In a paper on the Chemistry and Pharmacology of Strophanthus hispidus, it was pointed out by one of us that when strophanthin, the glucosidal active principle present in the seeds and several other parts of this plant, is subjected to the action of dilute acids, it yields, among other products, a crystalline body—strophanthidin. A brief description was also given of processes by which this body may be prepared, and of several of its characters and chemical properties.

The chemistry of strophanthidin will be more fully described in the present paper.

The experiments now to be described have for their object the investigation of the magnetic induction in an iron conductor under the influence of a current passing through it. The method of experiment was briefly in this wise. An iron tube was magnetised circularly by a current passed from end to end along its entire length; and the induction so produced in the iron was measured in terms of the current induced in a coil of wire wound longitudinally round the walls of the tube.

In the experiments four tubes were used, all of the same length and nearly the same external diameter. The internal diameters of one pair were approximately double those of the other. The various dimensions are given accurately in the following table, the tubes being distinguished as A, B, a, b. Each diameter measurement is the mean of eight measurements taken across different diameters.

In a new investigation of this kind it is always desirable to repeat the observations under as many conditions as possible. The variables are so many that with a limited experience it cannot be expected that the subject will be exhausted, or that the conclusions arrived at from early observations will be in all cases confirmed. As an opportunity offered in the beginning of 1890 for repeating the tests made the previous year on the amount of atmospheric dust at different places on the Continent, it seemed desirable that the old ground should be gone over again rather than that the investigation should be extended to new areas. The observations made in this country have also been confined to the same stations as in 1889; and in this paper I intend giving the results of a series of tests repeated at the same stations, at about the same dates, but under the conditions existing in 1890, as has already been given for 1889 in Part I. of this subject.

The discoverer of Nova Aurigæ is the Rev Thomas D. Anderson of Edinburgh, D.Sc. in Classical Philology. Dr Anderson is “almost certain” that he saw the star at 2 a.m. on January 24 of this year; it was then slightly brighter than χ Aurigæ. Unfortunately, he mistook it for 26 Aurigæ, which it precedes by about 6m 39s, merely remarking to himself that the star was brighter than he had previously thought it to be. Twice in the following week he made the same observation at about the same hour of the night. At last, on the morning of January 31, it flashed upon him that, after all, the star was not 26 Aurigæ, and that 26 Aurigæ had a much greater right ascension. He consulted a small star-map, and the discovety was made. Regretting that he had not earlier compared the map with the heavens, and thinking that the star might be well known to astronomers, Dr Anderson wrote an anonymous postcard to me on the same morning bearing the words:—“Nova in Auriga. In Milky Way, about two degrees south of χ Aurigæ, preceding 26 Aurigæ. Fifth magnitude, slightly brighter than χ.” I may add that Dr Anderson's plant consists of a small hand spyglass adapted to astronomical purposes by removing the front pair of lenses from the eyepiece. In this state it magnifies about ten times, and, of course, gives inverted images. Dr Anderson hopes that amateurs, although provided with only the most modest appliances, may, by his unexpected success, be induced to persevere in their observations.

Some years ago, when studying the electrical organs of the torpedo, I was forced to the conclusion that the nerves supplying the batteries had not been accurately described, and that notwithstanding the statements in the most recent works, the first electric nerve is not derived from the trigeminus. Finding some difficulty in making out the arrangement of the cranial nerves in the greatly specialised torpedo, I directed my attention, first to the skate, and later to certain sharks, more especially to the Greenland shark (Læmargus). I had not proceeded far before I was convinced that we had still much to learn as to the anatomy of the cranial nerves of both the higher and lower vertebrates.

In the paper on the sensory canals of Læmargus, communicated to the Royal Society in July last, it was pointed out that the arrangement of the sensory canals differed considerably in the Batoidei from that in Selachoidei, and it was mentioned that the sensory canals of the skate would be next described.

The skate has been selected chiefly because the sensory canals are more typical than in the torpedoes and the whip and sting rays. In the torpedoes some of the canals are in a vestigial condition; while in the rays proper they have in most species undergone great specialisation. But another reason is, that an account of the development of the lateral sense organs in the skate is likely ere long to be published; and, further, the skate will be more easily obtained and kept under observation than the rays, when physiologists eventually direct their attention to the lateral sense organs of Elasmobranchs.

In the two papers which I had the honour of reading to the Society in the spring of 1890, my object was, in the first place, to combat the vulgar idea that modern Greek is a corrupt and barbarous language, almost as far removed from classical Greek as Italian is from the dialect used by Horace and Virgil; and, secondly, to show that, between the two distinct strata in which Greek had flowed down continuously from Constantinople in A.D. 333 to the present day,—the literary structure used by educated men, and the Greek of the popular ballads used by the uneducated masses,—a compromise had been achieved by that great scholar and patriot, Adamantius Coraes. This compromise was made on the principle that the unity of action on which Greek nationality depends, requires that the learned classes should cheerfully adopt those few idiomatic peculiarities which had asserted themselves in the thought and expression of the great mass of the people; while the great body of the language bore visibly the stamp of those whose genius in Church and State had shaped it forth in the Attic and Byzantine periods. On this basis the modern Greek language was left at the death of Coraes in 1833. But it is not to be imagined that a formative rule of this kind, in the mode of national speech, could be established at a stroke.

