The phenomena and colours of the soap-bubble have been the subject of more frequent observation than any other facts in science. For nearly two centuries they have afforded amusement and instruction to the young, and have exercised the genius of the most distinguished philosophers. Hook and Newton ascribed the beautiful colours of the soap-bubble to the different degrees of thickness of the attenuated film, and this opinion has been implicitly adopted by every optical writer down to the present day. In the latest and best Treatise on Light, Sir John Herschel expresses the current theory more distinctly than others, when he says, “that the brilliant colours which appear on soap-bubbles consist of a regular succession of hues disposed in the same order, and determined, obviously not by any colour in the medium itself, in which they are formed, or on whose surfaces they appear, but solely by its greater or less thickness.…It is at first uniformly white, but as it grows thinner and thinner, by the subsidence of its particles, colours appear to begin at its top, where thinnest, which grow more and more vivid, and arrange themselves in beautiful horizontal zones about the highest point, as a centre.”

The recently published model of evolution and biogeography and the resulting classification of the Tetraconodontinae (Van der Made 1999) were criticised by Pickford (2001) on eight points. It was claimed that Conohyus giganteus is a suine, and that this ‘radically modifies tetraconodont systematics’. However, Pickford failed to demonstrate that the type specimen is a suine, and even if it were a suine, this would affect only one of over twenty species names; not a radical change of the proposed evolutionary model.

This study presents an appraisal of the Middle Eocene–Quaternary Dugong Supersequence of the Eucla Basin, offshore southern Australia. It combines details of the rock record with seismic-stratigraphical information, and the resulting stratigraphic framework provides constraints on the nature of the late post-breakup development of the southern Australian continental margin. It is well established that the onshore-to-mid-shelf succession comprises a predominantly aggrading-to-prograding unconformity-bounded succession of carbonate platform deposits; however, our analysis of the outer shelf–upper slope section challenges the widely held view that this shelf-margin wedge represents a distally steepened prograding carbonate ramp primarily modulated by global eustasy. Instead, our results show that the Middle Eocene–Quaternary succession is punctuated by a series of unconformities that reflect a persistent tectonic instability and differential vertical movements throughout the late post-breakup period, the genesis of which is most closely related to tectonic events. Moreover, the upper slope clinoform succession was constructed and shaped predominantly by alongslope processes, and four different contourite drift types are recognised based on their seismic-stratigraphic expression: elongate mounded drift (Quaternary); infill drift (Pliocene); plastered drift (Oligocene); and separated drift (Middle–Upper Eocene). The Quaternary drift – herein termed the ‘Eyre Terrace Drift’ – is a spectacular basin-scale deposit, over 500 m thick and traced for up to 200 km along the upper slope Eyre Terrace. Upslope-migrating sediment waves are associated with this drift. Key sedimentary attributes consistent with a contourite origin include fine-grained sediment, multi-scale gradational bed contacts and pervasive bioturbation. There is also evidence of episodic downslope mass-movement processes ranging from the large-scale Late Neogene Slide, which extends downslope for 15–20 km, to sporadic slumped beds and turbidites recovered in boreholes. The interaction of alongslope and downslope processes indicates a more dynamic sedimentary setting than previously assumed along the outer margin of the Eucla Basin.

James Croll was a pioneer in studies of the impact of the slowly changing orbital dynamics of the Earth on climate change. His book Climate and Time in their Geological Relations (1875) was far ahead of its time in seeking correlations between climate change, the occurrence of ice ages and perturbations to the Earth's orbit about the Sun. The astronomical cycles he discovered are now called ‘Milankovitch Cycles’ after the Serbian scientist whose research was first published in the Handbuch der Klimatologie in 1930. The celestial mechanical and astronomical background to Croll's research is the focus of this essay. The development of the understanding of the impact of perturbations of the elliptical planetary orbits by other bodies in the solar system paralleled new mathematical techniques, many of which were developed in association with celestial mechanical problems. The central contributions of many of the major mathematicians of the late 18th and 19th Centuries, including Euler, Lagrange, Laplace and Le Verrier, are highlighted. Although Croll's contributions faded from view for several generations, his pioneering insights have now been demonstrated to have been basically correct.

