In his Trattato di Pittura, written in 1435, Leon Battista Alberti recalls Zeuxis, who, judging his own paintings invaluable, refused to put a price on them. The nobility of art and the artist's interests are thus defended in a work which expressed above all the tendencies of a new generation. But it was also the first manifesto in a propaganda campaign whose fruits were to be fully realized a century later. The artist would finally come to be respected, paid for his pains on an equal basis with the man of letters (until he surpassed the latter), be renowned and assured of meriting his fame. Michelangelo rejoiced in the hardness of marble and bronze because these materials would assure the survival of his works over a long period. When Vasari sent him a copy of his Vite, he thanked him with a sonnet, in which he congratulates Vasari for his work on behalf of artists —and not only contemporary artists, since he also refers to those who, having lived in less fortunate times, had fallen into, or risked falling into, oblivion: Or le memorie altrui già spente, accese…

The accurate optical observation of alteration fringes developing in phlogopite flakes, shows that the morphology of the fringes is specific for some cations, such as Na, Mg and Ca, replacing K.

A careful chemical study of the exchange kinetics of interlayer K shows that, beside the classical effect of blocking the exchange reaction with cations such as K, Rb, Cs, NH4, it is possible to induce an increase of the rate of K exchange when adding to a concentrated solution of one cation, a very small amount of other cation such as Na or H. The effects of mixtures such as Ca-Na and Ca-H are reported here in detail. Attention is drawn to the decisive part played by the impurities which may be contained in the reagents used.

It is a strange and puzzling fact that philosophers have acted almost as though man were not sexual.

It's as though sex had no significance for human thought, or as though it made no difference that the thinker was also a sexual creature.

This philosophical blind spot has been remarked from time to time by one solitary observer or other. In the last century the German sociologist Georg Simmel noticed that the discussions in Plato's Phaedrus and the Symposium and “the very one-sided reflections of Schopenhauer,” apart from occasional individual comments, “are all that the great thinkers have contributed to this problem.” As Erwin Reisner sees it, philosophy has paid strikingly little attention to this phenomenon so absorbing to the poets. “Indeed, one can almost say, it has industriously ignored and skirted the subject, exactly so, as if it had to fear that it might be corrupted by the notion...”

The concept of revolution in Marxian theory telescopes an entire historical period: the final stage of capitalism; the transitional period of proletarian dictatorship, and the initial stage of socialism. It is in a strict sense a historical concept, projecting actual tendencies in the society; and it is a dialectical concept, projecting the counter-tendencies within the respective historical period, in as much as they are inherent in this period. These tendencies and counter-tendencies are manifestations of which Marxian theory and practice themselves are essential elements. Marxian theory itself is a power in the historical struggle, and to the degree to which its concepts, “translated” into practice, become forces of resistance, change and reconstruction; they are subject to the vicissitudes of this struggle, which they reflect and comprehend, but do not dominate. “Re-examination” is therefore an element of the concept of revolution, part of its internal development.

The i.r. spectra (4000-1200 cm-1) are obtained for several cation-substituted-montmonl-lonite-lysine complexes that were prepared at their natural pH’s. Analyses of the spectra of copper-, cobalt-, nickel- and zinc-montmorillonite films indicate that bidentate chelate complexes which contain protonated ∈-amino-groups are present in the interlamellar spaces. Investigation of the spectra of the hydrogen-, calcium- and natural-montmorillonite films indicates that the dominant adsorbed species for these complexes is a lysine cation in which both the α- and the ɛ-amino-groups are protonated while the carboxyl group is ionized.

