A Solution containing fluoride (0.4 n NH4F, 0.1 n HCl, n NH4Cl), permits the concentration of dioctahedral mica and dioctahedral vermiculite in mixed clay systems. Allophane, halloysite, kaolinite, and in particular, Mg-rich montmorillonite, biotite, and vermiculite of clay size, are destroyed in 24–48 hr at room temperature. A salt-free, NH4-saturated sample, weighing 80 mg, is shaken in 80 ml of the fluoride solution. The residue is washed with water and X-ray diffraction patterns made.

The method has use in characterizing some of the 2:1 layer silicates in clays. Anatase, if present, is also concentrated and is more positively identified by X-ray diffraction.

This paper attempts to show that the catalytic properties of zeolitic material may play a role in the synthesis of simple biological molecules from gases commonly found in extraterrestrial atmospheres. Linde X and Y molecular sieves cation-exchanged by Ca2+ and Fe3+ have been heated in the presence of carbon monoxide and ammonia. Amino-acids and u.v. absorbing substances identified by paper chromatography have been extracted from the solid. HCN, the basic molecule involved in the synthesis of those substances has been detected in the gas phase. It is proposed, on the basis of i.r. results, that the amino-acids are hydrolysis products of an undefined polymer.

The proposed method is a modification of one by Alexiades and Jackson (1965). Calcium exchange capacity (CaEC) and potassium exchange capacity (KEC) are determined, after removal of organic matter and free iron oxides, by saturating the exchange complex with centrifuge washings of pH 7 acetate solutions of Ca or K, respectively. Excess salt in solutions remaining in contact with the soil after saturation is determined by measuring the weight and concentration of the excess solution. The exchangeable cations and excess salt are then replaced by centrifuge washings with 1 N acetate solutions of Mg (for CaEC) or NH4 (for KEC), after overnight 110°C oven-drying to enhance K fixation for KEC. The replaced cations are determined and CaEC and KEC values are calculated. Per cent ‘vermiculite’ is based on the difference between CaEC and KEC (expressed in m-equiv/100 g) and an assumed ‘vermiculite’ in-terlayer exchange capacity of 154 m-equiv/100 g; percentage Vr = (CaEC-KEC/154) × 100. The ‘vermiculite’ interlayer fraction (VIF) of the CaEC may also be calculated; VIF= CaEC-KEC/CaEC. The measured ‘vermiculite’ is shown in quotation marks since the method is open to criticism regarding exactly what is being measured, the assumptions made, etc. and to emphasize that the determination procedure is an operational one for the characterization of cation exchange complexes.

Removal of free iron oxides increased both CaEC and KEC values of several soils but percentage Vr was little affected. The amount of K fixation was affected by the drying treatment employed after K saturation (none vs air-drying vs oven-drying). Thoroughly crushing Montana and African vermiculites dramatically increased their CEC and measured ‘vermiculite’ values, but had little effect with two samples of saprolite from chloritic metabasalt.

Recent work in social epistemology has drawn attention to various problematic social epistemic phenomena that are common within online networks. Nguyen (2020) argues that it is important to distinguish epistemic bubbles from echo chambers. An epistemic bubble is an information structure that merely lacks information or sources that would be relevant or important to the user. An echo chamber is a structure in which dissenting opinions are, not necessarily absent, but actively undermined, for example by instilling attitudes of distrust towards their adherents. Because of this, echo chambers are thought to be especially difficult to escape. In contrast, according to Nguyen, it is relatively easy to shatter an epistemic bubble: one simply introduces the missing information. In this paper, I argue that it is more difficult to shatter an epistemic bubble than has been recognised in the literature. The reason for this is the relationship between epistemic bubbles and interpretative resources. Despite their epistemic drawbacks, it is comparatively easy to gain knowledge from sources inside one's epistemic bubble because agents within a bubble share common ground. In contrast, it can be very difficult to gain knowledge from sources outside of one's bubble because interlocutors on the outside are less likely to have the shared context needed to facilitate communicative success. I argue that this problem suggests a different way to understand the nature of epistemic bubbles and our prospects for escaping them.

Montmorillonite, kaolinite, illite, and chlorite were found to adsorb bitumen and its pentane-soluble and pentane-insoluble fractions. The formation of clay-bitumen complexes is influenced by the nature of the exchangeable cation on the clay and by the solvent carrier which stabilizes the bituminous compounds. Ca-clays adsorb organic compounds more strongly than sodium forms except in the presence of nitrobenzene. Solvents of high dielectric constant, such as nitrobenzene, promote ionization so that the ion-exchange mechanism of adsorption is favored, whereas solvents of lower dielectric constant, such as chloroform, tend to solvate rather than to dissociate bitumens. The behavior of the montmorillonite-bi- tumen complex in variable relative humidity indicates that organic molecules adsorb primarily on external surfaces and cause the clay to become less hydrophilic than prior to treatment. Clay-organic complexes are sufficiently stable to resist powerful organic solvents. The clay-organic complex separated from the Athabasca oil sand behaves similarly during chemical treatment to complexes formed between bitumen and the four reference clay minerals.

