DUPLEX WEIGHING TUBE*
A new sample weighing and delivery device is presented.' Loss of sample with subsequent inaccuracy of analytical data is likely to occur when samples must be transfered from a watch glass or weighing bottle into a beaker or narrow neck receptacle. Flicking of sample may also occur when the material must be brushed out of the weighing bottle or off the watch glass with a camel's hair brush. When standard solutions are being prepared, the narrow neck of the volumetric flask presents a problem in transference, which is usually solved by inserting a funnel into the FIGURE1.-SmE VIEWOP DUPLEX flask, dusting the chemical out of the WEIGHINGT U B E weighing bottle or watch glass into the funnel and washing the chemical into the flask. Oftentimes the sample is dusted from the weighing receptacle onto glazed paper, then the paper slightly grooved and the sample bushed into the beaker, test tube, or flask from the the danger of loss due to dusting of the brush and to obviate the necessity of a weighing tube or bottle has been designed to incorporate the principle of a watch glass or weighing bottle, provided with an accessible and easily discharging FIGIT- 2.delivery end. The device consists of a wide-mouthed glass To, vaw tube with a flattened bottom side and a tapering delivery end turning up and away from the flattened side. The duplex weighing tube or bottle is shown in Figure 1. Details of size are given, but proportionally larger 0. smaller sizes are just as applicable. Figures 2 and 3 give 5x top and end view of the duplex tube. The use of ontside ground joints and caps on both ends enables the application of this weigh'mg tube or bottle for all pnrVIEW poses of weighing. The advantages in the specific details of the design given are as follows: (1) The large mouth provides for easy addition of or taking portions of the sample from the tube.
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Presented before the Division of Chemical Education of the American Chemical Society at the Atlanta meeting, April 7-11, 1930. 1 The conception of the duplex tube came from the use of an adapter by W. E. Eskew in weighing small samples of dye to transfer to a test tube. 1913
1914
JOURNAL OF CHEMICAL EDUCATION
Aucusr, 1930
(2) The designed slopes permit easy access of brush or stream of water into and against all parts of the interior. (3) The flattened side permits proper upright position during weighing and standing. (4) Distribution of the mass of glass assists in preventing the tube from easily toppling over. (5) Narrow end or stricture a t delivery end permits easy transfer of solids or liquids into narrow neck receptacle. (6) Variation of size for weighing larger or smaller samples does not involve proportional bulkiness.
