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Analyses for Co, Zn, and Pb on mixed bed and SA-2 cation exchange resin-loaded paper disks in amounts approaching the theoretical limits of detection were attempted. Based on the results, the definition of limit of detection which requires a line intensity above background equal to three times the square root of the background, using a 10-min count, was modified to the line intensity above background equal to three times the standard deviation of the background counted for 10 min on a series of blank disks. Chemical precleaning of the disks and corrections for paper density were shown to be advantageous for work close to the limit of detection by lowering the background count and reducing the weight-corrected standard deviation.

A paper chromatographic study of the amino acid compositions of several histo logical fractions of wool has been conducted. The fractions considered were epicuticle, cortical cell membranes, paracortex, and regenerated oxidized keratin. Samples of these fractions were hydrolyzed with hydrochloric acid, and quantitative analyses of the amino acid content of these hydrolysates were accomplished through a modification of the standard two-dimensional paper chromatographic technique. The epicuticle was found to contain normal amounts of cystine but extraordinarily large quantities of aspartic acid and glutamic acid. In addition to confirming the results of the phosphotungstic acid analyses for cystine reported in a previous paper [14], the chromatographic studies of the paracortex showed large amounts of the basic and small amounts of the dicar boxylic amino acids to be present. The extremely low total of amino acid content found in the cortical cell membranes indicated the possible presence of some nonprotein constituent.

A method to exclude mites and other contaminants from test tube cultures is described. It consists in covering the mouths of the tubes with cigarette paper which is applied by pressing the flamed r...

The manipulation of the physical characteristics of nonwovens and paper by variation of fiber and web geometry is briefly reviewed in terms of a new system of bonding in which the adhesive interfiber forces are a consequence of ionic chemical bonds. These bonds were created by the sequential covalent introduction of anionic sites onto the interior and exterior surfaces of microporous pulp and rayon fibers using a chloro-s-triazinyl fiber reactive dye and subsequent stoichiometric reaction with crosslinking polycations derived from ethylenimine. The tensile properties of both the pulp and rayon fiber assemblages were significantly augmented as a result of the development of both ionic inter- and intra-fiber bonds.

Two new Weibull probability plotting papers are presented. Their use is explained, and they are compared with other Weibull papers...

Resin-loaded papers composed of approximately 50% cellulose and 50% ion-exchange or chelating resin provide an ideal matrix for many X-ray spectrographic analyses. Standards are prepared by multiple filtration of solutions of known composition through the paper to achieve quantitative collection or by the use of a radiotracer as a monitor for nonquantitative collection. Solutions prepared fram unknown samples are processed in the same manner as the standards.Advantages of the resin-loaded papers are: reduction of interelement effects because standards and unknowns are present in a similar low X-ray absorbing matrix; physical parameters such as metallurgical history, grain size, and surface preparation are eliminated; and sampling errors are significantly reduced and sensitivity greatly increased by concentrating trace elements separated from large samples.Application of these papers to a variety of metallurgical, geological, and water samples will be summarized. The possible use of resin-loaded papers as standards for air pollution monitoring will be examined.

In a recent paper Weiss (1965) has suggested a simple model for a carrier-borne epidemic such as typhoid. He considers a population (of size m) of susceptibles into which a number (k) of carriers is introduced. These carriers exhibit no overt symptoms and are only detectable by the discovery of infected persons. He supposed that after the initial introduction of the carriers, the population remains entirely closed and no new carriers arise. The epidemic then progresses until either all the carriers have been traced and isolated or until the entire population has succumbed to the disease.

We illustrate a technique for computing certain integrals that arise in probability theory by giving a new derivation of a formula of Kingman. This formula contains the joint distribution of the processes F(t) = inf {s: X(t + s) = b} and B(t) = inf{s: X(t - s) = b} where X is a time homogeneous, continuous parameter, Markov process and b is a fixed point in its state space. We then extend this formula to the situation in which b is replaced by a finite set {b 1, …, b n }.

