The ability was investigated of two grasses Dactylis glomerata and Lolium perenne to take up K, Na, Mg, Ca, F, S and N from solutions, from soil and from fertilizers. The ratio of the cations and anions in the herbage was estimated. The difference in cation composition of grass species was related to the difference in selectivity between K, Na, Mg and Ca.Total uptake of cation equivalents in herbage was shown to be determined by the total uptake of anion equivalents and by an internal factor, related to metabolism which determined the cation-anion balance.The proportions of K, Na, Mg and Ca in total cations depended on availability as well as on the selectivity of the grass species.If availability and selectivity did not give rise to internal deficiencies of some elements, growth and assimilation could proceed.Mineral composition resulting from these processes could vary within limits. It was determined both by availibility of various elements and by plant species.

The ability was investigated of two grasses Dactylis glomerata and Lolium perenne to take up K, Na, Mg, Ca, F, S and N from solutions, from soil and from fertilizers. The ratio of the cations and anions in the herbage was estimated. The difference in cation composition of grass species was related to the difference in selectivity between K, Na, Mg and Ca.Total uptake of cation equivalents in herbage was shown to be determined by the total uptake of anion equivalents and by an internal factor, related to metabolism which determined the cation-anion balance.The proportions of K, Na, Mg and Ca in total cations depended on availability as well as on the selectivity of the grass species.If availability and selectivity did not give rise to internal deficiencies of some elements, growth and assimilation could proceed.Mineral composition resulting from these processes could vary within limits. It was determined both by availibility of various elements and by plant species.

Soil moisture characteristics (15 atm., 1/3 atm., etc.) were determined for 31 soil types representing the major great soil groups recognized in Illinois. In addition such physical properties as bulk density and mechanical analysis were also determined for the principal soil horizons. Available soil moisture and field capacity was shown to vary by textural classes for each soil group studied. For example it was found that silt loam soils of the Gray-Brown Podzolic averaged more available moisture in the A horizon than the Brunizems and Planosols. It was found that the available soil mositure was highly correlated with the 1/3-atm. percentage but not correlated with the 15-atm. percentage. The available moisture was controlled principally by the silt fraction.

One sample of H₂O₂-treated, iron oxide-extracted soil is treated with 2% Na₂CO₃ solution for 60 minutes and another with NaOAc of pH 3.5 for 15 minutes, at boiling. Both samples are washed with neutral NaOAc and the cation-exchange capacity is determined with Ca replaced with NaOAc. The difference obtained between the two samples is referred to as the “cation-exchange capacity delta value,” and averaged 100 me. per 100 g. for allophane from Ando soils of Japan developed on rapidly weathered volcanic ash and in some allophanes of Ross and Kerr. For example, the allophane content of fine clay of an Ando soil containing predominantly halloysite determined by delta value was 23.8% compared to 21.4% by water contents of constituent minerals.

Density changes produced in cotton and rayon fabrics by treatment with four thermo setting resin precondensates have been determined in density gradient columns. With the assumption that the density of resin cured in vitro corresponds to its density in the fiber, the results indicate that the predominant effect is fiber swelling, with very little resin being deposited in void spaces not previously accessible to the solvent mixture in the gradient column. Scouring the treated fabric to remove reaction residues lowers the density, indicating that the fiber structure does not collapse, presumably because it is stabilized by the reacted resin. The effect of resin concentration on moisture regain was also determined with these samples. The results are consistent with the changes in mechanical properties observed for cross-linking and non-cross-linking resins on cotton and rayon.

The relative uptakes of Sr and Ca were determined for crops grown in the field and greenhouse. Exchangeable Sr and Ca contents were determined in 93 plow layer samples representing 51 soil types in 11 widely scattered states. The average ratio was 1.3, with a range of 0.2 to 4.0, Sr atoms per 1,000 Ca atoms. The ratio varied more according to area than according to type of parent rock, and was similar to the ratio in surface water supplies. The ratios of Sr and Ca in alfalfa or wheat grown in the field were nearly equal to those in the exchangeable cations of the soil. Ten species of cultivated plants grown on 4 soils in the greenhouse had Sr and Ca ratios averaging 0.7 times those of the exchangeable cations in the soils. Small, but statistically significant, differences in relative Sr and Ca uptakes were found with different crops and soils.

The performance of a worsted serge in drycleaning and as trousers was studied. A 58's grade domestic wool was woven into a 13-oz. serge (standard 2/2 twill, 68 X 68) that was dyed gray. Fifty-four pairs of trousers were worn by college men for one, two, or three academic years (11, 22, or 33 weeks). Breaking strength was determined and microscopic examination of yarns for percentage of worn fiber ends was made in three locations of anticipated heavy wear—waist front, knee, and seat. Loss in strength was related to time in service. The rate of deterioration was greater during the second and third years than during the first, and greater for the filling than for the warp. The seat was the most severely worn area. The trousers gave satisfactory performance through the three years. Bursting strength and abrasion resistance were determined in parts where less wear was visible. After the third year, deterioration had advanced to an 18% loss in bursting strength and a 23% loss in resistance to abrasion, and air permeability increased to approximately double its original value. Drycleaning alone had little or no effect on the appearance or the physical properties of the swatches of serge which were cleaned in the same load with the trousers.

In order to calculate the stresses in the cords of an inflated tire, membrane theory is applied to the cord body. The equation describing the tire surface in terms of tire con struction parameters and cord properties has been given in the literature, but no solu tions have been reported, probably due to its complexity. A solution of this equation, obtained by numerical techniques on a digital electronic computer, is presented in this paper. It is shown how this equation is combined with the equilibrium equations of the surface and how the force components in the principal directions are determined and the cord stresses calculated. The cord stresses in inflated tires are nonuniform, decreas ing from crown to bead. The deformation of a simple cord network is considered, and it is shown how the cord stretch during tire expansion can be determined. It is found that the cord undergoes nonuniform stretch and shrinkage from crown to bead. These calcuations have been confirmed by experimental x-ray measurements on metal-shadowed cord. It is sug gested that the calculated and observed nonuniform cord stretch and shrinkage during tire expansion and curing are a direct result of the nonuniform cord tension.