495. The latter pole _e_ was now connected with the negative end of a voltaic battery, of forty pairs of plates four inches square, whilst the former pole _b_ was connected with the positive end. There was action and gas evolved at both poles; but from the intervention of the pure water, the decomposition was very feeble compared to what the battery would have effected in a uniform solution. After a little while (less than a minute,) magnesia also appeared at the negative side: _it did not make its appearance at the negative metallic pole, but in the water_, at the plane where the solution and the water met; and on looking at it horizontally, it could be there perceived lying in the water upon the solution, not rising more than the fourth of an inch above the latter, whilst the water between it and the negative pole was perfectly clear. On continuing the action, the bubbles of hydrogen rising upwards from the negative pole impressed a circulatory movement on the stratum of water, upwards in the middle, and downwards at the side, which gradually gave an ascending form to the cloud of magnesia in the part just under the pole, having an appearance as if it were there attracted to it; but this was altogether an effect of the currents, and did not occur until long after the phenomena looked for were satisfactorily ascertained. 496. After a little while the voltaic communication was broken, and the platina poles removed with as little agitation as possible from the water and solution, for the purpose of examining the liquid adhering to them. The pole _c_, when touched by turmeric paper, gave no traces of alkali, nor could anything but pure water be found upon it. The pole _b_, though drawn through a much greater depth and quantity of fluid, was found so acid as to give abundant evidence to litmus paper, the tongue, and other tests. Hence there had been no interference of alkaline salts in any way, undergoing first decomposition, and then causing the separation of the magnesia at a distance from the pole by mere chemical agencies. This experiment was repeated again and again, and always successfully. 497. As, therefore, the substances evolved in cases of electrochemical decomposition may be made to appear against air (465. 469.),--which, according to common language, is not a conductor, nor is decomposed, or against water (495.), which is a conductor, and can be decomposed,--as well as against the metal poles, which are excellent conductors, but undecomposable, there appears but little reason to consider the phenomena generally, as due to the _attraction_ or attractive powers of the latter, when used in the ordinary way, since similar attractions can hardly be imagined in the former instances.