The plant-available P in a group of soils was estimated at soil temperatures of 20° and 35° C on the assumption that the response to P obtained in a green-house experiment followed the Mitscherlich law. By multiple linear regression the dependence of the plant-available P on the following soil P fractions was calculated: (1) inorganic P soluble in a solution 0.03 N to NH₄F and 0.025 N to HCl; (2) organic P soluble in hot 1% K₂CO₃ and hydrolyzed by KOBr; (3) organic P soluble in hot 1% K₂CO₃ and not hydrolyzed by KOBr; and (4) organic P not soluble in hot 1% K₂CO₃. At 20° C the plant-available soil P was determined by inorganic fraction 1. Organic fraction 2 had no appreciable effect. At 35° C the plant-available soil P was determined by both inorganic fraction 1 and organic fraction 2. Organic fractions 3 and 4 were of no importance at either temperature. A probable cause of the observed results is that at 20° C the rate of organic P mineralization was low and the plant was dependent on inorganic fraction 1 originally present. At 30° C the plant was supplied with inorganic fraction 1 plus additional inorganic P from the mineralization of organic fraction 2.

Due to the difficulties involved in the visual estimation of amino acids in protein hydrolysates from serial dilutions on chromatograms a very simple photoelectric method was devised to facilitate the accurate estimation of amino acid concentration. Sources of errors which must be avoided are temperature fluctuations of the chromatographic tank, non-uniform application of ninhydrin to the filter paper, too high amino acid concentrations and discolorations of the filter paper by organic solvents. The method was applied to the analysis of silk fibroin and values were obtained which agreed well with those determined by previous workers.

Eight samples illustrating average and extreme types of Bikaner wool were selected from 28 samples received from the Government Livestock Farm at Hissar, India. These 8 samples were analyzed for fiber types, dividing them into true wool, hair, heterotype, and kemp fibers. Both the benzol test and microscopic cross-sectional images were used in the classification. Fiber thickness, stretched fiber length, and contour ratio were determined for the 8 samples along with the surface scale measurements for the different fiber types.

Measurements were made of the extension of nylon filaments under conditions of constant load for various lengths of time in air at 65% R.H. and in water. The extent of the recovery which took place after removal of the load was observed, and its dependence upon the magnitude and time of application of load, as well as upon the. immersion medium, was determined. Further recovery which could be effected by treatment with heat or swelling agents was investigated. Limitations in the use of the terms "elastic limit" and "nonrecoverable deformation" when applied to textile fibers are pointed out.

As a first step in studying the factors which determine the efficiency of cordage structures, a series of related experiments have been performed on the common cordage fibers. The basic mechanical properties of Manila and domestic Abaca, Sisal, Henequen, and Sansevieria fibers have been determined by a study of their one-time loading to rupture and repeated-tension char acteristics. Data are presented on: (1) those fiber properties deemed most significant in terms of cordage use; (2) the effects of processing fibers into yarns; and (3) mechanical properties under varying ambient atmospheric conditions representing some of the extreme environments under which cordage is used.

Results are reported on tests of breaking load and elongation of single fibers at constant specimen length from the length groups of 6 cotton samples. A description is given of the instrument used in these tests. Average weight fineness of the center section of fibers from each length group was determined, and the tenacity and "stiffness" of the fibers were calculated. A method is described of calculating a single-fiber tenacity "index" for a cotton sample from the tenacity values of 3 modal-length groups. A high correlation is demonstrated between this index and the weighted mean single-fiber tenacity for the whole sample.

The effect of surface deposits of N-hydroxymethyl polyhexamethylene adipamide on the felting shrinkage of wool has been determined. These polymers resemble the N-methoxymethyl poly amides in that the polymer itself is not particularly effective in preventing felting shrinkage of wool, but when the substituted polymer is applied to wool fabric and then converted to the un substituted polyamide on the fabric, its effectiveness in reducing felting shrinkage is very much increased. A deposit of approximately 3% by weight of polymer on the fabric has been found to eliminate entirely felting shrinkage of the fabric under the test conditions. The optimum degree of sub stitution of the polyamide for production of non-feltability is similar to that found for the N- methoxymethyl derivatives— vi., between 20% and 25% -NH groups substituted. The N-hydroxymethyl polyamides can be converted to the unsubstituted polymers either by hydrolysis—e.g., with acids—or by heating in air.