The bivalve ligament provides the thrust for shell opening, acting as the resistance in a lever system against which adductor muscle effort is applied. Usually, its outer lamellar layer is subjected to tensile stress, while the inner fibrous layer is compressed, with the pivotal axis located between them. However, opisthogyrate rostrate bivalves display a concave dorsal margin, and both the umbo and the postero-dorsal angle of the shell project dorsally to the ligament, which then fails to act as pivotal axis. Three opisthogyrate rostrate genera of unrelated lineages show somewhat different solutions to this morpho-functional challenge. In Cuspidaria (Anomalodesmata), the ligament is internal, subjected only to compression and ventral to the pivotal axis, a thickened periostracum develops, forcing the dorsal margins of the valves to act as pivotal axis, and the posterior parts of the shell's dorsal margins gape dorsally. In Nuculana (Palaeotaxodonta), the inner layer of the ligament is internal, the outer layer is external but reduced, and some species develop a dorsal ridge parallel to the commissural plane, on a level with the rostrum and acting as pivotal axis. In Pterotrigonia (Palaeoheterodonta) and other rostrate trigoniides, the ligament is external opisthodetic, but is allometrically reduced. Trigoniides may also develop a dorsal ridge.

Archaeopterid trees were the main components of most Late Devonian forests. Their aerial axes characterised by a eustele with mesarch primary xylem strands, leaf traces departing radially from cauline bundles and secondary xylem tracheids with radial pits arranged in groups, are referred to the genus Callixylon Zalessky. The nineteen species of Callixylon described to date from North America, North Africa, Europe, Xinjiang and several parts of Russia range from the late Givetian to the Mississippian. In this paper, we describe a new species of Callixylon from two specimens collected in the Famennian locality of Mader el Mrakib in eastern Anti-Atlas. Callixylon wendtii sp. nov. is characterised by the presence of sclerotic nests in the pith, a new character for the genus. Its wood shows narrow rays of variable height, with unevenly distributed ray tracheids. Small vascular traces crossing the wood within the two innermost growth rings are interpreted as evidence for short-lived leaves. This discovery adds to the diversity of the genus Callixylon in an area of northern Gondwana that may have been favourable to the establishment of a diverse community of archaeopterid trees.

The genus Cordulegaster is represented in Sicily by two species. From an examination of material recently collected there and from evidence in the literature it is concluded that one has previously been misidentified, here named C. boltonii trinacriae ssp. nov.: the other is the little-known C. bidentatus sicilicus Fraser, 1929. A key to males of the Old World species of Cordulegaster is provided and lectotypes for C. boltonii algiricus Morton, C. princeps Morton, C. insignis amasinus Morton, C. insignis nobilis Morton, C. coronatus Morton and a neotype for C. charpentieri (Kolenati) are designated.

Though the labours of M. De Luc, and of the excellent observers who followed him, have brought the barometrical measurement of heights to very great exactness, they have not yet given to it the utmost perfection it can attain. Some causes of inaccuracy are still involved in it; of which we ought, at least, to estimate the effects, if we cannot correct them altogether. The allowance made on account of the temperature of the air, implies in it a hypothesis that has not been examined, nor even expressed, and many other circumstances that affect the denfity of the atmosphere, have either been wholly omitted, or improperly introduced. The object of the present paper is to correct, the errors that arise from these causes, or, where that cannot be done, to assign the limits within which those errors are contained.

The systematic study of the cluster of orders lying at the base of the Dicotyledon phylum has of late years become of fundamental importance in view of the various theories advanced by different authorities as to the origin of the so-called Monocotyledons. The anatomical structure of many of these groups has been but little investigated from this aspect, and the present paper is the first of a series which it is hoped to publish with the object of discovering to what extent anatomy supports or contradicts one or other of views held on the phylogeny of flowering plants. One such research is already far advanced, viz. on the anatomy of the Magnoliaceæ, and another, the present contribution, deals with the stem structure of the Papaveraceæ. Although both researches have been retarded owing to one of the authors being engaged on war service, there would seem no reason for delaying the publication of such observations as have been made.

A method of conducting a resistivity sounding, up to a maximum spacing of 5 kilometres, is described. By conducting measurements, in a symmetrical fashion, about the sounding centre and in two perpendicular directions, it is possible to obtain results which are relatively insensitive to the orientation of the electrode array used and entirely related to the local area around the sounding centre. By choice of the progression of spacing used, it is also possible to express the results in terms of resistivity measures suitable for subsequent interpretation.

