GRAVITY-GRAY. Before, however, the argument on the extension of terrestrial gravity to the sphere of the moon could have become pregnant with so great a result, much investigation had to take place in other fields; and, in fact, Newton had, previously to conceiving the law, explained the three great Keplerian laws of order obtaining in the solar system by reference to an attractive force residing in the sun. These laws are-1. That the planets revolve round the sun in ellipses, having the sun for a common focus: 2. That every planet moves in such a way that the line drawn from it to the sun sweeps over equal areas in equal times: 3. That the squares of the times occupied by the several planets in their revolutions in their elliptic orbits, are proportional to the cubes of their mean distances from their common focus, the sun. From the law of equal | areas, Newton inferred that every planet is retained in its orbit by a force of attraction directed towards the centre of the sun; from the orbits being elliptical, he inferred that in each case this force varies in intensity according to the inverse square of the bodies' distance from the sun; while from the third law he inferred the homogeneity of the central force throughout the solar system. It was then, after being familiar with the notion of terrestrial gravity, and its action, through the researches of Galileo, Huyghens, and Hooke, and with the notion of a central force acting inversely as the square of the distance of its object, through his explanations of the laws of Kepler, that he put to himself the question: Is not the force with which the moon gravitates to the earth the same with gravity?—the force which causes a stone to fall on its surface. A question answered affirmatively on the supposition of gravity, like the sun's attraction, being a force diminishing with increase of distance, and according to the same law. The result was to bring the whole solar system, the planets and the sun, and satellites and their planets-the satellites being observed to obey the same laws of order with reference to their primaries that the latter obeyed in reference to the sun-under the law of gravitation. And the imagination lifted up by the grandeur of the conception, would refuse to limit the operation of that law to our own system, were there no facts to entitle us to extend it beyond. The phenomena of double stars, however, of themselves justify the extension and the statement of the law as we have given it in universal terms. It may be observed, in conclusion, that the Keplerian laws, which may be said to have been the basis of Newton's researches, are, owing to perturbations caused by the mutual action of the planets, &c., only approximately correct; and that these perturbations afford, when examined, a further proof of the truth and universality of the law of gravitation. For a notice of speculations as to the nature of the law of gravitation, see FORCE; see also FALLING BODIES, PROJECTILES, &c. GRAVITY, SPECIFIC. See SPECIFIC GRAVITY. GRAY, a small town of France, in the department of Haute-Saône, is situated on the slope of a hill overlooking a beautiful meadow, on the left bank of the Saône, 26 miles west-north-west of Besançon. It is commanded by the remains of an ancient castle, the residence in former times of the Dukes of Burgundy, and has a pleasing appearance from a distance, although its streets are crooked, narrow, and steep. G. is an important entrepôt for goods from the north-eastern districts of France, which are conveyed by the Saône to the south. Its trade is chiefly in corn, flour, timber, wine, iron, and colonial produce. Pop. 6188. GRAY, JOHN EDWARD, a distinguished living naturalist, who for more than thirty years has been connected with the British Museum. Profiting by the advantages which his position has afforded him, he has probably described and classified a larger number of animals than any other naturalist. In 1852, the date of the publication of the Bibliography of Zoology and Geology, by the Ray Society, his papers, memoirs, and books amounted to 425, and we may now place them at about 500. Among his works on natural history generally, may be noticed the Zoological Miscellany (1835-1845), which includes descriptions of numerous animals; his Spicelegia Zoologica (1828-1830); his Synopsis of the Contents of the British Museum (1840); and his Gleanings from the Menagerie and Aviary at Knowsley Hall (1846–1850). Amongst his contributions to mammalian zoology, may be mentioned his catalogues of the Ruminantia and Cetacea in the British Museum, and his 'Description of some New Genera and fifty unrecorded Species of Mammalia,' published in the Annals and Magazine of Natural History. The mammals collected in King's survey of the coast of Australia, and in the voyages of the Erebus and Terror, and of the Samarang, were also described by him. In the list of his memoirs, &c., already referred to, upwards of 100 are devoted to this class. His papers