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.

The research which forms the subject of this paper was undertaken in the hope that it might throw some additional light on the numerical relation existing between the bacteria present at various depths in ordinary soils, and in soils which had been used for purposes of interment. It was thought well to combine the chemical with the bacteriological examination for the purpose of determining to what extent the amount of organic matter present in the two classes of soil differed, and in what respect the organic matter of the one was different from that of the other, as well as to ascertain, if possible, to what extent the process of self-purification goes on in soil which has been used for burial.

In May 1891 I communicated a paper to this Society “On a Method of Observing and Counting the Number of Water Particles in a Fog,” and in July of the same year a paper “On the Solid and Liquid Particles in Clouds.” One conclusion to which the observations contained in these papers pointed was, that there existed a relation between the thickness or density in clouds and fogs and the number of water particles present. Though the figures did not show that this relation was very close, yet in all the fogs and clouds tested there was a rough relation between the thickness of the air and the number of water particles observed.

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 curious effects of rotation upon the path of a spherical projectile have been investigated experimentally by Robins and many others, of whom Magnus is one of the more recent. They have also been the subject of elaborate mathematical investigation, especially by Poisson, who has published a large treatise on the question. For all that, we know as yet very little more about them than Newton did in 1666, when he made his famous experiments on what we now call dispersion.

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.

At the meeting of the British Association in Edinburgh, in August 1892, the President of the Biological Section, Professor W. Rutherford, M.D., F.R.S., F.R.S.E., gave an able opening address on “The Colour-Sense,” in which he took occasion to speak at some length on that remarkable defect of vision called Colour-Blindness. After alluding to the large share of public attention it had lately attracted, both on scientific and popular grounds, he pointed out the unsatisfactory nature of certain statements lately put forward, and gave good reasons why the views still largely held on it in this country required revision.

The numerous analyses of sea-water by Forchhammer previous to 1865, and the later analyses by Dittmar, from samples collected during the “Challenger” Expedition, show that while the salinity—i.e., the amount of dissolved salts contained in 100 parts of seawater—varies greatly in different regions of the ocean, still the composition of these dissolved salts—i.e., the ratio of the constituents of sea-salts—remains practically the same in all the superficial waters of the ocean. Consequently, it is only necessary to determine the chlorine in a definite weight of water to ascertain at once the respective quantities of the other salts present in the sample. Dittmar's examination of the “Challenger” waters has, however, shown that lime is slightly, although distinctly, more abundant in samples of sea-water collected in greater depths than in those samples collected nearer the surface of the ocean, and Dittmar's tables showing the difference between the chlorine calculated from the specific gravity and the chlorine found by analysis point to differences in the composition of the sea-salts, but the observations are relatively so few, these differences so slight, so mixed up with observational errors, and so irregular in their geographical and bathymetrical distribution, that they cannot be said to indicate any general law other than a greater quantity of lime in deep water.

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.

Though a great deal has been written on the Eurypteridæ, and many points of their anatomy elucidated in the brilliant memoirs of Huxley and Salter, Hall, Woodward, Schmidt, &c, nevertheless many points of morphological importance remain obscure. This is perhaps to be attributed to the fact that nearly all the writers on this group have treated them rather from the systematic than the morphological standpoint. In dealing with remains so fragmentary and obscure as the majority of these fossils are, the value of some theory as to their relations among recent forms is enormous, both as suggesting points to be looked for and aiding in the interpretation of structures observed. The greater part of the work on this group was done before the arachnid relationship of Limulus was fully appreciated, and it is in the light of a possible relationship to this form, and also to the lower orders of terrestrial Arachnida, that it seemed to me to be worth while to revise the anatomy of the group. It has been necessary to include a certain amount of what is already well known in the description of the different genera, and I have taken special care to confirm, as far as possible, points which seemed to me to rest on insufficient grounds.

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.