Disko Island, (see Plate XV ), is situated in front of a bay in the continent of Greenland, within Davis' Strait, known by the name of Disko Bay, which is sometimes called, particularly in the old Dutch charts, Sydost Bay. This name is derived from an immense curvature, screened by innumerable islands, made in the continent by the sea. Disko Island is situated in 69° 14ʹ of N. latitude. It is distant from the continent towards the south 12 German miles; on the west and north it is surrounded by the sea of Davis' Strait; and on the east, it is separated by a narrow sound, distinguished by the name of Waygat by the Dutch, and by the Greenlanders Ikareseksoak. It stretches northward from 69° 14ʹ to 70° 24ʹ; and its greatest breadth, which is from Fortune Bay on the west, to Flakkerhuk, so named by the Dutch, on the east, is 10 German miles.

I Had last winter the honour of laying before the Royal Society a few hasty remarks on what are called the Parallel Roads of Glen Roy, suggested to me by an accidental ramble through that valley, in the course of a pedestrian tour in the West Highlands, during the previous August. My curiosity having been much excited by what I then saw, I was induced to revisit the highly interesting district of Lochaber, in the beginning of last June, and had thus an opportunity of devoting three whole days to a more complete inspection of these remarkable shelves, which I was surprised to find, were to be traced through a much more extensive stretch of country than former observation had led me to imagine. My first visit to Glen Roy was accidental; but upon this late occasion, I went with the purpose of endeavouring to put myself in possession of all the facts I could possibly collect, regarding these curious appearances; and in doing this, I had several advantages which I did not formerly enjoy.

In this paper I propose submitting to the Society some observations on the nature and history of the Marsh Poison, which, under the title of Marsh Miasmata, or Malaria, has ever been acknowledged as the undisputed source of Intermittent Fevers, and is believed, with good reason, to be the exciting cause of the whole tribe of Remittent Fevers;—of Endemic Fever, in fact, in every form, and in every part of the world.

During the summer of the present year (1820), while navigating with the ship Baffin, the icy sea in the immediate neighbourhood of West Greenland (the east side), several extremely curious appearances of distant objects, produced by the reflective and refractive properties of the atmosphere, were observed.

The subject of poisonous fish has long been a source of puzzle and speculation to the inhabitants of the West Indies. Much has been conjectured upon it, and numerous tests and theories been proposed, which have had for a time their believers and advocates; but all have been found to be equally baseless. The author of this paper, by a narrative of what he has himself seen and observed on the subject, proposes rather to shew to the Society what it is not, than what it actually is, and thereby to clear the way for the future successful investigation of this curious and interesting phenomenon, by dissipating many erroneous notions that stand in the way of the discovery of truth.

Throughout the greater part of the West Indies, the accident of meeting a poisonous fish is a rare and extraordinary occurrence. At Barbadoes, for instance, it happens so seldom, that the majority of even the best informed inhabitants can scarcely be made to believe, that it has ever taken place amongst them.

While examining an abandoned lead-mine in the vicinity of Stromness, in the year 1803, I found a mineral which, from its weight and appearance, I supposed to be carbonate of barytes. A few hasty experiments soon convinced me that it was a different substance; but circumstances occurring which prevented a more accurate investigation, the mineral lay neglected among the duplicates of my collection till last autumn, when having mentioned my doubts and conjectures respecting it to my friend Dr Murray of Edinburgh, I was strongly urged by that gentleman to undertake its analysis. During his short visit to Liverpool, a few preliminary experiments were begun, from which it appeared, that the mineral contained carbonate of strontia, and I have since completed its chemical examination.

On the 19th of February last, I had the honour of reading to this Society, some notices of the mode of working and polishing granite, by the natives of India.

One object of that paper was, from a view of the immense masses, which Indian artists are still in the habit of rendering obedient to their simple instruments, to deduce the probability of the similarity, if not of the identity, of the means now in use among them, with the processes by which the architects of the ancient world, raised the stupendous monuments which we still see in existence; and, as an instance of the very recent exercise of these arts, I mentioned the erection of a granite obelisk near Seringapatam, to the memory of the late Josiah Webbe, Esq. who died in the year 1805.

