The history of Cluny up to the death of Peter the Venerable may be extracted out of Mabillon’sAnnalesby means of the Index; the story is told in Helyot,Hist. des ordres religieux(1792), v. cc. 18, 19. Abridged accounts, with references to the most recent literature, may be found in Max Heimbucher,Orden und Kongregationen(1896), i. § 20; Herzog-Hauck,Realencyklopädie(ed. 3), art. “Cluni” (Grutzmacher); and Wetzer und Welte,Kirchenlexikon(ed. 2), art. “Clugny” (Hefele). The best modern monograph is by E. Sackur,Die Cluniacenser(1891-1894). In English a good account is given in Maitland,Dark Ages, §§ xviii.-xxvi.; the Introduction to G. F. Duckett’sCharters and Records of Cluni(1890) contains, besides general information, a description of the church and the buildings, and a list of the chief Cluniac houses in all countries. The story of the English houses is briefly sketched in the second chapter of F. A. Gasquet’sHenry VIII. and the English Monasteries(the larger ed., 1886).
(E. C. B.)
CLUSERET, GUSTAVE PAUL(1823-1900), French soldier and politician, was born at Paris. He was an officer in thegarde mobileduring the revolution of 1848. He took part in several expeditions in Algeria, joined Garibaldi’s volunteers in 1860, and in 1861 resigned his commission to take part in the Civil War in America. He served under Frémont and McClellan, and rose to the rank of general. Then, joining a band of Irish adventurers, he went secretly to Ireland, and participated in the Fenian insurrection (1866-67). He escaped arrest on the collapse of the movement, but was condemned to death in his absence. On his return to France he proclaimed himself a Socialist, opposed militarism, and became a member of theAssociation Internationale des travailleurs, a cosmopolitan Socialist organization, known as the “Internationale.” On the proclamation of the Third Republic in 1871 he set to work to organize the social revolution, first at Lyons and afterwards at Marseilles. His energy, his oratorical gifts, and his military experience gave him great influence among the working classes. On the news of the communist rising of the 18th of March 1871 he hastened to Paris, and on the 16th of April was elected a member of the commune. Disagreements with the other communist leaders led to his arrest on the 1st of May, on a false charge of betraying the cause. On the 24th of the same month the occupation of Paris by the Versailles troops restored him to liberty, and he succeeded in escaping from France. He did not return to the country till 1884. In 1888 and 1889 he was returned as a deputy to the chamber by Toulon. He died in 1900. Cluseret published hisMémoires(of the Commune) at Paris in 1887-1888.
CLUSIUM(mod.Chiusi,q.v.), an ancient town of Italy, one of the twelve cities of Etruria, situated on an isolated hill at the S. end of the valley of the Clanis (China). It was according to Roman tradition one of the oldest cities of Etruria and indeed of all Italy, and, if Camars (the original name of the town, according to Livy) is rightly connected with the Camertes Umbri, its foundation would go back to pre-Etruscan times. It first appears in Roman history at the end of the 7th centuryB.C., when it joined the other Etruscan towns against Tarquinius Priscus, and at the end of the 6th centuryB.C.it placed itself,under its king Lars Porsena, at the head of the attempt to re-establish the Tarquins in Rome. At the time of the invasion of the Gauls in 391B.C., on the other hand, Clusium was on friendly terms with Rome; indeed, it was the action of the Roman envoys who had come to intercede for the people of Clusium with the Gauls, and then, contrary to international law, took part in the battle which followed, which determined the Gauls to march on Rome. Near Clusium too, according to Livy (according to Polybius ii. 19. 5,ἐν τῆ Καμερτίων χώρᾳ,i.e.in Umbria near Camerinum), a battle occurred in 296B.C.between the Gauls and Samnites combined, and the Romans; a little later the united forces of Clusium and Perusia were defeated by the Romans. The precise period at which Clusium came under Roman supremacy is, however, uncertain, though this must have happened before 225B.C., when the Gauls advanced as far as Clusium. In 205B.C.in the Second Punic War we hear that they promised ship timber and corn to Scipio. The Via Cassia, constructed after 187B.C., passed just below the town. In the first civil war, Papirius Carbo took up his position here, and two battles occurred in the neighbourhood. Sulla appears to have increased the number of colonists, and a statue was certainly erected in his honour here. In imperial times we hear little of it, though its grain and grapes were famous. Christianity found its way into Clusium as early as the 3rd century, and the tombstone of a bishop ofA.D.322 exists. InA.D.540 it is named as a strong place to which Vitiges sent a garrison of a thousand men.