The first part of an experimental and theoretical investigation into the feasibility of transpiration cooled combustion chambers is discussed, as well as the design and testing of two Rolls-Royce ‘Dart’ porous flame tubes. The theory of heat transfer in porous materials is briefly described and correlations for heat transfer and pressure drop-mass flow are presented for selected samples of porous metal. Experimental results are presented in which the cooling efficiency of the original ‘Dart’ splash-cooled flame tube is compared with two porous replacements constructed from sintered woven wire porous metal compacts having different permeabilities. Tests were conducted at 1 and 4 atm pressure and some selected results are compared with theoretical predictions made with and without account being taken of the effect of coolant injection on the convective heat flux. The high effectiveness of transpiration cooling is clearly demonstrated but it is also shown that the distribution of static pressure in the annulus formed between the flame tube and the casing, both longitudinally and circumferentially, plays a very important part in the design of a porous flame tube.

Strictly many materials such as ceramics, cement and even metals should be classed as polymers since the atoms within them are bound by strong chemical bonds into large groups usually of indefinite size. This article will deal only with the synthetic organic polymers and, in fact, will consider mainly the plastics, little attention being given to rubbers and fibres.The industrial production of synthetic plastics has expanded greatly in the post-war years largely using petroleum as the starting material. The plastics produced do not have good mechanical properties compared, say, to metals and have other limitations such as poor resistance to heat and inflammability.

It is, and always will be, an honour to give the Handley Page Memorial Lecture, but for me the occasion has a special pietas because Sir Frederick Handley Page was a friend of mine for many years and I admired his extraordinary intelligence, pertinacity and independence of character. I had the honour to immediately follow him in two offices of high importance—as President of the RAeS and as Chairman of the Governors of this College, and as this is the last major lecture I intend to give, I am particularly happy that it is in his memory, just as the first major lecture I ever gave was in memory of that other great pioneer, Wilbur Wright.

Mean velocity and injectant concentration profiles are presented for the boundary layer on a flat plate with air injection through rows of discrete holes. An 8/1 pitch/diameter ratio was used. Three hole arrangements were studied in detail. For holes perpendicular to the surface, both in-line and staggered configurations were examined, while, for holes angled 45° downstream, only staggered holes were used. Some results are also presented for Freon injection and it is shown that this higher density injectant always gives higher concentrations at the wall. Angled injection is also shown to give improved cooling effectiveness.

In a recent paper Robinson has obtained an explicit formula for the expression of an invariant matrix of an invariant matrix as a direct sum of invariant matrices. The object of the present note is to show that this formula may be deduced from known properties of Schur functions, with the aid of a result which the author has proved elsewhere.

Twenty herbicides were tested for activity in a paper disc agar bioassay. The growth ofChlorella pyrenoidosaChick was inhibited by dinoseb (2-sec-butyl-4,6-dinitrophenol), diquat [6,7-dihydropyrido(1,2-a:2′,1′-c)pyrazinediium ion], paraquat (1,1′-dimetnyl-4,4′-bipyridinium ion), 3′,4′-dichloro-2-methylvaleranilide, propachlor (2-chloro-N-isopropylacetanilide), and linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea]. The growth ofBacillus subtilisCohn was inhibited by dinoseb, diquat, paraquat, and 3′,4′-dichloro-2-methylvaleranilide. This assay usingC. pyrenoidosaorB. subtilisoffers a convenient means for the testing of herbicides.

Two recent articles in this journal misidentify a theoretical orientation and then contrast this misidentification with another orientation. Archaeology does not gain in this way.

An acid hydrolysate of casein, vitamin-free casamino acids (Difco), is commonly used as the amino acid source in early phases of nutrition work. Frequently, it is necessary to replace such a complex source with an equivalent, defined mixture of amino acids. This change in the medium often results in longer lag periods and reduced yields. The difference in yields can be the result of incomplete information on the composition of the complex source. The purposes of this paper are to present more complete data on the amino acid composition of and to briefly discuss other organic components of vitamin-free casamino acids (Difco). Amino acids.-A composite amino acid analysis obtained by using paper chromatography is currently available for casamino acids and is given in TABLE I, Column A (personal communication from Mr. V. R. Wheat, Technical Service, Difco; 7 Oct., 1970). The technique of Moore and Stein (1963) provides a more rapid and accurate means of determining the amino acids in a mixture. The samples of casamino acids were stored in a desiccator prior to preparation of the solutions which were analysed on a Beckman-Spinco automatic amino acid analyser (Model 121; Spinco Division, Beckman Instruments, Inc., Palo Alto, California). The techniques used have been previously reported (Nolan, 1970a.). The results of duplicate analyses of three lots of casamino acids are presented in TABLE I (Columns C, D, E). The accuracy of the data within each lot is -+ 5.1% or better. The values for ammonia, cysteic acid and tyrosine were not included in the accuracy calculations either because of susceptibility to external conditions or because the concentrations were too low.

