bluuebunny/crossref_metadata_2025_split huggingface dataset:
The production of ethyl acetate from ethylene and acetic acid using clay catalysts
Authors: Gregory R. , Smith D. J. H. , Westlake D. J. 
Published: December 2006

AbstractWyoming bentonite, exchanged with cations of high charge density, is an efficient and selective catalyst for the production of ethyl acetate, in a single step, from ethylene and acetic acid. The reaction occurs in the interlamellar space of the clay where it is proposed that strong Brönsted acid sites on the clay coupled with highly polarized intercalated reactants produce a reaction which is otherwise difficult to carry out.
Some organic syntheses with clay-supported reagents
Authors: Cornelis A. , Laszlo P. , Pennetreau P. 
Published: December 2006

AbstractSome uses of clay-supported reagents in fine organic synthesis are discussed, in particular the catalysis of the phase-transfer preparation of formaldehyde acetals by quaternary ammonium montmorillonites. The preparation and some applications of clay-supported ferric nitrate, a new reagent which oxidizes alcohols into carbonyl derivatives, couples thiols into disulphides, nitrates phenols, and oxidatively couples pyrrole and benzaldehyde into tetra-phenylporphyrin, are also described
Microanalyses geochimiques de mineraux argileux de sediments preleves et Atlantique Nord (Forages du DSDP)
Authors: Debrabant P. , Delbart S. , Lemaguer D. 
Published: December 2006

ResumeL'analyse semi-quantitative, avec une microsonde électronique CAMEBAX, met en évidence des variations chimiques significatives dans des assemblages simples de minéraux argileux. La méthode est décrite et deux applications sont présentées et interprétées en termes de genèse et de paléoenvironnement. La microgéochimie d'illites et de chlorites du Crétacé inférieur (Marge du Maroc) évolue vers le haut de la série (diminution du magnésium) et semble influencée par une diagenèse salifère transformant des argiles détritiques. Des chlorites hypermagnésiennes apparaissent dans les sédiments les plus profonds, et autorisent l'hypothèse d'une authigenèse en milieu confiné. Les différentes smectites étudiées a la limite basalte-sédiment des sites 105 et 384 du DSDP (NW Atlantique) peuvent aisément être distinguées par leur microgéochimie avec Mg, Na, K, Al, Fe, Ti. Elles reflètent diverses sources volcaniques et leurs caractères sont très différents de ceux des smectites terrigènes communes.
X-ray powder transmission diffractometry determination of mica polytypes: method and application to natural samples
Authors: Wiewióra A. , Weiss Z. 
Published: December 2006

AbstractTransmission powder patterns of random and of highly oriented samples of natural micas have been recorded and compared with those calculated from structural data with the aid of the DIFK computer program modified to correct for preferred orientation. Intensities calculated from structural data for random and for highly oriented samples (symmetrical and oblique settings) are presented for 1M, 2M1, 2M2, 3T polytypes of muscovite, 1M, 2M1, 3T polytypes of paragonite and 1M (C2/m and C2 space groups), 2M1, 2M2, 3T polytypes of lepidolite.
Origin and evolution of smectites in Recent marine sediments of the NE Atlantic
Authors: Parra M. , Delmont P. , Ferragne A. , Latouche C. , Pons J. C. , Puechmaille C. 
Published: December 2006

AbstractPresent-day marine sediments around the emerged basaltic areas of Iceland and the Faeroe Islands are characterized by the abundance and predominance of smectites. Smectites increase regularly and systematically near volcanic areas. Their origin from (i) meteoric/deuteric weathering, (ii) hydrothermal products, (iii) neoformation in the marine environment or (iv) transformation during their transport to or stay in oceanic regions is considered in a comparative study of three types of environments on or near the Faeroe Islands. These are (1) a basaltic environment where phyllite minerals of deuteric and hydrothermal origin are abundant; (2) a soil environment formed on basaltic flows; (3) a marine sedimentary environment within adjacent sedimentary basins. This investigation clearly shows the link between hydrothermal and deuteric saponite-celadonite in basalt, Fe,Mg-smectite in Faeroe soils and Fe-smectite in marine sediments.
Note on the pleochroism of Adamite
Authors: Spencer L. J. 
Published: December 2006

