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.