Criticisms by Kriwet regarding recent work on pycnodont phylogeny are based on the use of additive characters. Therefore, applying transformation series in phylogenetic reconstruction is justified in theory and in practice, and an example of additional ontogenetic evidence supporting character ordering in pycnodonts is provided. Moreover, comments on some pycnodont genera are included, and the accurate taxonomic use of the genera Coelodus and Ocloedus is emphasised.

In the Paper which I had the honour of submitting to the Society, on the Two New Fluids in mineral bodies, I have given the index of refraction for the most expansible of the two, as it exists in the cavities of Amethyst; but as I had not then ascertained the refractive power of the second fluid, and as the principal phenomena of the two fluids, especially those which related to their properties when taken out of the cavities, were observed in specimens of Topaz, it became desirable to have an approximate measure of the refractive power of both of them, as they exist in that mineral. As the fluid in Amethyst had never been examined in the open air, its identity with that in Topaz was inferred solely from the equality of their expansion by heat, so that the determination of the refractive power of the latter was necessary to establish either a difference between these two substances, or their perfect identity.

(1.) The inquiry which, with its results, I propose to lay before the Society, was suggested by the following passage in the very popular Treatise on Logic by Dr Whately, now Archbishop of Dublin.

“As in the case of two probable premises, the conclusion is not established except upon the supposition of their being both true, so in the case of two (and the like holds good with any number) distinct and independent indications of the truth of some proposition, unless both of them fail, the proposition must be true: we therefore multiply together the fractions indicating the probability of the failure of each—the chances against it—and the result being the total chances against the establishment of the conclusion by these arguments, this fraction being deducted from unity, the remainder gives the probability for it.

This research was undertaken with a view to ascertaining if metallic chlorides have any tendency to combine with a further quantity of chlorine. The well-known fact that potassium iodide unites with iodine to form a tri-iodide suggested that potassium chloride might, under suitable conditions, form a similar compound with chlorine. The method of investigation which first presented itself was to expose crystals of various chlorides to the action of dry chlorine gas at low temperatures, when any chemical action taking place would be expected to show itself in changes in the appearance of the crystals. A few experiments were made with no apparent result, and the method finally adopted was to determine the quantity of chlorine absorbed by solutions of the salts. It was thought that in this way quantitative results could be obtained which would reveal any tendency towards the formation of perchlorides. If a body having the formula KCl3 could be shown to exist, it would strengthen the position of those chemists who contend that the generally accepted ideas regarding atomicity need modifying. The discovery of a compound having the formula KCl2 would be a still stronger argument. At an early stage, however, the research resolved itself into an investigation of the solubility of chlorine gas in solutions of metallic chlorides in water, the question of the existence of perchlorides becoming a side issue. The influence of salts in solution on the solubility of gases in water is a subject of considerable interest, as throwing light on the nature of solution in general. Of late, certain chemists are inclining to adopt the old view that solution should be included under the general head of Chemical Action.

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.

Soil conservation on the Loess Plateau is important not only for local residents but also for reducing sediment downstream in the Yellow River. In this paper, we report a decrease in soil erosion from 2000 to 2010 as a result of the ‘Grain for Green' (GFG) Project. By using the Revised Universal Soil Loss Equation and data on land cover, climate and sediment yield, we found that soil erosion decreased from 6579.55tkm–2yr–1 in 2000 to 1986.66tkm–2yr–1 in 2010. During this period, there was a major land cover change from farmland to grassland in response to the GFG. The area of low vegetation coverage with severe erosion decreased dramatically, whereas the area of high vegetation coverage with slight erosion increased. Our study demonstrates that the reduction in soil erosion on the Loess Plateau contributed to the decrease in the sediment concentration in the Yellow River.

The susceptibility of rocks to weathering into soils and the subsequent weathering of the solum itself are important both with respect to sediment formation and to agriculture. Residual soils developed on some rock types representative of the major soil associations of NE Scotland have consequently been examined in detail in an attempt to assess the weatherability of both the rocks and the derived soils. Methods based on chemical composition have been supplemented by potential methods related to the production of poorly-ordered aluminosilicate material and to depolymerisation of the silicate framework in the minerals present. In general, there is, as would be expected on the basis of increasing energy supply and increasing entropy, an increase in the amount of monomeric silica towards the surface and this appears to be closely related to the amount and nature of the poorly-ordered aluminosilicate. The results suggest that only the purely chemical methods can currently enable a reasonable assessment to be made of the susceptibility of a rock or soil to further weathering.

For two centuries and a half the ampullary canal system of Elasmobranch fishes has occupied the attention of a series of investigators, who have treated the subject from a variety of standpoints, and have amassed a considerable literature representing, in spite of repetition and some conflicting statements, a gradual advance to a fuller knowledge regarding the occurrence and the structure of the organs in question.

