Professor Turner reported that in accordance with the remit made by the Society at last Ordinary Meeting, the Council recommended the following changes in the Laws of the Society:—

“That Law XVII be cancelled, and the following Law be established in its place:—

“That there shall be formed a Council consisting, first, of such gentlemen as may have filled the office of President, and, secondly of the following to be annually elected, viz., a President, six Vice-Presidents (two at least of whom shall be resident), twelve Ordinary Fellows as Councillors, a General Secretary, two Secretaries to the Ordinary Meetings, a Treasurer, and a Curator of the Museum and Library.”

The author explained that he was glad to be able to bring before the Society some apparatus illustrative of Dr Crookes's splendid researches on what he calls radiant matter. This he was able to do by the skill of Mr Gimingham, who had prepared some splendid vacuum tubes for him lately. He valued those researches very highly, because they brought most conclusive evidence to bear upon the truth of the kinetic theory of gases; because they gave us a clear insight into the action of the electric current and discharge; because they promise to help us in forming a notion of what electricity really is; and because we may also hope from these researches to get some knowledge of the nature of molecules.

“That there shall be formed a Council consisting, first, of such gentlemen as may have filled the office of President, and, secondly of the following to be annually elected, viz., a President, six Vice-Presidents (two at least of whom shall be resident), twelve Ordinary Fellows as Councillors, a General Secretary, two Secretaries to the Ordinary Meetings, a Treasurer, and a Curator of the Museum and Library.”

In January and February 1879 Mr J. Y. Buchanan communicated to this society two papers, on the distribution of temperature under the ice in Linlithgow Loch. In these papers he gives a most interesting and valuable series of temperature observations made by him, of the water, at different points, and at different depths, in the loch while it was covered with ice. He also gives the temperatures as taken by him under similar circumstances in Loch Lomond. These observations by Mr Buchanan disclose a somewhat unexpected thermal condition of the water.

I propose making a few brief observations on the relations in which we stand to the aborigines of the Andaman Islands, their place in the economy of this convict settlement, and their more noticeable habits and customs. In the consideration of the latter, I shall only state such information as I have obtained myself from conversation with, and personal observation on the manners of the natives. Detailed monographs on their ethnology, &c., have been written already by several observers, and are to be found in the “Transactions of the Anthropological Society,” &c.

The author, after referring to the paper by Pfankuch, who obtained by the action of sulphide of potassium upon chloroform a crystalline substance which he held to be a compound of sulphide of potassium and sulphoform, and to the paper by Bouchardat on sulphoform, gives a detailed account of his own investigation.

The products formed when chloroform acts on an alcoholic solution of sulphide of potassium (prepared by dissolving caustic potash in alcohol, saturating one-half with sulphuretted hydrogen and then adding the other half) are sulphydrate of potassium and thioformiate of potassium (HCOSK, analogous in constitution to thiacetate). The action is probably as follows :— HCCI3 + 2K2S = 3KCI + HCSSK, and HCSSK + H2O = HCOSK + H2S, this sulphuretted hydrogen forming sulphydrate with the sulphide of potassium.

The author commenced by stating that although these researches lead him to believe in the existence of two planets revolving in orbits external to that of Neptune, and although there was a great deal of evidence to show that he had actually determined the elements of the orbits, yet the latter point, being dependent on a coincidence of probabilities only, cannot be considered a certainty until the planets are observed.

The author accepts the theory of cometary orbits which supposes that these bodies, wandering through space, are attracted by the sun into the solar system so as to pursue parabolic orbits, and that some of these, in passing a planet, may have their velocity diminished, in which case they will afterwards describe an ellipse in a definite period.

The recent exhibition by Professor G. Forbes of some of the latest of Mr Crookes' experiments, together with what I had read or heard about their explanation, led me to infer that I might determine directly the velocity of the luminous particles near the negative pole (and perhaps at other parts) of a vacuum tube by means of observations of the spectrum made in directions perpendicular to, and parallel to, the lines of motion of the incandescent particles of gas.

The first annexed diagram represents a thermometer constructed to show absolute temperature realised for the case of water and vapour of water as thermometric substance. The containing vessel consists of a tube with cylindric bulb like an ordinary thermometer; but, unlike an ordinary thermometer, the tube is bent in the manner shown in the drawing. The tube may be of from 1 to 2 or 3 millims. bore, and the cylindrical part of the bulb of about ten times as much. The length of the cylindrical part of the bulb may be rather more than of the length of the straight part of the tube. The contents, water and vapour of water, are to be put in and the glass hermetically sealed to enclose them, with the utmost precautions to obtain pure water as thoroughly freed from air as possible, after better than the best manner of instrument makers in making cryophoruses and water hammers. The quantity of water left in at the sealing must be enough to fill the cylindrical part of the bulb and the horizontal branch of the tube. When in use the straight part of the tube must be vertical with its closed end up, and the part of it occupied by the manometric water-column must be kept at a nearly enough definite temperature by a surrounding glass jacket-tube of ice-water.

