Magnetic Observations

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Fmttiifitet, Enlargement Winter

of Localit Qxxarters of

SKETCH MAP TO snow APPROXIMATE POSITIONS OF SOUTH MAGNETIC POLE. A. " Discovery " Expedition. B. Lieut. SHACKLETON'S Expedition. C. " Southern Cross " Expedition.

NATIONAL

ANTARCTIC

EXPEDITION

1901-1904 £ I uo \icaThcrY\s -^

MAGNETIC

PREPARED

UNDER

THE

OBSERVATIONS

SUPERINTENDENCE

OF THE

ROYAL

SOCIETY

r

LONDON :

PUBLISHED BY THE ROYAL SOCIETY 1909

v

1/5

CONTENTS.

Page

Preface, by Sir A. GEIKIE, K.C.B., Pros. R.S Introductory Note, by L. C. BmiNACCHi Historical Note, by Dr. C. CHIIEE, F.R.S Explanation of Tallies of Hourly Values Tables of Hourly Values Table of Days made use of for Diurnal Inequalities

DISCUSSION

OF

THE

vii 1 5 7 g 71

OBSERVATIONS,

BY DR. C. CHREE,

F.15.S.

CHAPTP;R i. INSTRUMENTS AND RECORDS. Sections 1-5. Instruments 6, 7. Scale Values of Curves

Page 73 75

8, 9. Temperature Coefficient of Vertical-P'orce Magnet CHAPTER BASE-LINE VALUES.

.

76

II.

ANNUAL INEQUALITY.

SECULAR CHANGE.

10, 11. Declination and Horizontal-Force Base-Line Values 12, 13. „ „ „ Mean Monthly Values 14. „ „ „ Secular Change 15, 16. „ „ „ Annual Inequality 17-19. Vertical- Force Base-Line Values and Temperature Corrections CHAPTER

78 80 81 81 83

III.

DIURNAL INEQUALITIES AND THEIR DISCUSSION. 20-22. Diurnal Inequalities of Declination, Horizontal Force and Vertical Force 23-24. Explanation of Diurnal-Inequality Tables and Curves . . Diurnal-Inequality Tables XII-XXII 25 Non-Cyclic Changes 26-28. Discussion of Declination, Horizontal Force, and Vertical-Force Inequalities 29. Diurnal Inequality of Inclination 30. ,, „ South and West Components Figures 1-13, illustrating Diurnal Inequalities

104

CHAPTER DIURNAL INEQUALITIES. „

c and a Coefficients

IV.

FOURIER COEFFICIENTS.

31, 32. Fourier a and b Coefficients 33-35.

...

87 89 90 100 101 102 103

117

a 2

121

CHAPTER V. Sections FOURIER COEFFICIENTS ANNUAL VARIATION. 36, 37. CHAPTER ABSOLUTE DAILY RANGES.

Page 129

VI.

DAILY MAXIMA AND MINIMA.

38-43. Absolute Daily Ranges of Declination, Horizontal Force and Vertical Force 44, 45. Incidence of Daily Maxima and Minima CHAPTER

131 138

VII.

TERM-HOUR AND SPECIAL RECORDS. 46, 47. Term-Hour Records from 48. „ „ 49-51. „ „ 52. Antarctic Record during 53. Pulsations 54.

Mauritius Christchurch Antarctic Winter Quarters Solar Eclipse

146 147 148 151 151

Antarctic Record on exceptionally Quiet Day CHAPTER

152 VIII.

RECORDS OF DISTURBANCES FROM CO-OPERATING STATIONS AND WINTER QUARTERS. 55-62. 63-76. 77-84.

Comparative Records from Falmouth, Colaba, Mauritius, and Christchurch Antarctic Records of Disturbances Various Representative Types of Antarctic Disturbances CHAPTER

153 158 166

IX.

MATHEMATICAL ANALYSIS OF DISTURBANCES, AND THEIR DISCUSSION. 85. 86-88. 89, 90. 91-101.

General Discussion of Theories

170

Case of Sphere of Magnetic Material in a Uniform Field Definition and Nature of Disturbances Analysis of Selected Disturbances recorded at the Co-operating Winter Quarters CHAPTER

, . Stations

and

at

170 173 175

X.

102-108. Special Type of Disturbance

186 CHAPTER

XI.

109-114. Comparison of Antarctic Magnetic Disturbances and Aurora APPENDIX

A.