Of pre-Roman or Roman buildings in the town itself there are few remains, except for some fragments of the Etruscan town walls composed of rather small rectangular blocks of travertine, built into the medieval fortifications. Under it, however, extends an elaborate system of rock-cut passages, probably drains. The chief interest of the place lies in its extensive necropolis, which surrounds the city on all sides. The earliest tombs (tombe a pozzo, shaft tombs) are previous to the beginning of Greek importation. Oftombe a fossothere are none, and the next stage is marked by the so-calledtombe a ziro, in which the cinerary urn (often with a human head) is placed in a large clay jar (ziro, Lat.dolium). These belong to the 7th centuryB.C., and are followed by thetombe a camera, in which the tomb is a chamber hewn in the rock, and which can be traced back to the beginning of the 6th centuryB.C.From one of the earliest of these came the famous François vase; another is the tomb of Poggio Renzo, or della Scimmia (the monkey), with several chambers decorated with archaic paintings. The most remarkable group of tombs is, however, that of Poggio Gaiella, 3 m. to the N., where the hill is honeycombed with chambers in three storeys (now, however, much ruined and inaccessible), partly connected by a system of passages, and supported at the base by a stone wall which forms a circle and not a square—a fact which renders impossible its identification with the tomb of Porsena, the description of which Pliny (Hist. Nat.xxxvi. 91) has copied from Varro. Other noteworthy tombs are those of the Granduca, with a single subterranean chamber carefully constructed in travertine, and containing eight sarcophagi of the same material; of Vigna Grande, very similar to this; of Colle Casuccini (the ancient stone door of which is still in working order), with two chambers, containing paintings representing funeral rites; of Poggio Moro and Valdacqua, in the former of which the paintings are almost destroyed, while the latter is now inaccessible.
A conception of the size of the whole necropolis may be gathered from the fact that nearly three thousand Etruscan inscriptions have come to light from Clusium and its district alone, while the part of Etruria north of it as far as the Arno has produced barely five hundred. Among the later tombs bilingual inscriptions are by no means rare, and both Etruscan and Latin inscriptions are often found in the same cemeteries, showing that the use of the Etruscan language only died out gradually. A large number of the inscriptions are painted upon the tiles which closed the niches containing the cinerary urns. The urns themselves are small, often of terra-cotta, originally painted, though the majority of them have lost their colour, and rectangular in shape. This style of burial seems peculiar to a district which E. Bormann (Corp. Inscr. Lat.xi., Berlin, 1887, p. 373) defines as a triangle formed by the Clanis (with the lakes of Chiusi and Montepulciano, both small, shallow and fever-breeding), on the E., the villages of Cetona, Sarteano, Castelluccio and Monticchiello on the W., and Montepulciano and Acquaviva on the N. In Roman times the territory of Clusium seems to have extended as far as Lake Trasimene. The local museum contains a valuable and important collection of objects from the necropolis, including some specially finebucchero, sepulchral urns of travertine, alabaster and terra-cotta, painted vases, stonecippiwith reliefs, &c.
Two Christian catacombs have been found near Clusium, one in the hill of S. Caterina near the railway station, the inscriptions of which seem to go back to the 3rd century, another 1 m. to the E. in a hill on which a church and monastery of S. Mustiola stood, which goes back to the 4th century, including among its inscriptions one bearing the dateA.D.303, and the tombstone of L. Petronius Dexter, bishop of Clusium, who died inA.D.322. The total number of inscriptions known in Clusium is nearly 3000 Etruscan (Corp. Inscr. Etrusc., Berlin, 475-3306) and 500 Latin (Corp. Inscr. Lat.xi. 2090-2593). To the W. and N.W. of Chiusi—at Cetona, Sarteano, Chianciano and Montepulciano—Etruscan cemeteries have been discovered; the objects from them formed, in the latter half of the 19th century, interesting local collections described by Dennis, which have since mostly passed to larger museums or been dispersed.
See G. Dennis,Cities and Cemeteries of Etruria(London,1883), ii. 290 seq.; L. Giometti,Guida di Chiusi(Poggibonsi, 1904). (T. As.)
