Fluorescence
The rendering of invisible Rays visible
Vision not the only Sense appealed to by the Solar and Electric Beam
Heat of Beam
Combustion by Total Beam at the Foci of Mirrors and Lenses
Combustion through Ice-lens
Ignition of Diamond
Search for the Rays here effective
Sir William Herschel's Discovery of dark Solar Rays
Invisible Rays the Basis of the Visible
Detachment by a Ray-filter of the Invisible Rays from the Visible
Combustion at Dark Foci
Conversion of Heat-rays into Light-rays
Calorescence
Part played in Nature by Dark Rays
Identity of Light and Radiant Heat
Invisible Images
Reflection, Refraction, Plane Polarization, Depolarization,
Circular Polarization, Double Refraction, and Magnetization of
Radiant Heat


LECTURE VI.

Principles of Spectrum Analysis
Prismatic Analysis of the Light of Incandescent Vapours
Discontinuous Spectra
Spectrum Bands proved by Bunsen and Kirchhoff to be characteristic
of the Vapour
Discovery of Rubidium, Cæsium, and Thallium