An EDTA procedure is described for the direct determination of Ca and Mg in soils and plant tissue. These elements are determined in the ammonium acetate leachate of soils and in the 1N HNO₃ solution of the plant ash. Calcium is separated from Mg by precipitating calcium sulfate from ethanol and is determined in the precipitate. Magnesium is determined in the supernatant solution. Manganese may be present in concentrations likely to interfere with the Mg titration, but this interference is easily eliminated. The accuracy and precision of the method are well within the limits required for routine analyses.

Two types of fabric, a tightly constructed worsted and a woolen of more open con struction, have been milled in laboratory stocks. Curves of (i) shrinkage in both warp and weft directions, as a function of time, and (ii) the mean displacement d of those fiber portions which have moved, also as a function of time, have been determined for each fabric. In the case of the worsted, the latter curve is linear for the first 5 hr of milling, although the former shows acceleration of the rate of shrinkage at about 2 1/2 hr. This indicates that fiber displacement is the primary result of milling and that shrinkage is a secondary result. From these curves the curve of linear shrinkage against d has been determined for each fabric. For the worsted this curve, after d has been corrected for shrinkage, consists of two linear regions. Their intersection marks a change in the mechanism of felting, which is also revealed by the appearance of straightened lengths of fibers and subsequently by the acceleration in the shrinkage-time curve. The configuration of the fibers as milling proceeds has been studied, and in the case of the worsted fabric additional curves have been determined, relating the fraction of the total fiber length which is straightened to the duration of milling, to d, and to the linear shrinkage. The induction period, an interval at the beginning of milling during which no shrinkage occurs, is also discussed.

It was determined that a thermometric titration procedure could be used to obtain the cation-exchange capacities and heats of neutralization of acid-saturated clays. The endpoints of these titration curves were much sharper than those commonly obtained by potentiometric or conductometric methods. Cation-exchange capacities calculated from thermometric titration curves of H-exchanges agreed fairly well with those determined by the BaCl₂-TEA method. Heats of neutralization for Arizona, Mississippi, Southern and Utah bentonites were found to be: −13.3 ±2, −15.9 ±3, −16.1 ±1 and −15.5 ±2 kcal. per eq., respectively. The heat of neutralization of humic acid was −13.2 ±1 kcal. per eq. and that of Al-saturated Mississippi bentonite was −5.5 kcal. per eq. The large difference in the heat of neutralization of the H- and Al-saturated exchangers causes titration curves for the two to have widely differing slopes. This allows determination of the proportions of H and Al saturations of mixed H-Al clays from the titration curves. The possible use of thermometric titrations in determining the course, mechanism and rate of a number of chemical reactions in soils is discussed and concluded to be excellent.

Manganese, extractable by sodium hydrosulfite and referred to simply as free Mn in this paper, was determined for 21 Iowa soil profiles. The soil profiles studied included Wiesenbodens, Planosols, Gray-Brown Podzolic soils, and Brunizems. Brunizems, in general, have either little change in free Mn with depth or a slight decrease in the most acid part of the solum. Free Mn in Gray-Brown Podzolic soils and forest Planosols is at a maximum in the A₂ horizon and at a minimum in the B₂ horizon. In prairie Planosols, by contrast, minimum values for free Mn occur in the A₂ horizons, and maximum or near maximum values occur in the B₂-B₃ horizons. Free Mn in Wiesenbodens increases from the A₁ to the B₂ horizon. The distribution of free Mn in Brunizems apparently is a function of pH of the solum, whereas in the prairie Planosols and Wiesenbodens reducing conditions and/or pH may be controlling factors. The distribution of free Mn in Gray-Brown Podzolic soils and forest Planosols may be due in part to pH and reducing conditions, and in part to factors that cannot be determined by data available.

Aggregate and structural stabilities were determined on samples taken under 10 cropping systems on Beltsville silt loam soil. Water stability of aggregates from 2 mm. to 4.76 mm. in diameter was measured by the wet-sieving method of Bryant, Bendixen, and Slater. Structural stability was determined on samples < 2 mm. and < 1 mm. by the air-to-water permeability ratio method of Reeve. The measurement of soil aggregate stability by wet-sieving distinguished six different groups of cropping systems according to Duncan's Range Test (4). The order of placement of the cropping systems was in agreement with other experimental results of Wilson et al. concerning the effect of cultivation and forage crops on aggregate stability. The measurement of structural stability by the air-to-water permeability ratio method did not distinguish soil structural differences associated with the cropping systems. Attempts to increase the sensitivity of the air-to-water permeability ratio failed. Water permeability offers some promise as a measurement of structural stability differences associated with cropping systems.

Fifteen Hereford heifers fed solely on restricted quantities of sorghum grain were bled at intervals during the 24-hr period before and after parturition. Blood samples were analysed for glucose, inorganic phosphate, haemoglobin and packed cell volume. Calcium, magnesium, total protein, albumin and globulin were determined on serum. There was a moderate decrease in blood glucose levels prior to parturition and a significant rise to peak values at or about parturition. Blood inorganic phosphate levels showed a significant decline. No significant changes were evident in blood haemoglobin, packed cell volume, serum calcium and magnesium levels. Total protein and globulin levels in serum decreased significantly when compared with the values obtained some weeks before and after parturition. The diurnal variations in blood glucose, haemoglobin and packed cell volume were determined on three steers bled at 2-hr intervals throughout a 24-hr period. Two of these steers were fed solely on restricted amounts of sorghum grain; the other received a restricted amount of lucerne chaff. No regular pattern of diurnal variation was evident, although blood glucose levels tended to rise after feeding. The magnitude of changes due to the time of day at which calving took place was considered insufficient to affect conclusions with regard to changes in blood constituents associated with parturition.

SynopsisAn equation describing the uptake of water by plants is described. Greenhouse experiments support the equation and show that the iower limit of water availability is determined by the rate of water transmission through the soil to the plant roots. An appreciable amount of water is shown to move vertically in the root zone.

A comparatively rapid and economical method of assessing the viability of P. microbothrium metacercariae was developed by modifying the technique described by Wikerhauser (1960). The effects of various methods of storage and of age on metacercarial viability were determined. The highest viability was observed for metacercariae five to 16 days of age. A close correlation between in vitro viability and actual in vivo viability was recorded.

The fatty acid composition of the cholesterol esters, triglycerides, phospholipids, and free fatty acids from the pooled plasma of four grass-fed, maiden heifers was determined by gas-liquid chromatography. Special attention is drawn to the composition of the C18 fatty acids, and particularly to the presence of C18 tri-unsaturated fatty acid as a major component (22.9% w/w) of the acids esterified to cholesterol since workers in other laboratories have not detected this acid in ox plasma cholesterol esters or have found it in only very small amount.

The polar-symmetric problem of thermoelasticity for a multilayer sphere is solved. Using this solution and based on the analogy between a libre thermal strain in an elastic body and a libre eigenstrain in a galvanic coating, the problem of determination of residual stresses (eigenstresses) in a multilayer galvanically grown sphere is solved. The compatibility problem of the solution is considered. As an example, residual stresses are determined for a coating on a thin-walled spherical substrate (application of equations (38) and (51) which modify the Mills method [7]).