Beryllium is determined spectrographically on air sample filter papers by direct sparking of the filter paper mounted on a silver disk which revolves on a rotating platform electrode apparatus eccentric from a silver counter electrode. The procedure is fast and precise, with a minimum of sample handling and can be used with samples containing as little as one mμg of beryllium

The action of trypsin on oxidized normal and copper-deficient wool has been ex amined by ( i ) N -terminal-residue estimations and (ii) paper electrophoresis and chromatography on the tryptic digests. Trypsin readily solubilizes oxidized wool but does not digest it completely, probably because of its high cysteic-acid concentration. Little difference was found between normal and copper-deficient wool, although the latter gave a smaller amount of a certain group of acidic peptides. Preliminary tests on the chromatography of the tryptic digests using ion-exchange resins are reported.

A spectrographic method for the determination of as little as 0.3 µg tellurium in nickel-base alloys has been developed. The method utilizes a preliminary separation and concentration of tellurium by precipitation of the metal with stannous chloride. The precipitate is then filtered and the filter paper ashed in the spectrographic electrode. Tellurium is measured by a dc arc technique.

The amino-acid compositions of oxidized normal and copper-deficient wool from one sheep and of two components separated from them at pH 6 have been measured by ion exchange chromatography. The differences between the "soluble" and "insoluble" components are those expected from previous work. The "insoluble" components from normal and copper-deficient wool appear to be identical, although there is a small dif ference in the "soluble" components. Attempts at fractionating the "soluble" components , by chroniatogrtphy, paper electrophoresis, and dialysis gave indications of heterogeneity but were not very successful.

This paper reviews the literature on the microbiological deterioration of woolen textiles; it lists wool-destroying micro-organisms, describes the factors governing their growth and activity on wool, and discusses the mode of attack by micro-organisms on wool. Also, the methods developed for prevention of deterioration of woolen textiles by micro-organisms are described.

Excised leaves of Canada thistle (Cirsium arvense (L.) Scop.) ecotypes and bean (Phaseolus vulgaris L., var. Red Kidney) metabolized 3-amino-l,2,4-triazole-14C (amitrole) to the same radiolabeled products, but they were produced at different rates as shown by thin-layer and paper chromatography. Bean leaves metabolized amitrole to a metabolic product (Unknown II) probably β-(3-amino-1,2,4-triazolyl-1-) α-alanine approximately three times taster than Canada thistle leaves, while Canada thistle converted Unknown II to another product (Unknown I) about 10 times faster than did bean. Thus Unknown II accumulated in bean, and Unknown I in Canada thistle. This reaction sequence in Canada thistle was evidently an irreversible consecutive first order reaction. A difference in the rate of metabolism was observed between susceptible and resistant ecotypes of Canada thistle.

Biochemical systematics has provided additional criteria for characterizing taxa already defined by conventional morphological, geographical, ecological, and cytological observations. Paper chromatography has been used for the rapid, efficient separation of relatively small molecules (Alston and Turner, 1963) and zone electrophoresis for relatively large molecules, such as proteins or enzymes (Leone, 1964), to detect meaningful differences or similarities among species within a genus. Clare (1963) separated soluble proteins in mycelial extracts of species of the fungal genus Pythium by zone electrophoresis and obtained patterns which appeared to characterize each species. Meyer et al. (1964) used culture filtrates of strains from 2 species of the fungal genus Fusarium to obtain esterase and phosphatase zymograms. Their reports suggested that zone electrophoresis might provide a useful tool in fungal taxonomy. Raper and Fennell (1965) recently published an extensive revision of the fungal genus Aspergillus. The numerous and apparently well defined species assigned to different groups in this genus offered suitable material to determine whether zymograms might provide an additional method to distinguish species. This report presents the results of a preliminary survey of leucine aminopeptidases, esterases, and phosphatases in mycelial extracts of 15 species of Aspergillus which were detected in starch gels after zone electrophoresis.

