and reflects the state of science as it was understood by the author at that time.