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"Suppose our volume of hydrogen to unite with the volume of chlorine; if one particle of hydrogen combines with one particle of chlorine, it is evident that we should have four pairs; that is four particles of hydrogen chloride. These four particles of hydrogen chloride would occupy the same volume as four particles of hydrogen, or of chlorine, since dqual numbers of particles of gases occupy equal spaces. We should then expect one volume of hydrogen chloride to be formed." -Brownlee 1907

Combinational Volume

"Suppose our volume of hydrogen to unite with the volume of chlorine; if one particle of hydrogen combines…