upon birds are comparatively few (twenty-nine); he seems to have left them to his brother, GEORGE ROBERT GRAY, who superintends this department of the Museum, and who is well known as the author of The Genera of Birds, and of various Museum catalogues of this class. His contributions to herpetology have been extensive and very valuable, and upwards of 60 of his papers are devoted to the classification of reptiles, to the description of new species, or to the consideration of their structure and habits. On the mollusca, his memoirs, in 1852, amounted to 119, and many have since been added. In this department, he has been admirably assisted by Mrs Gray, whose Figures of Molluscous Animals for the Use of Students are accompanied by his descriptions. Upwards of 70 papers have been devoted to the Articulata (crustaceans, insects, &c.) and to the Radiata (star-fishes, sea-eggs, &c.). He has thus been an active contributor to almost every department of zoology. GRAY, THOMAS, an English poet, was born in London on the 26th December 1716. His father, Philip Gray, a money-scrivener, was of a disposition so violent, that his wife was obliged to separate from him; and it was mainly through her exertions that her son was placed at Eton, and afterwards at Cambridge. At Eton, he made the acquaintance of Horace Walpole, the son of the prime minister; and when his college education was completed, he accompanied his friend on a tour through France and Italy. After spending a year in the search of the picturesque and in the exploration of picture-galleries, the friends quarrelled, and G. returned to England, and went to Cambridge to take his degree in civil law. At the university, the greater portion of his life was spent, breathing the serene air of noble libraries, and corresponding with friends, as only the men of that day could correspond. In 1756, in consequence of a practical joke, he removed from St Peter's College to Pembroke Hall. He had a just appreciation of the natural beauty of his native country, and rambled in Scotland, Wales, and the English lake counties. He made notes wherever he went, and wrote copious descriptions of what he had seen to his literary friends. He published his Ode to Eton College in 1747, and his Elegy written in a Country Churchyard two years afterwards. His Pindaric Odes appeared in 1757; but however much they might dazzle the GRAY-GREAT BASIN. imagination with brilliant imagery, and charm the ear with involved and intricate harmony, they did not touch the popular heart like the Elegy. On the death of Colley Cibber, he was offered, but declined, the post of poet-laureate. Shortly after he was appointed Professor of Modern History. Fastidious in his tastes, fond of books and lettered ease, indisposed to mingle in the great world, but delighting to comment upon it in letters to friends, blessed with a reputation peculiarly dear to a scholar's heart, comparatively rich, his life glided on imbittered but by one enemy-gout. Dining one day in the college hall, he was severely attacked, and after suffering a week, he died on the 30th July 1771, aged 55 years. He was buried by the side of his mother at Stoke near Eton. The poetry of G., with the exception of the Elegy which everybody knows-has never become popular; yet in its own sphere it is very perfect; delicately if not richly imaginative, curiously studded with imagery; exquisitely finished, like miniatures painted on ivory. But his subjects are often remote, and out of the track of ordinary human feelings. GRAY, in Heraldry, signifies a badger. GRA'YLING (Thymallus vulgaris), a fish of the family Salmonide, and of a genus distinguished from salmon, trout, &c., by smaller mouth and much smaller teeth, and by the greater size of the dorsal fin. The scales are also much larger. The G. is found in many streams in England, but is, however, very local; and of two rivers in the same neighbourhood, one often contains it, and the other does not. A supposition that it was brought to England by the monks, is unsupported by any evidence. It is found in the Eden and the Esk in Cumberland, in the Clyde in Lanarkshire, and in the Orkney Islands. It is plentiful in many parts of Europe, and equally in Switzerland and in Lapland. It inhabits clear streams, with rocky or gravelly bottoms, and seems to require an alternation of stream and pool.' It will live in clean newly made ponds in hard soil, although it does not breed in them, but will not live in those of muddy bottom. Its food consists chiefly of flies and aquatic larvæ, and it is taken by angling in the same manner as the trout. It sometimes attains the weight of four or five pounds. The back and sides are silvery gray, Grayling (Thymallus vulgaris). marked with numerous longitudinal dusky streaks; the dorsal fin is spotted, the spots arranged in lines across the fin. The abdominal line is almost straight, the dorsal line is considerably elevated. The G. is greatly esteemed for the table, but requires to be cooked when newly caught, when it has an odour which has been compared to that of wild thyme. It spawns in April or May, and is in the best condition when trout are out of season, in October and November.