Hydrogen.

(4) Hydrogen.—Only a marked reduction in brilliancy of the whole spectrum.

Oxygen, N and H.

(5) Oxygen.—An impure tube, showing O (some of the lines hydrocarbon?), N, and H spectra simultaneously. With one wire the O lines still remained fairly bright, the N and H being only faintly seen.

Water-gas.

(6) Water-gas.—Same effect.

Turpentine vapour.

(7) Turpentine Vapour.—Same effect as ether, but the H lines could be faintly seen.