a circumstance extremely favourable to their working, since the great inclination which the beds assume would otherwise carry them down beyond the reach of the miner, were it not that their broken edges are thus brought up again and made to outcrop on the surface.

The 'coal-measures,' or strata in which the beds of coal occur, usually alternating with clay and sandstone, are almost absolutely restricted to that group of the great geological series which used to be termed the transition series-that is to say, to the formations between the metamorphic rocks and the secondary limestones, &c., and more particularly to the upper Paleozoic formations between the Devonian and Permian groups, and in these, to the interval between the old red sandstone, the mountain or coral limestone and millstone grit below, and the new red sandstone and magnesian limestone above. From this circumstance (their coral substratum), from the nature of the fossils they enclose, and from the form and distribution of the carboniferous districts, it is inferred that their depositions took place in comparatively shallow seas, receiving the vegetable spoils of densely-clothed islands abounding in plants of a tropical character, and, in particular, with arborescent ferns, flags, reeds, and large trunks of succulent plants. Few animal remains, and scarcely a single shell or coral, are found in the coal-measures, while the vegetable forms, sometimes most beautifully preserved (though more ordinarily completely obliterated), which they contain, sufficiently prove their whole mass to consist of vegetable matter consolidated by heat (after undergoing a specific peatifying action by long submersion in water) under a pressure sufficient to retain the more volatile portions of their structure in combination with the carbon, forming bitumen and all the varieties of hydrocarbon, which, as is well known, the distillation of coal yields in abundance. Where the heat has been very violent, the coal is converted into anthracite or blind coal,' culm' or 'Welsh coal,' which is almost pure carbon; and in some instances, in the neighbourhood of trap-dykes, into true coke, evidently from the effect of heat under insufficient pressure.

6

The coal-measures would seem to mark an epoch of great interest in the geological history of the world, from the circumstance that whereas their strata bear every mark of great disturbance and violent dislocation, those incumbent on them are for the most part horizontal or comparatively little inclined. Such, at least, is the case in the great coal-series of England and the Netherlands, and such is the impression strongly left by the moderate inclination and slight disturbance of the sandstones immediately incumbent on the great coal-fields of North America.

Coal occurs in immense abundance in all those parts of England, Scotland, and Wales, where the strata above specified crop out, especially-(1.) In Northumberland and Durham, in a district the central point of which is somewhere about Jarrow, at the mouth of the Tyne, in which it has been calculated that between five and six thousand millions of tons of workable coal exist. (2.) In South Yorkshire, Nottingham, and Lancashire. (3.) In Staffordshire and Warwick, in a region having Ashbyde-la-Zouch for its centre. (4.) In what may be called the western and south-western coal districts, comprising Anglesey, Flintshire, Shropshire, South Gloucester, Somerset, Monmouth, and Glamorgan. (5.) The Scotch coal-field, occupying the great central lowland of Scotland. (6.) The Irish provinces of Leinster, Munster, and Connaught, and the counties of Tipperary and Tyrone. The larger portion of the whole area of Ireland, indeed, is occupied by the carboniferous formations.

On the continent of Europe, coal occurs in Belgium in the district about Liege; in France in the neighbourhood of Vienne on the Rhone. The south of Europe is, generally speaking, destitute of coal. It has hitherto been found but very sparingly in Russia. It has, however, been lately discovered, though of inferior quality, at a depth of 360 feet, near Moscow. By far the greatest system of coal-deposits known, however, is that of the United States of America. It is considered that the State of Pennsylvania consists, in about one-third of its area, of coalfields belonging to the great Appalachian system of coal-measures, which extend altogether over upwards of 60,000 square miles. One of the seams in this formation, near Pittsburg, is worked through a large extent of its outcrop as an open quarry. The Illinois coal-field, which covers an area as large as England, in Illinois, Indiana, and Kentucky, consists of horizontal strata, and has numerous seams of excellent coal. Michigan, New Brunswick, Nova Scotia, and Vancouver's Island all yield coal in abundance. It occurs at the height of 14,750 feet in the Peruvian Andes. A great coal-field has been also ascertained to exist at St. Catherine's in Brazil, extending 140 leagues along the coast from Loguna in that province, almost to Monte Video, and 60 leagues inland from the Atlantic to St. Gabriel, and perhaps further.

Coal is also found in a vast number of other localities both in Asia and Australia, in Asia Minor (on the coast of the Black Sea, near Trebizond), in Borneo, Formosa, Tasmania, and New Zealand. In India, coal occurs on the Damoda river; also in Sylhet and Cashar.

Sulphur often accompanies salt and gypsum. It is produced in abundance, accompanying the latter mineral and sulphate of strontia (all three superbly crystallised), in the mines of

Catolica in Sicily. The greater part of the sulphur of commerce is procured from Solfataras' or volcanic half-extinguished vents, where from 'Fumaroles' and fissures in the soil the sulphur is sublimed. The Solfatara, emphatically so called, near Naples, supplies an immense quantity. There exist also great masses of sulphur, constituting almost mountains, such as the Sulphur Island of the Luchu Archipelago. Great quantities occur among the volcanoes of Iceland, of Java, and of the Andes. It is one of the most universal of volcanic products.