The papers on the Geology of Benguella published in the Transactions (vol. li, part iii, No. 13, 1916, pp. 495–536) had to be issued without the report on the Cephalopods, an omission the more disappointing as they formed the largest and most instructive part of the Cretaceous collection.

In spite of its remote situation, the Old Red Sandstone of Shetland attracted a considerable amount of attention from geologists during the last century. It is exposed in excellent coast sections, which often yield very beautiful cliff scenery; and, in addition to being the most northerly of the stratified rocks of Great Britain, it includes a rich succession of volcanic and intrusive rocks which are of great interest and variety. The axis or backbone of the Shetland archipelago consists of gneiss, mica schist, slate, and limestone, with epidiorites, serpentine, and talc schists. On each side of this there is an area of Old Red Sandstone; that on the east extending from Sumburgh Head, in the extreme south, to Rovey Head, a little north of Lerwick, and comprising also the islands of Bressay, Noss, and Mousa. On the west side of Shetland the Old Red Sandstone Series is much altered, probably by the heat of the granite and other intrusive rocks, so that they often have the appearance of quartzite, and were for a long time regarded as belonging to the metamorphic series. In 1879, however, Peach and Horne (28) showed that, in places, they contained fossil plants which indicated that they belonged to the Old Red Sandstone formation.

In view of the differences observed in the pharmacological action of tetra-methyl- and tetra-ethyl-ammonium chlorides, it seemed of interest to investigate the actions of the methyl-ethyl-ammonium compounds. The chlorides of these compounds—namely, tri-methyl-ethyl-ammonium chloride, di-methyl-di-ethyl-ammonium chloride, methyl-tri-ethyl-ammonium chloride—were kindly prepared for me by Dr J. E. Mackenzie, who has published the mode of preparation and the analysis of them.

The only references I have found to the pharmacological action of the members of this series are brief statements by Tappeiner and Boehm. Tappeiner says that tri-ethyl-methyl-ammonium chloride, unlike tetra-methyl-ammonium chloride, does not produce temporary paralysis of the respiration; Boehm that tri-methyl-ethyl-ammonium chloride, like tetra-methyl-ammonium chloride, causes contracture of an isolated frog's muscle when a solution is applied to it.

Since reading this paper, I have seen Sir Benjamin Brodie's paper on “The Calculus of Chemical Operations,” read before the Royal Society of London.

The two papers resemble one another, merely in being applications of mathematical language to chemistry. They entirely differ in method, object, and result.

I may here mention, what I have omitted to state explicitly in the paper, that I have no idea of attempting to substitute a functional notation for that in common use. I only propose to use a functional notation to express certain general and serial relations in those cases where the common atomic notation is inconvenient or obscure.

Electron backscatter diffraction (EBSD) is used to determine the detailed crystallographic orientation of calcite crystals of craniid brachiopods in the context of shell ultrastructure. Sections of shells of two Recent species, Novocrania anomala and Novocrania huttoni, are analysed to provide 3D crystallographic patterns at high spatial resolution. The c-axis of semi-nacre calcite crystals is oriented parallel to the laminae that define the ultrastructure of the secondary layer. This orientation differs from that of rhynchonelliform calcitic brachiopods where the c-axis is perpendicular to the length of morphological fibres and to the shell exterior.

Neuropteris plicata was described by Sternberg in 1826, from a specimen from Mireschau, Bohemia, but the species seems to be very rare and imperfectly known. As other ferns have been identified as N. plicata in error, I give a figure of what I believe to be Sternberg's plant, an identification with which my friend M. Zeiller entirely agrees.

I also figure and describe a new species of Neuropteris, which is identical with that identified as N. plicata by Roehl, but from which species it is essentially distinct.

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.

Nine species of Echinoidea were described by De Loriol From Benguella and mainly from the neighbourhood of Dombe Grande.

1. One of his species, Epiaster catumbellensis, is common in the Lobito district. It is recorded by Be Loriol from the Inflata beds at Catumbella, and the younger Cyprina ivensi sandstone at Dombe Grande. It is a variable species. According to the dimensions given by De Loriol, the length varies from 25 to 36 mm., and the breadth varies from 88 to 94 per cent, of the length and the height from 66 to 77 per cent, of the length. His illustrations show that the species has two chief forms: in one the shape is depressed and the posterior margin is nearly vertical; in the other the posterior interambulacrum is subcarinate, and the posterior margin is more sloping owing to the projection of the lower posterior corner. In De Loriol's figure, pl. viii, No. 4, the posterior margin has a slope of only 7° from the vertical; in his fig. 5 this slope is 15° from the vertical.

All observers are agreed that the bones of the plastron and some bones of the carapace are simple membranous bones, arising from centres formed in a pre-existing fibrous membrane. Considerable difference of opinion exists as to the development of the costal and neural plates of the carapace.

