CONTENTS 



Page 



Introduction i 



I. Solar radiation measurements 3 



1. Objects and stations 3 



2. Instruments and methods 3 



3. The variation of the sun's radiation 6 



4. Periodicities in solar variation lO 



5. Analysis of the solar variation 1 1 



6. Synthesis of solar variation 14 



7. Long-range predictions of solar variation 14 



II. Weather responsive to periodic solar changes 15 



8. Sun-spot influence 15 



9. Preparation of weather data i7 



10. Amplitudes of periodicities diminished by smoothing 18 



1 1. Sun-spot data 19 



12. Corrections of solar periods 21 



13. Full lines required in the statistical tabulations 21 



14. Berlin, Germany. Departures from normal temperatures 22 



A. Segregated with reference to sun-spot numbers 22 



a. The i i-month periodicity 22 



b. The 8-month periodicity 26 



c. The 7-month periodicity 28 



d. Dependence of phase on sun-spot activity 29 



e. Dependence of phase on epoch counted from 1819 29 



B. Analyses grouped in periods of ii^ years r.nd 23 years, based 



on January 1819 as date of departure, and including 



all data 35 



a. The l l-month periodicity 35 



b. The 21-month periodicity 38 



c. Progressive removal of determined periodicities 41 



d. Criterion for true and false periodicities and limit to 



the number of periodicities 43 



C. Residuals after removal of evaluated periodicities 49 



D. Analyses by intervals not integrally related to 23 years 51 



15. Other analyses 54 



16. Conclusions derived from analyses of Berlin and other temperatures 



, and precipitations 54 



17. Summary of preceding studies and their guidance toward those 



which follow 56 



18. A test of the 23-year hypothesis in the precipitation of southern 



New England 56 



19. A lake level test of the 23-year hypothesis 57 



20. A fishery test of the 23-year hypothesis 64 



21. A test of the 23-year hypothesis in the flow of the River Nile 67 



22. A test of the 23-year cycle in the widths of tree rings 69 



23. A test of the 23-year cycle in Pleistocene varves 71 



24. A test of the 23-year cycle in Eocene varves and tree rings "71 



25. A weather test of the 23-year hypothesis 75 



2(i. Causes 80 



Summary 88 



iii 



