(f) Single wires were successively attached to the negative and positive poles, and the cobweb streamers and glow before described obtained. The magnet was found to have no decided effect on either of these.
Plücker tube placed between poles of magnet with negative wire only attached.
(6) The Plücker air-tube (Plate XVII. fig. 2) was placed between the poles of the magnet, and the negative wire only was connected with the straight electrode. A pale violet glow was seen round this electrode, and another, but rather fainter, glow of a similar description at the ring electrode, the intermediate space being filled with a salmon-coloured light. This violet glow was condensed into an arc by the action of the magnet. Reversing the current, the violet glow still remained at each electrode, and that between the poles of the magnet was still influenced into an arc.
Geissler tube substituted, with similar results.
(7) An air Geissler tube was substituted for the Plücker tube, with very much the same result. Whichever wire was attached, a violet glow appeared at the connected electrode, and a fainter one of the same character at the other; and the magnet influenced both. The connecting salmon-coloured glow was faint.
Globular receiver treated with phosphoric anhydride.
(8a) The globular receiver had some phosphoric anhydride shaken into it; and it was then exhausted. The cobweb streamers and violet glow each appeared according to which wire was connected. There was no marked difference between the receiver with the anhydride and without; except that in the former case the streamers and glow were reduced in extent and strength, and were comparatively faint.
Discharge in water-vapour described.
(b) The anhydride having been washed out, first with plain and afterwards with distilled water, some drops of the latter were allowed to remain in the receiver. On exhaustion a vapour-cloud was formed, and the discharge passed (both terminals being connected with the coil) through this. The rosy stream of light was formed as usual, but was more flickering and unsteady. As the exhaustion was lessened, the rosy stream disappeared, and the cobweb streams began to fill the receiver. These were, however, not so bright and sharp as in a dry receiver, but were faint and broad; while some diffused and nebulous streams of light, running (slightly bent) from pole to pole, and from ¼ to ⅜ of an inch broad, were intermixed with them. When one wire only was connected, the glow and streamers from the electrode were very faint.
Large bell-receiver and plate described. Receiver exhausted and stream of light formed.