Abstract
When distilled water is filtered through cellophane membranes which have been evacuated prior to several days' soaking in water, it is found that the rate of filtration usually decreases during the first hour, finally reaching an essentially constant value. We predicted that it should be possible to raise or lower the value of this final “steady” rate of filtration by adding varying amounts of ThCl4 to the water. The preliminary results given below show that the steady rate of filtration is affected by ThCl4.
The membrane was placed between glass cylinders and supported by a coarse alundum disc. Filtration was carried out at 10 cm. Hg. The rate of filtration was determined by following through a microscope equipped with a micrometer eye-piece the displacement of the meniscus in a capillary. A solution of 10-3 gms. ThCl4 per liter gave a 25% increase in the rate of filtration over that of distilled water. Solutions of 1 gm. and of 10 gm. ThCl4 per liter showed a decrease in the rate of filtration of 29% (average of 5 determinations) and 35% (average of 3 determinations), respectively. A solution of 10-2 gm. ThCl4 per liter showed no large effect. A hypothesis concerning the mechanism of these processes, together with an extension of experimental results, will appear in a subsequent communication.
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