The publication by the Royal Society of Edinburgh of the hourly observations made at the observatory on the summit of Ben Nevis along with corresponding observations at Fort-William at the sea level is an important contribution to meteorological science. The study of this work reveals at once the important characteristic of the Ben Nevis Observatory. It is situated on a true peak, and that the highest point in the British Islands. Its height above the sea is such that it is usually enveloped in cloud, and its records are for the most part those of an observatory established in the clouds, and in an atmosphere habitually saturated with moisture.

The earlier mineralogists laboured under two great disadvantages. They could not readily, on account of the small number of students of chemistry, call in the aid of that science: and at the time when mineralogy was becoming a distinct branch of science chemistry was in itself crude as well as cumbrous. They were thus forced to rely chiefly upon external properties; and, where crystalline form was absent, they were confined to what may be called physical properties alone.

Their knowledge of the composition of bodies being thus limited and uncertain, the old nomenclature was to a considerable extent founded upon external features alone.

The first instalment of this paper was devoted in great part to the general subject involved in its title, but many of the illustrations were derived from the special case of the flight of a golf-ball. Since it was read I have endeavoured, alike by observation and by experiment, to improve my numerical data for this interesting application, particularly as regards the important question of the coefficient of resistance of the air. As will be seen, I now find a value intermediate to those derived (by taking average estimates of the mass and diameter of a golf-ball) from the results of Robins and of Bashforth. This has been obtained indirectly by means of a considerable improvement in the apparatus by which I had attempted to measure the initial speed of a golf-ball. I have, still, little doubt that the speed may, occasionally, amount to the 300, or perhaps even the 350, foot-seconds which I assumed provisionally in my former paper:—but even the first of these is a somewhat extravagant estimate; and I am now of opinion that, even with very good driving, an initial speed of about 240 is not often an underestimate, at least in careful play. From this, and the fact that six seconds at least are required for a long carry (say 180 yards), I reckon the “terminal velocity” at about 108, giving v2/360 as the resistance-acceleration.

1. The integral occurs so frequently in various branches of research that, as far back as 1783, Laplace suggested that it would be useful to tabulate its values for successive ranges of integration. It is employed in investigations on the theories of refraction, conduction of heat, of errors of observation, of probabilities, etc. These are familiar to physicists and need not be dwelt upon.

The unusually fine stem which forms the subject of this paper was found by Mr T. Kerr, of Edinburgh, in rocks of Calciferous sandstone age exposed in a railway cutting at Dalmeny, Linlithgowshire. Mr James Bennie, of the Geological Survey of Scotland, called the attention of Mr Kidston to the fossil, and the latter very generously placed part of the specimen in the hands of one of us for investigation.

The laps referred to below are parts of the external boundary of the figure, and are supposed to be described with the sun. The first specification of a lap refers to the side of the figure, the second to its position on the side.

We have already accounts of the development of the Müllerian ducts of reptiles from Braun (1), Mihalkovics (2), Hoffmann (3), and Wiedersheim (4). All of these writers agree in saying that the Müllerian ducts arise quite independently of the segmental ducts; but in view of recent attempts to show that in the other groups of vertebrates there are forms in which the Müllerian ducts are derived from the segmental ducts, it seemed expedient to reconsider this conclusion, and I have accordingly examined the development of the ducts in Crocodilus biporcatus, Chelone viridis, and Lacerta agilis.

As regards the derivation of the Müllerian ducts from cœlomic epithelium, I can only confirm the above-mentioned authorities; but I am able to supplement what they say as to the first foundation and the formation of the anterior end. I find that the anterior end is formed in reptiles, very much as in amphibians, by a modification of the cœlomic epithelium in the region of the pronephros. Backward growth proceeds independently alike of the segmental duct and of the epithelium of the body-cavity posterior to the ostium abdominale.

Among the specimens from the Yorkshire Coal Field which have been collected by Mr W. Hemingway, Barnsley, and submitted to me for examination at various times, are the remains of several cones which are referable to the genus Sigillariostrobus, Schimper.

Notwithstanding the great frequency of the genus Sigillaria in the Coal Measures, and especially in the Middle Coal Measures, examples of their fructification are very rare. This is the more remarkable, as specimens of Sigillaria, showing cone scars, though not common, are occasionally met with. Possibly, however, the apparent rarity of Sigillarian cones is due, in part, to our inability at present to distinguish them in all cases from cones generally placed under the name of Lepidostrobus, which latter genus there is every reason to believe comprises cones that belong to several genera of Lycopods.

The immediate purpose of the present research was the investigation of the temperature at different pressures of boiling mixtures of steam and salts, analogous to the well-known freezing mixtures of ice and salt.

When steam is blown through common salt in coarse powder, it condenses to water, which dissolves some of the salt, and the resulting brine is kept boiling by the arrival of more steam. The temperature of this boiling mixture is quite constant so long as there is an abundant supply both of steam and of salt, and as the atmospheric pressure does not change, it is about 8·5° C. above the temperature of boiling water when the barometric pressure is the normal of 760 mm. When the barometric pressure is 560 mm. this excess has fallen to 8·0° C. Most other salts behave in a similar way.

The experiments described in this paper were commenced with the view, not only of determining the absolute thermal conductivity of nickel, but also of comparing the results found by Forbes's and Ängstrom's methods for the same specimen. Although some readings were taken for Ängstrom's method, that part of the investigation was not completed, because it was found that the experimental errors — unavoidable, on account of the necessity of measuring rapidly changing temperatures—would be too great for the results to be of any value. The thermal conductivity of a portion of the bar of nickel used for Forbes's method was determined by a direct method involving the determination only of steady temperatures, and the results so obtained are given in the latter portion of this paper.

The former paper (5) on the Anatomy of Cephalodiscus was incomplete in certain particulars, which I am now in a position to add. These are mainly in regard to the alimentary canal, the nervous system, and the reproductive organs. To the present description of these will be appended an account of the budding processes, which are a very conspicuous feature of the species.

The various structures in the marsupial shoulder girdle are so unquestionably homologous with similar structures in the girdle of the human subject and of the Eutheria generally, that there has never been any difficulty in interpreting the parts in terms of human anatomy; but when the elements are compared with those in what we may consider to have been the ancestral condition, such as is exemplified in the shoulder girdle of the Monotremes, or of the Anomodonts, or in the more distantly related conditions met with in modern Reptiles and Amphibians, we are confronted with quite a number of difficulties, to which the most varied solutions have been applied by different morphologists. The chief difficulty in the way of comparing the typical mammalian girdle with that of the lower forms, is that in the girdle of the higher mammals certain structures are rudimentary, and, further, that the forms that have hitherto been examined have been so far removed from the ancestral stock that even a study of the early developmental conditions fails to give any clues that are more satisfactory than those afforded by comparative anatomy. Though it has been suspected that further results would be obtained from the study of the early condition in Marsupials and Monotremes, the embryos of these groups that have hitherto been studied have been too old to yield much further evidence than that obtained by a study of the adult forms.

1. The existence of relations between the coaxial minors of a determinant was first discovered by MacMahon in 1893. The whole literature of the subject is comprised in three papers, viz.:—

MacMahon, Phil. Trans., clxxxv. pp. 111–160.

Muir, Phil. Mag., 5th series, xli. pp. 537–541.

Nanson, Phil. Mag., 5th series, xliv. pp. 362–367.

My present object is to continue the investigation of the relations in question, and more particularly to draw attention to an explicit expression for a determinant of the 4th order in terms of its own coaxial minors. At the outset some fresh considerations regarding determinants in general will be found useful.