The outer surface of the skull does not correspond in shape to the outside of the brain. If it had corresponded there would have been no difficulty in determining the form of the brain from an inspection of the form of the head.

The shape of the brain does correspond to the wall of the cranial cavity. This wall is formed by the inner table of the cranial bones, which table, though separated from the brain itself by the cerebral membranes, is moulded upon the exterior of the organ.

The very beautiful experiment of Mr Sang, communicated to the Society on the 7th April, 1873, suggested to me, as soon as I heard him read his description of it, an explanation which was confirmed by a subsequent examination of his specimens. Some remarks made to me by members of the Council of the Society, three days afterwards, led me to write, and deposit (under seal, as Mr Sang had announced that he was still prosecuting his inquiry) with the Secretary the following hastily written document, which has been since that time in his possession, and is now printed verbatim.

As far as I am aware, the sense of rotation has not hitherto been recognised either by physiologists or by psychologists as a distinct sense, but a little consideration and a few experiments seem to me to be enough to show that it really is so. By means of this sense we are able to determine—a, the axis about which rotation of the head takes place; b, the direction of the rotation; and c, its rate.

John Stuart Mill was born in London on the 20th of May 1806, and died at Avignon on the 8th of May 1873. He was of Scotch descent. He was connected with Edinburgh not only as having been an honorary member of this Society, but because his father, James Mill, the historian of British India, and author of the “Analysis of the Human Mind,” received his academical education here. His grandfather was a small farmer, at Northwater Bridge, in the county of Angus, of whom I find nothing more recorded. The father, by his extraordinary intellectual promise when a boy, drew the attention of Sir John Stuart, then member for Kincardineshire, by whom he was sent to the University of Edinburgh, at the expense of a fund, established by Lady Jane Stuart and some other ladies, for educating young men for the Church of Scotland. Towards the end of last century, James Mill attended the classes in Arts and Divinity. He was a pupil of Dalziel, the Professor of Greek, whose prelections he attended, I believe, for three sessions, and his philosophical powers were called forth by Dugald Stewart's lectures in Moral Philosophy.

In abstract dynamics the instantaneous reversal of the motion of every moving particle of a system causes the system to move backwards, each particle of it along its old path, and at the same speed as before, when again in the same position. That is to say, in mathematical language, any solution remains a solution when t is changed into – t. In physical dynamics this simple and perfect reversibility fails, on account of forces depending on friction of solids; imperfect fluidity of fluids; imperfect elasticity of solids; inequalities of temperature, and consequent conduction of heat produced by stresses in solids and fluids; imperfect magnetic retentiveness; residual electric polarisation of dielectrics; generation of heat by electric currents induced by motion; diffusion of fluids, solution of solids in fluids, and other chemical changes; and absorption of radiant heat and light. Consideration of these agencies in connection with the all-pervading law of the conservation of energy proved for them by Joule, led me twenty-three years ago to the theory of the dissipation of energy, which I communicated first to the Royal Society of Edinburgh in 1852, in a paper entitled “On a Universal Tendency in Nature to the Dissipation of Mechanical Energy.’

In the treatment of questions which relate to the equilibrium vibrations of elastic solids, it is usual to suppose the substance to start from a state without strain, and in general to consider only the case of small distortions, for which squares and products of the space-variations of displacement may be neglected. The mathematical solution depends, in the first instance, on the expression of the work done in distorting an element. This, as was first done by Green, is expressed in terms of six functions of the distortions termed strains.

After describing the general appearance of these terraces, the author referred to the discussions which had taken place as to their formation. More than fifty years ago it was conclusively proved by Dr Macculloch and Sir Thomas Dick Lauder, that these parallel roads are the margins of ancient lakes, and since then the question has been whether these were freshwater or sea lochs. Mr Darwin, Dr Eobert Chambers, Professor Nichol, and others, have contended that they were marine; while Agassiz, Dr Milne Home, Mr Jamieson, and others, have maintained that they were freshwater.

Certain individuals appear to be incapable of appreciating musical sounds. They cannot distinguish one melody from another; and if by many repetitions of the melody in their hearing, they at last appear to know it, the addition of one or more of the parts of the harmony again renders the music unrecognisable to them. The question naturally arises, Is this defect owing to any peculiarity in the structure of the internal ear of persons so constituted which prevents them hearing certain sounds, or is it to be referred to the condition of the brain? On the other hand, many have what is termed a “fine ear,” by which we understand the faculty of appreciating, remembering, and, in some cases, of successfully imitating musical sounds. Have those individuals the organ of hearing more delicately developed?