The study of a normal process in an organ so especially prone to disease as is the human uterus, is beset with many difficulties; so many foreign conditions are apt to be present, giving a false impression as to what this process really is. That this is the case to no small degree, when the character of the changes which occur in the normal involution of the uterus after child-birth is the subject of observation, is shown by the variety of opinions held and stated by doubtlessly competent observers; for while one holds that the muscle undergoes a fatty degeneration, another holds that no such fatty change occurs; while one asserts that only a certain number of the fibres degenerate and disappear, another states that so complete is the destruction, that not one single fibre present in the uterus before birth survives the process; while another goes to the extent of saying, that the puerperal uterus can in no way be distinguished from a uterus that has undergone an inflammatory process.

Until very recently existing information concerning the eggs and oviposition of British fishes, and more especially marine fishes, was of the most fragmentary character. In the standard works upon Ichthyology, such as Owen's Anatomy of Vertebrates (vol. i. Fishes), it is comprised in a few vague sentences; while the original papers published by British ichthyologists are not numerous, and refer, for the most part, to fresh-water species. Within the last few years, however, attention has been more systematically directed to the subject, and the enlightened views of the late Royal Commission on Trawling, and more especially of its chairman, the late Earl of Dalhousie, has given a fresh impetus to the study of the development and life-history of our food-fishes, as preliminary to a thorough investigation of their habits, food, so-called migrations, and general life-history.

The solid matter floating in our atmosphere is every day becoming of greater and greater interest as we are gradually realising the important part it plays in the economy of nature, whether viewed as to its physical, physiological, or meteorological aspects. One fundamental point on which we have at present very little information of anything like a definite character, is as to the number of solid particles present in our atmosphere. We know that they are very numerous, and it seems probable that the number varies under different conditions of weather; but what number of particles are really present under any conditions, and how the number varies, we have at present very little idea. In this field of research the physiologists are far in advance of the physicists, as they have devised means of counting the number of live germs floating in our atmosphere, and already we have a good deal of information as to how the number varies under different conditions.

Until a few years ago it was the general opinion among metallurgists that the presence of manganese in steel exceeding the proportion of 1 per cent, is prejudicial to the value of the steel, inasmuch as a higher percentage of manganese has the effect of lowering markedly its tensile strength and toughness. But in 1884, Messrs Hadfield & Company, of the Hecla Steel Works, Sheffield, exhibited, at a meeting of the Institute of Mechanical Engineers, a number of samples of steel containing upwards of 10 to 15 per cent, of manganese, and submitted the results of experiments, which showed that the samples were, in point of tensile strength and hardness, in no way inferior to steel. Again, in 1888, Mr R. A. Hadfield read to the Institute a paper on the subject, giving the details of a large number of tests, which brought to light some interesting mechanical properties of alloys of manganese and iron. Since its introduction, these alloys (and particularly that containing 10 to 15 per cent, of manganese, known as “manganese-steel”) have been studied by several physicists, and further peculiarities have been found. It appeared desirable that the thermal conductivity of so peculiar a substance should be investigated. The present paper is an account of experiments made in the Physical Laboratory, Edinburgh University, with a view to the determination of its thermal conductivity. In the reduction of such experiments a knowledge of the specific heat is necessary, hence there is also given an account of experiments whereby the specific heat was determined.

The preliminary notices published by me in 1870 and 1872, on the action and chemistry of Strophanthus, indicated that it was likely to prove of value as a therapeutic agent; and so early as the year 1874, I had applied the substance in a few cases to the treatment of disease. Before sufficient data, however, had been obtained to justify any conclusions regarding its value as a therapeutic agent, the observations were interrupted by my leaving Edinburgh to occupy a public office in England, in connection with which it was impossible to conduct observations on the treatment of disease. In 1879, opportunities were again afforded to resume the interrupted observations, and results confirmatory of the anticipations which had been raised by the earlier physiological observations were gradually collected. The publication of a few of these results at the Cardiff meeting of the British Medical Association in 1885 has led to Strophanthus gaining a wide recognition as an important therapeutic agent, and to the production of numerous papers dealing with its botany, chemistry, pharmacology and therapeutics, not only in this country, but also in the continent of Europe and in America.

In a former paper I described certain experiments on the relations of magnetism and twist in iron and nickel, the chief results of which it may be well to give briefly here. When an iron or nickel wire is under the influence of longitudinal and circular magnetisations, it twists in a direction which is definitely related to the direction of the magnetising forces. This effect in iron was discovered by Wiedemann, and for convenience I shall call it the Wiedemann Effect. It was pointed out by Clerk Maxwell that the Wiedemann effect might be explained as a consequence of the earlier discovery made by Joule, that iron lengthens in the direction of magnetisation, and contracts at right angles thereto. Led by a consideration of Barrett's discovery of the shortening of nickel wire in the direction of magnetisation, I determined to test nickel in the same way in which Wiedemann had tested iron. It was quite obvious that, if Maxwell's explanation of the Wiedemann effect were the true one, nickel wire should, ceteris paribus, twist in a sense opposite to that in which iron twists. The experiment when made completely fulfilled the expectation. Thus, when an iron wire, with one end fixed, is traversed by an electric current in the direction in which it is at the same time longitudinally magnetised, the wire is twisted so that the free end rotates right-handedly with reference to the traversing current, or the longitudinal magnetisation. In nickel, on the contrary, the corresponding rotation is left-handed. This was the chief conclusion arrived at in my earlier paper; and a little consideration will show how very readily the Wiedemann effect, whether in iron or in nickel, is explained in terms of the simpler strains studied by Joule and Barrett.

