The highly specialised features of the Compositæ leave little room for doubt that the family is an advanced one, and it is not without significance that the vast majority of its species should be herbaceous plants; shrubby species are infrequent, while trees are of the rarest occurrence. The markedly herbaceous habit is further emphasised if attention is confined to the large and widespread genus Senecio, comprising over 2000 species, for, although they include plants of very diverse habit, few attain to tree dimensions, or possess a well-developed, perennial, woody trunk. Herbs or shrubs account for 99 per cent, of the species, the former greatly predominating. The remainder comprises a small group of about 20 species, which have assumed the arborescent habit.

That there must be a medium forming a continuous material communication throughout space to the remotest visible body is a fundamental assumption in the undulatory Theory of Light. Whether or not this medium is (as appears to me most probable) a continuation of our own atmosphere, its existence is a fact that cannot be questioned, when the overwhelming evidence in favour of the undulatory theory is considered; and the investigation of its properties in every possible way becomes an object of the greatest interest. A first question would naturally occur, What is the absolute density of the luminiferous ether in any part of space? I am not aware of any attempt having hitherto been made to answer this question, and the present state of science does not in fact afford sufficient data. It has, however, occurred to me that we may assign an inferior limit to the density of the luminiferous medium in interplanetary space by considering the mechanical value of sunlight as deduced in preceding communications to the Royal Society from Pouillet's data on solar radiation, and Joule's mechanical equivalent of the thermal unit.

The greater part of this Monograph is devoted to detailed descriptions of 1426 samples of deposits from the floor of the Atlantic Ocean stored in the Challenger Office, Edinburgh, which had been collected during thirty-five cruising expeditions between 1857 and 1911. The remaining part discusses the results of the work.

Plant miospore assemblages obtained from eight beds of the Foulden sequence, ranging from Bed 1 to Bed 17, are basically similar to each other in stratigraphical significance. The presence of Convolutispora circumvallata, Crassispora trychera and Schopfltes claviger and the absence of Lycospora pusilla suggest assignment to the Schopfites claviger-Auroraspora macra (CM) Biozone. This indicates the Courceyan Stage of the British Dinantian and the late Tournaisian (Tn3) of the Belgian Series. Comparable miospore assemblages have been described from Cementstone Group localities elsewhere in Berwickshire, East Lothian, Ayrshire and northern England. Preservation, and lack of marine palynomorphs and scolecodonts, suggest non-marine deposition. The presence of vitrinite fragments and megaspores as well as miospore tetrads suggests little transport before deposition.

Some time ago, at the request of Professor Ewart, I undertook an examination of the skull and visceral skeleton of the Greenland shark, Læmargus microcephalus. This I readily consented to do, not only because no attempt had yet been made to describe these structures in this shark, but because they claim careful consideration in view of the recent work by Professor Ewart on the cranial nerves of Elasmobranchs.

In this paper I shall endeavour, without entering into too much detail, to point out some of the more salient features of the skull and visceral skeleton of Læmargus, and to compare them with those of other Elasmobranchs where that seems necessary.

I have made preparations of the above-named structures from the heads of several specimens of Læmargus. The sharks from which the heads were taken were of various sizes, the smallest being about six feet in length, and the largest twelve. As might have been expected, the skeletal parts of these heads are very similar to each other, but I have noticed among the few specimens I have examined points of difference, which make me wish I had a larger number of preparations at my disposal, to enable me to decide the more usual conditions.

The greater part of Kintyre is composed of metamorphic rocks. For the study of these rocks it is convenient to divide the peninsula into three separate areas as follows:—

A. Northern Kintyre.

B. The south-western corner of the peninsula.

C. A triangular area stretching from Campbeltown Loch southward (fig. 1).

A. With the exception of a few isolated patches of Palæozoic sandstones, conglomerates, and lavas, and igneous rocks of several ages, Northern Kintyre is composed of sedimentary schists and grits, metamorphic limestones, and schistose igneous rocks which, as a rule, are associated with the limestones.

Systems of ordinary linear differential equations are of great importance, both from a practical and from a theoretical point of view. They figure largely in dynamical problems; and Jacobi has shown that the general problem of determining the order of any system of ordinary differential equations whatever can be reduced to the problem of determining the order of a linear system with constant coefficients. Nevertheless, the present state of the theory of such a system still leaves something to be desired. It is true that a logical and systematic process for the solution was given by Cauchy. This consists in first replacing the system by another in which only first differential coefficients occur, by introducing as auxiliary variables the successive differential coefficients of the various dependent variables up to the highest but one, and then reducing this system to the “normal form” by calculating the differential coefficients as linear functions of the dependent variables. It happens, however, when we attempt to do this, that we are led to a system consisting partly of differential equations of the form

where fr, denotes a linear function of x1, …., xs, partly of a number of non-differential equations connecting the remainder of the variables with x1, …., xs. The order of the system—that is to say, the number of independent arbitrary constants required for its complete solution—is the number of differential equations in the normal form; but no rule is readily deducible from the method for determining beforehand how many of the equations in the normal system will be differential equations, so that we cannot predict the order of the system without actually going through the labour of reduction. Moreover, the normal form is in practice often not the most convenient for the purposes of solution.