A resistivity sounding curve, conducted in this manner at Rookhope, shows the existence a highly resistive basement at interpreted depths which are in reasonable accord with the known depth to the Weardale granite in this area.

I. The Parallel Roads of Lochaber have presented to geologists a problem, which is still unsolved. Dr Macculloch, about sixty years ago, when President of the Geological Society of London, first called attention to these peculiar markings on the Lochaber Hills, by an elaborate Memoir afterwards published in that Society's Transactions. He was followed by Sir Thomas Dick Lauder, who in the year 1824, read a paper in our own Society, illustrated by excellent sketches. His paper is in our Transactions. The next author who attempted a solution was the present Mr Charles Darwin. He maintained that these Roads were sea-beaches, formed, when this part of Europe was rising from beneath the Ocean. He was followed by Professor Agassiz, Dr Buckland, Charles Babbage, Sir John Lubbock, Robert Chambers, Professor Rogers, Sir George M'Kenzie, Mr Jamieson of Ellon, Professor Nicol, Mr Bryce of Glasgow, Mr Watson, and Mr Jolly of Inverness. Sir Charles Lyell, though he wrote no special memoir, treated the subject pretty fully in his works, giving an opinion in support of the views of Agassiz.

It has been known for a length of time that the presence of a non-volatile substance diminishes the vapour pressure of the solvent in which it is placed, and as the boiling point of a solvent or a solution is the temperature at which the vapour pressure is just equal to, or overcomes the pressure of the atmosphere, it follows that a solution has a higher boiling point than the solvent. Amongst the first experimenters in this field were Faraday, Legrand, Griffiths, and Raoult. TO Raoult we owe much for his development of the subject.

By the discovery of the different refrangibility of light, Sir Isaac Newton laid open the true cause of the principal imperfection of refracting telescopes; and having inferred from the experiments which he made, that the refraction of the different rays composing the prismatic spectrum, was always in a given ratio to the refraction of the mean refrangible ray, this great philosopher was led to conclude, that the imperfection which he had discovered in dioptrical instruments was without remedy.

The Lower Devonian Posongchong Formation (Wenshan, Yunnan Province, southwestern China) consists of a series of continental deposits with an outstanding plant megafossil diversity. More than 20 years ago, this formation was interpreted as ‘Siegenian' (∼Pragian) in age based on palynology. However, such interpretation needs further evidence because of the known differences between the dispersed spore assemblages from South China and Euramerica/northwestern Gondwana. Here, we present new dispersed spore assemblages recently recovered from the Posongchong Formation. The isolated spore diversity is highly diverse, with 18 genera and 32 species. The recognised taxa include, among others, Ambitisporites avitus, Aneurospora conica, Aneurospora posongchongensis sp. nov., Aneurospora xujiachongensis, Apiculiretusispora plicata, Archaeozonotriletes chulus, Concentricosisporites agradabilis, Dibolisporites echinaceus, Emphanisporites rotatus, Gneudnaspora divellomedia, Latosporites ovalis, Retusotriletes triangulatus, Tetrahedraletes medinensis and Verrucosporites polygonalis, with Aneurospora and Retusotriletes being the most abundant forms. The known Posongchong palynoflora (previous spore data included) suggests that the Posongchong Formation assemblages can be correlated with the Pragian interval of the polygonalis–wetteldorfensis Oppel Zone (PoW). This age determination is supported by the presence of index species of PoW, such as Verrucosporites polygonalis, Dictyotriletes subgranifer and Camarozonotriletes parvus (sensu Steemans, 1989), the latter being known only from the Pragian of Belgium and Germany. Recent advances in the study of the marine faunas in the overlying sequences also indicate a Pragian age for the Posongchong Formation. This new investigation of the Posongchong palynoflora highlights differences of abundance at species level between the Gondwanan–Laurussian floras during the Early Devonian.

Dear Sir,

As the following paper refers in a great measure to the general theorems published by your father, I now commit it to your care, and that of my friend Mr Playfair, Professor of Natural Philosophy. I wish it to be communicated to the Royal Society of Edinburgh, and, if approved of, to be inserted in their Transactions as soon as possible. Indeed, I trust, that even simple as it is, it will not be altogether unacceptable to that learned body.

