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.