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1826] of the acid consists of two proportionals of sulphuric acid, twenty of carbon, and eight of hydrogen; these constituents forming an acid equivalent in saturating power to one proportional of other acids. Hence it would seem, that half the sulphuric acid present, at least when in combination, is neutralized by the hydrocarbon; or, to speak in more general terms, that the hydrocarbon has diminished the saturating power of the sulphuric acid to one half. This very curious and interesting fact in chemical affinity was, however, made known to me by Mr. Hennell of Apothecaries' Hall, as occurring in some other compounds of sulphuric acid and hydrocarbon, before I had completed the analysis of the present acid and salts; and a similar circumstance is known with regard to muriatic acid, in the curious compound discovered by M. Kind, which it forms with oil of turpentine. Mr. Hennell is, I believe, on the point of offering an account of his experiments to the Royal Society, and as regards date they precede mine.

It may be observed, that the existence of sulphuric acid in the new compounds, is assumed, rather than proved; and that the non-appearance of sulphurous acid, when sulphuric acid and naphtha line act on each other, is not conclusive as to the non-reaction of the bodies. It is possible that part of the hydrogen of the naphtha line may take oxygen from one of the proportions of the sulphuric acid, leaving the hypo sulphuric acid of Welter and Gay-Lussac, which with the hydrocarbon may constitute the new acid. I have not time at present to pursue these refinements of the subject, or to repeat the analyses which have been made of naphtha line, and which would throw light upon the question. Such a view would account for a part of the overplus in weight, but not for the excess of the sulphuric acid obtained, above two proportionals.

The glowing salt of baryta was now analysed by a process similar to that adopted for the flaming salt. The specimen operated upon was pure, and in a distinctly crystalline state. It had been heated to about 440° F. for three hours in a metallic bath. Ten grains of this salt, exposed to air for forty hours, increased only 0.08 of a grain in weight. These, when converted into sulphate of baryta by heat and sulphuric acid, gave 4.24 grains. Seven grains by carbonate of baryta, oxide