Owen speaks of the ossification “as extending from the ribs and neural spines into the substance of the neural and costal plates. The ribs and spines enter into the composition of the carapace.”

Gegenbaur questions whether the ribs of the Chelonia “are not in reality enormously developed transverse processes, and considers that the neural and costal plates have developed in the integument.”

Claus remarks that the spinous processes of eight of “the thoracic vertebræ (2nd to 9th) appear in the middle line as horizontal plates (neural plates), the ribs of the same vertebræ are transformed into broad transverse plates (costal plates).”

Huxley says that the neural plates and the costal plates exist as expansions of the cartilages of the neural spines and ribs of the primitive vertebræ, before ossification takes place. This being the case, the “neural and costal are vertebral and not dermal elements, however similar they may be to the nucleal, pygal, and marginal plates.”

The object of the present paper is to show how, by graphic methods, we may find the relation between the effort exerted at one part of a machine in motion, and the resistance overcome at another part; the solution found is rigorous for all motions in one plane, and takes count of the friction, weight, and inertia of the parts. It also takes into account the stiffness of ropes or belts.

The paper shows that we may represent any machine, at any given instant, by a frame of links, the stresses in which are identical with the pressures at the joints of the machine. This self-strained frame is called the dynamic frame of the machine, and may be so drawn as to represent the machine either rigorously, taking into account friction, weight, inertia, and rigidity, or approximately, omitting some of the conditions under which the machine works.

Moreover, it is shown that for all machines (in which the motions can be represented as in one plane), the dynamic frame is of one type, either simple or compounded. The dynamic analysis of machinery into parts represented by this simple frame is believed by the author to be novel. It is consistent with the kinematic analysis of Reuleaux.

The first ichthyosaurian specimens discovered from the Upper Triassic of the Russian Arctic (Kotelny Island, New Siberian Islands) are described herein. They include the remains of large- to small-bodied ichthyosaurians originating from six stratigraphic levels spanning the lower Carnian to middle Norian. The material is mostly represented by isolated vertebrae and ribs, which are not possible to accurately diagnose, but also includes specimens comprising associated vertebrae and a fragmentary skeleton that preserves cranial remains (parabasisphenoid, fragmentary quadrate, partial mandible and hyoids). Based on vertebral and rib morphology, we identify the specimens as representatives of the following taxonomic groups: large-bodied shastasaurids, medium-sized indeterminate ichthyosaurians with a single rib facet in the presacral centra, and small euichthyosaurians with double rib facets present throughout the presacral vertebrae that likely represent toretocnemids and/or basal parvipelvians. In addition, the cranial and mandibular remains preserved in one of the specimens, ZIN PH 5/250, were studied using micro-computed tomography. Its mandible is highly similar to that of toretocnemids, whereas the parabasisphenoid demonstrates a peculiar combination of both plesiomorphic and derived character states, providing the first detailed data on this cranial element in a Late Triassic ichthyosaurian. Furthermore, the specimen also demonstrates a distinctive condition of rib articulation in the anteriormost presacral (cervical) vertebrae, which together with other features allows for the erection of a new taxon – Auroroborealia incognita gen. et sp. nov. Although the phylogenetic position of this taxon is uncertain due to its fragmentary nature, its anatomy, indicating toretocnemid or parvipelvian affinities, further supports the previously hypothesised sister-group relationships between these two clades. The morphology of the parabasisphenoid and vertebral column of the new taxon is discussed in broader contexts of the patterns of evolution of these skeletal regions in ichthyosaurs.

James Croll's Physical Theory of Secular Changes of Climate emerged during an age of revolution in geology that included the rise of the glacial theory and the search for its underlying causes. According to Croll, periods of high eccentricity are associated with the persistence of long glacial epochs, within which glaciations occur in alternate hemispheres when winter is at aphelion every ~11,000 years; however, astronomical forcing is only able to produce glaciation by means of physical agencies (climate feedbacks) that amplify the small effects of varying seasonal irradiation. Croll understood the importance of interglacial deposits because they provided evidence for the occurrence of multiple glaciations within his long glacial epochs. He was aware of the limitations of the terrestrial record and suggested that deep-sea sediments would contain a continuous succession of glacial-interglacial cycles. Contrary to a widespread view, however, Croll was not envisaging the advent of palaeoceanographic exploration avant la lettre, but instead was drawing attention to the inadequacy of the land record as a testbed of his astronomical theory. Yet, the marine record did eventually deliver a test of astronomical theories almost exactly 100 years after the publication of his 1875 book Climate and Time in their Geological Relations. Here, we provide an historical account of the technological and scientific developments that led to this and a summary of insights on astronomically paced climate changes from marine, terrestrial and ice core records. We finally assess Croll's ideas in the context of our current understanding of the theory of ice ages.