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4. “ It appears that deplilogisticated water,” or,which may be a better name for the basis of waterand air, the element you call humor, “ has a more“ powerful attraction for phlogiston than it has for“ latent heat, but that it cannot unite with it, at least“ not to the point of saturation, or to the total expul-“ sion of the heat, unless it be first made red-hot,” ornearly so. “ The electric spark heats a portion of it“ red-hot, the attraction between the humor and the“ phlogiston takes place, and the heat which is let“ loose from this first portion heats a second, which“ operates in a like manner on the adjoining parti-“ cles, and so continually, until the whole is heated“ red-hot and decomposed.” Why this attractiondoes not take place to the same degree in the com-mon temperature of the atmosphere, is a question Iam not yet able to solve; but it appears, that, insome circumstances, “ deplilogisticated air can unite,“ in certain degrees, with phlogiston, without being“ changed into water.” Thus Dr. Priestley has found,that by taking clean filings of iron, which alone pro-duce only inflammable air of the purest kind, andmercurius calcinatus per se, which gives only thepurest dephlogisticated air, and exposing them toheat in the same vessel, he obtained neither dephlo-gisticated nor inflammable air, “ but in their place“ fixed air.” Yet it is well known, that a mixtureof dephlogisticated and inflammable air will remainfor years in close vessels in the common heat of theatmosphere, without suffering any change, the mix-ture being as capable of deflagration at the end ofthat time as it was when first shut up. These facts