Sulphur, phosphorus; iodide of sulphur, per-iodide of tin; orpiment, realgar; glacial acetic acid, mixed margaric and oleic acids, artificial camphor; caffeine, sugar, adipocire, stearine of cocoa-nut oil, spermaceti, camphor, naphthaline, resin, gum sandarach, shell lac.

406.  Perchloride of tin, chloride of arsenic, and the hydrated chloride of arsenic, being liquids, had no sensible conducting power indicated by the galvanometer, nor were they decomposed.

407.  Some of the above substances are sufficiently remarkable as exceptions to the general law governing the former cases.  These are orpiment, realgar, acetic acid, artificial camphor, per-iodide of tin, and the chlorides of tin and arsenic.  I shall have occasion to refer to these cases in the paper on Electro-chemical Decomposition.

408.  Boracic acid was raised to the highest possible temperature by an oxy-hydrogen flame (401.), yet it gained no conducting powers sufficient to affect the galvanometer, and underwent no apparent voltaic decomposition.  It seemed to be quite as bad a conductor as air.  Green bottle-glass, heated in the same manner, did not gain conducting power sensible to the galvanometer.  Flint glass, when highly heated, did conduct a little and decompose; and as the proportion of potash or oxide of lead was increased in the glass, the effects were more powerful.  Those glasses, consisting of boracic acid on the one hand, and oxide of lead or potassa on the other, show the assumption of conducting power upon fusion and the accompanying decomposition very well.

409.  I was very anxious to try the general experiment with sulphuric acid, of about specific gravity 1.783, containing that proportion of water which gives it the power of crystallizing at 40 deg.  Fahr.; but I found it impossible to obtain it so that I could be sure the whole would congeal even at 0 deg.  Fahr.  A ten-thousandth part of water, more or less than necessary, would, upon cooling the whole, cause a portion of uncongealable liquid to separate, and that remaining in the interstices of the solid mass, and moistening the planes of division, would prevent the correct observation of the phenomena due to entire solidification and subsequent liquefaction.

410.  With regard to the substances on which conducting power is thus conferred by liquidity, the degree of power so given is generally very great.  Water is that body in which this acquired power is feeblest.  In the various oxides, chlorides, salts, &c. &c., it is given in a much higher degree.  I have not had time to measure the conducting power in these cases, but it is apparently some hundred times that of pure water.  The increased conducting power known to be given to water by the addition of salts, would seem to be in a great degree dependent upon the high conducting power of these bodies when in the liquid state, that state being given them for the time, not by heat but solution in the water[A].