The hydroxyl orientations in 31 dioctahedral and trioctahedral 2:1 phyllosilicate structures have been determined by electrostatic energy calculations. These structures included micas, brittle micas, and other related minerals exhibiting ordered as well as disordered cation distributions. The dioctahedral micas and brittle micas were examined with and without the interlayer cation. A range of orientations from 1.3° to 183.3° (the angle ρ between the O-H and (001) measured with respect to the M1 site) were found. The orientations for the dioctahedral structures represent a continuum of values whereas the trioctahedral species exhibit two possible orientations separated by an energy barrier. One orientation is near 90° the other is near 180°. The latter orientation results from a concentration of charge on the interlayer (IC) and tetrahedral (T) sites at the expense of the octahedral (M) sites. A multiple regression analysis of all 31 structures, using as predictors the a and b cell parameters, d001, and the charges for T, IC, M1, and M2 sites, was performed. This analysis indicated that the important factors are the charges for IC, T, and M2 sites. When treated as a separate group, one finds the same factors for the dioctahedral structures. The trioctahedral orientations are determined by the charge on the M2 site and the amount of tetrahedral rotation. Using these two predictor equations, the value of ρ can be estimated with a standard deviation of 4.7° and 2.9° for the dioctahedral and trioctahedral cases, respectively.

A vermiculite (Libby, Montana) sample obtained from the Zonolite company contained mostly coarse-grained separates with only 8–7 per cent clay. The 2–50 μm fraction was used for particle-size reduction studies by wet and dry grinding, and size-fractionated into < 2, 2–5, 5–20 and 20–50 μ sizes. About 18 per cent of the sample was attrited to clay after 64 hr of wet grinding, but as much as 59 per cent of the sample was attrited to clay after only 10 min of dry grinding. There was no evidence of damage to the crystal structure of derived clays or silts except for the 20–50 μm fraction from dry grinding.

The observed CEC values of all the fractions decreased as grinding progressed, except for the 2–5 μm fraction from wet grinding where the CEC increased. The decrease in CEC was attributed to an accumulation of biotite, either as a discrete mineral and/or a mixed-layer assemblage of biotite and vermiculite attrited to the clay fraction. In contrast, the fraction showing an increase in CEC was due to an increased concentration of higher charge-density (CEC) vermiculite. Biotite-free CEC data for vermiculite suggested that, in general, the coarser vermiculite separates had a higher CEC than the finer ones.

The susceptibility of minerals in the Libby vermiculite to cleavage by grinding was: vermiculite > hydrobiotite > biotite.

The addition of a 10% talc internal standard to North Pacific sediments allows the relative abundances of clay minerals to be determined both accurately and precisely by X-ray powder diffractometry. Linear programming can be used to generate factors for converting talc-normalized peak areas to weight percentages; hence, absolute clay-mineral abundances can be estimated. This procedure minimizes residuals (nondiffracting or poorly crystalline components), but its accuracy is untested. Even this procedure results in an average residual of almost 30% for North Pacific sediments; other peak-area to weight conversion schemes generate even larger values.

In general, there is no correlation between clay-mineral abundances estimated from talc-normalized peak areas and abundances derived from the assumption that the sum of smectite, illite, kaolinite, and chlorite is 100%. This accounts for the past difficulties in relating bulk-sediment chemistry to clay mineralogy.

Nitrogen adsorption at 78°K and carbon dioxide sorption at 195°K on homoionic lithium, sodium, caesium, calcium, lanthanum and hexane diammonium saturated montmorillonites have been examined by means of V-n plots. In the case of carbon dioxide, sorption on the lithium saturated clay was used as a standard for comparison of the other samples.

The nitrogen plots indicate that most of the surface area lies in super-micropores of approximately 10 Å equivalent plate separation. Variations between cations are attributed to differences in the structure of the porous matrix formed on drying rather than differences in the degree of entry into quasi-crystalline regions. While the initial sorption of carbon dioxide clearly is influenced by the solvation properties of the cations, the subsequent reversibility of the isotherms and linearity of the V-n plots indicates that for all but the largest cations the same sorption process is occurring on surfaces external to the quasi-crystalline regions

Aluminum-substituted hematites (Fe2−xAlxO3) were synthesized from Fe-Al coprecipitates at pH 5.5, 7.0, and in 10−1, 10−2, and 10−2 M KOH at 70°C. As little as 1 mole % Al suppressed goethite completely at pH 7 whereas in KOH higher Al concentrations were necessary. Al substitution as determined chemically and by XRD line shift was related to Al addition up to a maximum of 16–17 mole %. The relationship between the crystallographic a0 parameter and Al substitution deviated from the Vegard rule. At low substitution crystallinity of the hematites was improved whereas higher substitution impeded crystal growth in the crystallographic z-direction as indicated by differential XRD line broadening. At still higher Al addition crystal growth was strongly retarded. The initial Al-Fe coprecipitate behaved differently from a mechanical mixture of the respective “hydroxides” and was, therefore, considered an aluminous ferrihydrite.

Many online messages now contain emoji – these small images have quickly become an important means of communicating. Yet they have not yet been taken seriously in philosophy of language. In this exploratory paper, I attempt to remedy this neglect by analysing the communicative functions of emoji. I argue that emoji have at least three communicative functions. Firstly, they can serve a replicative function, in that they can play the same role as words and punctuation, thereby replicating the function of existing written communicative devices. Secondly, they can serve a compensatory function, in the sense that they can be used to make up for features of face-to-face conversation which are lost in written online conversation. Thirdly, they can serve supplementary functions, in that we can perform new communicative acts with emoji which we could not previously perform either in written or face-to-face communication.

Trommeslåtter (drum tunes) have played a vital role in Norwegian traditional music for several hundred years. This article examines the development and performance of drum tunes in Norway, with a special focus on the work of Johannes Sundvor in transcribing drum music. We present several examples and analyse tunes from Sundvor’s collection. We also demonstrate how this Norwegian drum tradition is related to a tradition of European military drumming. The article concludes with a discussion of aspects of interpretation and an outline of the status of drum tunes today.