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The amount of sulfate found in anodic coatings formed on pure aluminum anodes in sulfuric acid electrolytes increased as the current density and concentration of acid increased, but decreased as the temperature was raised. Chemical analysis showed that the coatings consisted substantially of A120~ and SO3 with practically no water.Factors affecting solubility of the coatings, such as heat developed within the coating, and time of immersion, were investigated. Rapid changes in current and voltage, which occurred in the first 15 sec after application of current, gave certain clues as to the possible mechanism of pore formation.

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under similar conditions from the concentrated distillery residues. Some fermentation tests were also set up with unhydrolyzed and hydrolyzed blackstrap, but because of the small increases in the invert sugar upon hydrolysis the additional alcohol yields were erratic. Experiments of this nature would have to be made on a much larger scale to furnish reliable results. CONCLUSIONS 1.When the reducing substances in the unfermented residue from blackstrap molasses are heated with acid, the reducing power first increases to a maximum because of the formation of fermentable sugars by the hydrolysis of the sugar anhydrides and sugar-amino acid condensation products, and then decreases again through the destruction of the fermentable sugars.2. Within the experimental limits of pH 0.2 to 2 and temperatures between 40°and 100°C. the maximum reducing power increases with the acidity at constant temperature, and with the temperature at constant acidity. The rate of destruction follows the same rule._ 3. Increase in the concentration decreases the rate of hydrolysis and increases the rate of destruction.4. Upon fermentation with yeast the sugars formed by hydrolysis yield alcohol, but the alcohol recovery is much smaller than the theoretical because fermentation inhibitors are formed from the sugars by the effect of acid at high temperature.5. When blackstrap' molasses is treated with acid under the same conditions as distillery residue, the reducing power also increases to a maximum and then decreases again, but the increases are small because the acid exerts a destructive effect on the sugars in the molasses. For this reason a marked increase in alcohol yield upon hydrolysis cannot be expected. Whether alcohol can be produced economically from hydrolyzed distillery residues would have to be decided by large scale experiments.

statements neglect the possibility that considerable changes may occur in the relative values of electrode potentials in going to fused salt electrolytes, as indicated above in the qualitative series. Furthermore, simple consideration of the equilibrium constant for the exchange reaction shows that, in certain cases, even if the two metals have the sanie standard electrode potential in the fused salt system it should be possible, by proper choice of the concentration of the ion of the less noble metal and of other conditions, to minimize metal transfer to the extent that reliable data could be obtained. Thus, data on electrode potentials in fused salt systems might show that certain alloy systems could be studied for which the emf method was formerly thought to be unsuitable.S. SENDEROFF: Since making the measurements described in the paper, we have done some calculations which indicate that the inversion of the positions of copper and nickel in the emf series should not have been so surprising to us and to others who have observed it. We calculated the equilibrium constants, K, at 730~ for the reaction, MCI,, + n/2H2(g) ~ M + nHCl(g) from Brewer's thermodynamic data for the metal halides at elevated temperatures. When log K thus calculated was tabulated for about a dozen metals, a list was obtained which is equivalent to the idealized emf series to be expected at that temperature, since log K for the reaction is proportioned to E ~ against a hypothetical hydrogen electrode at that temperature. Negative values of log K would correspond to the "active" metals above hydrogen, and positive values to the "noble" metals below hydrogen. It turns out that on the basis of this strictly thermodynamic calculation, Cu + and nickel are both below hydrogen, and nickel is below copper. Some other metals whose potentials have been measured fall in the correct order.While we have not carried this further as yet, it seems that as more thermodynamic data at high temperatures become available, it will be interesting to compare such calculations with potential measurements to throw light on the state of the electrolyte in molten salts, and to judge the reversibility of electrode systems. ANODIC BEHAVIOR OF ALUMINUM AND ITS ALLOYS IN SULFURIC ACID ELECTROLYTES Ralph B. Mason and Phyllis E. Fowle (pp. 53-59)R. C. SI~OONER~S: The authors are to be congratulated on a clear and interesting presentation of their investigation of conditions governing the anodizing of aluminum and its alloys. It is regretted that the paper does not discuss in detail the voltages required under the various conditions employed, since this information is essential for consideration of the coating formation mechanism.The coating ratio-metal loss curves in Fig. 2 and 3 at 72 amp/ft 2 which tilt upward are of special interest. Their shape is attributed to a decreased rate of solution of the coating at the bottom of the pores because of a build-up of solution products within the pore channels. Later in the paper, the possibility is mentioned that the "pores are fe...