The variety of Apophyllite to which I have given the name of Tesselite, from the beautiful combination of tesselæ which it exhibits in polarised light, is one of the most singular substances in the mineral kingdom. The agency of that species of light, indeed, seemed necessary to the developement of its peculiar structure; but I have since succeeded in confirming and extending my former results, by the application of the microscope; and have been led to observe several new phenomena, which not only throw much light on the structure and properties of this curious mineral, but which affect the fundamental principles of crystallography.

Having heard at Port-of-Spain of an appearance that went by the name of the Mud Volcanoes, we took the opportunity when surveying the southern quarter of Trinidad, to examine them. They are situated near Point Icaque, the southern extremity of the island, on an alluvial tongue of land, that has been appended to the primitive rocks, where no doubt the land originally terminated. This appendage is several miles in length, and points directly into one of the mouths of the Oronoko, on the mainland, about twelve or fifteen miles off.

We landed nearly opposite to where we were told we should find the mud volcanoes, and after making our way about five miles through the woods, across the sandy isthmus, we came upon two plantations very pleasantly situated, amidst a group of remarkable round little hills, each from eighty to a hundred feet in height.

Having had frequent opportunities, during my residence in France, of seeing a great many Repeating Reflecting Circles, several of which I have observed with, and having found much consistency in the results deduced from observations made with them, it occurred to me, that if I could engage Mr Troughton to execute one for me, it would be a most perfect instrument. This he accordingly did; and I trust that the observations made with it, which I am about to communicate, will perfectly justify the opinion I had formed of its precision. The instrument is only of about six inches radius, divided in gold to 20″. I have always been in the habit of choosing for latitudes 30 repetitions, when the weather would permit, divided into three series of 10 each, and reading the angle or arc run through during the series, which completely destroys every imperfection of the division, or reading. In order to determine the time, I have always found six repetitions quite sufficient to give it as correct as equal altitudes.

Those who have devoted much of their attention to mathematical inquiries, must have had frequent occasion to admire mire the unexpected and intimate connection which subsists between branches of their science apparently the most remote and unconnected with each other; and repeated observation will have convinced them, that no researches, however recondite or abstruse, should be neglected, because they appear to stand isolated and detached from the body of the science. These reflections appear to have been felt with strongest force, by those who have most contributed to its advancement, and were particularly insisted on by Maclaurin, in the Preface to his Geometria Organica. The present Paper will add another example, to instances already numerous, of the latent affinity between departments of mathematics, usually regarded as the most opposite.

The quarry of Niteshill, from which this very interesting petrifaction was taken, lies about three miles south-east of Paisley, and is part of a coal formation. It consists of white sandstone, which in many parts is deeply stained by an impregnation of iron. Two very thin seams of excellent coal occur immediately under the sandstone, with the intervention of a few feet of till or blaize. The strata dip to the south, and crop out about a hundred yards north of the spot from whence the tree was taken. At this spot the face of rock is about sixteen feet; fourteen feet above the tree, and one under; another foot being occupied by the stem itself.

The part which has been detached from the rock consists of stem and roots, five feet of stem, and two of roots, different views of which I have endeavoured to represent in figures 1, 2, & 3.

The value of the Chronometer for finding the Longitude at Sea, being, by the experience of many years trial, fully established, I am induced to offer to the Royal Society some remarks on the change of rate observed in this instrument, when on ship-board. This change of rate, that had usually been supposed to arise from the motion of the ship, has recently heen attributed, by Mr Fisher, who accompanied Captain Buchan in his Voyage towards the North Pole in the year 1818, ‘to the magnetic action exerted by the iron in the ship upon ‘the inner rim of the Chronometer's balance, which is composed of steel.’ I apprehend, however, that it will be very easy to show, that although the alteration of rate may be, and most probably is, owing to magnetism, yet the magnetic action of the iron in the ship, excepting in cases where chronometers are placed in immediate contact with large masses of iron, can contribute but in a very small degree to the error in question.

