It will conduce to clearness if, before making any remarks, I take the liberty of reproducing the title of this address in a slightly enlarged form. In order to convey a precise idea of my object, it will be desirable to frame it thus:—

“On the Evidence (prior to the Excavations commenced in A.D. 1755) for the Destruction of Pompeii and Herculaneum by the Eruption of Vesuvius in A.D. 79.”

It will be seen from this way of putting the case, that I propose to confine my attention to documentary evidence. The reference to Vesuvius is also important, because it might conceivably be maintained, and indeed it has been maintained within the present century, that these cities were destroyed by other agencies, and not by the outburst of the neighbouring volcano.

Sterium retirugum, Cke.: coriaceo-membranaceum, murinum; pileo effuso e cupulari explanato, confluentë, marginato; ambitu pallide fimbriato; bymenio subvelutino, rcticulato-venoso, murinaceo.

Ad ramos. B.C.S. Nos. 1310 (junior), 1341 bis.

Thametes Socotrana, Cke., pileo sessili seraiorbiculari, tenui, coriaceo zonato-sulcato, velutino, albo; contexto, concolore, poris magnis dentatis, demum confluentibus, umbrinis.

Ad truncos. B.C.S. No. 1342.

Microthamnion Breviarticulatum, Dickie, ramulis alternis, articulis diametro æqualibus vel duplo-longioribus, diam. ·0002 unc.

Lyngbya Scabrosa, Dickie, cæspitosa, viridi-nigrescens, trichomatibus flexuosis, ærugineo-cœruleis, articulis diametro duplo-brevioribus, vaginis scabrosis, achrois, diam. ·001 unc.

Sowerby's whale is one of the rarest of the cetacea which frequent the British seas. It was first recognised as a distinct species by Mr. James Sowerby, from a specimen cast ashore in 1800 on the coast of Elgin, and named by him Physeter bidens. From that time to the present no properly authenticated specimen has been obtained in Scotland, although it is not unlikely that a skull in the Museum of Science and Art in this city, a description of which I gave to this Society in 1872, may have belonged to an animal captured in the Scottish seas. Two, if not three, specimens have been obtained on the Irish coast, but I know of no example of this whale having been caught in England. In my former communication to this Society, I referred to two specimens taken in France (Havre, Calvados), one at Ostend, one on the coast of Norway, and one on the coast of Sweden, and this completed the record of this animal so far as I could find a reference in zoological literature.

Obs. Diagnoses specierum novarum ampliores et observationes variæ, enumeratio completa omnium Lichenum a participibus expeditionum oculatiss. Balfourio (B.C.S.) et Schweinfurthio (Schweinf.) in hac neglectissima insula lectorum mihique benevole submissorum, nec non indicatio locorum accurata in Balfourii opere integro currente anno edendæ sunt.

The investigation was at first undertaken with a view of determining how the blue colour of the water of the Mediterranean is produced, and of finding the explanation of the different colour phenomena seen in that sea. The investigation was afterwards extended to other waters.

The experiments were made with a special view of determining whether the selective reflection or the selective absorption theory gave the correct explanation of the blueness seen in water.

An attempt is made in this paper, mainly from the point of view of the Society's “Boulder Committee,” to examine and classify the surface-deposits of a comparatively small compact area, which is bounded on the north and north-east by the river Spean, on the south and south-west by the river Nevis, on the west and northwest by the Lochy and the Caledonian Canal, and on the east and south-east by the Nevis range of Mountains. Reference is also made to the district between the Nevis and Loch Linnhe, including Auchintore and part of Glen Nevis. The body of the paper is limited to the statement of phenomena. It is felt, however, that the chief value of a record of facts is to lead to a definite knowledge of the forces which underlie them, and of the laws of which they are the expression.

The phenomena accompanying the disruptive discharge of electricity are, in the present state of electric science, among the most interesting known, because they are the least understood, and, so far as we know, the least concordant with our preconceived ideas. The simplest way of representing the facts is to imagine with Faraday that the non-conducting medium, or dielectric, between two charged conductors is the seat of mechanical stress, consisting of tension along, and pressure perpendicular to, the lines of force. The rupture of the dielectric may then be conceived as a phenomenon precisely analogous to the rupture of an elastic body under stress. We are thus led to the conclusion that the commencement of the rupture happens at that particular point where the tension first reaches a certain value, called the breaking tension or dielectric strength, which depends merely on the material of the dielectric, and on its physical condition at the time being. The main thing in any experiment on dielectric strength is to know the tension at the point where the rupture begins.

Plena descriptio Botanices Socotrensis quantum nobis cognitæ, brevi tempore subjicietur Societati Regiæ Edinensis ut in suis Actis in lucem emittatur et divulgetur. Quoniam verum spatio certo temporis opus erit ut singulæ partes et minutiæ Floræ tam abundantis et copiosæ plene elaborentur et perlustrentur, et quoniam perplures formæ endemicæ tarn generum quam specierum in ea Flora comprehenduntur, oportet et congruit opportunis temporis intervallis, opere progrediente, breves diagnoses novarum plantarum in medium proponere, ut prioritas vindicetur nominibus quæ his novis tribuantur, et quæ in volumine Actorum Societatis Regiæ publice emittentur.