Decomposition of cellulosic fibers by thirteen strains including three species of the obligately anaerobic genus Ruminococcus has been investigated with regard to the effects of the chemical composition and physical state of the fiber. Of the thirteen strains only six were actively cellulolytic. In test systems containing 50 mg of fiber in 10 ml of medium, nearly complete solubilization of substrate was observed in 11 to 14 days. The substrates were jute, cotton, alfalfa, filter paper, and varous materials derived from these. As with other cellulolytic systems, crystalline celluloses and coarse particles were resistant to attack. Gravimetric assays indicated that lignification reduced digestibility more than could be predicted from the lignin content alone, suggesting that in part the resistance of lignified fibers results from masking of the cellulose. The protective effect of lignification in jute is further supported by the fact that alfalfa stems having the same lignin content as jute were about five times as digestible as jute. Acid treatment enhanced the resistance of both jute and cotton to degradation. Alkali treatment decreased resistance to degradation of both jute and cotton, the effect on jute being particularly pronounced. Pure α-celluloses were rapidly degraded regardless of their origin. Stimulation of cellulose degradation by the hemicellulose present in the holocellulose was negligible.

A study was made of the changes in degree of polymerization (DP), water retention value (WRV), and yield when high α-sulfite pulp (α-SP) is beaten or swollen with zinc chloride or sodium hydroxide and treated with cellulase. For a sample swollen with sodium hydroxide, the decrease in DP is large, and the DP decreases easily to a value which corresponds approximately to the level of DP in acid hydrolysis. On the other hand, a sample treated with zinc chloride solution shows a small decrease, while a beaten sample indicates an intermediate DP value. It is assumed from these results that sodium hydroxide swells the amorphous region of the fiber greatly but has little effect on the crystalline region, whereas zinc chloride swells the crystalline region but its swelling effect on the amorphous region is not very great. Cellulase can be utilized for analyzing the structure of cellulose fiber.

A paper chromatographic method for determining the extent of damage by oxidizing or alkaline solutions to wool fabrics of unknown history is described. The presence of other textile fibers does not constitute an interference.

A method is described for isolating the lumen contents of the cotton fiber by digestion of the cellulose in chilled 72% sulfuric acid. Microscopical observations on the isolated "lumens" as well as the lumen in the whole fiber are reported. The isolated lumens appeared tubular in shape, and electron micrographs of thin sheets of the membrane material showed an unoriented, granular structure. The lumen residue isolated by sulfuric acid was found to be completely hydrolyzed by 1% sodium hydroxide, but only partly hydrolyzed in dilute mineral acid. Amino acid determination by paper chromatography disclosed no free amino acids in the lumen material; but in an acid- hydrolyzed sample, glutamic and aspartic acids, valine, alanine, and probably serine and arginine were found, in addition to several unidentified amino acids.

Improved methods for the measurement of spectral line intensities have been developed. Such techniques are based on the authors' modification of the partial Seidel function, referred to as B-functions. A conversion table for these is given. A scale calibrated in B-functions has been incorporated into a Hilger microphotometer enabling such values to be obtained directly without the use of conversion tables. B-values can be plotted directly on to the linear co-ordinate of semilog graph paper if the self-calibration method is used for evaluating line intensities, there is an attendant time saving and improvement in the accuracy of background extrapolation. A nomographic technique developed for use in conjunction with this scale, results in a rapid evaluation of line intensities but with some loss of precision. It is concluded that the technique will result in an improvement of some existing photometric methods.