The effect of surface deposits of nylon and N-substituted nylons on the abrasion-resistance and felting shrinkage of wool has been determined. N-methoxymethyl nylons are much more effective than nylon itself, when applied from solution, in increasing the abrasion-resistance of wool fabric, but not in decreasing the felting shrinkage of the fabric. If the N-methoxymethyl nylon is first applied to the wool fabric from alcoholic solution and then hydrolyzed in situ by approximately 2N HCl, the polymer is found to confer non-felting properties on the wool. A deposit of approximately 3% by weight of polymer has been found to eliminate entirely the felting shrinkage of wool fabric under the conditions of test. The optimum degree of substitution of the nylon for the production of non-feltability is between 5% and 6% combined formaldehyde, which corresponds to between 20% and 24% —NH groups substituted. The effectiveness of these polymers in increasing abrasion-resistance and decreasing felting shrinkage is explained on the basis of their adhesion to and covering power on the wool fiber.

A detailed soil survey was made for forestry purposes in the Keuper hill area of Stromberg in north-west Wnrttemberg. The soil profiles consisted chiefly of heavily weathered diluvial deposits, usually clayey, sometimes sandy, not rich in lime, and numerous deposits of loess. The Keuper deposits (the most recent deposits of Trias) underlying the soils hardly had any part in their structure. Most soils had moved by soil slip during the glacial period, giving rise to special mixed soils and a multilayered structure. Native weathered soils seldom occurred. From the structure of the shifted material, the land morphology and the slope governing solifluction, 3 terraces could be distinguished. These resulted from the main layers of hard sandstone between the Red and the Grey Keuper Clays.In most of the forests there were slightly podzolized brown forest soils. The growth of all types of timber was determined by the soil units. Growth of the native oak, beech and hornbeam, and the introduced conifers pine, European larch, and spruce distinguished different types of deciduous forest soils of the former middle forest. The economics were discussed first of oak and then of beech. The chief conifer was pine, mixed either with oak or beech according to situation. Its growth on heavy clay in basins was outstanding. European larch was particularly suited to solifluctive soils, consisting of a clayey subsoil with a loamy topsoil. The failure so far of spruce through drought and bark beetles was ascribed entirely to its situation in dry valleys.

This work deals with the nitrates determination bj r the phenoldisulfonic acid method in the soils of São Paulo State. Several modifications were introduced which led to outline an analytical procedure. The nitrates are extracted by percolation, with a solution of H2SO4 0,01 N which is efficient in obtaining clear filtrates without clay and it is a saving time procedure. The ratio employed to remove soil nitrates is one weight of soil for three volumes of the extractor. The H2SO4 solution was the best extractor found because it dissolves less organic matter from the soil than other methods. Also, with the method described, the operation of removing chlorides is easy and it is possible to use a blank determination. Losses of nitrates are significant when chlorides are present in concentration as high as 11 e.μg (3.9 p.p.m.). The efficient removal of chlorides by using silver sulfate, can be performed only in acid extracts, if losses of nitrates are to be avoided. The solution free from chlorides must be neutralized with NaOH 1 N because acid reaction causes loss in nitrates which are liberated as HNO3 (gas). The residual organic matter is destructed with hydrogen peroxide after drying the solution. The hydrogen peroxide always has nitrates and the quantity of them must be determined. The residual salts from the above treatments are attacked with phenoldisulfonic acid and this solution dilutes to a convenient volume and neutralized with ammonium hidroxide (1 + 1). The color intensity developed in this reaction is read in an AC model Fisher Electrophotometer with B-425 filter calibrated for nitrates. The best readings are between 3-45 or 0,25-16,5 e.μg of NO-3.