Page:Proceedings of the Royal Society of London Vol 1.djvu/500

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When any decompositions are effected by means of the voltaic battery, it is known that one of the constituents is attracted towards the positive pole, and the other to the negative. Of the ultimate chemical elements a very small proportion is attracted by the former, by far the greatest part being attracted by the negative pole ; and it is thence inferred that these are themselves possessed of inherent positive electricity.

Although all the differences observable between voltaic and com- mon electricity have already been shown to depend solely upon difference of quantity and of intensity, Mr. Brande has thought it would be desirable to trace their relation, with regard to a series of phenomena that have not yet undergone a comparative examination.

When the ﬂame of a candle is interposed between two bodies oppositely electriﬁed, Mr. Cuthbertson observed that heat passes to the negative surface, and thence inferred the passage of the electric ﬂuid in the same direction. It occurred to Mr. Brande, that possibly this effect might depend on the nature of the substance employed as the combustible body; and by substituting the ﬂame of phosphorus instead of the candle, he found the effects were reversed: for then the positive surface became considerably warmer than the negative, the ﬂame itself being now visibly attracted towards the positive ball, instead of inclining like the ﬂame of the candle toward the negative.

The rapid formation of acid matter during the combustion of phosphorus, appeared sufﬁcient to occasion the attraction of this ﬂame to the positive side, in conformity to What occurs in voltaic experiments; and Mr. Brande conceives the carbon and hydrogen which abound in the ﬂame of the candle to be the cause why that ﬂame takes the opposite direction.

When the ﬂame of oleﬂant gas was substituted, the negative ball was 10° warmer than the positive; the ﬂame of sulphuretted hydrogen gave only 3° excess to the negative ball; that of phosphuretted hydrogen communicated 2° to the positive ball. Arseniuretted hydrogen heated the negative ball most, though the fumes of white arsenic were visibly drawn toward the positive ball. With ﬂames of hydrogen or of carbonic oxide the difference of temperature was too small to be fully depended on, but the ﬂame of the latter was directed towards the positive ball. With respect to sulphur, no particular direction was observed to be given to the ﬂame, but the vapour passed toward the positive ball. When potassium in a state of combustion was placed between the electriﬁed balls, both the ﬂame and the fumes were drawn to the negative conductor. The attraction of other fumes being tried, not in the state of combustion, ammonia afforded no distinct result. Muriatic gas was visibly attracted by the pasitive pole; and nitrous acid gas was also drawn. in the same direction. The fumes that arise from benzoin and from