Chlorite and illite are commonly associated with ubiquitous secondary K-rich feldspar in the rocks located immediately above and below the Precambrian-Paleozoic unconformity in southwestern Ontario, and elsewhere in the mid-continent of North America. This alteration assemblage is attributed to long-distance migration of hot brines driven westward by orogenic processes originating along the eastern seaboard of North America. The δD and δ18O values of chlorite and illite, plus K-Ar dates for secondary K-rich feldspar and illite, were used to determine the nature, origin, and timing of the fluids that altered Precambrian granites and their overlying rocks in southwestern Ontario. The δ18O values of the chlorite-forming fluids are best explained by initial hot brines (≥50°C) evolved mostly from seawater. Secondary K-rich feldspar formation followed shortly thereafter, as the fluids cooled and perhaps mixed with meteoric water. Regional migration of the brines was induced by Taconic orogenic events to the east. The hydrogen and oxygen isotopic compositions for the secondary illite of the early to mid-Carboniferous indicate its crystallization from local meteoric water at low temperatures (40–55°C). Infiltration of local meteoric water into the Paleozoic and uppermost altered Precambrian rocks occurred during uplift, erosion, and subaerial exposure of local arches in southern Ontario. The local basement reactivation and associated secondary illite formation in this portion of the North American hinterland was likely a distal expression of east-coast Acadian and Alleghanian orogenic activity.

The adverse report of the Academy of Sciences, published in 1784, failed to put an end to the proselytism of Mesmer's early followers, nor did it scale down their ambitions to gain scientific recognition. The allure of mystery, the taste for wonders and the call of the unknown prevailed, and throughout that century numerous clashes occurred between the scientific establishment and those demanding its recognition. Their demand was founded not so much on a theoretical construct as on people's personal experiences as actors or witnesses, which were perceived to be true simply because they were nearly always profoundly disturbing. The fact is that, despite the observations of scientists such as Faraday, anyone could put questions to an ecstatic in a state of trance, have a medium summon the dead, or communicate with the “other world” by table-turning. Insofar as it rejected the validity of the most commonly accepted “research programmes”, the challenge to the institutions that were the guarantors of received knowledge was a major one.

The influence of tartaric acid and pH on chemical composition, morphology, surface area, and porosity of short-range ordered Al precipitation products was studied. Samples were prepared (1) at pH 8.0 and at the tartaric acid/Al molar ratios (R) ranging from 0 to 0.25 and (2) at R = 0.1 and in the pH range of 4.7 to 10.0. In Al precipitation products formed at pH 8.0, the organic C content increased from 8 g/kg (R = 0.01) to 93 g/kg (R = 0.25), whereas the Al content decreased from 363 g/kg (R = 0.01) to 271 g/kg (R = 0.25). The specific surface of the materials was particularly high (>400 m2/g) when samples were prepared at R < 0.1, but drastically decreased when samples were prepared at R > 0.1 (e.g., 78.6 m2/g at R = 0.25). When the C content was relatively high (>45 g/kg), aggregation between the particles was promoted, and the specific surface, thus, decreased. Electron optical observations showed that such samples were strongly aggregated. In the materials prepared at R = 0.1, but at different initial pH values, the C content decreased from 90 g/kg (pH = 4.7) to 25 g/kg (pH = 10.0). As a consequence, the lower the initial pH, the lower was the specific surface of the Al precipitation products. Tartaric acid plays an important role in both Pertubation of crystallization of Al hydroxides and promotion of aggregation of the reaction products. The two processes counteract in influencing the specific surface and pore volume of Al hydroxides.

Heating treatments greatly affected the specific surface and porosity of Al precipitation products. The specific surface and porosity of the samples generally increased by increasing the temperature up to 400°C and then decreased. Small amounts of C still remained after heating some samples for 12 hr at 600°C.

