IV 



CONTENTS 



PAGE 



V. Analysis of terrestrial 

 records — continued 

 Cycles in 42 western groups .... 93 

 Evaluation of cycles in the 



42 groups 97 



Records of past climates 98 



Sequoia chronology and cycle 



recurrence 99 



Sequoia chronology cycles. . 104 



Central Pueblo chronology 105 



Central Pueblo chronology 



cycles 106 



Geological material for cycle 



analysis 108 



Its character 108 



Buried trees, cycles 109 



Buried trees 110 



Yellowstone fossil trees 110 



Yellowstone fossil trees, 



cycles Ill 



Analyses of other geological 



material 115 



VI. Relation between terres- 

 trial and solar records. 116 



Early results 116 



Evidence of solar relation in 11- 

 year cycle 122 



General resemblance in 



cycle types 122 



Evidence by cyclograms. . . . 122 

 . The 11-year cycle and its 

 half value, the Hellmann 



cycle 123 



Dearth cycles 125 



Summary 126 



Longer cycles 126 



Frequency periodograms and 

 the cycle complex 128 



PAGE 



VI. Relation between terres- 

 trial AND SOLAR RECORDS — 

 continued 

 Complex from geological 



material 130 



Physical cause of climatic cycles. 131 

 VII. The cycle problem and long- 

 range FORECASTING 133 



The problem 133 



The Arizona results 134 



Mississippi Valley 135 



Coast States 136 



Relation to the sun 137 



Prediction technique 138 



Fundamentals of prediction. 138 

 Cycles in the Pueblo area . . 139 

 Application to winter rain- 

 fall of the Pueblo area 139 



The 23-year cycle 139 



The 19-20-year cycle 140 



The 14-year cycle 140 



The 11^-year cycle 140 



Appendix 142 



Studies of the cyclograph — E. 



Schulman 143 



Introduction 143 



Description of the instrument. . . 143 



Operation 145 



Cyclogram formulae 146 



Construction of frequency period- 



ogram 147 



Errors of the instrument 148 



Errors in cyclogram analysis .... 150 



Probability tests 153 



Presentation of cycle data 154 



Cycle summation curves 155 



An automatic optical periodo- 



graph — A. E. Douglass 164 



Variable Star tests 164 



Bibliography 166 