When a mineral of the montmorillonite group, saturated with Na cations, is placed in a dilute solution of hydrochloric acid, and maintained at 200°C, it should alter and produce the corresponding mineral of the kaolinite group, according to the following reaction: triphormic clay + H+ ⇌ diphormic clay + SiO2 + Na+. The formation of the diphormic clay should depend only on the value of the [Na+]/[H+] ratio, for the various temperatures used in the process. In a number of experiments, a few minerals of various types were subjected to this alteration process, carried out under a wide variety of conditions; namely, duration of the alteration treatment, clay and acid concentrations and value of the [Na+]/[H+] ratio. Formation of kaolinite, was not found but instead either an amorphous gel, or a well-crystallized boehmite, or else no dissolution at all of the initial mineral. We have already shown that a feldspar, when subjected to an alteration under similar conditions, never produces kaolinite, but forms a poorly crystallized boehmite instead. This intermediate product is the only one able to fix silica in its numerous active sites, and thus produce kaolinite. In this investigation we sought to induce a formation of poorly crystallized boehmite, from montmorillonites, with a view to a subsequent growth of kaolinite. This was achieved by inserting layers of aluminum hydroxy-polymer between the layers of a montmorillonite, followed by an alteration conducted under the same conditions as previously. At the end of a 17 hr treatment, a number of fibers of poorly crystallized boehmite (pseudo-boehmite b) appeared. At the end of a 15 days period, large amounts of kaolinite were formed, and kaolinite alone remained at the end of one month. These experiments substantiate the need of some ‘storage’ of the aluminum in an intermediate poorly crystallized mineral. This is an essential preliminary condition to any formation of clay. This clay can be formed only when the silica-monomer can be fixed on active sites of the intermediate product.

The internal surface area of Na-Wyoming bentonite was determined for linearly swelling pastes, using a physically based equation which describes such swelling. Information required is simply the linear relationship between interplatelet spacing, determined by X-ray powder diffraction, vs total water content determined gravimetrically. However, before the three-unknown parameter equation can be so applied, that portion of external-pore water, which normally increases linearly commensurately as interstitial water increases, must be decreased to zero. This was accomplished by adding dilute quantities of NaCl salt to the clay-paste system to decrease the attractive forces between positive-edge and negative-face sites, and stirring vigorously to further destroy the card-house structure and align the clay platelets.

At the centre of Chinese affairs lies a profound paradox. China is governed, with unquestioned authority, by the most dogmatic Marxians in the world—Russian communists, to them, are weak-kneed backsliders. The central principle of Marxian doctrine, to which they adhere with religious intensity of conviction, is the Materialist Conception of History—the doctrine that changes in the methods of production, and in the relationships between economic classes, peasants, wage earners, and capitalists, determine the whole course of politics, culture, religion, everything else in human affairs.

But in their actions the rulers of China have shown themselves fanatically concerned to demonstrate the exact opposite, namely the belief that political decision and agitation, backed by sufficient force, will enable them to over-ride all the facts of economics.

No serious argument proves that mythology is only a by-product or a residue of history. On the contrary, a certain number of analyses and theoretical reflections on the myth suggest that different levels of meaning, covering the whole body of mythology, demonstrate a great autonomy and that if the hunt, for example, introduces a series of myths, in a society as fundamentally agricultural as Greece in the first millenium, it is not a distant echo but rather is faithful to the social means of production of a horde of hunters who had crossed the clearings of History some millenia before, but in a less diffuse manner because the cynegetic activity constitutes an excellent operative in the scheme of the myth. For a series of reasons: the hunt, a fundamentally masculine activity where the confrontation with wild animals results in bloodshed in order to procure a meat complement, contrasts with the cultivation of the land but is closely linked with warfare. If this is completely the privilege of the male, because it is a work of death, the production of cultivated foods, on the contrary, takes place on the level of gestation and reproduction, even if working the land in Greece is assumed by men.

A specimen montmorillonite (Arizona bentonite) was treated with hydroxy-aluminum solutions of various basicity. The cation exchange sites of this clay were found not to be homogeneous in their strength of retaining hydroxy-aluminum polymers; this strength varied from very weak, with which the Al polymers were only loosely held, to very strong, with which stable interlayer Al-clay complexes were formed. When a large amount of clay was treated with a small amount of solution, the polymers were held only in positions of strong affinity; the polymers were difficult to extract with neutral salt solutions and did not change to crystalline Al(OH)3 during prolonged aging. When a small amount of clay was treated with a large amount of solution, the exchange sites were completely occupied by polymers; a portion of these polymers was easily extractable with neutral salt solutions and, during aging, changed to Al(OH)3. This contrast is significant in any attempt to compare results obtained under different experimental conditions and to correlate laboratory experimentation with the occurrence of gibbsite and interlayer Al-clay complexes in nature.

The effects of bending on diffraction profiles and intensities have been directly evaluated. It has been shown that:

1. (1) bending may cause large reductions in intensities or even the total loss of them

2. (2) due to bending, the profile of the reflection may become asymmetrical and it may display two or more maxima

3. (3) bending effects vary with the class of reflections and they become larger with the increasing order of diffraction, and

4. (4) the interference function for a bent lattice must be evaluated for each set of lattice parameters, whereas the interference function for an undeformed lattice can be made invariant with respect to lattice parameters.