MENSURATION.

Exercises on triangles. (1) A ladder 50 ft. in length reaches a window on one side of a street 38 ft. from the pavement, and without moving the foot of the ladder it will reach a window on the other side of the street 44 ft. from the pavement; what is the width of the street? (2) There is a field in the form of a right-angled triangle, the shorter sides of which are 10.35 chains and 674 chains respectively; what is the length of the third side in yards?

(3) A kite is flying attached to a string 212 yards in length. The distance of the person holding the string from another who stands immediately below the kite is 87 yards; allowing 20 yards for the curvature of the string, at what height is the kite from the ground?

THE SUPERIOR IMPORTANCE OF THE STUDY OF ENGLISH HISTORY.

(From the History of Civilisation in England,' by Mr. Buckle.)

It is evident that, inasmuch as the great advantage of studying past events consists in the possibility of ascertaining the laws by which they were governed, the history of any people will become more valuable in proportion as their movements have been least disturbed by agencies not arising from themselves. Every foreign or external influence which is brought to bear upon a nation is an interference with its natural development, and therefore complicates the circumstances we

seek to investigate. To simplify complications is, in all branches of knowledge, the first essential of success. This is very familiar to the cultivators of physical science, who are often able, by a single experiment, to discover a truth which innumerable observations had vainly searched; the reason being, that by experimenting on phenomena, we can disentangle them from their complications; and thus isolating them from the interference of unknown agencies, we leave them, as it were, to run their own course, and disclose the operation of their own law.

This, then, is the true standard by which we must measure the value of the history of any nation. The importance of the history of a country depends not upon the splendour of its exploits, but upon the degree to which its actions are due to causes springing out of itself. If, therefore, we could find some civilised people who had worked out their civilisation entirely by themselves,-who had escaped all foreign influence, and who had been neither benefited nor retarded by the personal peculiarities of their rulers,-the history of such a people would be of paramount importance; because it would present a condition of normal and inherent development; it would show the laws of progress acting in a state of isolation; it would be, in fact, an experiment ready-made, and would possess all the value of that artificial contrivance to which natural science is so much indebted. To find such a people as this is obviously impossible; but the duty of the philosophic historian is, to select for his especial study the country in which the conditions have been most closely followed. Now, it will be readily admitted, not only by ourselves but by intelligent foreigners, that in England, during, at all events, the last three centuries, this has been done more constantly and more successfully than in any other country. I say nothing of the number of our discoveries, the brilliancy of our literature, or the success of our arms. These are invidious topics; and other nations may perhaps deny to us those superior merits which we are apt to exaggerate. But I take up this single position, that of all European countries, England is the one where, during the longest period, the government has been most quiescent, and the people most active; where popular freedom has been settled on the widest basis; where each man is most able to say what he thinks, and do what he likes; where everyone can follow his own bent, and propagate his own opinions; where, religious persecution being little known, the play and flow of the human mind may be clearly seen, unchecked by those restraints to which it is elsewhere subjected; where the profession of heresy is least dangerous, and the practice of dissent most common; where hostile creeds flourish side by side,

and rise and decay without disturbance, according to the wants of the people, unaffected by the wishes of the Church, and uncontrolled by the authority of the State; where all interests, and all classes, both spiritual and temporal, are most left to take care of themselves; where that meddlesome doctrine called Protection was first attacked, and where alone it has been destroyed; and where, in a word, those dangerous extremes to which interference gives rise, having been avoided, despotism and rebellion are equally rare, and concession being recognised as the groundwork of policy, the national progress has been least disturbed by the power of privileged classes, by the influence of particular sects, or by the violence of arbitrary rulers. That these are the characteristics of English history is notorious; to some men a matter of boast, to others of regret. And when to these circumstances we add, that England, owing to its insular formation, was, until the middle of the last century, rarely visited by foreigners, it becomes evident that, in our progress as a people, we have been less affected than any other by the two main sources of interference-namely, the authority of government, and the influence of foreigners. In the sixteenth century it became a fashion, among the English nobility, to travel abroad; but it was by no means the fashion for foreign nobility to travel in England. In the seventeenth century, the custom of travelling for amusement spread so much, that, among the rich and idle classes, there were few Englishmen who did not, at least once in their life, cross the Channel; while the same classes in other countries, partly because they were less wealthy, partly from an inveterate dislike to the sea, hardly ever entered our island, unless compelled to do so on some particular business. The result was, that in other countries, and particularly in France and Italy, the inhabitants of the great cities became gradually accustomed to foreigners, and, like all men, were imperceptibly influenced by what they often saw. On the other hand, there were many of our cities in which none but Englishmen ever set their feet; and inhabitants even of the metropolis might grow old without having once seen a single foreigner, except, perhaps, some dull and pompous ambassador, taking his airing on the banks of the Thames. And although it is often said that, after the restoration of Charles II., our national character began to be greatly influenced by French example, this, as I shall fully prove, was confined to that small and insignificant part of society which hung about the court; nor did it produce any marked effect upon the two most important classes-the intellectual class, and the industrious class. The movement may, indeed, be traced in the most worthless parts of our literature-in the shameless productions of Buckingham, Dorset, Etherege, Killi