[Sidenote: Changes in spectrum when magnet was excited.] When the magnet was put on, the marked character of the absorption spaces was lost. The sets of lines in the yellow-green and green started up intensely bright, while those in the blue only slightly brightened. The misty appearance was altogether lost, and the bright lines all shone up upon a perfectly dark background, with a strikingly metallic look; we could not, however, trace change of position or actually new lines. It seemed as if lines which had been faint in the yellow-green and green region suddenly increased in intensity, the other parts of the spectrum not being similarly influenced. They quite flashed up when sudden contact was made with the magnet commutator. _Iodine-tubes._ [Sidenote: Iodine-tube No. 1.] This tube (No. 1) had been used for photographic purposes, and the bulbs were partly obscured by a white deposit. [Sidenote: Lighting-up described. Effect of touching one wire with the finger.] On lighting it up, both bulbs were filled with a violet-grey diffused light, with much coarse well-marked lenticular stratification. This stratification was mainly lost on changing the direction of the current, but made its reappearance when one conducting-wire was touched with a finger. This effect was still more marked when one finger of each hand was applied to the wire. The capillary stream was of a pale lemon-yellow. On putting on the magnet the light in the whole tube was nearly extinguished, a faint thin stream of condensed light running through the centre of the tube alone remaining. [Sidenote: Effect of the magnet.] On placing the bulbs between the magnet-poles, effects were produced similar to those in the case of the tube, after described (p. 144, and marked Si Fl₆), but in a less marked degree. [Sidenote: Tube again tested.] The iodine-tube was subsequently again tested, and it lighted-up better than on the last occasion, showing nearly the same effects in bulbs and capillary, the former having somewhat of a rosy tint and the latter an amber. [Sidenote: Magnet effects. The spectrum described. Change when magnet was excited.]