Corrensite or ‘corrensite-like’ minerals occur in dike-intruded shales and siltstones of the Montana Group and Colorado Group (Early Cretaceous) in Western Montana. The < 1 μm size fraction of one specimen of this “corrensite-like” material has been studied in detail. X-ray diffraction data and chemical analysis indicate that this specimen is a regular or nearly regular interstratification of chlorite and dioctahedral smectite. Also described are other samples, which contain corrensite and additional phases. These samples were taken at several localities where basic dikes have intruded these shales and siltstones.

Scanning electron microscopic (SEM) examination of the quartz isolated from chert of Transvaal and Swaziland, of 2000 and 3400 million year (MY) ages, respectively, in southern Africa revealed marked differences in quartz morphology. Well-defined individual euhedral quartz crystals, with polyhedral triple-point faces, were clearly evident on freshly fractured Transvaal chert surfaces as well as with the quartz isolates from the chert. The morphology and coarseness suggest crystal growth with little, if any, metamorphism; however, the δ18O values of 23.8–24.1‰ suggest crystallization temperatures of perhaps 40–45°C. In contrast, fracture surfaces of the older, strongly metamorphosed Swaziland cherts revealed a high degree of grain intergrowth which inhibited fracture between quartz grains. Quartz isolates from these showed strongly interlocked quartz crystal clusters and elongated chips of quartz with poorly defined irregular faces. Intercalation of mineral veins in the cherts on a mm scale and the intergrown character of the quartz grain boundaries provide evidence that the latter cherts have been strongly metamorphosed and recrystallized, in keeping with 14.6–15.1‰ δ18O values, corresponding to 80°C fractionation with water. The SEM micrographs of the fine quartz (1–10 µm) isolated from the Otavi dolomite formation of the 700-MY Damara System and from the 2000-MY Transvaal Dolomite Series revealed well-defined subhedral and euhedral quartz crystals of small size which, together with the 26.9–27.8‰ and 23.8‰ δ18O values, respectively, indicate that these dolomites have been affected little, if any, by post-depositional metamorphism; their crystallization temperatures fall in the range of 25–30 and 40–45°C, respectively.

The 1–5 μ size fractions of different ground muscovites were treated for a 30-day period for K+ removal with a pH 7.5 solution containing sodium tetraphenylboron. The initial K+ contents ranged from 211 to 219 me/100 g. After the extraction period, the final K contents ranged from 21 to 37 me/100 g. The apparent structural charge on the expanded material decreased to values ranging from 156 to 184 me/100 g, which are within the charge range for natural vermiculites. The b-dimensions of these laboratory-produced vermiculites were found to vary with the exchange ion and with the hydration state of the ion. For hydrated samples, saturation with Cs+, Li+, and Mg2+ ions increased the observed b-dimension in comparison to that of the corresponding parent mica, whereas saturation with Sr2+ and La3+ ions had little effect on b. After dehydration at 350°C, only Cs+-saturated samples had a b-dimension greater than that of the parent mica. The observed b-dimension for the dehydrated samples was found to be a direct function of the crystal radius of the interlayer ion. Apparently, as the ion dehydrates, the surface oxygen triads rotate until some of the oxygens “lock” onto the ion, limiting the minimum b-dimension. Before dehydration, however, the water of hydration in the interlayer region is evidently held with sufficient energy to limit rotations of the oxygen triads that give rise to a decrease in b. When Li+ and Mg2+ ions occupy the interlayer region, their water network apparently even produces a slight increase in the observed b-dimension.

The electrical conductivity of saturated kaolinite clay-water-electrolyte systems of different particle size distributions and of illite and montmorillonite clays were determined over the frequency range of 50–108 c/s. The conductivity increases as the frequency increases, and the experimental values show two distinct dispersions, one in the low frequency range and the other in the high frequency range. The frequency range over which the first dispersion occurs is experimentally shown to be dependent on particle size. The average particle size is uniquely related to the frequency at which half the dispersion occurs. The magnitude of conductivity variation, the high frequency conductivity and the streaming potential values are related to the microscopic permeability coefficient. This microscopic permeability coefficient, evaluated from a knowledge of the above electrical properties, is shown to be uniquely related to the Darcy permeability coefficient at various consolidation states of the kaolinite clays. Similar unique relationships have been observed in illitic clays.