. Carnegie Institution of Washington publication. MEASUREMENTS WITH ZINC AMALGAMS. 31 by a potential measurement, calculating -i- from the equation in which â n- and T were known. As this was not done, no amalgam derived from No. 3 was ever measured against any derived from No. 1. Two independent sets of results were thus secured, which by their agreement established certain con- clusions beyond a reasonable doubt. The possibility of polarizing the most dilute amalgams during measure- ments was considered. Momentary currents ranging from to volt and flowing in alternate direction
. Carnegie Institution of Washington publication. MEASUREMENTS WITH ZINC AMALGAMS. 31 by a potential measurement, calculating -i- from the equation in which â n- and T were known. As this was not done, no amalgam derived from No. 3 was ever measured against any derived from No. 1. Two independent sets of results were thus secured, which by their agreement established certain con- clusions beyond a reasonable doubt. The possibility of polarizing the most dilute amalgams during measure- ments was considered. Momentary currents ranging from to volt and flowing in alternate directions through a resistance of a thousand ohms can transfer only infinitesimal amounts of zinc. Still, the expected potential was roughly calculated before measurements, to avoid excessive differences at the first contact, and before the final readings were made the cell was shaken to renew the surface of the amalgams. The data and calculations for a typical case follow: Composition of Amalgam. (1) Pipette of amalgam No. 3 = (2) Pipette of amalgam No. 3 = Amalgam No. 3 = (1) Tube -\- mercury = (2) Tube -f- mercury = Weight of mercury = Weight of amalgam No. 3 = Total weight of diluted amalgam = This diluted amalgam was called No. 4. Zinc Dissolved in Ammonia during Mixing. Reading. Ferrocyanide in burette (1) Ferrocyanide in burette (2) Ferrocyanide used Needed for end-point Total zinc dissolved X gram. grams of amalgam containing per cent of zinc, or gram of zinc, were used; gram zinc is almost exactly per cent of total. Therefore, the concentration ratio calculated from the weights of amalgam and mercury must be multiplied by to correct for zinc Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resem
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