692.  When perchloride of mercury was subjected to the voltaic current, it did not conduct in the solid state, but it did conduct when fluid.  I think, also, that in the latter case it was decomposed; but there are many interfering circumstances which require examination before a positive conclusion can be drawn[A].

  [A] With regard to perchloride and periodide of mercury, see now 1340,
  1341.—­Dec. 1838.

693.  When the ordinary protoxide of antimony is subjected to the voltaic current in a fused state, it also is decomposed, although the effect from other causes soon ceases (402, 801.).  This oxide consists of one proportional of antimony and one and a half of oxygen, and is therefore an exception to the general law assumed.  But in working with this oxide and the chloride, I observed facts which lead me to doubt whether the compounds usually called the protoxide and the protochloride do not often contain other compounds, consisting of single proportions, which are the true proto compounds, and which, in the case of the oxide, might give rise to the decomposition above described.

694.  The ordinary sulphuret of antimony its considered as being the compound with the smallest quantity of sulphur, and analogous in its proportions to the ordinary protoxide.  But I find that if it be fused with metallic antimony, a new sulphuret is formed, containing much more of the metal than the former, and separating distinctly, when fused, both from the pure metal on the one hand, and the ordinary gray sulphuret on the other.  In some rough experiments, the metal thus taken up by the ordinary sulphuret of antimony was equal to half the proportion of that previously in the sulphuret, in which case the new sulphuret would consist of single proportionals.

695.  When this new sulphuret was dissolved in muriatic acid, although a little antimony separated, yet it appeared to me that a true protochloride, consisting of single proportionals, was formed, and from that by alkalies, &c., a true protoxide, consisting also of single proportionals, was obtainable.  But I could not stop to ascertain this matter strictly by analysis.

696.  I believe, however, that there is such an oxide; that it is often present in variable proportions in what is commonly called protoxide, throwing uncertainty upon the results of its analysis, and causing the electrolytic decomposition above described[A].

[A] In relation to this and the three preceding paragraphs, and also 801, see Berzelius’s correction of the nature of the supposed now sulphuret and oxide, Phil.  Mag. 1836, vol. viii. 476:  and for the probable explanation of the effects obtained with the protoxide, refer to 1340, 1341.—­Dec. 1838.

697.  Upon the whole, it appears probable that all those binary compounds of elementary bodies which are capable of being electrolyzed when fluid, but not whilst solid, according to the law of liquido-conduction (394.), consist of single proportionals of their elementary principles; and it may be because of their departure from this simplicity of composition, that boracic acid, ammonia, perchlorides, periodides, and many other direct compounds of elements, are indecomposable.