CONTENTS. 



Page 



Preface, by Sir A. GEIKIE, K.C.B., Pros. R.S vii 



Introductory Note, by L. C. BmiNACCHi 1 



Historical Note, by Dr. C. CHIIEE, F.R.S 5 



Explanation of Tallies of Hourly Values 7 



Tables of Hourly Values g 



Table of Days made use of for Diurnal Inequalities 71 



DISCUSSION OF THE OBSERVATIONS, BY DR. C. CHREE, F.15.S. 



CHAPTP;R i. 



INSTRUMENTS AND RECORDS. 



Sections Page 



1-5. Instruments 73 



6, 7. Scale Values of Curves 75 



8, 9. Temperature Coefficient of Vertical-P'orce Magnet . 76 



CHAPTER II. 

 BASE-LINE VALUES. ANNUAL INEQUALITY. SECULAR CHANGE. 



10, 11. Declination and Horizontal-Force Base-Line Values 78 



12, 13. Mean Monthly Values 80 



14. Secular Change 81 



15, 16. Annual Inequality 81 



17-19. Vertical- Force Base-Line Values and Temperature Corrections 83 



CHAPTER III. 

 DIURNAL INEQUALITIES AND THEIR DISCUSSION. 



20-22. Diurnal Inequalities of Declination, Horizontal Force and Vertical Force 87 



23-24. Explanation of Diurnal-Inequality Tables and Curves . . 89 



Diurnal-Inequality Tables XII-XXII 90 



25 Non-Cyclic Changes ... 100 



26-28. Discussion of Declination, Horizontal Force, and Vertical-Force Inequalities 101 



29. Diurnal Inequality of Inclination 102 



30. ,, South and West Components 103 



Figures 1-13, illustrating Diurnal Inequalities 104 



CHAPTER IV. 

 DIURNAL INEQUALITIES. FOURIER COEFFICIENTS. 



31, 32. Fourier a and b Coefficients 117 



33-35. c and a Coefficients 121 



a 2 