The mineral adamite (Zns(AsO4)2.Zn(OH)2), discovered by C. Friedel in 1866 on specimens from Chafiarcillo, Chile, has since been found at only two other localities, namely Cape Garonne in France and Laurion in Greece. At the original locality it would appear to be of rare occurrence, since in the literature mention is made of only two specimens.It was therefore of interest to find in the British Museum collection a good specimen of adamite from Chafiarcillo. This was found amongst the hornsilvers, and the associated adamite had been thought to be fluorite, which indeed, at first glance, with its violet colour and good cleavage, it closely resembles in appearance. The crystals are remarkable by reason of their very strong pleochroism, and as this feature of adamite has previously received no mention it has been thought worthy of placing on record.
Lattice-like inclusions in Calcite from North Burgess, Ontario
Authors: Graham R. P. D. 
Published: December 2006

The pale celestite-blue calcite which occurs on the eastern half of Lot 13, Range V, of North Burgess township, Lanark county, Ontario, contains very remarkable lattice-like inclusions of a hydrous magnesium silicate.The calcite forms crystalline masses belonging to the Grenville series, which has a very extensive areal development in certain parts of Ontario. The texture varies from medium to very coarse, in which the individual cleavage-rhombs of calcite measure one inch or more in diameter. Repeated twinning on e (0112) or (101) is almost invariably exhibited, and is especially pronounced in the more coarsely crystallized varietiea Both the twinning and the crystalline character are results of the very intense metamorphism to which this Archaean limestone has been subjected.
On the origin of septarian structure
Authors: Alfred Richardson W. 
Published: December 2006

In the Geological Magazine for 1918 there appeared three papers discussing the origin of tile system of cracks ill septarian nodules. Dr. A. Morley Davies opened the discussion in a paper where, after a summary of earlier literature, he again put forward an older idea. Without adducing evidence, he considered :
(a)that interposition of particles between those of the original matrix caused expansion which set up tensile strain in the growing body ;(b)that the cracking of the nodule was due to the relief of those tensile
stresses.
The crystalline structure of zircon
Authors: Binks W. 
Published: December 2006

In a proper recently published by Prof. Vegard is contained an analysis of the structure of the zircon group of crystals, which belong to the tetragonal holohedral class, the axial ratio being approximately a : c = 1 : 0.656.As the present work was completed when the above paper appeared, it is interesting to find that the principal deductions concerning the structure of zircon, ZrSiO4, are confirmatory. The parametral values are, however, slightly different. This difference, though small in itself, is found to introduce larger discrepancies between the observed and calculated intensities of reflection.
A simple and accurate constant-volume pyknometer for specific gravity determinations
Authors: Ellsworth H. V. 
Published: December 2006

Experience with the usual types of glass pyknometers long ago convinced the writer that these instruments as ordinarily used are subject to considerable errors and may be quite unreliable when dealing with small quantities of material, It is true there are forms intended to be used in conjunction with a very precisely regulated water-bath which are capable of giving results of high accuracy, but this method of determination at constant temperature involves too much time and trouble for routine mineralogical work. But no matter what the design of glass pyknometers, and their variety is legion, in actual practice they suffer in common from tile defects of the material of which they are constructed.The heavy-solution method is inconvenient ; it cannot be used for the heavier materials and there is often danger of contaminating the material which may be intended for analysis.
The identification of dumortierite as grains; dumortierite in Cornish granite
Authors: Groves A. W. 
Published: December 2006

The following notes are intended to bring to the notice of workers on heavy mineral grains the possible confusion between blue tourmaline, purple tourmaline, glaucophane, lepidolite, andalusite, pleochroic sillimanite, and dumortierite. Dumortierite (when blue) is very liable to be passed over as the more common mineral glaucophane, the optical properties of the cleavage-flakes of these minerals being similar in several respects.Having seen a grain of dumortierite from the Wealden of Surrey, kindly lent me by Mr. H. A. Hayward, I was impressed by the remarkable nature of its pleochroism. A day or so later, while examining some concentrates of the Blackheath Beds of Shirley, Surrey, belonging to Mr. G. M. Davies, I came across a single grain which he had described as glaucophane. The pleochroism seemed too intense for a grain of glaucophane of that thickness, and it occurred to me that the tint observed, when the grain was in the position of maximum absorption, was exactly that of the dumortierite grain.
On the determination of the optic axial angle and crystal-forms from observations by the Becke method in thin sections
Authors: Collingridge Harvey 
Published: December 2006