Nontronite and microbes were detected in the surface layers of deep-sea sediments from Iheya Basin, Okinawa Trough, Japan. Nontronite, an Fe-rich smectite mineral, was embedded in acidic polysaccharides that were exuded by microbial cells and electron microscopy showed that the nontronite layers were apparently oriented in the polysaccharide materials. We propose that the formation of nontronite was induced by the accumulation of Si and Fe ions from the ambient seawater and that extracellular polymeric substances (EPS) served as a template for layer-silicate synthesis. Experimental evidence for this hypothesis was obtained by mixing a solution of polysaccharides (dextrin and pectin) with ferrosiliceous groundwater. After stirring the mixture in a sealed vessel for two days, and centrifuging, Fe-rich layer silicates were identified within the precipitate of both the dextrin and pectin aggregates, whereas rod-shaped or spheroidal Si-bearing iron hydroxides were found in the external solution. Microbial polysaccharides would appear to have affected layer-silicate formation.

It is a cliché to say that the poor countries are becoming poorer and poorer while the rich ones become richer and richer. Previous experience shows that it is an illusion to count on mankind's sense of solidarity to resolve this dilemma. And yet we are dealing with a problem that is real, vast, and urgent. The developed world uses its knowledge and technological opportunities to sustain and increase its wealth, and in the race for scientific and technical advances the “Third World” faces the serious risk of never being able to catch up. Seen in this light, it is understandable that some people have allowed themselves to be seduced by the notion that in order to achieve a better equilibrium in the world all that is required is to return to a “more natural” life in which science and technology no longer play a dominant role. It seems to us, however, that this vision is unrealistic because it does not take account of the fact that human nature pushes us toward competition and that the kind of solidarity that would compensate for, and mitigate, this competitiveness works successfully only on a small scale (e.g., within the family or clan) or in very special circumstances (e.g., wars, natural catastrophes).

An indirect Fourier transformation applied to small-angle X-ray scattering data has been used to determine the thickness and surface properties of two common clay minerals. For an illite system, the particle density distribution function (PDDF) generated by the analysis gave a correct description of particle geometry, and the calculated electron density profile was in accordance with the theoretical electron density distribution for this mineral. This approach provides the opportunity to determine the thickness of fundamental particles of illite while avoiding the difficulties encountered in other methods. Both the PDDF and the electron density profile accurately predict the thickness of Na-montmorillonite layers, and the results suggest that an electron inhomogeneity exists at the interface of this mineral.

Immortality is one of the themes of this issue, and thus I would like to talk about two Graeco-Egyptian ceremonies promising the overthrow of death, one of them actually bearing the title apathanatismos, to render immortal. The detailed texts of both ceremonies can be found among the Greek papyri. The standard edition is Karl Preisendanz’ Papyri Magicae Graecae, and they are thus clearly regarded as magical.

It has never been easy to understand what intellectuals are, whether they still exist, or whether they are vanishing into a huge ‘cultural middle class’ where high culture and mass culture meld into one another. With particular reference to Italy, Alfonso Berardinelli looks back at the undisputed intellectuals of the past, suggesting that they were their own critics and most determined detractors at the same time, yet full of confidence in their capacity to lay down laws for organizing and developing society. In contrast, today's intellectuals seem to embrace anonymity, and in a context defined as postmodern, they have given up being an elite that judges, whose duty is not only to produce knowledge but also to propose values and social models.

This is the obituary of Alice Thorner, an American scholar-specialist of the social history of India, who spent most of her career in France. She first worked with her husband, Daniel Thorner (1915-74), who briefly taught in Pennsylvania before being expelled from the USA by McCarthy. They lived in India from 1952 to 1960, where they worked on Land and Labor. They settled in Paris in 1960 when Daniel was appointed to the EPHE 6th section (now EHESS) where he taught the economic (especially agrarian) history of India up to his death, and became a member of the Centre of Indian Studies created by Louis Dumont. Alice, who travelled to India every year, continued her own research on gender studies, on working-class women, and on the town of Bombay. This paper, written by a younger colleague and friend, uses personal anecdotes to sketch Alice's career; it also lists her principal publications.