-There are several other species of Thymallus, none of which are British. One of them, T. signifer, a very beautiful fish, inhabiting the clear affluents of the Mackenzie River, is called GRAY'S INN, one of the four Inns of Court having the sole power of calling persons to the degree of barrister-at-law. See INNS OF COURT. GRAZALE'MA, a small town of Spain, in the province of Cadiz, and situated about 60 miles east-north-east of the city of that name in a strong position on a rocky hill approachable only by a Sierra de Ronda on the east, and the Cerro de narrow and easily defended ledge, between the S. Cristoval on the west. It was compared by the French (a whole division of whom were here repulsed by the inhabitants) to a land Gibraltar. A great deal of smuggling, and, it is suspected, robbery, is carried on by the inhabitants. 6600. Pop. GRAZIO'SO, an Italian term in Music, meaning with graceful expression. GREASE, a term of general application to all oily or fatty matters, but generally to those having It is more some degree of solidity, as tallow. specially applied to fatty matters which are so deteriorated with dirt or other impurities as to be unfit for candle-making and other manufactures requiring some degree of purity in the material. Grease is largely employed as machinery, and especially for the wheels of carriages. The grease employed for the axles of carriages and carts consists of the most inferior kinds of grease mixed with a little tar. a lubricant for In commerce, the term Mares' Grease is now well known. It is the fat of horses which are killed in large numbers at Buenos Ayres and Monte Video; and their products, consisting of hides, grease, bones, and hair, are largely exported to this and other countries. Owing to the practice of slaughtering the mares chiefly, this particular kind of fat has been designated Mares Grease. It is a very oily fat, and so penetrating, that it is difficult to make casks sufficiently tight to prevent leakage. It is used for lubricating machinery, for which it is well adapted. RAILWAY GREASE is, in reality, a kind of soap, a small portion of soda being mingled with the materials to effect an imperfect saponification. The object is to prevent the too rapid melting of the material, which, without this precaution, would be excessively rapid, owing to the heat caused by the friction of wheels revolving with such rapidity. It is also made of very superior materials, and consists generally of the vegetable fats called cocoa-nut oil and palm-oil; sometimes animal fat is used. This composition is placed in small metal boxes on the axles, with which they communicate by a small hole, so that, as the axle heats the surrounding parts, the grease in the boxes melts, and runs through the little orifice on to the axle. See BEAR'S GREASE. GREAT BASIN, or FREMONT'S BASIN, a remarkable tract of country in North America, lying in the west of Utah Territory, and bounded on the W. by the Sierra de Nevada, and on the E. by the 61 GREAT BEAR LAKE-GREAT BRITAIN. Wahsateh Mountains. It is said to be 500 miles in extent from east to west, and about 350 from north to south; is girdled round on every side by high mountains, while detached groups cross its whole area; and lies at an elevation of about 5000 feet above sea-level. The Humboldt River Mountains, with an elevation of from 5000 to 7000 feet above the surrounding country, traverse the plateau near its centre. This basin contains many lakes and rivers whose waters never reach the ocean, but are either taken up by evaporation, or are lost in the more arid districts. The G. B. is essentially a desert. Some portions of it are covered by a yielding mass composed of sand, salt, and clay; others by a crust of alkaline and saline substance. GREAT BEAR LAKE. See BEAR LAKE, GREAT. GREAT BRITAIN. Under this head are noticed-1. The Island of Great Britain-its geology and geography; 2. The United Kingdom of Great Britain and Ireland-its general statistics, &c. Historical sketches of England and Scotland down to the union of the two kingdoms are given under their respective names; the history of Ireland to its union with Great Britain is also given under its own name, together with its geography. The ISLAND OF GREAT BRITAIN SO called to distinguish it from Britannia Minor, or Little Britain (see BRETAGNE) in France-lies between lat. 49° 57′ 30′′ and 58° 40′ 24′′ N., and between long. 1° 46′ E. and 6° 13′ W., and is the largest island in Europe. It is bounded on the N. by the Atlantic, on the E. by the North Sea, on the S. by the English Channel, and on the W. by the Atlantic, the Irish Sea, and St George's Channel. The most northerly point is Dunnet Head, in Caithness; the most southerly, Lizard Point, in Cornwall; the most easterly, Lowestoft Ness, in