Some years ago the writer read a paper on the determination of the optic axial angle of a crystal by the Becke method. This proposed method was to record the trace of the optic axial plane when horizontal, the position of one axis, and the extinction-direction. From these data and the established constants of the microscope, the position of the second optic axis may be found, as the extinction bisects the angle between the centre of the pole of the section and the two optic axes. Hence, the optic axial angle may be determined.Considerable errors arise in these determinations owing to defects in the optical system of the microscope, and also to the inability to determine the exact position when the trace of the optic axial plane is parallel to the E-W. lines in the microscope.
On the orientation of kamacite in meteoric iron
Authors: Young James 
Published: December 2006

The present note arises out of a paper by O. B. Bøggild, to which my attention was drawn recently, concerning the peculiar segregation of kamacite which gives rise to the Widmannstätten figures produced by etching plane sections of the octahedrite meteoric irons.As the figures which occur in these meteorites are met with on a much smaller scale in many alloys, the structure to which they owe their origin must be of special interest to those engaged in the study of metals.
The meteoric stone seen to fall in the Mangwendi native reserve, Southern Rhodesia, on March 7, 1934
Authors: Lightfoot B. , Macgregor A. M. , Golding E. 
Published: December 2006

This is the first meteorite to be recorded from either Southern or Northern Rhodesia. It fell at about 12.45 p.m. on March 7, 1934, on the right bank of the Shawanoya river in the Mangwendi native reserve, about forty miles east of Salisbury. The latitude and longitude of the spot are 17° 39ʹ S., 31° 36ʹ E.The recovery of the meteorite was made through the efforts of the Rev. F. J. Gits, S.J., who is in charge of St. Paul's Mission. Three loud detonations were heard from a direction north-east of the Mission Station followed by a loud rushing sound. Father Gits, who was out in the open at the time, involuntarily ducked his head. His inquiries failed at first to elucidate the cause of the explosions, which were also heard at Arcturus, Macheke, and Mtoko, that is, over a radius of at least fifty miles.
Murnpeowie (South Australia), a granular type of meteoric iron
Authors: Spencer L. J. 
Published: December 2006

Apreliminary account of this fine mass, weighing 2520 lb., of meteoric iron was given in 1910 by L. Laybourne Smith, who at that time was Registrar of the South Australian School of Mines and Industries in Adelaide; but the promised detailed description with chemical analysis never appeared. Except for a small piece cut off one corner (upper left-hand corner in fig. 1) the mass is preserved intact in the Museum of that Institution, and none of the material appears to have been distributed to other museums. Casts of the mass were, however, made for the South Australian Museum in Adelaide, and one of them was presented to the British Museum in 1917 (B.M. 1917,360), where in the meteorite collection it is a very striking object (fig. 1).Recently, at the suggestion of Mr. R. Bedford of the Kyancutta Museum, the Council of the South Australian School of Mines has generously presented to the British Museum a piece of this meteoric iron, together with the milling cuttings, with the request that the description of it should be completed.
The determination of small amounts of copper in rocks
Authors: Groves A. W. 
Published: December 2006

In modern petrology increasing importance is being attached to the content of minor chemical constituents, the determination of which is now frequently required, whereas hitherto they have usually been disregarded. In consequence, methods for their accurate determination in small amount have not always been fully worked out. Copper is a case in point, and it is already clear that the method here advocated will show that this metal is much more widely distributed in rocks than is generally realized. Moreover, the use of a large sample, such as 20-50 grams, is no longer necessary.In attempting to apply to rocks the very sensitive colorimetric method described by T. Callan and J. A. Russell Henderson, various difficulties were encountered, and modifications were developed whereby the method can be adapted to the determination of from 0·001-0·25 % of CuO in silicate rocks and minerals. The reagent used is sodium diethyl-dithio-carbamate, which gives a yellow colour with copper in slightly ammoniacal solution. The authors give a list of other metals which also give a coloration or turbidity with this reagent.
Metasomatism associated with the greenstone-hornfelses of Kenidjack and Botallack, Cornwall
Authors: Tilley C. E. 
Published: December 2006