This graphical technique utilizes only three types of artifacts from the collection to the seriated. The relationship between the three selected types is plotted on three-pole graph paper. The points on the graph are clustered along a line representing change through time; hence the archaeological materials are arranged in their correct temporal sequence. Data from Paragonah, Utah, and Pindi, New Mexico, two Southwestern sites for which the time sequence is known, are used for empirical tests of the seriational technique. In both cases there is close agreement between the results of the seriation and the time sequence revealed by field evidence. SERIATION, or the arrangement of archaeological materials in their chronological order by overlapping of similar traits in different finds, has a long history dating back to the "Sequence Dates" of Petrie (1904). In recent years, increased attention has been given to problems of seriation; two notable advances include the graphical technique developed by Ford (Ford and Willey 1949); and the statistical method proposed by Brainerd (1951) and Robinson (1951). Despite certain shortcomings, both of these methods work and both of them provide more sensitive measures of chronological difference than anything we have had heretofore. Some criticisims of the methods have been raised (Lehmer 1951; Bennyhoff 1951) and it is apparent that seriation techniques are neither a substitute for good field techniques nor for an adequate typology (Dixon 1956). Still, I am convinced from my own application of both of these methods to the field data from excavations, that the following statements are valid: 1. Both the Ford and the Brainerd-Robinson methods yield results that are consistent with the field data. In many cases the methods can be checked against stratigraphy, building superposition, and other field observations (Belous 1953; Collier 1955). If the results are not consistent with the field observations, other methods of age determination must be applied (Dixon 1956). *Presented at the 57th Annual Meeting of the American Anthropological Association, November 23, 1958, Washington, D.C. 2. Seriation methods provide a more detailed picture of temporal change than stratigraphy and field observations alone. Application of these methods can give a more objective determination of the number of cultural periods present, can indicate interruptions in the temporal sequence, and can sometimes indicate the presence of mixed or disturbed collections in the sequence. Application of seriation techniques is not mere data-juggling, but an extremely useful adjunct to ordinary methods of analysis. DESCRIPTION OF THE METHOD In beginning a seriation, the first step is selection of the trait to be seriated. This trait must have the following characteristics: (1) abundance; (2) measurable diversity (more than one type); (3) long time span in terms of the sample seriated (the feature should occur throughout the time span studied). If pottery is present this is likely to be the best feature for seriation, although this is not always true. In southern California it is seldom possible to seriate pottery collections on a statistical basis because there is not enough diversity of types. Assuming that pottery is used for the seriation, the next step is to reduce the number of pottery types to three for purposes of the analysis. The reduction to three types may be done in several ways: 1. Selecting the three most abundant types will usually work. In this case all other types are omitted from the seriation, although they may sometimes be used as a check on the results as described below. 2. In cases where a large part of the pottery sample consists of a common type (such as a plainware), occurring in about the same proportion throughout the time span of the sample, the common type may be skipped and the seriation done with the next three most common

Two similar tetrasaccharides, one neutral and one acidic, were isolated from the products released by the attack of a xylanase on the in situ reduced 4- O -methyl- D -glucurono- D -xylan from aspen ( Populus tremuloides ). Paper chromatography, gel filtration behavior, methylation followed by reduction, and mass spectrometry showed that the oligosaccharides were O -(4- O -methyl-α- D -glucopyranosyluronic acid)-(1→2)- D -xylotriose and- O -(4- O -methyl-α- D -glucopyranosyluronic acid)-(1→2)- D -xylotriose. Independent of the acidic or neutral substituent on the present xylan chain, the enzymic cleavage led preferentially to oligosaccharides substituted at the nonreducing end. The existence, in wood, of a few uronic acid substituents of the D -xylan in the esterified form was confirmed, and their linkage to lignin postulated.

The biodegradability of several packaging films was determined; the degradation of the polymeric films, polypropylene and poly(vinyl chloride), was compared to a coated paper and several coated cellophanes. The films were buried in bacterially-active soil and the extent of bacterial degradation was determined by measuring the reduction in tensile strength as a function of burial time. The results show that the polymeric films do not degrade after five weeks of soil burial while the glassine and cellophanes do degrade. Surprisingly, the cellophane films decompose at a faster rate than the coated glassine sheet.

Fire-history investigations in the Jackson Hole area of northwestern Wyoming reveal that most current stands of aspen and lodgepole pine regenerated following extensive fires between 1840 and 1890 and that widespread fires occurred in the 1600s and 1700s. White man's major effect on the fire incidence has been the successful suppression during the past 30–80 yr. Successional changes in the absence of fire include the deterioration of aspen stands, massive invasions of subalpine fir in lodgepole pine stands, great increase in conifer cover, heavy fuel buildups in lodgepole pine and Douglas fir stands, and increase in sagebrush and other shrubs. Steps are being taken, starting in 1972, to allow fire to play a more natural role in Grand Teton and Yellowstone National Parks. Teton National Forest plans experimental prescribed burning to determine whether fire can stimulate successful aspen regeneration in the presence of large numbers of wintering elk.