Christchurch Term-Day Observations APPENDIX

193

201 B.

An Examination of Antarctic Disturbances from October, 1902, to March, 1903, which are simultaneous with Arctic Disturbances discussed by Prof. Ku. BlRKELAND . . 246

ILLUSTRATIONS.

Map of South Victoria Land (frontispiece). Sketch of magnetographs as mounted (p. 3). Figs. 1-13. Declination and other curves and diagrams (pp. 104-116). Plates (at end of volume) — Plate I. — Term Hours, quick run, at Mauritius. i, II. — „ „ slow run, at Mauritius. „ III. — „ „ June 15, and July 1, 1902, at Christchurch. „ IV.— „ Hour, June 15, 1902, at Winter Quarters. ,, V.— „ „ July 1, 1902, at Winter Quarters. „ VI. — „ Hours, April 1 and 15, and June 1, 1902, at Winter Quarters. » VII.— ,, „ July 15, and August 1 and 15, 1902, at Winter Quarters. „ VIII.— „ „ September 1 and 15, and October 1 and 15, 1902, at Winter Quarters. .. IX. — „ „ November 1 and 15, and December 1 and 15, 1902, at Winter Quarters. »i X. — „ „ January 1 and 15, and February 1 and 15, 1903, at Winter Quarters. „ XI. — Record during Solar Eclipse at Winter Quarters (September 21, 1903). XII.—" Pulsations " (February 2, 1903). „ XIII. — Eecord during especially Quiet Day (June 27 and 28, 1903). „ XIV.— Disturbance of May 8, 1902, at Co-operating Stations. >. XV. — „ „ August 20, and November 6 and 24, 1902, at Co-operating Stations. „ XVI— „ „ April 5 and 6, 1903, at Co-operating Stations. „ XVII.— „ „ June 19, and July 26, 1903, at Christchurch. XVIII.— „ „ August 22, 1903, at Christchurch. „ XIX. — „ „ August 25 and 26, 1903, at Co-operating Stations. „ XX. — „ „ December 13, 1903, at Falmouth. „ XXI. — „ „ December 13, 1903, at Colaba and Mauritius. XXII.— „ „ May 8 and 9, 1902, at Winter Quarters. „ XXIIL— „ „ August 21, 1902, at Winter Quarters. „ XXIV.— „ „ November 7, 1902, at Winter Quarters. „ XXV.— „ „ November 24, 1902, at Winter Quarters. „ XXVI.— „ „ April 6, 1903, at Winter Quarters. „ XXVII.— „ „ June 19, 1903, at Winter Quarters. „ XXVIII.— „ „ June 28, 1903, at Winter Quarters. „ XXIX.— „ „ June 29, 1903, at Winter Quarters. „ XXX.— „ „ July 26, 1903, at Winter Quarters. „ XXXI. — „ „ August 17, 1903, at Winter Quarters. „ XXXII.— „ „ August 22 and 23, 1903, at Winter Quarters. „ XXXIII.— „ „ August 26, 1903, at Winter Quarters. „ XXXIV.— „ „ August 26, 1903, at Winter Quarters. „ XXXV.— „ „ October 12 and 13, 1903, at Winter Quarters. „ XXXVI.— „ „ December 13 and 14, 1903, at Winter Quarters. Plates XXXVII to XLIII. — Representatives of different Types of Disturbance at Winter Quarters.

PREFACE.

THE volume of "Physical Observations" of the National Antarctic Expedition, 1901-1904, under C;i|itain It. F. SCOTT, R.N., which was published in the summer of 1908, included a report on one portion of the Magnetic work. This Report consisted mainly of a reduction of the absolute and relative observations by Commander L. W. P. CHETWYND, R.N. It contained, also, an account by Mr. HKKNAI nil of the Observatory site in McMurdo Sound, of the geological features of the district, of the instruments employed, and of other matters, likewise Tables of the Hourly Values of Declination, Horizontal Force and Vertical Force on term-days at different observatories during 1902-1903, and a report by Mr. R. C. MOSSMAN Dr. W. S. BRUCE.

and Dr. CHREK

on the Magnetic Observations of the "Scotia," under

The present volume, with its detailed Tables of Hourly Values and its exhaustive discussion of the Observations, completes the presentation of the Magnetic work of the "Discovery." The Royal Sorietv, in arranging for this investigation, was fortunate, with the sanction and co-operation of Dr. GLAZKI:I: