An argument which I had stated against the Huttonian Theory of the Earth, in so far as it relates to the operation of a central heat, was honoured some time ago with a reply by a distinguished Member of the Society. Respect for the opinion of Mr Playfair led me to consider attentively the reasoning he employed; and still feeling some confidence in the grounds on which the original argument rests, I propose to offer a few observations with regard to it. The question farther involves the consideration of the mode in which heat is distributed at the surface of the globe. This, when minutely investigated, presents a very perfect arrangement, by which the escape of caloric is prevented, while its equal distribution is more effectually attained; and the subject, under this point of view, may have some interest, independent of its relation to any controversial discussion.

Those philological studies which have been cultivated among polished nations, for their subserviency to literary taste, and their influence on the formation of correct habits of speaking and writing, have gradually suggested the more profound science of Universal Grammar. The business of this science is, not merely to dictate the best manner of connecting words with one another, but to investigate the origin of the various distinctions existing among them, and to discover in what instances these distinctions are dictated by occasional convenience or partial caprice, and in what instances they are essential to the purposes of language. By the aid of these investigations, philosophers have even hoped to trace some of the most important laws of human thought, and to obtain a solution of the most difficult problems of metaphysics. Some of the attempts made to realise these expectations have displayed great ingenuity; but, even with this qualification to recommend them, they have often failed to establish principles on a foundation sufficiently sure to preclude controversy.

During a series of experiments in which I was lately engaged, for the purpose of determining the law of the polarisation of light, by successive reflexions from plates of parallel glass, I observed that all the images of the luminous body which were formed by more than one reflexion, were crossed by parallel fringes of coloured light, when the two plates had a small inclination to each other; and that these fringes suffered considerable changes, by varying the position of the plate with regard to the incident ray.

The distinguished person who is the subject of this memoir, was born at Boghall, in the parish of Baldernock, near Glasgow, in the year 1739. His father, John Robison, had been early engaged in commerce in Glasgow, where, with a character of great probity and worth, he had acquired considerable wealth, and, before the birth of his son, had retired to the country, and lived at his estate of Boghall.

Some months ago, in investigating the anatomy of the eyes of fishes, I washed off the back silvery part of the choroid coat of the haddock, with a hair pencil, and about half a teaspoonful of water. The latter became of a milky colour, and on examining a drop of it, with an Ellis's aquatic microscope, I found the milkiness to be owing to innumerable slender, flat, silvery spicula, which had composed the substance of the choroid. They seemed to be in constant motion, apparently rolling upon their axes, but having no degree of progressive movement. The light reflected from their surface was very brilliant, like that from polished silver, and often disappeared, and again returned, with alternations so rapid, as to produce a twinkling, very like that of a fixed star.

If such tremendous agents did in reality exert their influence in the Alps, it is not conceivable that other countries, situated lower, and composed of materials much more frail, could have been spared. We hear in fact of similar traces, more or less distinct, in all quarters of the globe. From the bones of animals, natives of the hottest climates, which are found over a frozen region of vast extent in the Russian empire, Pallas concludes, that an enormous torrent had transported their carcases across the ridge of Tartary.

The Memoir which I am about to submit to the consideration of the Royal Society, relates to the melancholy history of a boy who was born blind and deaf; and who, of consequence, has derived all his knowledge of things external from the senses of Touch, of Taste, and of Smell.

In examining the changes which light undergoes during its passage through transparent bodies, we not only receive information respecting the properties of that mysterious agent; but we are in some measure made acquainted with the composition of the substances themselves, and with the manner in which their ingredients are combined. The optical phenomena, therefore, which bodies exhibit in their action upon light, are so many tests, to which the philosopher may have recourse, either in supplying the place of chemical analysis, or in correcting and modifying its results. A difference in the optical properties of two bodies, is generally an infallible indication of a difference in their elementary principles; and whatever confidence we may place in the skill of the chemist, or in the accuracy of his methods, the mind can never rest satisfied with the results of an analysis which is directly opposed by optical phenomena.

The Quadrature of the Conic Sections, and the Computation of Logarithms, are problems of considerable importance, not only in the elements of Mathematics, but also in the higher branches of that science. On this account, every successful attempt to simplify their resolution, as well as any new formulæ which may be found applicable to that purpose, must always be interesting, and must in some measure contribute to the improvement of mathematical knowledge.

Ancient Revolutions of the Mineral Kingdom.—Vain attempts to explain them.—Dependence of Geology on Chemistry.—Importance of the Carbonate of Lime.—Dr Black's discovery of Carbonic Acid, subverted the former theories depending on Fire, but gave birth to that of Dr Hutton.—Progress of the Author's Ideas with regard to that Theory.—Experiments with Heat and Compression, suggested to Dr Hutton in 1790.—Undertaken by the Author in 1798.—Speculations on which his hopes of success were founded.

The most mountainous parts of Scotland are situated in its western and north-west districts. From those parts of the country, several chains of mountains branch off, and continue their courses in various directions, and to various extent. The most extended of those chains is that of the Grampians. This chain takes its rise from nearly about the centre of the above alpine district, and continues its course in a direction almost due east, or perhaps a little to the south of that point, until it disappears in the German Ocean, betwixt the towns of Aberdeen and Stonehaven.

The mineral to which I have given the name of Sodalite, was also put into my hands by Mr Allan. In the Greenland collection which he purchased, there were several specimens of a rock, obviously primitive. In the composition of these, the substance of which I am about to treat, formed a constituent, and, at first appearance, was taken for felspar, to which it bears a very striking resemblance.

The specimen which formed the subject of the first of the following analyses, was brought from the banks of the river Dee, about seven years ago, by my friend Mr James Mill, who at that time resided in Aberdeenshire. By him I was informed, that considerable quantities of it are found in different parts of the bed of that river,—that it is called by the inhabitants ironsand,—and that they use it for sanding newly written paper. I tried some experiments in the year 1800, in order to ascertain its nature; but was too little skilled at that time, both in mineralogy and practical chemistry, to manage an analysis of any considerable difficulty.

The phenomenon about to be described, was seen on August 6. 1806, about seven in the evening; the air being very still, and a little hazy. The tops of the four turrets of Dover Castle usually appear above the hill, lying between Ramsgate and Dover; but, at the above-stated time, not only the tops were visible, but the whole of the Castle, appearing as if it were situated on the side of the hill next to Ramsgate, and rising as much above the hill as usual.

It is a singular fact in the history of science, that, after all the attempts of the most eminent modern mathematicians, to obtain a simple and satisfactory demonstration of the fundamental property of the lever, the solution of this problem given by Archimedes, should still be considered as the most legitimate and elementary. Galileo, Huygens, De la Hire, Sir Isaac Newton, Maclaurin, Landen, and Hamilton, have directed their attention to this important part of mechanics; but their demonstrations are in general either tedious and abstruse, or founded on assumptions too arbitrary to be recognised as a proper basis for mathematical reasoning. Even the demonstration given by Archimedes is not free from objections, and is applicable only to the lever, considered as a physical body.

In the original charter of the Royal Society, it was provided that the collections of the Society should be deposited, if belonging to Natural History, in the Museum of the University, and if to Antiquities, in the Library of the Faculty of Advocates. Much inconvenience, however, could hardly fail to result from this arrangement, especially when the researches of the Society, having, as of late, been much turned to Geology, it became an object to collect together the specimens which served to illustrate the subjects under discussion, and to have them at hand when reference should be necessary.