In a paper entitled 'Hornfelses from Kenidjack, Cornwall' 1 the nature and origin of the rock types characterized by anthophyllite and cummingtonite occurring in the aureole of the Land's End granite were discussed.Since these rocks were 'investigated in 1928 the writer has extended his study of them both in the field and in the laboratory, with the result that further light on the origin of these rock types has been obtained. It is the purpose of these notes to examine in more detail the evidence which is considered to add to their understanding. In the Kenidiack paper the petrography of the rocks was described at some length and in the present paper petrographic data will be given only in so far as they supplement the previous account, which may be consulted for a detailed statement.
X-ray studies on pyrolusite (including polianite) and psilomelane
Authors: Vaux George 
Published: December 2006

One of the most promising uses of X-ray diffraction methods in mineralogy is the study of those minerals which are opaque and whose crystals are extremely minute. Although recent methods of ore examination by reflected polarized light have given valuable information about these substances, their application to soft, powdery materials is extremely difficult, an objection which does not apply to X-ray methods.Pyrolusite (including polianite).—The present study had for its main objective an attempt to settle, by X-ray examination , the uncertainty existing as to the relationship between polianite and pyrolusite, Work already carried out by St. Johns has suggested that polianite and pyrolusite are identical, since they have the same cell sides as found from powder photographs.
The Paragenesis of Kyanite-amphibolites (With Plate XX.)
Authors: Tilley C. E. , Vincent H. C. G. 
Published: December 2006

In an earlier paper the writer has discussed the paragenesis - kyanite-omphacite as observed in certain ec|ogites. The fate of this association under conditions of retrograde metamorphism has led to a consideration of rocks showing the paragenesis amphibole-kyanite, a point which is briefly taken up in the present communication. Rocks containing this latter assemblage include two groups, the one better known, of sedimentary origin, the other essentially igneous in origin.Here are included members of the para-amphibolites, biotite-hornblende- schists, and hornblende-Garbenschiefer derived from sediments of the character of calcareous and dolomitic shales. The best-known examples come from the Alps—particularly the Triassic and pre- Triassic sediments on the south side of the St. Gotthard massif.
An X-ray examination of some potash-soda-felspars
Authors: Chao S. H. , Smare D. L. , Taylor W. H. 
Published: December 2006

The systematic classification of the potash-soda-felspars is of the greatest interest and importance to the mineralogist, but problems demanding physical investigation are raised in work carried out recently by Dr. Edmondson Spencer, who has described the results of exhaustive chemical, optical, and thermal investigations of a representative collection of these minerals. Dr. Spencer has very kindly allowed us to examine by X-ray methods a large number of his specimens, so that for the first time it has been possible to make a fairly complete survey of potash-soda-felspars of known chemical composition and with accurately measured optical properties.This paper presents the results of our general survey of potash-soda-felspars with compositions ranging from nearly pure potash-felspar to approximately 50 % soda-felspar. The natural minerals, and the same minerals after specified heat-treatment, have been examined. We do not discuss in detail the interpretation of our results in terms of the atomic structure of felspars; the subject is extremely complicated, and it is necessary to await the results of other investigations now in progress in this laboratory before attempting a complete structural interpretation.
The structure of orthoclase
Authors: Chao S. H , Hargreaves A. , Taylor W. H. 
Published: December 2006