Among the problems for the study of which the remarkably varied geology of the British Isles offers peculiar facilities, perhaps none ranks higher in importance or in general interest than the history of volcanic action. Placed on the oceanic border of an ancient continental area, the region of Britain has lain within the limits where hypogene activity is specially prone to manifest itself. From early geological times this activity has been displayed in various characteristic forms. Hence, within the geological records of Britain there has been preserved a more continuous and complete chronicle of volcanic phenomena than, so far as I am aware, has yet been discovered in any tract of similar size on the face of the globe. The rocks of the country have been investigated so long and so minutely that their general chronological succession has been accurately ascertained, and hence the precise horizon of each volcanic episode can be definitely fixed. The varying phases of eruptivity in different geological periods can be made out, and a large body of evidence can thus be amassed bearing on the general question of the past history of volcanism.

A copy of Mr Marrat's paper “On the Fossil Ferns in the Ravenhead Collection” having come into my hands, I was led to visit the Liverpool Free Public Museum in 1886, and again in 1887, with the object of examining this interesting collection, and while doing so I received every assistance from Mr Thomas J. Moore, the Curator, and Mr F. P. Marrat, to whom I take this opportunity of expressing my indebtedness for the many kindnesses I received while studying the Ravenhead plants. I have further the pleasure of acknowledging the privilege accorded me by the Museum Committee, through the kind offices of the Rev. H. H. Higgins, which allowed me to have a number of specimens sent to Stirling, where I could more advantageously examine them than in the Museum, where the literature of the subject is limited.

I have explained at some length, in my “Reply to Prof. Boltzmann,” the circumstances under which the present inquiry originated and has been pursued. Of these I need now only mention two:—first, the very limited time which I can spare for such work; second, the very meagre acquaintance I possessed of what had been already done with regard to the subject. My object has been to give an easily intelligible investigation of the Foundations of the Kinetic Theory; and I have, in consequence, abstained from reading the details of any investigation (be its author who he may) which seemed to me to be unnecessarily complex. Such a course has, inevitably, certain disadvantages, but its manifest advantages far outweigh them.

Of these gigantic thermometers, with their bottle-sized bulbs, their long capillary intermediate tubes, and their upper enlarged bores for scale-reading purposes, an account of their construction and being placed in position for observation on June 26, 1879, is to be found in Part II. Vol. XXIX. of the Transactions of the Royal Society, Edinburgh, for 1879–80, and it is only proposed in the present place to give an account of their performances since that time.

The purpose of the present paper is to ascertain how far it is possible to find exact solutions or values of x, y, &c., in equations between variables, so that the forms of plane curves and contour-lines of surfaces may be exactly determined. No approximate methods have been admitted, and only those methods have been used which are applicable to algebraic equations of every degree and any number of variables. In the examples given I have generally selected equations of even degree and even powers of the variables. But every such solution evidently includes the solution of the non-central equation of half the degree having corresponding terms and equal coefficients. The methods of solution employed are founded on the following introductory theorem or principle, which may be described as that of Homogeneous or Linear Variation of the quantities.

Teilia Quarry, from which the fossils described in this paper have been collected, is situated about a quarter of a mile north-east of the village of Gwaenysgor, which is distant about five miles from Rhyl and one from Prestatyn.

The geology of the district has been fully described by Mr G. H. Morton, F.G.S., from whose paper the following notes are compiled:—

A considerable part of North Flintshire is occupied by a great development of limestone, which is generally referred to in writings on the subject as “Carboniferous Limestone.” It forms a tract of hilly ground, some of the higher points rising to a height of over 800 feet. These limestones lie immediately beneath the Cefn-y-Fedw sandstones, and occupy a hollow of considerable extent in Silurian strata.

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.

The fragmentary nature of our knowledge of the behaviour of the more strongly basilous hydrates and carbonates at high temperatures is owing chiefly to the absence of a suitable material for the necessary crucibles. Unfortunately there is no metal which combines the infusibility of platinum with the chemical inertness of gold, in opposition to fiery-fluid caustic alkalies. But the corrosive action of these on platinum, as I showed some years ago, is a function only of the peroxides formed from them by the action of atmospheric oxygen, and, consequently, can easily be prevented by operating in an atmosphere of hydrogen or nitrogen.

On the Fossil Plants collected during the Sinking of the Shaft of the Hamstead Colliery, Great Barr, near Birmingham.

The area comprised in the county of Stafford embraces five coal fields—

I. The Goldsitch Moss Coal Field, in the extreme north-east of the county.

II. The Cheadle and Churnet Valley Coal Field.

III. The Wetley and Shafferlong Coal Field.

IV. The Coal Field of the Potteries.

V. The South Staffordshire Coal Field.

The three first mentioned are of small extent, and as I know little of their fossil flora they are omitted from this series of papers on the Carboniferous Flora of the Staffordshire Coal Fields.

I, however, devote a separate communication to the fossil plants met with while sinking the shaft of the Hamstead Colliery, Great Barr, as a considerable part of the rocks passed through during this operation is clearly Upper Coal Measures, not Permian, as has been generally stated. The palæontological evidence, therefore, becomes of special importance in determining the age of the red shales occurring in the upper part of this sinking, which have been usually mapped as Permian.