A new method involving trials on 40 grain and 50 grain samples has been proposed for the determination of fiber maturity using the Micronaire. Tests on 130 samples have revealed that this method is significantly correlated with fiber maturity determined by the standard caustic soda swelling technique and is as efficient as the spacer technique. Further, the theoretical basis for extending the use of Micronaire for determination of cotton fiber maturity is also discussed.

Fire largely determined the composition and structure of the presettlement vegetation of the Boundary Waters Canoe Area as well as the vegetation mosaic on the landscape and the habitat patterns for wildlife. It also influenced nutrient cycles, and energy pathways, and helped maintain the diversity, productivity, and long-term stability of the ecosystem. Thus the whole ecosystem was fire-dependent.At least some overstory elements in virtually all forest stands still date from regeneration that followed one or more fires since 1595 A.D. The average interval between significant fire years was about 4 yr in presettlement times, but shortened to 2 yr from 1868 to 1910 during settlement. However, 83% of the area burned before the beginning of suppression programs resulted from just nine fire periods: 1894, 1875, 1863–1964, 1824, 1801, 1755–1959, 1727, 1692, 1681. The average interval between these major fire years was 26 yr. Most present virgin forests date from regeneration that followed fires in these years. Significant areas were also regenerated by fires in 1903, 1910, 1936, and 1971. Most major fire years occurred during prolonged summer droughts of subcontinental extent, such as those of 1864, 1910, and 1936. Many fires were man-caused, but lightning ignitions were also common. Lightning alone is probably a sufficient source of ignitions to guarantee that older stands burned before attaining climax. Dry matter accumulations, spruce budworm outbreaks, blowdowns, and other interactions related to time since fire increase the probability that old stands will burn. Vegetation patterns on the landscape were influenced by such natural firebreaks as lakes, streams, wetlands, and moist slopes. Red and white pine are most common on islands, and to the east, northeast, or southeast of such firebreaks. Jack pine, aspen-birch, and sprout hardwood forests are most common on large uplands distant from or west of such firebreaks.A Natural Fire Rotation of about 100 yr prevailed in presettlement times, but many red and white pine stands remained largely intact for 150–350 yr, and some jack pine and aspen-birch forests probably burned at intervals of 50 yr or less. There is paleoecological evidence that fire was an ecosystem factor before European man arrived, and even before early man migrated to North America. Probably few areas ever attained the postulated fir-spruce-cedar-birch climax in postglacial times. To understand the dynamics of fire-dependent ecosystems fire must be studied as an integral part of the system. The search for stable communities that might develop without fire is futile and avoids the real challenge of understanding nature on her own terms.To restore the natural ecosystem of the Canoe Area fire should soon be reintroduced through a program of prescribed fires and monitored lightning fires. Failing this, major unnatural, perhaps unpredictable, changes in the ecosystem will occur.

Es wurde der Einflus ebener Versetzungsanordnungen auf das Eindringen dazu senkrechten Magnetflusses in supraleitende Niobeinkristalle bei 4,2°K experimentell untersucht. Die Dichte der Versetzungen ϱ wurde mittels Atzgrubchen und Elektronentransmission bestimmt. In einem einfachen Modell kann aus der Remanenz der gemessenen Hysteresekurve auf die Kraft geschlossen werden, die einen Abrikosovschen Flusfaden Versetzungen schneiden last. Diese Kraft liegt fur Versetzungsdichten von 2 · 106 bis 5 · 1010 cm−2 zwischen 4 · 10−7 und 1,4 · 10−4 dyn/cm und ist proportional √ϱ. Ferner wurden die Auswirkungen verschiedener Oberflachenbehandlungen auf die Magnetisierungskurve verfolgt und modellmasig interpretiert. Die Wechselwirkung zwischen Flusfaden und Oberflachen fuhrt zu einer Hysterese, nicht aber zu einer Remanenz. A study is made of the effect of planar arrays of dislocations on flux penetration into niobium single crystals at 4.2°K. The dislocation densities ϱ are measured by etch pits and by electron transmission. The measured hysteresis, (in particular trapped flux,) is used to calculate the interaction force between an Abrikosov flux line and the dislocations lying perpendicular to it. For ϱ between 2 × 106 and 5 × 1010 cm−2 the measured interaction force varies between 4 × 10−7 and 1.4 × 10−4 dynes/cm, and it is proportional to √ϱ. The interaction between flux lines and surfaces is studied following various surface treatments. In agreement with simple theory this interaction leads to hysteresis without trapped flux.