In the early Carboniferous, the portion of continental crust that now constitutes Scotland lay within the hinterland of a large continent that extended westwards to what is now the western parts of North America, eastwards to what is now the Urals and northwards towards what is now Arctic Canada, Greenland, Scandinavia and Russia. Open ocean probably lay at between 600 and 1000 km to the south. Whereas mountainous terrane lay to the north of the Highland Boundary fault, the Scottish Midland Valley, like the Northumberland Trough further south, was a region of low relief subject to periodic marine incursions.

A period of block faulting and concomitant basaltic volcanism commenced at the beginning of the Carboniferous at c. 350 Ma. This had manifestations in various regions of the British Isles from the south-west of England to the west of Ireland and as far north as the Midland Valley (Francis 1978, 1991; Upton 1982; Cameron and Stephenson 1985).

The Coal Measures of the South Wales Coal Field fall into three well-marked divisions:—

I. The Upper Pennant or Upper Penllergare Series.

II. The Lower Pennant Series.

III. The White Ash Series.

In 1885 I paid a visit to this Coal Field, with the object of studying its Fossil Flora, hoping by this means to ascertain the relative position of the Welsh Coal Measures to those of the other Coal Fields of Britain.

At the end of 1926 a paper by Dr Maclaren entitled “Development of Cavia: Implantation” was published in the Transactions of the Royal Society of Edinburgh (2). In this he dealt with the process of implantation of the blastocyst, and incidentally gave a tentative interpretation of the nature of the layers of which it was formed. The paper was to have been followed by a further contribution dealing especially with the earlier stages in the history of the blastocyst. This was held up for various reasons, and was not ready for publication until 1930, when there appeared appaperd on the subject by Professor Hill and Dr Sansom (6). This forestalled to a considerable extent Dr Maclaren's demonstration of the facts of observation, but there remained to him more than a dozen examples of free blasto-cysts at younger stages of development than the earliest figured in their paper, and indeed of any other worker on the development of Cavia. He then thought that it might be more interesting and instructive if the fixed and sectioned material were controlled by observations on the living blastocyst. A technique for this was developed, and apparatus designed by which living blastocysts could be observed and photographed. Eminently successful in the case of mammals with large blastocysts and tardy implantation, the results obtained in Cavia were disappointing owing to the excessive minuteness of the blastocyst, and to its being very early involved in one of the crypt-like recesses in the mucosa.

It is held by many that the body temperature shows certain fixed diurnal and seasonal variations which cannot be accounted for by the action of the various influences, such as muscular exercise, ingestion of food, sleep, etc., which are known to affect the rate of heat production and heat loss. These variations are believed to be associated with corresponding changes in the tissue activities, and to a large extent to be independent of environmental conditions.

The following is the first of a series of papers which I intend to issue on South African Alcyonaria. During a lengthened residence at the Cape of Good Hope, I devoted special attention to the Alcyonaria collected on board the Government steam trawler Pieter Faure. Professor Hickson has contributed two papers on Cape Alcyonarians to the volumes Marine Investigations in South Africa; but since then a large number of forms have been dredged, and there still remain in the collection entrusted to me many unidentified and undescribed species. In this first instalment I have confined myself to the Alcyonacea. The present work has been carried on in the Zoological Institute and Museum of Natural History, Berne, and it would be difficult to overstate my indebtedness to Professor Studer, who, besides giving me much valuable advice, stimulus, and encouragement, placed the entire literature of the subject at my disposal.

Oxroadopteris parvus gen. et sp. nov. is described from a single incomplete curved stem, 12 cm long and 8 mm diameter, having a cylindrical exarch protostele and sparganum outer cortex. Attached are 8 incomplete bifurcate petioles in probably 2/5 phyllotaxy. Each petiole has a swollen base with sclerotic nests. Petiole lengths increase upwards. Each petiolar trace is small, U-shaped in cross-section, bipolar, and divides to form similar smaller bundles in two secondary rachises.

We undertake a re-interpretation of eighteen sheets of the 1: 100,000 Geological Survey map of Italy. Developing the tectonic discoveries of G. Steinmann and S. Lencewicz we group the pre-Middle Miocene rocks of the district in four structural units beginning with the lowest as follows: (1) The rocks seen through the Carrara Window; (2) Spezia Nappe; (3) Liguria Nappe; (4) Genoa Nappe. Our account mainly concerns the Liguria Nappe. In it we find too much layering to admit of G. I. Migliorini's invocation of successive piecemeal landslips. We also cannot agree with certain important features of R. Staub's synthesis of Mediterranean tectonics.

