4. Absorption of Radiant Heat by Gases. [*]
5. Formation of Invisible Foci. [*]
6. Visible and Invisible Rays of the Electric Light. [*]
Figure 1. Spectrum of Electric Light. [*]
7. Combustion by Invisible Rays. [*]
8. Transmutation of Rays: Calorescence. [*]
9. Deadness of the Optic Nerve to the Calorific Rays. [*]
10. Persistence of Rays. [*]
11. Absorption of Radiant Heat by Vapours and Odours. [*]
12. Aqueous Vapour in relation to the Terrestrial Temperatures. [*]