The rich agricultural tract of country that forms the north-western part of East Lothian, undulating uniformly from the foot of the chain of the Lammermuirs towards the Firth of Forth, swells near Haddington into the cluster of the Garlton Hills, and the neighbouring masses of Traprain Law and North Berwick Law.

The rocks that build up this elevated ground are lavas and tuffs that were produced during the period of volcanic activity that characterised the deposition of the Lower Carboniferous beds of Scotland. In East Lothian their eruption followed close on the deposition of the sandstones and marls that constitute the base of the calciferous sandstone group.

For many years geologists have recognised the occurrence of at least two boulder-clays in the British Islands and the corresponding latitudes of the Continent. It is no longer doubted that these are the products of two separate and distinct glacial epochs. This has been demonstrated by the appearance of intercalated deposits of terrestrial, freshwater, or, as the case may be, marine origin. Such interglacial accumulations have been met with again and again in Britain, and they have likewise been detected at many places on the Continent, between the border of the North Sea and the heart of Russia. Their organic contents indicate in some cases cold climatic conditions; in others, they imply a climate not less temperate or even more genial than that which now obtains in the regions where they occur. Nor are such interglacial beds confined to northern and north-western Europe. In the Alpine Lands of the central and southern regions of our Continent they are equally well developed. Impressed by the growing strength of the evidence, it is no wonder that geologists, after a season of doubt, should at last agree in the conclusion that the glacial conditions of the Pleistocene period were interrupted by at least one protracted interglacial epoch. Not a few observers go further, and maintain that the evidence indicates more than this. They hold that three or even more glacial epochs supervened in Pleistocene times. This is the conclusion I reached many years ago, and I now purpose reviewing the evidence which has accumulated since then, in order to show how far it goes to support that conclusion.

The Upper Silurian rocks of the Gutterford Burn, in the Pentland Hills, have for some time been known to contain Eurypterid remains, but the fossils procured from these beds—chiefly owing to the exertions of Mr Hardy of Bavelaw Castle, and Mr Henderson, late Curator of the Phrenological Museum—have never been submitted to a thorough examination. When, therefore, by the kind permission of Sir R Murdoch Smith, Director, and Dr E. H. Traquair, Keeper of the Natural History Collection in the Edinburgh Museum, I was given an opportunity of examining Mr Henderson's collection, which was acquired by the Museum some years since, I entered upon the work with the expectation of finding some new and interesting forms which would repay description. My expectations in this respect have been more than fulfilled, as the collection has yielded five undoubtedly new species, one of which I have made the type of a new genus. If to these one adds at least two other new species which are in the collection of Mr Hardy of Bavelaw, and which I hope to have the pleasure of examining and describing at some future time, one is justified, I think, in saying that the Gutterford Burn is unequalled among Eurypterid localities with regard to the variety of forms it has yielded. Unfortunately the bed which has yielded these specimens is limited in extent, and further work on it would entail quarrying operations on a somewhat extensive scale.

The remarkable development of igneous rocks associated with the Torridon sandstone and Cambrian strata in Assynt, Sutherlandshire, forms one of the striking geological features of that region. In the various papers descriptive of the ancient sedimentary formations of the North-West Highlands by former observers, references are made to the lithological characters of these crystalline rocks and to their mode of occurrence.

Few subjects are of greater practical importance than the mode of action of the valves of the heart, inasmuch as these structures are so frequently the seat of pathological changes which produce serious disturbances throughout the whole circulatory system.

On the general principles of the mode of action of the aortic and pulmonary valves all investigators seem to be agreed. When we turn to the auriculo-ventricular valves we find that, while in some of the best known text-books their action is considered as so thoroughly investigated and completely understood as to merit no discussion, and to require only the briefest description, in others the mechanism is admitted to be imperfectly comprehended, and is described in the most obscure and indefinite manner.

Our knowledge of this remarkable genus of freshwater Oligochæta is at present entirely due to Dr Gustav Eisen. Within a year or two of discovering the type species, Sutroa rostrata, Dr Eisen found a second species, evidently referable to the same genus, which has been named Sutroa alpestris. Examples of both of these species have been most kindly forwarded to me by Dr Eisen; and I therefore take the opportunity of offering a few observations upon the structure of the genus, and upon its relations to other Oligochæta, as I am able, in a few matters, to supplement Dr Eisen's papers.

The account given by Eisen of Sutroa alpestris is evidently based upon a study of the living worm; it is therefore very full as regards the vascular system, but not quite so detailed where it concerns the generative organs, which are more conveniently studied by the section method. It is more especially to these organs that I desire to again draw attention.

Short synopses of my earlier results were given in the Gardeners' Chronicle for April and July 1890. Until after the publication of these I was not aware that some advance had already been made in the direction indicated, and my best thanks are due to Dr Masters for calling my attention to one or two publication's on the subject.

In 1831 Professor J. S. Henslow compared a hybrid Digitalis with its parents in a wonderfully minute way, when we consider the degree to which histology had advanced in his time. He demonstrated that in the size and shape of the hairs and other structures, the hybrid was intermediate between its parents. Wichura and Kerner have proved that the same is true of Willows and Pulmonarias respectively.