Suffolk; and the most westerly, Ardnamurchan Point, in Argyleshire. Its greatest length is about 608 miles, and its greatest breadth (from Land's End to the east coast of Kent) about 320 miles; while its surface contains about 89,600 square miles. Geology. The geology of G. B. is of peculiar importance. The rocks of the earth's crust having been first systematically studied and expounded here, British geologists have given to the world the names whereby the various strata are known, and British rocks form the typical series of the earth's strata. The whole recognised series of stratified deposits occur in Britain, one or two only being more fully developed elsewhere; and it is only in these singular cases that the foreign equivalents are taken as the types. British geology is no less important from the influence it has had in the development of the country. The mineral wealth, especially the coal and the iron, are the real sinews and muscles of Britain's mighty power. No other country has similar advantages in such an area. We shall, in this sketch of the distribution of the British rocks, follow the order of the strata, beginning with the lowest and oldest. It may be said that, in general, the mountainous regions of the north and west are formed of the oldest sedimentary rocks, and that, as we move south-eastwards, we gradually pass over newer strata, until, in the east of England, we come to the only extensive Pleistocene deposits in the country. The base rocks of the whole series occur in the Outer Hebrides, in Tiree and Coll, and along the western shores of Sutherland and Ross. The true position of these strata has been only recently determined by Murchison and Geikie, who, noticing that their strike was at right angles to the beds resting above them, discovered that they were older than the superimposed Cambrian rocks. They consider them to be the equivalents of the Laurentian system, described by Sir W. Logan in Canada. The predominant rock is crystalline gneiss. A band of limestone occurs on the north-east shore of Loch Maree, but this has hitherto proved unfossiliferous. Resting on the convoluted edges of this old gneiss, on the mainland, and forming the basement rocks in Cumberland, Anglesey, and North Wales, we have the Cambrian series of deposits. In Scotland, these rocks are brownish-red sandstones and conglomerates; in England and Wales, they are composed of sandstones, gritstones, and slates. A few fossils, chiefly impressions of supposed fucoid plants, annelid tracks, and zoophytes, have been found in the slates. The Silurian measures occupy a large portion of the surface of the country. The typical rocks occur in Wales, extending over the western portion of the principality from Pembroke to Denbigh, and including the northern portions of Pembroke, Caermarthen, and Brecknock, the whole of Radnor and Montgomery, the south-west of Denbigh, and the whole of the counties to the west. The oldest or Lower Silurian beds are next the coast. The series consists of an immense thickness of shales, slates, and sandstones, with intercalated limestones more or less pure. Immense tracts have hitherto proved devoid of fossils; in other districts, the calcareous rocks are almost entirely composed of the remains of marine invertebrate animals, while the shales abound in zoophytes and crustacea. The high lands in the north of Lancashire and south of Westmoreland are Silurian; but it is in Scotland where these strata are most extensively developed; indeed, almost the whole country consists of Silurian strata, with the exception of a large trough in the centre, occupied with newer rocks. A line drawn from Dunbar to Girvan forms the northern limit of these beds in the south of Scotland. Except the lower half of the valley of the Tweed, the whole region from this line to near the base of the Cheviots is Silurian. The rocks are chiefly greywacke, with scattered beds of impure limestone. The chief fossils are graptolites, crustacea, and mollusca. The lead-mines of Wanlockhead and Leadhills are in this district. A line drawn from Stonehaven to Helensburgh would mark the termination of the Silurian strata, which compose the whole of the north of Scotland, with the exception of the newer beds on the north-east coast, and the Laurentian and Cambrian series already described. All the series is greatly metamorphosed; the lower strata are converted into quartzose flagstones and quartz rock, the upper into chlorite and mica-slate, and quartzose and gneissose rocks. The Old Red Sandstone strata, consisting of conglomerates, coarse and fine grained sandstones, and dark-coloured schists, with the characteristic fossils of ganoid and placoid fish, overlie the Silurians in several districts in Scotland. Nearly all Caithness and the seaward portions of Sutherland, Ross, Cromarty, Inverness, Nairn, and Moray, belong to these strata. A broad band, rising on the east coast between Stonehaven and St Andrews, stretches across the country to