It has also been shown that the results of Whetham on the conductivity of potassium dichromate and those of Spitalsky on the catalysis of diazoacetic ester by chromate solutions are in substantial accord with the results from this investigation, and that the conclusion drawn by Spitalsky that his experiments indicated that the hydrochromate ion is not present in any considerable quantity in dilute solutions of chromic acid and potassium dichromate is an erroneous one. I n conclusion, I wish to

more »

... hank Prof. A. A. Noyes for suggesting this investigation and for his ever-willing advice throughout its execution. The object and scope of the investigation. Previous investigations. Apparatus, Method of measurement. The unit of permeability. The effect of changing the pressure upon the permeability of collodion, of gold beater's skin, of parchment paper, of porcelain. The results of the pressure experiment's and Poiseuille's formula. Permeability of collodion at different temperatures. Calculation to test the applicability of Poiseuille's fbrmula. The effect of changing the temperature upon the permeability of parchment paper, of porcelain. Discussion of results and theory. Summary.