A Simple Modification of Victor Meyer's Apparatus The Victor Meyer method far the determination of the molecular weight of a volatile substance is employed in one of the first experiments carried out in the undevgmduale physical chemistry laborat,ory. I t can be a frustrating experience t o the fresh student because the apparatus does not work satisfactorily, if the following t v o conditions are not fully realized: (1) the vapors produced during a previou determinat,ion should be removed from the inner volstilizing tube, as otherwise, some of thesevapors will escape into the cooler connecting p a t s and will condense there and (2) the volittiliaslion of the substance in any determination should be rapid enough t o avoid the possibility of part of the vapors difillsing to the cooler parts and condensing there. T o ensure the full realization of these two conditions, a simple modification of the inner volatilizing tube is suggested here. As shown in the figure, the bottom of the inner tube is opened and the inner part of a joint is sealed to it. A small length of a narrow tube carrying the outer part of the joinl. is attached and secured firmly with springs. This tube serves a3 the bottom of the volatilizing tube and enablc5 the substance to volatilize rapidly because the substance experiences the besting effect of the surrounding steam much more in the narrow tube than in the middle of the bigger bulb. In addition, the modification is very convenient for removing the vapom of a previons determination. By dehching the bottom tube, the main inner tube is made open st both ends and expulsion of the vapors can he carried out rapidly and thoroughly.
596
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Journal of Chemical Education