Helensburgh and Dumbarton on the west. The same strata appear again in Haddington, Berwick, and Roxburgh, in Lanark, and in Ayrshire. An extensive tract of these strata occurs in South Wales and the neighbouring English counties, extending from the Silurian district to the Severn and the Bristol Channel, and containing in a large basin the South Wales coal-field. The highly fossiliferous strata of North Devon, and of South Devon and Cornwall, belong to this period. They consist GREAT BRITAIN. of slates, sandstones, and limestones, and contain numerous corals and shell-fish. The strata of the Carboniferous period may be said to occupy a broad tract extending from the Bristol Channel to the base of the Cheviots. They are not continuous between these limits, but are broken up in some places by the appearance on the surface of older strata, while in others they are covered by newer deposits. The various detached coal-fields are (1) the South Wales, in Glamorgan and Pembroke; (2) the Bristol, and (3) the Forest of Dean, in Gloucester; (4) the Forest of Wyre, in Worcester; (5) Shrewsbury, and (6) Colebrook Dale, in Shropshire; (7) North and (8) South Staffordshire; (9) Warwickshire; (10) Leicestershire; (11) Flint and Denbigh; (12) Lancashire; (13) York and Derby; (14) Cumberland; and (15) Northumberland and Durham. In the northern portion of this great tract of coal measures, where the millstone grit and carboniferous limestone are largely developed, no seams of coal of any value are contained. The limestone in Derby is rich in metallic ores. The carboniferous strata of the north of England extend beyond the Cheviots into Scotland, forming a narrow band from the Solway to the North Sea, in the counties of Dumfries, Roxburgh, and Berwick. The only coal-field in this district is one of small extent at Canonbie, in Dumfriesshire. The carboniferous strata in Scotland, with the exception just stated, are confined to the immense trough between the Silurian measures on the south and the Old Red Sandstone on the north, which is completely occupied by them, except where the Old Red Sandstone rises to the surface. Considerable tracts of sandstone and limestone without coal break up the true coal-bearing measures into the following coal-fields: the MidLothian, the Fife, the Lanark and Stirling, and the Old Cumnock, in Ayrshire. Besides coal, the whole of the carboniferous series contain immense stores of argillaceous carbonate of iron, the ore from which is produced the great bulk of the iron used in the country. The sandstones of this period form beautiful and durable building-stones, the limestones are of great commercial value, and many of the less indurated shales are good fireclays. Permian strata, consisting of magnesian limestone and sandstone coloured with oxide of iron, occupy a considerable area in Durham, and border the carboniferous rocks in Dumfries, Cumberland, Westmoreland, Lancashire, Cheshire, Shropshire, Stafford, Worcester, Warwick, Nottingham, and York, and in Glamorgan. The sandstone is quarried for building. The typical triple series of the Triassic measures occur in Germany; the British representatives consist of variously coloured sandstones and marls. They occupy a considerable surface in Lancashire, Cheshire, Shropshire, and Stafford, and extend as a ribbon of varying breadth, from the mouth of the Exe, through Devon, Somerset, Gloucester, Worcester, Warwick, Leicester, Nottingham, York, and Durham, to the coast at Hartlepool. The only deposits of rock-salt in Britain occur in the Triassic rocks of Cheshire and Worcestershire. series of limestones, sandstones, and shales, which occupy a belt of nearly 30 miles broad, from Yorkshire to Dorsetshire, passing through Lincoln, Northampton, Huntingdon, Bedford, Buckingham, Oxford, and Wilts. The best building materials in England are obtained from these strata. Oolite strata occur in Scotland at Brora and in Skye. In the Brora Oolite, a seam of coal 34 feet in thickness has been worked for upwards of a century. It is the thickest bed of pure vegetable matter detected in any Secondary formation in Britain. The fresh-water Wealden series, with their abundant remains of reptiles, fishes, shells, and insects, occur in Kent and Sussex, in the Isle of Wight, and in the south of Devon. The beds of the Cretaceous period, consisting chiefly of chalk with intercalated sands and clays, all very rich in fossil remains, occupy a broad tract to the east of the Oolite strata, and parallel to them. Beginning a little north of Flamborough Head, they may be traced through York and Lincoln, then across the Wash into Norfolk, Suffolk, Hertford, Buckingham, Oxford, Berks, to Hampshire, where they separate into three arms, the one extending south-westward through Wilts and Dorset to the south coast; another taking a south-east direction to Beachy Head; and the third stretches as a narrow band in an easterly direction through Surrey and North Kent, widening out as it nears the coast, where