The communication received from Dr Dyce chiefly consists of a description of a singular affection of the nervous system, and mental powers, to which a girl of sixteen was subject immediately before puberty, and which disappeared when that state was fully established. It exemplifies the powerful influence of the state of the uterus on the mental faculties; but its chief value arises from some curious relations which it presents to the phenomena of mind, and which claim the attention of the practical metaphysician. The mental symptoms of this affection are among the number of those which are considered as uncommonly difficult of explanation. It is a case of mental disease, attended with some advantageous manifestations of the intellectual powers; and these manifestations disappearing in the same individual in the healthy state.

When I lately mentioned to you in conversation, the disease in the eyes of horses in India, occasioned by the presence of a worm within the ball of the eye, I thought that you might probably have heard of it before; but as you had not, and are desirous of further information upon the subject, I now take this method of mentioning the circumstances to you, so far as I know them.

The animal occasioning this disease, is termed by the natives about Madras, the “Worm” in the Horse's Eye, by using the corresponding words in their respective languages. I have been told that in Bengal it is called the “Sānp” or the Snake in the Horse's Eye. As it seems more to resemble a fish or an aquatic insect, it might perhaps with more propriety be regarded as an eel.

The figures, sculptured in full relief, and here represented by the four drawings in Plate XXIV., are idols brought from India in the year 1800, by Francis Simpson, Esq., which I had the honour of presenting to the Society at his request.

According to information with which I have been favoured by gentlemen conversant with the literature of India, these idols are Cali, Suria and Buda.

The author of the Naval Tactics is one of those men who, by the force of their own genius, have carried great improvements into professions which were not properly their own. The history both of the sciences and of the arts furnishes several remarkable examples of a similar nature. Fermat the rival, sometimes the superior of Descartes, one of the most inventive mathematicians of a most inventive age, was by profession a lawyer, and had only devoted to science the time that could be spared from the duties of a counsellor or a judge: about fifty years earlier, also, his countryman Vieta had made a like digression from the same employment, and hardly with inferior success.

Perrault, who, in the façade of the Louvre, has left behind him so splendid a monument of architectural skill and taste, was a physician, and not only practised, but wrote books on medicine. Dr Herschell too, who has made more astronomical discoveries than any individual of the present age, betook himself to the study of the heavens as a relaxation from professional pursuits.

Of the various rocks of which the Earth's surface is composed, there are some which present very satisfactory indications of their origin; while others, when considered in that respect, seem to be placed almost beyond the reach of hypothesis. The Granite and Trap rocks, by extending their ramifications among their contiguous neighbours, distinctly avow, not only a subsequent formation, but, in many instances, they present the most unequivocal marks of an igneous origin. The Limestones and Sandstones, however, are equally constant in their indications of aquatic deposition, although, at the same time, the assistance of another agency may sometimes be inferred, when their consolidation and position are taken into the question. Of all the rocks with which I am acquainted, there is none whose formation seems to tax the ingenuity of theorists so severely, as the White Limestone or Chalk, in whatever respect we may think fit to consider it.

In plates of Rock-Crystal cut perpendicular to the axis of the prism, an unusual kind of polarisation had been observed in the colours seen along the axis. The phenomena were subsequently analysed by M. Biot, who remarked, that in some specimens of quartz, the succession of tints appeared by turning the doubly refracting prism from right to left, while in other specimens the same succession was developed by turning the prism from left to right; and he concluded from his experiments, that the quartz impressed upon the particles of light a rotatory motion, and that this property belonged to the ultimate particles of silex, and was independent of their mode of aggregation.

The same species of colours was afterwards observed, about the same time, by MM. Biot and Seebeck, in transmitting polarised light through considerable thicknesses of some essential oils, and solutions of sugar and camphor; and this new fact seemed to confirm the supposition that the colours were not dependent upon crystallisation.