In September 1872 a whale of some magnitude was seen floundering in shallow water at Snab, Kinneil, about a mile from Bo'ness, on the Firth of Forth. Some men proceeded to the spot and fastening a rope round its tail, hauled it closer to the shore, and then killed it. I was not at home at the time, but on reading a notice of its capture in the Scotsman of September 26, I wrote to my assistant, the late Mr A. B. Stirling, to go and see the animal.

In treating, by the method of quaternions, the question which forms the basis of Minding's Theorem, I had the advantage of being guided by Professor Tait's paper on that subject (T. R. S. E., 1880), and it is only by varying his method that I could hope to present the question under a new aspect.

In the present chapter Dr. Heddle considers the ores of manganese, iron, chromium, and titanium.

He finds that almost all the manganese in Scotland occurs in the form of an ore of little value—psilomelane.

Iron, he has observed in minute laminable specks, in the free or metallic condition, at two localities, but sheathed in both cases in magnetite. The quantity was too small for determining the presence or absence of nickėl, but he conjectures that these specks may have been minute meteorites, which had fallen into the ocean in which the rock was being formed.

He has found two ores of iron new to Britain,—turgite and martite,—the one near Oban, the other in Bute.

1. In experimenting from time to time on the floating of solid metal on molten metal, the author has observed various phenomena, of which the present paper is descriptive, and this more especially with regard to cast iron and the well-known property of the solid floating on the molten iron as frequently witnessed in foundry ladles.

Some years ago the author made a number of experiments with pieces of cast iron of different shapes and sizes, which were placed on the surface of a large ladleful of molten cast iron, the results obtained being as follows:—

Several pieces of pig iron were first tried; these at first sank and a rush of hot metal took place upwards, but after a few seconds they rose to the surface, and floated with very little of their bulk above the molten metal.

Bœdeker (Annalen, 123, 61), by the action of potassium cyanide on bismuth nitrate, obtained a reddish-brown salt, to which he assigned the formula Bi2O5.2H2O. In an examination of the oxides of bismuth in conjunction with Hoffmeister and Robbs (Chem. Soc. Jour., 1881; Proc., p. 21), I had occasion to prepare Bœdeker's salt; a slight study of its properties proved it to be a compound of no little interest. When a concentrated aqueous solution of potassium cyanide is added to a solution of metallic bismuth in excess of nitric acid, and the mixture is boiled, a brownish-red solid and a more or less dark red liquid are obtained, and quantities of hydrocyanic acid are evolved. When the excess of nitric acid is nearly neutralised by potash before addition of potassium cyanide, the colour of the solid is a much lighter brown, and the supernatant liquid is nearly or quite colourless.

This paper is a continuation of the author's previous paper on “The state of carbon in iron and steel, a new hypothesis of the hardening of steel” (read on the 19th December 1881, see p. 368), and is an attempt to give an explanation in accordance with the views given out in that paper of the manner in which the various elements most common in steel exert their influence in so materially modifying the properties of the metal.

The following are the elements the action of which is considered, viz., silicon, sulphur, phosphorus, manganese, chromium, tungsten, and titanium.

The properties of flames of various kinds as generating electricity and as serving to conduct a voltaic current, as also their behaviour under the influence of a charge of electricity, have been investigated by several philosophers. But, so far as we know, the effect of flame on the electric spark has not been methodically observed, or at all events has not been methodically measured. This was the problem which at the opening of the College session presented itself to us, and the results now attained by a course of experimenting appear capable of throwing some light on the solution.

We first made a number of tentative experiments, for the purpose of finding out the general aspect of the phenomena, and the conditions most favourable for exact measurement. An ordinary Bunsen burner served to supply a flame luminous or non-luminous. It was always connected with the earth, and the charged body was in general a disc of 4 inches diameter, connected along with a large Leyden jar to the insulated conductor of a Holtz machine. We tried the disc in a position above the flames, but found that the disturbing conditions introduced were, as was to be expected, rather numerous, namely, the heating of the disc and the covering of it with soot, and the melting of the gutta-percha covering of the connecting wire. Hence for a series of measurements we preferred the disc placed in a position at the side, as represented in the accompanying figures. (See Plate IV. a).

The best figures of the nervous system of these animals are those of Lacaze-Duthiers, in his Paper Sur les Otocystes des Mollusques, and in that Sur le Système Nerveux des Gastéropodes. By a careful study of the nervous system of these two gasteropods, chiefly by cutting sections, I have discovered one or two small points in their anatomy which, as far as I can make out, have hitherto escaped attention.

These two types, though so closely allied, differ to a considerable extent in the arrangement and structure of certain of their ganglia; compare the figures given by Lacaze-Duthiers of the nervous system of Lymnæus on Plate xvii. in Volume i. of his Archives with that cf Planorbis on Plate iii. of the same volume. It will be seen at once that the cerebral ganglion of Lymnæus is far more complicated than that of Planorbis, consisting of five separate lobes, while that of Planorbis appears to be made up of not more than two.