it occupies the district between Ramsgate and Folkstone. Eocene strata, consisting of clays, sands, and marls, abounding in fossils which apparently indicate a sub-tropical climate, occupy the valley of the Thames, from Hungerford to the sea, and from Canterbury to Saxmundham, as well as a large district in Dorset, Hants, and Sussex, from Salisbury west to Dorchester, and east almost to Hastings. Unless the beds in Mull, containing the numerous impressions of leaves of exogenous plants, are Miocene strata, there are no representatives of this period in Britain. The Pliocene deposits of ferruginous shelly sand and marl known as red crag occur chiefly in Suffolk. The still more recent Pleistocene deposits of fresh-water sand and gravel, and mammaliferous crag, are found on the coasts of Norfolk, Suffolk, Essex, and Kent. The till and glacial beds of the same age are scattered as superficial deposits over large districts in Britain. Fossiliferous beds of this age occur in Caithness, in the valley of the Clyde, and in Lancashire; they contain remains of mollusca, many of which still live in the seas of boreal America. Minerals-Coal.-There were 2936 collieries in Britain in 1860; from these were raised 83,923,273 tons of coal. The greatly increasing consumption of coal has originated fears as to the possibility of the exhaustion of our mineral fuel. It appears that, while in 1820, only 15,000,000 tons were raised, in 1840, the amount had reached 30,000,000, and in 1860, it was nearly 84,000,000. At the same rate of increase, the known coal, within a workable distance from the surface, would last at least 100 years. But the consumption, during the last 20 years of the century, would, at the present increasing ratio, amount to 1464 million tons a year, a quantity vastly greater than can possibly be used. We need not, therefore, now begin to fear lest our coal-fields should be speedily used The Lias consists of white sandstones, limestones, shales, marls, and alum slates. They abound in fossils, especially in the remains of reptiles, fishes, mollusca, and encrinites. The strata of this age occupy a band between the Trias and the Oolite, up. extending from Lyme Regis to the mouth of the Iron.-Formerly, the only iron produced in the Tees. Two small tracts of Lias occur, the one in country was obtained from the greensand of the Glamorgan, and the other in Shropshire. In Scot-south-east of England, and from the brown hæmaland, small patches exist at Brora in Sutherland, and in the islands of Skye, Eigg, and Mull. The Oolite measures are composed of an extensive tite of the Dean Forest. The ore was smelted with charcoal. But the introduction of coke and coal for smelting, and the discovery of numerous GREAT BRITAIN. additional and unthought-of deposits, especially in connection with coal-bearing strata, has immensely increased the production of iron, and met the greatly increased demands for this important metal. In 1760, when charcoal alone was used for smelting, not more than 25,000 tons of iron were produced; while in 1860, no less than 3,826,752 tons were obtained from 8,024,206 tons of ore. The market value of the metal was £12,703,950. The most important ore is the ferruginous shale, or impure argillaceous carbonate of iron, which occurs in connection with every coal-field in Britain. The brown and red hæmatite, associated with the oldest Paleozoic rocks, yield also a large amount of metallic iron. Tin is obtained from only two counties-Cornwall and Devon. In 1860, the 143 mines produced 10,460 tons of metallic tin, worth £748,827. Copper is principally obtained from the same two counties. There are about 160 different mines, which produced, in 1860, 180,883 tons of ore, yielding 11,797 tons of metallic copper, worth £1,270,438. Besides this, there was a yield of 13,789 tons of ore, producing 935 tons of metal, worth £100,691, chiefly from the counties of Lancaster, Caermarthen, and Anglesey, very small quantities being supplied from mines in Cumberland, Chester, Cardigan, and the Isle of Man. Lead and Silver are obtained from the same ore from numerous mines in Palæozoic districts all over the country. The most productive English mines are in Northumberland, Durham, Cumberland, York, and Derby, in Shropshire, and in Cornwall and Devon. Small quantities are obtained in Somerset, Westmoreland, Stafford, and Chester. All the Silurian counties of Wales contain mines. The Isle of Man yields nearly 3000 tons of ore. In Scotland, the most productive mines are at Wanlockhead and Leadhills; but the counties of Argyle, Perth, and Kirkcudbright also supply small quantities. The total amount of ore raised in 1860 was 86,648 tons, yielding 61,962 tons of metal, worth £1,382,541. From this there were separated 535,355 ounces of silver, worth £142,222. Zinc is obtained from Cornwall and Devon, Cardigan and North Wales, Derby, Cumberland, and the Isle of Man. The produce in 1860 was 14,972 tons of ore, valued at £138,471. The metallic zinc obtained from this would amount to about 500 tons. Sulphur Ores (iron pyrites) were raised in different parts of G. B., chiefly in Cornwall, to the extent, in 1860, of 36,410 tons, worth £25,584. Small quantities of the following minerals are also raised in Cornwall, viz., arsenic, manganese, gossan, nickel, silver-copper, fluor-spar, and wolfram. Salt occurs in Cheshire and Worcestershire: no less than 1,552,529 tons were produced in 1860. It is estimated that the whole mineral produce of G. B., including stones, and pottery, and brick-clays, amounted in 1860 to £45,000,000. Physical Geography.