Chapter III

Some specific Descriptions of Auroræ: pp. 16-30.

Capt. Sabine’s Auroræ: p. 16.

Aurora seen at Sunderland, February 8th, 1817: p. 16.

Dr. Hayes’s Aurora, 6th January, 1861: pp. 16, 17.

Prof. Lemström’s Aurora, 1st September, 1868: pp. 17, 18.

Mr. J. R. Capron’s Aurora, October 24th, 1870: pp. 18, 19.

Mr. Barker’s red and white Auroræ, 9th November (1870?): p. 19.

Mr. J. R. Capron’s Aurora, February 4th, 1872: pp. 19, 20.

Cardiff, Aurora seen at: p. 21.

Mr. J. R. Capron’s Aurora, February 4th, 1874: pp. 21, 22.

Mr. Herbert Ingall’s Aurora, July 18th, 1874: pp. 22, 23.

Mr. J. R. Capron’s white Aurora, September 11th, 1874: pp. 23, 24.

Dr. Allnatt’s Aurora, June 9th, 1876: p. 24.

Herr Carl Bock’s Lapland Aurora, October 3rd, 1877: p. 25.

Rev. T. W. Webb’s Aurora: pp. 25, 26.

English Arctic Expedition, 1875-76: p. 26.

Aurora Australis: pp. 26-29.

Prof. Piazzi Smyth’s typical Auroræ: pp. 29, 30.

CHAPTER IV.

Phenomena simulating Auroræ: pp. 31-32.

Auroric Lights (Kinahan): pp. 31, 32.

Luminous Arch: p. 32.

CHAPTER V.

Some qualities of the Aurora: pp. 33-51.

Noises attending Auroræ: pp. 33, 34.

Colours of Aurora: pp. 35-37.

Height of Aurora: pp. 37-40.

Phosphorescence attending Aurora: pp. 41-44.

Aurora and Ozone: pp. 44, 45.

Polarization of Aurora light: pp. 45, 46.

Number of Auroræ: p. 46.

Duration of Aurora: p. 47.

Travelling of Auroræ (Donati): pp. 47, 48.

Geographical distribution of Auroræ (Fritz and Loomis): pp. 48, 49.

Extent and principal zone of the Aurora: pp. 50, 51.

CHAPTER VI.

Aurora in connexion with other Phenomena: pp. 52-69.

Auroræ and Clouds: pp. 52-54.

Aurora and Thunder-storms: pp. 54, 55.

Aurora and Magnetic Needle: pp. 55-58.

Auroræ, Magnetic Disturbances, and Sun-spots: pp. 58-62.

Aurora and Electricity: pp. 62-64.

Aurora and Meteoric Dust: pp. 64, 65.

Aurora and Planets Venus and Jupiter: pp. 66, 67.

Aurora and Zodiacal Light: pp. 67-69.

CHAPTER VII.

Aurora-like patches on the partially-eclipsed Moon: pp. 70-77.

CHAPTER VIII.

Aurora and Solar Corona: pp. 78-81.

CHAPTER IX.

Supposed Causes of the Aurora: pp. 82-87.

Prof. Lemström’s Theory: pp. 87, 88.

Theories of MM. Becquerel and De la Rive: p. 88.

M. Planté’s electric experiments: pp. 89, 90.

PART II.

THE SPECTRUM OF THE AURORA.

CHAPTER X.

Spectroscope adapted for the Aurora: pp. 91-93.

Spectrum of Aurora described: pp. 94-100.

Flickering of the green line: p. 100.

Mr. Backhouse’s graphical spectra of four Auroræ: p. 101.

Lord Lindsay’s Aurora-spectrum, October 21, 1870: p. 102.

Spectrum of the Aurora Australis: pp. 103, 104.

Professor Piazzi Smyth’s Aurora-spectra: p. 104.

Author’s Catalogue of the Auroral lines: pp. 104-106.

Theories in relation to the Aurora and its spectrum: pp. 106, 107.

CHAPTER XI.

The comparison of some Tube and other Spectra with the Spectrum of
the Aurora: pp. 108-120.

Hydrogen-tube: pp. 108-110.

Carbon- and oxygen-tubes: pp. 110-114.

Geissler mercury-tube and barometer mercurial vacuum: pp. 114, 115.

Air-tubes: pp. 115, 116.

Phosphorescent tube: pp. 116, 117.

Spark in air: p. 117.

Spark over water: p. 117.

Phosphoretted-hydrogen flame: pp. 117, 118.

Iron-spectrum: p. 118.

Spectrum of mercury: p. 119.

Table of coincidences: p. 119.

CHAPTER XII.

Notes on Professor Ångström’s Theory of the Aurora-spectrum: pp. 121-127.

CHAPTER XIII.

The Oxygen-spectrum in relation to the Aurora (Procter and Schuster):
pp. 128-131.

PART III.

MAGNETO-ELECTRIC EXPERIMENTS IN CONNEXION WITH THE AURORA.

INTRODUCTION: pp. 133-135.

CHAPTER XIV.

Examination of Geissler-tubes under action of the Magnet: pp. 136-146.

Nitrogen-tubes: pp. 136, 137.

Oxygen-tubes: p. 138.

Hydrogen-tubes: pp. 138, 139.

Water-gas tube: p. 139.

Ammonia-tube: pp. 139, 140.

Carbonic-acid tube: p. 140.

Chlorine-tubes: pp. 140, 141.

Iodine-tubes: pp. 141-143.

Bromine-tubes: pp. 143, 144.

Silicic fluoride-tubes: p. 144.

Sulphuric-acid tubes: pp. 144, 145.

Sulphur-tube: pp. 145, 146.

CHAPTER XV.

Effect of Magnet on a capillary Glass Tube: pp. 147, 148.

Action of magnet on a bar of heavy glass: pp. 147, 148.

CHAPTER XVI.

Effect of Magnet on wide Air (Aurora) tube: pp. 149-153.

Stratification (note on): pp. 149, 150.

Effect of magnet on Plücker (air-) tube: pp. 150-152.

Effect of magnet on Plücker tube (tin chloride): pp. 152, 153.

Effect of magnet on tin-chloride Geissler tube: p. 153.

CHAPTER XVII.

Effect of Magnet on bulbed Phosphorescent Tube: pp. 154-156.

Effect of magnet on small phosphorescent (powder) tubes: pp. 156,
157.

Lighting-up tubes with one wire only (Marquis of Salisbury’s
observations): pp. 157, 158.

CHAPTER XVIII.

Action of the Magnet on the Electric Spark: pp. 159, 160.

CHAPTER XIX.

The Discharge _in vacuo_ in Larger Vessels, and Magnetic Effects
thereon: pp. 161-165.

Some of Baron Reichenbach’s magnetic researches tested: pp. 165, 166.

Summary of the foregoing Experiments and their Results: p. 167.