The structure of sanidine was described by Taylor in 1933, and Taylor, Darbyshire, and Strunz in 1934 extended the investigation to include the potassium-barium-felspars and albite, and presented a small amount of experimental data for potash-soda perthitic felspars and for members of the plagioclase series. X-ray work on the potash-soda perthitic felspars has recently been reported by Ito and Inuzuka, by Ito, and by workers in this laboratory, and a preliminary report of an examination of the plagioclase felspars is given in a thesis presented by one of us (S.H.C.) in 1939 for the degree of Ph.D. in the University of Manchester.The investigations to be described in this paper, as well as those already published from this laboratory, form part of a programme of researches dealing with various aspects of the problem of felspar structure, undertaken in an attempt to obtain a correlation between the physical and chemical properties on the one hand and the details of the structure on the other.
On sulphatic cancrinite and analcime (eudnophite) from Loch Borolan, Assynt
Authors: Stewart F. H. 
Published: December 2006

The minerals to be described in this paper were collected, in conjunction with W. E. Fraser, who was carrying out a detailed study of the borolanite, from the road-metal quarry, opened in 1938, at Allt a' Mhuillin, Loch Borolan, Assynt, Scotland. They occur in pegmatitic patches and veins in borolanite.This mineral is one of the chief constituents of the pegmatites. It forms large cleavable masses, associated with orthoclase, melanite, and a little dark mica. Calcite, sphene, zircon, and orthite are present as accessories. It often fills interstices between crystals of orthoclase. A preliminary examination has indicated that it is a common constituent of the spots in some types of borolanite, and further work will have to be done to determine its importance in this connexion. This is the first definite record of the occurrence of cancrinite in Britain.
The Gibeon shower of meteoritic irons in South-West Africa (With Plates I and II)
Authors: Spencer L. J. 
Published: December 2006

The presence of much native iron in Great Namaqualand was heard of in 1836 by the traveller Sir James E. Alexander, but he himself did not see any of the masses, and the material he acquired consisted only of small fragments that had been detached by the natives for pointing their weapons. An approximate chemical analysis of this material, made by Sir John Herschel, proved it to be meteoritic. A fragment weighing 2 grams which Alexander presented to the Geological Society of London in 1838 was transferred to the British Museum collection of meteorites in 1911. This appears to be all of his material that has been preserved.Various other vague reports and travellers' tales have mentioned the presence of large masses of iron beyond the old mission station of Bethany, between there and Beersheba, and on the east side of the Great Fish River. A critical summary of these accounts was given by Sir Lazarus Fletcher in this magazine.
The orientation of Widmanstetter figures in a random section
Authors: Melmore Sidney 
Published: December 2006

The problem of determining the orientation of Widmanstetter figures has recently arisen in a paper by Dr. L. J. Spencer on the Gibeon shower of meteoritic irons in South-West Africa: the method of attacking it to be described here will be applied to the crystals illustrated in plate II of his paper.By producing the faces of a regular octahedron in all possible directions a set of six congruent prisms is formed, as shown in fig. 1. The Widmanstetter figures are the traces of these prisms in a plane of section. The section across any one of the prisms by a plane normal to its axis is a rhomb whose angles are those of a face of the rhombic-dodecahedron, that is to say, 70° 31′ and 109° 28′.
On the origin of the name ‘quartz’
Authors: Tomkeieff S. I. 
Published: December 2006

Quartz is the commonest of minerals and reference to any dictionary will show that it is crystalline silica, but how or when this substance acquired the name quartz seems to be a still unsolved mystery.Theophrastus, the pupil and successor of Aristotle, in his book on stones (19), mentions among other stones used for engraving seals, a stone called crystal This name, apparently, is derived from cold, and contract. It would seem from this that the ancient Greeks, as implied by Pliny, believed crystal (modern quartz) to be a variety of supercooled ice. In point of fact the formation of crystal in nature is explained by the earliest writers in a different way. Diodorus Siculus (circa 30 B.C.) suggests that crystal was formed from water hardened by heavenly fire, while Pliny the Elder (circa A.D. 60) says that crystal is ‘a substance which assumes a concrete form from excessive congelation’, and goes on to explain that crystal is only to be found ‘in places where the winter snow freezes with the greatest intensity’ (15, Book 37, 2, 9). Pliny's description of crystal, however, leaves no doubt that he applied this name to the crystalline variety of silica which is now called quartz.