The instrument exhibited to the Royal Society consisted of a U-shaped glass tube stopped at both ends, containing sulphurous. acid liquid and steam. The process by which the sulphurous acid is freed from air, which was partially exhibited to the Royal Society, is as follows:—

Begin with a glass U tube open at both ends, and attach to each a small convenient, very fine, and perfectly gas-tight, stop-cock. Placing it with the bend down in a freezing mixture, condense pure well-dried sulphurous acid gas direct into it from the generator till it is full nearly to the tops of the two branches.

This is a case of fluid motion, in which the stream lines are approximately circles, with their centres in one line (the axis of the vortex) and the velocities approximately constant, and approximately equal at equal distances from the axis. As a preliminary to treating it, it is convenient to express the equations of motion of a homogeneous incompressible inviscid fluid (the description of fluid to which the present investigation is confined) in terms of “columnar co-ordinates” r, θ, z, that is co-ordinates such that r cos θ = x, r sin θ = y.

Attention was drawn to the statements made on the position of peculiar comb-like fringes on the branchiæ of the basking shark by Gunnerus, Pennant, Low, Mitchell, Foulis, Brito Capello, Cornish, Steenstrup, Pavesi, P. & H. Gervais, Percival Wright, and Allman, and to the structure of these fringes by Hannover and MM. Gervais. The author then proceeded to give a detailed description of the structure of the plates forming these fringes from a specimen presented to him by the Rev. M. Harvey of St. John's, Newfoundland, the general summary of which is as follows: the whole periphery of a plate consisted of a hard unvascular dentine, the tubes in which were very distinctive; in a considerable part of the shaft these tubes arose from a single central pulp cavity, but in the semilunar attached base of the plate the single central cavity did not exist, but was replaced by a set of anastomosing vascular canals, which collectively represented a pulp cavity, and which gave origin to numerous characteristic dentine tubes.

The entire collection comprises from 150 to 200 species, the majority of which are new to science.

As yet only some of the more abnormal Synascidiœ and about half the Ascidiœ simplices have been carefully examined. The present paper is the preliminary report on the ASCIDIÆ, the first family of the Ascidiœ simplices.

Since last meeting of the Society I have found that Broch (in Dove's Repertorium) employed the combination of prism, Nicols, and quartz plate, for the purpose of measuring the rotatory power of quartz for different wave-lengths. I do not find, however, that he suggests its use for the determination of wave-lengths according to one definite standard. Nor does he seem to have used great thicknesses of quartz, which is essential to accuracy in the application I have proposed. In the Annales de Chimie, 1846, there is a translation of a part of Broch's paper, with the remark that the process, which he called a new one, was due to Fizeau and Foucault. Their paper, however, refers to quartz cut parallel to the axis; but it introduces the question, very important so far as my object is concerned, of the interference of two polarized rays after one has been retarded more than the other by very many wave-lengths.

The subject on which I have the honour of addressing you this evening is one far more complicated and difficult than that of the paper which I read to the Royal Society of Edinburgh some short time since. We have to deal, not with the surface of a country and the position of places of which the ancient names are still extant, but with a ruined city, buried to a depth of from 30 to 50 feet in rubbish on which modern buildings having been erected, and with a topography in which, there is scarcely a single important point which has not been controverted by one or more well-known writers.

The author visited the Faröe Islands last summer in company with Mr Amund Helland of Christiania. They made various traverses across the largest and most important islands, and touched here and there at several of the smaller ones. They have constructed a geological map of the group, upon which is shown the outcrop of the coal-seams of Suderöe, the direction of numerous dykes of basalt, the position of great intrusive sheets of the same rock; and the trend of the glaciation is indicated by arrows. The introductory part of this paper gives some account of the geological observations made by previous writers—Jorgen Landt in 1800, Mackenzie and Allan in 1815, Trevelyan a year or two later, Forchhammer in 1824, Robert Chambers in 1854, and Johnstrup in 1873. The general physical features of the islands are next described, the extent of land being roughly estimated at about 600 square miles.

On Monday, March 1, 1880, a strong breeze from the S. W., marked at 1 o'clock P.M. in meteorological observation, as equal to 15 miles per hour, prevailed, after which the force of the wind rapidly increased, shifting to W.N.W. until about 2 o'clock when it became a perfect hurricane, accompanied by a storm of snow and sleet. The velocity of the wind must have been betwixt 40 and 50 miles per hour, and partly from heavy black clouds covering the sky, and partly from the dense sheet of snow which was drifting along, everything became obscured.

Some years ago, while I was still working at knots, Professor Cayley told me of De Morgan's statement that four colours had been found by experience to be sufficient for the purpose of completely distinguishing from one another the various districts on a map.

I had previously shown that if an even number of boundaries meet at each point on a diagram, two colours (as on a chess-board) will suffice for the purpose. But in a map, boundaries usually meet in threes.