57Fe Mössbauer spectra of two synthetic samples of ferrihydrite, recorded at 4.2 K in applied fields of up to 9 T, have been analysed by a mean-field model. The samples exhibit two and six X-ray diffraction peaks. It is shown that only one ferric ion site is present in the mineral, and that in this site the ions are octahedrally coordinated. The spectra show the presence of different magnetic states: ferrimagnetism in two-line ferrihydrite, and antiferromagnetism in six-line ferrihydrite. The ferrimagnetism in two-line ferrihydrite is analysed in terms of random fluctuations arising from the small numbers of ferric ions per particle, and it is shown that the different magnetic states may arise purely as a result of these fluctuations.

Recent historical work on changing perceptions of the human body has been influenced by Michel Foucault's contention that the self of western individualism was created by new regimes of disciplining the body. A different approach is taken here, one that focuses on how individual bodies came to be viewed as separate and inviolable, that is, as autonomous. The separateness and inviolability of bodies can be traced in the histories of bodily practices as different as portraiture and legal torture. After 1750, regular public exhibitions, themselves a new feature of the social landscape, showed increasing numbers of portraits in London and Paris. The proliferation of individual likenesses encouraged the view that each person was an individual, that is, single, separate, distinctive and original. At the same time, the tide turned against judicially sanctioned torture and cruel punishment. Long-held notions of sacrificial punishment and truth through pain withered under the pressure of new experiences of the body that in turn facilitated the emergence of new conceptions of rights of individuals.

Fellini attempted to be painter, poet and musician in making Satyricon, a ‘free adaptation of Petronius's classic’, as the subtitle indicates. The film can be divided into three parts. The central section of the triptych is devoted to a hermaphrodite character. This figure, borrowed from Ovid, is the incandescent heart of the film, in which very many types of the dual and ambiguity are required to embody all the varieties of love and death. Hermaphroditus sums up the poetic, plastic and philosophical intentions carried by these figures. He also draws the shadow of their strange silhouette towards a proto-Christian horizon, which the film's three-part construction sets out to reveal.

Authigenic chlorites and illites coexisting in clastic reservoir sandstones have been studied by energy dispersive X-ray spectroscopy (EDS) in the transmission electron microscope (TEM). All 16 samples studied are drill or sidewall cores from sandstones of relatively uniform age situated offshore Norway with burial depths ranging between 2400 m and 5000 m and representing temperatures between 90°C and 180°C. Chlorites and illites with authigenic equilibrium type texture and morphology were analyzed by EDS. Tetrahedral Al and octahedral Fe+Mg in chlorite increases with burial at the expense of Si and vacant octahedral positions in the chlorite structure. Illites show a clear increase in K. These factors indicate that a continuous chemical modification of these minerals takes place in the diagenetic interval studied through continuous dissolution and precipitation reactions.

Laboratory-hydrolyzed and commercial OH-Al solutions were characterized using kinetics of Al-ferron color development, kinetics of structural OH neutralization with H+, 27Al NMR spectroscopy, and sulfate precipitation. The results showed that the Al13 complexes having the Keggin structure were dominant only in fresh, laboratory-hydrolyzed OH-Al solutions of OH/Al molar ratio = 1.8 and above. These species gradually converted to other polynuclear forms that reacted with ferron slowly, were not detectable by 27Al NMR spectroscopy, and yielded different basic Al sulfates following Na2SO4 addition. These more stable complexes can best be interpreted to have a Al(OH)3-fragment structure. In the three commercial aluminum chlorohydrate (ACH) solutions studied, Al13 complexes accounted for a small portion of the total Al present. More than 80% of the Al was present as species that were not detectable with NMR spectroscopy and resembled the slow-reacting complexes in aged, laboratory-hydrolyzed OH-Al solutions. Small portions of the slow-reacting complexes appeared to be submicron particulates that acted as nuclei for gibbsite formation or aggregates of Al13 complexes that dispersed to Al13 upon dilution. Polyaluminum chloride (PA) solution resembled the moderately aged laboratory-hydrolyzed OH-Al solutions.

