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As an initial part of a general program for the study of the acidic and basic characteristics of textile fibers, a study has been made of the dependence on pH of the amounts of hydrochloric acid and of potassium hydroxide taken up by wool from aqueous solutions. The effect on this dependence of the maintenance of a constant ionic strength by additions of a neutral salt, potassium chloride, has also been determined. Most of the measurements were made at 0° C to minimize the effects of decomposition brought about by exposure to extreme concentrations of acid or base.The maximum acid-binding capacity, independent of ionic strength, is 0.82 millimole per gram; the maximum base-binding capacity is greater than 0.78 millimole. With salt absent, no appreciable binding of acid or base occurs in the pH interval, 5 to 10, but the amount bound increases very sharply as these limits are exceeded. When salt is present, the amount of acid or base bound changes with pH more gradually, and there is no wide region in which combination fails to occur; the point of zero combination is sharply defined and is near pH 6.4. The positions of the titration curves with respect to the pH axis are different at every ionic strength. The differences are larger than can be attributed to the effect of salts on the dissociation of acids; thus, in dilute solutions an n-fold change in the total concentration of chloride ions produces a change almost as great as would be produced by a similar n-fold change in the concentration of hydrogen ions. This approach to stoichiometric dependence of the acid bound on the concentration of anions as well as of hydrogen ions accounts for the greater steepness of the titration curve when the source of both ions is the acid alone.The dependence of acid bound on anion concentration or base bound on concentration of cations is explained by treating the electrostatic restrictions arising from the existence of two phases as a case of partial dissociation of protein salts. A possible alternative analysis by means of the Donnan equilibrium is also presented, and factors to be considered in making a final choice between the two treatments are described in detail. Either analysis predicts that the positions of the curves wi, th res~t to the pH axis should, at high salt concentrations, approach a limit which should correspond to the titration curve of the same protein in the dissolved state. This prediction is supported by the fact that the data for wool agree very closely at high salt concentrations with those for a similar but soluble protein, egg albumin.On the basis of this comparison, a detailed analysis is undertaken of the composition of the titration curve in terms of the constituent di-acidic and di-basic amino acids of wool. This analysis leads to the conclusion that the binding of acid and base by wool occurs at the free carboxyl, imidazole, amino, and guanidino groups, but that no combination of base with the tyrosine hydroxyl group takes place in the pH range of this investigation.I The state of comb...

It is frequently stated that one fabric dries faster than another, usually with reference to house hold conditions of drying on a line. However, the data of this report show that by and large all fabrics dry at the same rate under these conditions (rate being expressed as weight of water evaporating per unit area per unit time), but that the time of drying depends upon the amount of water originally held, so that some fabrics dry sooner than others. The main portion of the drying time shows this constant rate of drying, although there is a final period which is short compared to the main drying period, during which the rate of drying decreases. The water-holding capacity of a fabric depends upon how the fabric is supported (vertically or horizontally) and upon the mechanical treatment given to remove water. For simple drainage in the vertical position, the water-holding capacity of small samples is more closely correlated with fabric thickness than with fabric weight. The kind of fiber—i.e., wool or cotton-and large differ ences in moisture affinity, as shown with Vinyon, also affect the water-holding capacity. How ever, these factors have almost no effect on rate of drying, since this is controlled by the resistance of air layers to the passage of heat. The thickness of these air layers is sufficient under ordinary conditions to smooth-over the fabric surface irregularities, even when these are rather large, as in rib knits or in cellular or waffle fabrics. Increasing the hairiness of the surface in order to give more area for evaporation is sometimes proposed as a means of increasing the drying rate, but results show that this is without effect except for extremely high, open naps, for which the effect is the opposite-the thickness of the layers of still air is increased and the drying retarded.

An investigation has been made of the mode of attack of cellulose by periodic acid during the early stages of the oxidation (that is, oxidation of approximately 1 percent of tb~ glucose residues). Under these conditions, it is shown that the reaction is confined to oxidation of the secondary hydroxyl groups to aldehyde groups, and results in a rupture in the carbon chain between carbon atoms 2 and 3 of the glucose unit. In accordance with this mechanism it is shown that two moles of aldehyde groups are produced for each mole of oxidant consumed. The aldehyde groups of the periodic acid-oxycellulose can readily be converted to carboxyl groups, titration of which provides an independent check on the content of the former.Periodic acid-oxycellulose is characterized by its susceptibility to further attack by alkaline solutions. The a lkali-sensitivity of these materials, as measured by solubility in hot dilute sodium hydroxide and by cuprammonium fluidity, appears to be proportional to the content of aldehyde groups. However, upon conversion of all of the a ldehyde groups to carboxyl groups, the alkali-lability practically disappears. The results suggest that the sensitivity of periodic acid-oxycellulose to alkali does not depend solely on the rupture of the glucose ring between carbon atoms 2 and 3, but is related to the specific instability towards alkali of the dialdehyde formed during the oxidation. CONTENTS Page