The aquatic diplocaulid nectridean Keraterpeton galvani is the commonest taxon represented in the Jarrow Coal assemblage from Kilkenny, Ireland. The Jarrow locality has yielded the earliest known Carboniferous coal-swamp fauna in the fossil record and is, therefore, of importance in understanding the history and diversity of the diplocaulid clade. The morphology of Keraterpeton is described in detail with emphasis on newly observed anatomical features. A reconstruction of the palate includes the presence of interpterygoid vacuities and new morphological details of the pterygoid, parasphenoid and basicranial region. The hyoid apparatus comprising an ossified basibranchial element has not been reported previously in nectrideans. The structure of the scapulocoracoid and primitive nature of the humerus is described and the presence of a five-digit manus confirmed. Previously unrecognised accessory dermal ossifications are present in the pectoral girdle. Keraterpeton longtoni from the Bolsovian in Staffordshire, England, is also described and newly figured. The primitive condition in diplocaulids is defined on the basis of the earliest occurrence at Jarrow and discussed in relation to functional morphology and mode of life. The evolution of the diplocaulid clade is assessed in relation to the revised diagnoses that define the primitive condition in Keraterpeton.

In 1843 I presented a paper to the Royal Society of Edinburgh, giving an account of experiments made on the boiling point of water in the Alps, under various barometric pressures. My object was twofold: first, to describe an apparatus which I considered more practically available than those previously in use; and, secondly, to give a simple, and, as I believed, new formula for computing heights from such observations.

With reference to the second point, I became aware, some time after the publication of my paper, that Sir John Leslie had proposed to compute heights by the thermometer, assuming the change of the boiling point to be exactly in proportion to the height ascended. While cheerfully conceding to Sir John Leslie priority on this point, I submit that he did not bring forward experiments to justify its practical adoption.

Before submitting the results of my examination of the silicates, it is incumbent upon me to give an outline of the processes adopted for their analysis, seeing that the amount of confidence which is to be placed in the results must rest very immediately thereupon.

1. Determination of the Water. — In all silicates which were found, after thorough drying, to give out moisture when heated in the closed tube, the amount of loss upon ignition was calculated as water. About 2 grammes, crushed in the diamond mortar, were first merely heated throughout in the air-chamber of a water-bath, the contact temperature of which was 212° Fahr., the temperature of the air-space being never below 199°. The weight after this heating was taken; and, except in the case of a mineral functioning in any peculiar way, the loss in weight was estimated as hygroscopic moisture. The mineral was now continuously heated in the bath until the weight was found to be constant. It was then exposed for the space of one hour to a full red heat, in the flame of a Bunsen burner, after which it was re-weighed. Finally, it was exposed for ten minutes to a heat approaching whiteness, in a three-jet Griffin blast-furnace, again re-weighed, and again heated in this furnace, until the weight was constant.

Abundant as are the localities in which garnet is found in Scotland, there are but few which yield specimens such as can be analysed.

This is on account of an intermixture of quartz—for the most part in a granular form—the granules being promiscuously scattered throughout the mass of the crystals. In three localities the intermixture is not promiscuous, but has been governed by some intermittent crystalline action. These localities are Glen Skiag in Ross, where, around a central nucleus of leucitoidal crystals of garnet, translucent quartz is arranged in layers which alternate with those of the garnet, conformably to the figure of its crystal.

The two other localities are the first and third granitic veins to the east of Portsoy; in both of which garnet of a pale brown colour is laced with quartz, which is arranged in a graphic manner, as in the felspar from an adjacent vein. At no other locality do I know of such an occurrence. The appearance of a section of a rhombic dodecahedron is somewhat like the figure.

Before giving a description of the specimen which forms the subject of this communication, it seems desirable that a brief summary of the literature dealing with the internal structure of Sigillaria, and some general remarks on the classification of the genus, should be given.

More for the purpose of convenience than on scientific grounds, the genus Sigillaria is usually divided into four groups. These groups were originally supposed by their founders to be of generic value, but experience has shown that the characters on which they were founded are more or less common to all four divisions, and in some cases the distinctive divisional characters even occur on the same specimen.

1. In the course of some inquiries concerning the power of metallic substances to conduct intense electrical explosions, an account of which was honoured by a place in the Philosophical Transactions for the year 1827, I sought to obtain a comparative measure of the conducting power, in the heat evolved by the metal, at the time of transmitting the charge. The instrument employed for this purpose, was, in principle, that of a common air thermometer, the given metal, the subject of experiment, being drawn into a wire, and passed air-tight across its bulb. This simple contrivance, I have since extended to the general purposes of an electrometer, so as to estimate the force of any ordinary electrical accumulation. The results arrived at with voltaic combinations, seem, for the most part, of much practical utility; and therefore some account of them may, I trust, be found worthy of the attention of the Royal Society of Edinburgh.