I am,

Dear Sir,

Most sincerely your, &c.

Jas Glenie.

In 1889 the Scottish Meteorological Society decided on making observations on the dust in the atmosphere at their Observatory on Ben Nevis. Having prepared the plans for the apparatus to be used for counting the dust particles, I visited the Observatory on the 1st of August of that year, and, after consulting with Mr Omond, decided that the tower of the Observatory was the best place for fitting up the instrument. The apparatus was afterwards made by White of Glasgow, and fitted up in the Observatory on 5th June 1890.

The chemical, physical and mineralogical characteristics of five soil profiles developed on volcanic material on the Anatolian plateau of Turkey have been studied. The soils, which are mainly Entisols, have high pH values in the range 7·5 to 8·0, low amounts of organic matter (usually <1·0%), low available water capacities and a low to medium ability to sorb phosphate. The soil parent materials are basalts and tuffs which often contain large proportions of volcanic glass. Weathering of this material in the prevailing semi-arid climate results in the development of a smectite-dominated clay fraction with small amounts of kaolinite. The smectite usually yields anomalously high X-ray spacings, probably due to interstratification and absorption of interlamellar material. The characteristics of the Anatolian soils are in marked contrast to those of Andepts which have formed on similar parent materials in humid, temperate climates.

Aristotle has a saying, which he has frequently repeated and which is often quoted, to the effect that the same degree of precision is not attainable in all branches of inquiry, and that it would be just as absurd to exact demonstration from a politician or an orator, as to accept probable reasoning from a mathematician. It is a saying full of truth and acuteness. To the cultivators of ethical and political philosophy, for whom it was intended, it is invaluable both as an encouragement and a warning; and yet, in behalf of the latter more especially, I often wish that it had never been said. Proceeding from such a master, I am persuaded that it has often tempted them to rest satisfied with a degree of success far short of the limits which the nature of their subjects really imposed; whilst, on the other hand, it has afforded an apology for excluding social and political philosophy from the meditations of learned bodies like this. I do not mean that they have been formally excluded. I know that the constitution of this, and of most similar societies, has always embraced the social as well as the physical sciences. But so rarely have those of us who were occupied with the former availed ourselves of the privileges of Fellowship, that it has come to be regarded almost as a matter of admission on our part, that our subjects defy scientific treatment: that when we talk of tracing out laws of social wellbeing or progress, we use words which either have no meaning at all, or which indicate a very faint analogy between the methods which we affect to follow and those really employed in the physical sciences: and that pretty nearly all that can be done is to hand us and our subjects over to the companionship of party politicians and popular declaimers.

It has long ago been remarked by the Abbé Hauy, that the property of Double Refraction is not possessed by any of those crystals the form of whose integrant molecule is distinguished by its symmetry, such as the Cube and the Regular Tetraedron. This class of minerals comprehends Fluate of Lime, Muriate of Soda, Spinelle Ruby, Muriate of Ammonia, Alum and the Diamond; and though M. Hauy had examined only a very small number of doubly refracting crystals, yet, with the exception of the Diamond, which I have found in many cases to possess the property of Double Refraction, his remark was confirmed by the experiments of Malus, Biot and myself, who considered all the crystals of this class as exercising no more action upon polarised light than a mass of water.

I am not aware of any account having been published of the Coal-fields in East and Mid Lothian, or of any attempt to institute a geological survey of the country in which they are situated. Sinclair, the author of a well known work intituled “Satan's Invisible World,” published also in 1672 a treatise on Hydrostatics, in which he takes notice of the Prestongrange coals, and of the whinstone-dike that intersects them. Williams, in his “Mineral Kingdom” (published) in 1810, gives some information regarding the direction of the Gilmerton and Loanhead coal-seams. But the information contained in both these works, even respecting the coal-strata,—which alone they professed to treat of, is extremely vague, and generally very erroneous. Dr Hibbert was the first geologist who with a scientific eye entered on the district, in order to describe with fulness and accuracy any of its rocks. His discovery of the Saurian remains in the limestone-quarries of Burdiehouse, led him to a minute inspection of the strata in which they were imbedded, and to a consideration of the relative position of these particular strata in the Mid-Lothian coal-field.