La formation des Nuages Altocumulus Translucidus

Résumé Dans cette étude l'explication de la formation des nuages Ac tra part de la supposition que l'air dans ce type de nuages est plus froid que l'air environnant, ce qui provoque certains courants convectifs dans la région du nuage. Ces courants ressemblent à ceux qui sont supposés par la théorie thermoconvective actuelle. D'après notre avis se trouvent des courants descendants audessous des petits nuages qui composent l'Ac tra, et les petits nuages qui forment l'Ac tra sont des corps séparés dont la température est moindre que la température de l'air environnant: c'est pour cela qu'ils tombent. Au contraire, d'après la théorie thermoconvective actuelle, l'air audessous de petits nuages monte et dans la distribution de la température des discontinuités n'existent pas.

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Summary In this paper the explanation of the formation of clouds Ac tra is based on the assumption that the air in the cloud is colder than the surrounding air, causing convective currents in the region of the cloud. These currents are not unlike those assumed by the existing thermoconvective theory. According to the author's view there are descending currents under the cloudlets of which the Ac tra is made, and these cloudlets are separate bodies at a lower temperature than that of the surrounding air, so that the cloudlets fall. On the contrary, according to the existing thermoconvective theory, the air under the cloudlets rises and there are no discontinuities in the distribution of the temperature.

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Rapport présenté le 26 Avril 1962 à la Xème Assemblée Générale de laSocietà Italiana di Geofisica e Meteorologia (26–28 Avril 1962)     

Correlation of atmospheric occurences over the United States with some physical and chemical parameters. Part III: Frequencies of precipitation

Summary Correlation between some physical and chemical variables, measured at 28 stations of the United States Weather Bureau Network, and seasonal and annual frequencies of precipitation, has been attempted with the aim of gaining insight into the bearing of such variables, on occurrence of precipitation. — Concurrent trends of frequencies with local temperature functions, altitude parameters, precipitable water vapour increments, and some chemical species have been found.Contribution of the «Centro Nucleazione Aerosoli» of the National Research Council of Italy, Via Vettore 4 (Monte Sacro),Roma.     

Neue ZnS-Polytypen (9R, 12R und 21R) in mesozoischen Sedimenten NW-Deutschlands

Summary Argillaceous sediments of jurassic and lower cretaceous age in NW-Germany contain in several localities authigenous ZnS-polytypes. The crystals with a maximum height of 2 mm exhibit hexagonal-pyramidal and trigonal-pyramidal habit.With X-ray rotation and precession technique the following polytypes could be identified: Sphalerite (3 R = 3 C) 211, 411, 6H 9R, 12R, 15R and 21R.The 9 R-, 12 R- and 21 R-polytypes have not until now been described elsewhere.The structures of the new polytypes were determined as 9R=(21), 12R=(13) and 21R=(3112).Oriented intergrowths of R- and H-polytypes were frequently observed. From the intergrowth-phenomena arguments for the environmental conditions of formation can be deducted.[/p]     

Phase Equilibria in the Metamorphic Rocks of St. Paul Island and Cape North, Nova Scotia

A suite of schists—one from the garnet zone, 19 from thestaurolite zone, 2 from the kyanite isograd, and one from thekyanite zone—were separated into their constituent minerals.Chemical analyses of one chlorite and of 23 sets of coexistingbiotites and garnets were carried out by photometric and titrametricprocedures. Plots of garnet-biotite tie-lines from divariantassemblages on appropriate phase diagrams result in intersectingtie-lines which cannot be ascribed to experimental error. Theoreticalconsiderations argue that at equilibrium, at the same pressureand temperature or at constant pressure and varying temperature,tie-lines of divariant assemblages should not intersect. Possibleexplanations require that diffusion equilibrium of Fe and Mgbe restricted to volumes smaller than that of a hand specimenor that P as well as T varies considerably. Emission spectrographicdeterminations of Fe and Mg in biotite indicate that the Fe/Mgratio varies among biotites little more than a centimeter apart.Such a variation would argue more in favor of a lack of diffusionequilibrium.     

Structure and petrology of an alpine peridotite on Cypress Island,Washington, U.S.A

A study of the structural petrology of a peridotite exposed on Cypress Island in Skagit Co., Washington, U.S.A. has been carried out. The Cypress peridotite is, by virtue of its composition, structure and associations, typical of ultramafics of the alpine type. It contains relict layering and accumulative textures which show it to have originated by crystal settling from a magma of unknown initial composition. Parallelism of lineations and b-axes of folds in the layering with well-developed [100]-maxima in the fabrics of olivine crystals is considered to have arisen through a penetrative deformation of the mass accompanied by plastic flow or recrystallization of the olivine. An indication of the minimum temperature of the deformation is provided by cross-cutting veins of pyroxenite which have not participated in the folding. The most satisfactory interpretation of the overall fabric of the peridotite is that it was deformed, possibly during intrusion, as a crystal mush, and that filter pressing due to compaction of the solid particles by plastic flow or recrystallization removed all but a small percentage of the magmatic fraction which then crystallized following cessation of the movements.     

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An attempt to the explanation and to the prediction of the eleven-year cycle of solar activity

Summary According to the author the reason of the subsistence of the 11 years' sunspot cycle is to be found in the conjunction of the planets. As a result of the investigations it has been stated that from among the nine planets the joint tidal effect of Venus-Jupiter-Earth is a decisive factor in the variations of sunspot activity. The above three planets are every 10.4 years and 12.0 years respectively, in a close conjunction. The mean value (11.2 years) is in an almost full accordance with the average cycle-period. The fluctuations of the period of the cycle come from the fact that the planets' getting into approximately one line takes a different time within each cycle. This time delay is the cause of the stronger or weaker sunspot activity, and of the shorter or longer cycles.