-The physical features of a country are intimately connected with its geological structure. The older Palæozoic rocks produce mountainous regions, intersected with deep and narrow valleys. The newer strata seldom rise to a great height. Their high lands are rounded undulations of the strata, except where igneous rocks are intruded, and the valleys are broad and shallow. In Scotland, we have, consequently, two extensive mountainous districts, occupied chiefly with rocks of Silurian age, and an intervening valley filled up with Old Red Sandstone and Carboniferous measures. The northern mountain region is intersected by the Great Glen, which is a fissured anticlinal axis in the Silurian strata. It is difficult to group the mountains in this district. The Grampians from Aberdeen to Argyle shew the most marked linear arrangement; the greatest eminence in this range is Ben Lawers (3945 feet). Between the Grampians and the Great Glen a succession of great eminences occur, the highest of which, and the culminating point of the whole British Isles, is Ben Nevis (4406 feet). To the north of the valley of the Caledonian Canal, the region is a confused mass of mountains, reaching in Ben Attow a height of 4000 feet. Caithness consists of plains of undulating sandstone, covered with drift; the headlands and sea-cliffs in this county are bold and striking. The coast-line of the Paleozoic region of the north of Scotland is repeatedly broken by numerous and large friths or sea-lochs, and the interior abounds in picturesque lakes. The Silurians of the south of Scotland form an extensive mountain range crossing the island from St Abb's Head to Stranraer. The rocks are less indurated than in the north, and the scenery is consequently not so wild. The mountains have generally broad flattened forms, intersected by deep pastoral glens, which widen out into broader valleys and dales. The principal heights are Hartfell (2790 feet) and Black Larg (2890 feet). The great central valley of Scotland embraces the basins of the Clyde, Forth, and Tay. It contains several tracts of rich table-land, and is frequently broken through by igneous rocks, chiefly trappean, which project into bold and picturesque hills. England and Wales, in the Cambrian and Silurian districts, have the same mountainous character as similar districts in Scotland; but as so much of England is occupied with newer strata, it may be considered on the whole as a level country, traversed by ridges of varying elevation, which form the water-sheds of the country. The range, beginning with the Cheviot Hills, is continued from the borders of Scotland southwards, as the Pennine range, through Northumberland, Cumberland, Westmoreland, Lancashire, and Yorkshire, to the middle of Derbyshire; it varies in height from 1200 to 3000 feet, reaching its highest summit in Crossfell, Cumberland, which is 3383 feet high. The band of Lias and Oolite, extending from Yorkshire to Dorset, forms a tortuous range of table-land, rising sometimes into hills to the height of 1500 feet, and throughout its course presenting generally a bold escarpment to the west, and having a gentle slope to the east. To the west of this range of table-land are the valleys of the Yorkshire Ouse, the Trent, and the Severn; on the east, the Great Ouse and the upper portion of the Thames. Beyond these two rivers, the country rises into a range of low chalk-hills, which follow the cretaceous strata from Norfolk to Wilts, dividing with the strata into three ranges, two of which take an easterly direction through Sussex and Surrey and Kent, bordering the Wealden strata, and forming the South and North Downs. Devon and Cornwall are mountainous, from the intrusion of granite and other igneous rocks through the Palæozoic strata. The details of the physical geography are given under the names of the several counties, lakes, rivers, &c. Climate. The climate of G. B. derives its peculiar character from the insular situation of the country, taken in connection with the prevailing direction of the winds. It is mild and equable in a remarkable degree, the winters being considerably warmer, and the summers colder than at places within the same parallels of latitude. For at least three months, the mean monthly temperature ranges between 50°0 and 60°0; for other three months it continues about 60°0, or occasionally a little higher, seldom |