“Go to the quality of the active principle; abstract it from the material, and contemplate it by itself. Then determine the time; how long, at furthest, this thing, of this particular quality, can naturally subsist.”—Marc. Aurel., Book ix. sect. 25.

The recent extensive therapeutic use of cocain has naturally aroused great interest with regard to its chemical constitution. As is well known, when heated with dilute mineral acids, it takes up two molecules of water, and becomes decomposed into benzoic acid, methyl alcohol, and another alkaloid ecgonin. When cocain, however, is simply heated in watery solution for some hours, a less complete decomposition ensues, the solution depositing on evaporation a crystalline substance, which is benzoylecgonin.

The forms of the uniaxial systems may be regarded as derived from forms, or parts of forms or combinations, of the regular system by uniform expansion or contraction in a direction parallel to the axis of the uniaxial system, i.e., normal to a face of the cube for the tetragonal, and normal to a face of the octahedron for the hexagonal system. Faces, therefore, which are, in the regular form or combination, at right angles to or parallel to such axis, retain their relative angular position unchanged in the uniaxial form or combination, and can be represented by means of indices referring to the rectangular axes of the regular system, whatever be the amount of the deformation (expansion or contraction). These faces are prism faces, parallel to the axis, and basal faces at right angles to it. All other faces have their angular position affected by the deformation.

The second, only, of two short papers which I communicated to the Society a month ago, on points connected with the Kinetic Theory of gases, took account of the greater probability of collision between two particles as their relative speed is larger. I propose now to calculate the effect of this consideration on the results of my first paper.

I will commence my paper with a brief description of the typical characters of a reef in this region, referring particularly to the distribution of the corals. There would appear to be a large number of new specific forms among the reef-corals of these islands, whether hydroid or actinoid. Out of nearly seventy species that I sent to the British Museum, almost a quarter are new or undescribed; and there is every probability that similar success will fall to the lot of other collectors in these seas. There is yet much to be learned of the fauna of the deeper parts of the reef-coral zone; and patient dredging will doubtless yield fruitful results. Here, not improbably, will be found the corals of deep-sea genera and the Rhynconella that I discovered in an upraised barrier-reef in the Shortland Islands. Having only a small canoe, I was not able to dredge in these depths; but I may remark, as a good omen for others, that, when sounding off a reef on one occasion, I brought up from a depth of 14 fathoms a new and very distinct species of Distichopora (D. ochracea), which is described and figured by Mr J. J. Quelch in the Annals and Magazine of Natural History for July 1885.

In the course of the autumn of this year (1885) I have taken several occasions to determine the distribution of temperature in the water of Loch Lomond. The results of these observations are interesting, as indicating the march of temperature in the different layers at different localities in the lake, and also the gain and loss of heat with the changing seasons.

In January I read a paper on the salinity of the Firth of Forth, in which the law governing the distribution of salt in that estuary was pointed out. It appeared that in the eastern or seaward part of the Firth the change in mean salinity per mile was very slight, and the tidal range was small, while both decreased gradually as the sea was approached. On the other hand, the riverward half of the Firth showed a rapid alteration in density along its length, and a correspondingly great range between high and low tide.

This paper contained an account of the experimental evidence in support of the theory of solution enunciated in a paper “On the Nature of Solution,” communicated to the Society in January 1883. Solution of a salt in a liquid is a consequence of the attraction of the molecules of the liquid, for a molecule of the salt (adhesion), exceeding the attraction of the molecules of salt for one another (cohesion). As the number of dissolved salt molecules increases, the attraction of the molecules of liquid for the molecules of salt becomes more and more balanced by the mutual attraction of the salt molecules. When these two forces are in equilibrium, saturation ensues.

An occurrence of an extraordinary nature took place in the kitchen of this house on Monday evening, the 8th inst. The kitchen is in the area, and whilst the office-keeper and his wife and servant girl were seated in front of the fire, suddenly, about twenty minutes past eight, a terrific rumbling sound was heard in the chimney. Fearing that something was about to topple about their ears, they all sprang aside, and no sooner had they done so than a large sheet of flame issued from the chimney, and without disturbing the ashes in the grate, or touching the grate itself, swept close past the office-keeper, who was standing nearest to the fire-place, and extinguished the gas.

During the spring of 1882 Mr Burton and I communicated some preliminary experiments on a new method of measuring the heats of combination of the metals with the halogens.

In several papers communicated to the Society within recent years the thermal effect of compressing water has been dealt with by various observers. The present paper gives the results of experiments of a similar kind to ascertain the thermal effects of compressing certain solids and liquids. These experiments were conducted in the University of Edinburgh, under the superintendence of Professor Tait.