Cotton has been made unusually resistant to degradation by weather by first dyeing it with certain light-stable vat dyes and following this with partial acetylation. Vat dyeing alone or partial acetylation alone do not make cotton significantly more resistant to deterioration by sunlight than undyed fabrics, except for a few colors which do have a protective effect. However, when these two processes are combined, excellent re sistance to solar radiation is added to the excellent mildew- and rot-resistance of partially acetylated cotton. Data were obtained on a number of individual vat-dyed and vat-dyed and acetylated cotton materials that had been exposed to outdoor weathering. From the results of these tests, it is estimated that the combination of vat dyeing with light fast colors and acetylating may more than double the outdoor service life compared to cotton vat dyed only, or acetylated only, with somewhat better color retention when the cotton has been both dyed and acetylated.

A quantitative laboratory method for evaluating levelness of acid wool dyes is described. The procedure consists of running half of a normal yarn-dye cycle and then making additions of white yarn and dye liquor equal in amount to those in the original batch. The second half of the cycle is then run, and the yarns are removed. Reflectances of the two dyed yarns are determined on a G. E. recording spectrophotometer and a "levelness index" is calculated as the ratio of dye concentration on the yarn added at the mid-point of the cycle to that on the yarn started at the beginning of the cycle. The technical background of the test method is outlined and the results of tests on repre sentative dyes are tabulated. It is shown that the test method has sufficient flexibility to permit examinations of the effects of dyeing variables on levelness. An example is cited showing the effect of salt concentration on levelness of Alizarine Cyanine Green CG ex. (C. I. 1078). The example above is applied to plant production, and the levelness of 500-pound Hussong stock-dyed batches is evaluated by spectrophotometer reflectances, converted to dye concen tration, of stratified samples from the batches of stock. It is shown that the coefficient of dye concentration variation among the 8 samples from a plant batch is proportional to the laboratory "levelness index."

The study analyzes the causes for lea count variation on the basis of experiments in the pilot mill, detailed investiga tions at mill level, and theoretical considerations. The extent of influence of various sources of count variation is studied. A relationship between count C.V. and strength C. V. is derived.

Artificial and natural weather exposure tests were made with unfinished and with protectively finished cotton duck samples. The treating agents employed were chiefly mineral pigments, film-forming resins, and vat dyes, alone and in combinations. The finishes were ranked in order of excellence on the basis of amounts of original strength retained by individual samples in both types of exposure. The results of the natural and accelerated tests were compared and then correlated by a statistical method and by a simple computation of agreement among groups of good, intermediate, and poor performance. Although statistical interpretation of the data indicated a positive corre lation between the 2 types of tests, the relationship was not sufficiently constant to justify reliance on the accelerated techniques employed in predicting the behavior of finished cotton textiles in outdoor service conditions.

Four field studies and two growth-chamber studies were used to evaluate the compatibility of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) in suspension fertilizer on corn (Zea maysL. ‘Pioneer 321’). Crop yields and tissue analyses were used to determine effects of atrazine on fertilizer availability. Visual and pictorial comparisons determined effects of fertilizer on atrazine phytotoxicity. Fertilizer-herbicide combinations compounded 230 days or sooner before application produced no change in atrazine phytotoxicity or fertilizer availability in growth chamber studies. Preplant-incorporated treatments displayed better fertilizer availability than preemergence treatments in the field. Preemergence treatments resulted in greater atrazine phytotoxicity under drought conditions. No problems of physical compatibility were encountered with the mixtures.