The chemical composition of hydrothermal chlorite was determined by means of more than 200 electron microprobe analyses (EMPA) in almost all of the 70 chlorite-bearing samples taken from 5 boreholes in a study of the active geothermal system of Los Humeros, Mexico. Bulk rock composition of 6 different volcanic lithologies, as well as available in situ temperatures and chemical compositions of chlorite, were analyzed by principal component analysis (PCA) in order to test the dependence of chlorite composition on physicochemical parameters. The results show that chlorite minerals display a wide range of chemical compositions in this hydrothermal system that reflect the particular conditions of crystallization episodes: The Na + K + 2Ca values are low (from 0 to 0.6) and they show no correlation patterns with octahedral vacancies (¤) in chlorite, indicating that compositional variations are not due to the intergrowth of smectite and/or illite. The octahedral occupancy of most chlorite is relatively high (from 11.3 to 11.95), especially that from a high-temperature range, as is the case of metamorphic chlorite. The octahedral occupancy seems not to be related to other chemical variables of chlorite from the G3, G4 and G5 lithologic units, suggesting that the lack of complete occupancy is not dependent on “contamination” by other silicates (such as quartz). Cationic substitution in tetrahedral sites in chlorite is small and via a Tschermak exchange (MgVISiIV ↔ AlVIAlIV). To preserve a charge balance in the structure, an octahedral substitution of R2+ by Al3+ accompanies the Tschermak exchange. The chemical composition of hydrothermal chlorite is very similar to that of metamorphic chlorite but slightly different from equivalent phases found in diagenetic environments. In hydrothermal chlorite the SiVI, AlVI and ¤ decrease, whereas the AlIV and Fe2+ contents increase with the degree of alteration and depth, the same way as in chlorite formed in diagenetic high-temperature environments. The ferrous iron content, in general, increases with depth and temperature; however, whole-rock chemistry affects the iron distribution in chlorite of Los Humeros. Changes in the oxygen fugacity of fluids at depth also affect the iron distribution in chlorite, XFe = Fe/(Fe + Mg), which ranges from 0.30 to 0.38 in oxidizing conditions and from 0.39 to 0.60 in reducing conditions. Finally, the chemical composition of chlorite in Los Humeros appears to change with temperature, but the correlations of ¤ and AlIV with temperature are more variable than in another nearby active geothermal system located in Los Azufres, Mexico. This implies that geothermometers based on chlorite composition and empirically calibrated in some geothermal systems cannot be generalized and it is necessary to consider other physicochemical variables.

The twentieth century in Africa, more than elsewhere in the world, has been an era of startling and unprecedented changes. These changes have been most dramatic with respect to the sociopolitical organization of the continent. While at the beginning of the century, most of Africa, particularly sub-Saharan Africa, had hardly emerged from prefeudal or feudal social formations, the advent of European colonialists, whose avarice for conquest and colonial territories was fueled by the blossoming technological capabilities of the Industrial Revolution and the expansionist market demand of a new and burgeoning capitalist economy in Europe, transformed the face of Africa forever.

To obtain Cu-kaolinites with a controlled range of chemical compositions, syntheses were performed by hydrothermally ageing gels with kaolinite stoichiometric compositions. Gels were prepared with sodium metasilicate and nitrates of octahedral cations. Temperature of synthesis was 250°C with a corresponding equilibrium water pressure of 38 bars.

Three samples with copper contents ranging from 0.1 to 7% and another one with the chemical composition of the Cu end-member were synthesized. While this fourth sample led to tenorite after the hydrothermal treatment, the three others crystallized well into kaolinite.

Up to almost 1% CuO was measured by TEM in some isolated ‘clean’ and hexagonal kaolinite particles. EPR and XPS spectroscopies were consistent with an octahedral position of Cu2+. In IR spectra, vAl-OH-Cu absorption bands were not observed, but vAl2OH bands appeared more and more blurred when Cu content of samples increased. Weak bands situated at 868 cm−1 and 840 cm−1 are tentatively attributed to δAlCuOH. By differential thermal analysis, a downward shift of 20°C in temperature of the endothermic peak from the less Cu-rich sample to the most Cu-rich one, argued for the existence of some Al-OH-Cu bonds, whose binding energies are presumed to be less than the Al-OH-Al ones.

In view of these results, Cu2+ appears incorporated in the octahedral sheet of kaolinite. Moreover, this incorporation is made without major perturbation of the kaolinite structure.