Muscovite is so easily recognised by its optical properties that the only cases which seemed to me to call for analysis were those which, from being possessed of characteristic colour, were of special interest. Of these the most singular is a variety found rarely in the great vein of Ben Capval, Harris; it occurs in crystals of a peculiar green tint, the crystals are small and have somewhat of a pearly lustre.

The rows of a determinant of the nth order having been separated into two sets, one containing the first p rows and the other the rest, if each minor of the pth degree formed from the first set be multiplied by a minor, called its complementary, formed from the second set, and the result have its sign chosen in accordance with a certain law, it is well known as an elementary theorem that the aggregate of the products thus obtained is equal to the original determinant.

There is no department of natural science which is so defective in its general scheme of arrangement as mineralogy; and its sectional grouping is, if possible, still more defective.

Such correlations as are expressed by the terms, “the Micas,”—“the Felspars,”—“ the Garnets,” &c., are only admissible if the substances united in such groups are included under one general formula, and function in a more or less similar manner as rock-formers.

While trying to verify by actual statistics some of the “ Laws of Population” first enunciated by Malthus, a curious fact was observed, viz., that some seasons of the year are more prolific in the number of births than others.

This led to the further investigation of the subject, the results of which are before the Society.

Since the liver is an organ whose due activity is indispensable for the maintenance of health; since it is frequently the subject of disorder, and consequently receives a large share of attention from the physician, it is obviously of great importance that he should possess precise knowledge of the manner in which it is affected by medicinal agents.

In a former paper read before the Society, and published in the Society's “ Transactions,” on ” Some New Bases of the CnH2n—11N series,” obtained from the “ vitriol-tar,” from the distillation of shale, evidence was given of the isolation of three bases of this series, in addition to the Leucoline, Iridoline, and Cryptidine of G. Williams.

In the first paper read before this Society “ On some New Bases of the Leucoline Series,” and published in the Society's “ Transactions,” it was stated that amongst other methods proposed for separating the members of the series and identifying the higher bases, was the process of converting the mixed bases into methyl-iodide compounds by digesting them with the iodide at a high temperature, and separating by fractional crystallisation the bodies so produced. It was found, however, that repeated crystallisation of these bodies could not be effected without great risk of their decomposition. This process was, therefore, abandoned in favour of fractional distillation.

In a paper published in the Transactions of this Society for Session 1877–78, I described an experiment which showed, that if a moderately strong current, such as that from four or five Bunsen cells, be led through two jam-pots filled with fragments of carbon, and if any sound be uttered strongly in the one jampot it will be reproduced distinctly, although faintly, in the other. In this experiment it has been found that the fragments of carbon may be replaced by any kind of loose contact, such as microphones, or a handful of screw-nails put into each jam-pot, or vibrating springs beating against metallic stops, or nails laid across each other in log-hut fashion, and that in each case an effect similar in kind, although it may be differing greatly in degree, is produced. Hence it may be almost laid down as a general experimental result, that if an electric circuit conveying a tolerably strong current contain two places of loose contact, A and B, and if any sound be produced loud enough at A a similar sound will be heard proceeding from B.

Although the Spectrum whose linear record is now presented to the Royal Society, Edinburgh, is unfortunately not so perfect as it might have been with better apparatus (but which I did not possess)—yet it represents the labour and expense connected with two voyages in 1877–1878 to Portugal; and many weeks work there in both years, with the sun in a more favourable position for observing really solar, and not telluric, or atmospheric, phenomena, than is ever, at any time, obtainable in Great Britain.

The genera, which I at present include under the family term Platysomidæ, are the following:—

1. Eurynotus, Agassiz.

2. Benedenius, Traquair.

3. Mesolepis, Young.

4. Eurysomus, Young.

5. Wardichthys, Traquair.

6. Cheirodus, M'Coy.

7. Platysomus, Agassiz.

These openings, which are also present in numbers on the region of the cheek, indicate the ducts of numerous mucous glands which lie immediately underneath the mucous membrane. The tongue of Beluga does not appear to differ much from that of other toothed whales. In Globiocephalus intermedius, according to Macalister, not only the tip, but also the margins of the organ are free, whereas in Beluga the latter are attached along nearly their whole length. Dr Murie refers to the presence of a distinct froenum in Globiocephalus melas, but this structure is not recognisable in Beluga.

The geographical area embraced in the present memoir forms a well-marked basin traversed along its centre by the estuary of the Forth. It is bounded on the north by the chain of the Ochil Hills, on the south by the range of the Pentland and Lammermuir uplands. Towards the west it joins along a low watershed the basin of the Clyde, while eastwards it dips under the waters of the North Sea. Within this defined space the Carboniferous rocks occupy what may be described as one great synclinal trough, varied by innumerable smaller synclines and anticlines. Save where cut out by powerful dislocations, their lower members rise up along the margins of the basin, while their highest portions cover a smaller area in the centre. The older formations forming the northern and southern boundaries of the area belong chiefly to the Lower Old Red Sandstone, in the Lammermuir district to the Lower Silurian. The Carboniferous rocks everywhere rest upon them unconformably.