CLUWER(Cluver, Cluvier, Cluverius),PHILIP(1580-1623), German geographer and historian, was born at Danzig in 1580. After travelling in Germany and Poland (where he learnt Polish), he began the study of law at Leiden, but he soon turned his attention to history and geography, which were then taught there by Joseph Scaliger. After campaigning in Bohemia and Hungary, suffering imprisonment, and travelling in England, Scotland and France, he finally settled in Holland, where (after 1616) he received a regular pension from Leiden Academy. In 1611 he began to publish his works. He died at Leiden in 1623. His principal writings are:Germania Antiqua(1616),Siciliae Antiquae libri duo, Sardinia et Corsica Antiqua(1619), and the posthumousItalia Antiqua(1624) andIntroductio in Universam Geographiam(1629).
CLYDE, COLIN CAMPBELL,Baron(1792-1863), British soldier, was born at Glasgow on the 20th of October 1792. He received his education at the Glasgow high school, and when only sixteen years of age obtained an ensigncy in the 9th foot, through the influence of Colonel Campbell, his maternal uncle. The youthful officer had an early opportunity of engaging in active service. He fought under Sir Arthur Wellesley at Vimiera, took part in the retreat of Sir John Moore, and was present at the battle of Corunna. He shared in all the fighting of the Peninsular campaigns, and was severely wounded while leading a storming-party at the attack on San Sebastian. He was again wounded at the passage of the Bidassoa, and compelled to return to England, when his conspicuous gallantry was rewarded by promotion without purchase. Campbell held a command in the American expedition of 1814; and after the peace of the following year he devoted himself to studying the theoretical branches of his profession. In 1823 he quelled the negro insurrection in Demerara, and two years later obtained his majority by purchase, In 1832 he became lieutenant-colonel of the 98th foot, and with that regiment rendered distinguished service in the Chinese War of 1842. Campbell was next employed in the Sikh War of 1848-49, under Lord Gough. At Chillianwalla, where he was wounded, and at the decisive victory of Gujrat, his skill and valour largely contributed to the success of the British arms; and his “steady coolness and military precision” were highly praised in official despatches. He was made a K.C.B. in 1849, and specially named in the thanks of parliament.
After rendering important services in India Sir Colin Campbellreturned home in 1853. Next year the Crimean War broke out, and he accepted the command of the Highland brigade, which formed part of the duke of Cambridge’s division. The brigade and its leader distinguished themselves very greatly at the Alma; and with his “thin red line” of Highlanders he repulsed the Russian attack on Balaklava. At the close of the war Sir Colin was promoted to be knight grand cross of the Bath, and elected honorary D.C.L. of Oxford. His military services, however, had as yet met with tardy recognition; but, when the crisis came, his true worth was appreciated. The outbreak of the Indian Mutiny (q.v.) called for a general of tried experience; and on the 11th of July 1857 the command was offered to him by Lord Palmerston. On being asked when he would be ready to set out, the veteran replied, “Within twenty-four hours.” He was as good as his word; he left England the next evening, and reached Calcutta on the 13th of August. After spending upwards of two months in the capital to organize his resources, he started for the front on the 27th of October, and on the 17th of November relieved Lucknow for the second time. Sir Colin, however, considered Lucknow a false position, and once more abandoned it to the rebels, retaking it in March 1858. He continued in charge of the operations in Oudh until the embers of the revolt had died away. For these services he was raised to the peerage, in 1858, as Lord Clyde; and, returning to England in the next year, he received the thanks of both Houses of Parliament and a pension of £2000 a year. He died on the 14th of August 1863.
Though not a great general, and lacking in the dash which won England so many victories in India, Lord Clyde was at once a brave soldier and a careful and prudent leader. The soldiers whom he led were devotedly attached to him; and his courteous demeanour and manly independence of character won him unvarying respect.
See Sir Owen Tudor Burne,Clyde and Strathnairn(“Rulers of India” series, 1891); and L. Shadwell,Life of Colin Campbell, Lord Clyde(1881).
See Sir Owen Tudor Burne,Clyde and Strathnairn(“Rulers of India” series, 1891); and L. Shadwell,Life of Colin Campbell, Lord Clyde(1881).
CLYDE(Welsh,Clwyd, “far heard,” “strong,” theGlottaof Tacitus), the principal river of Lanarkshire, Scotland. It is also the name of the estuary which forms the largest and finest firth on the west coast.
1.The River.—Daer Water, rising in Gana Hill (2190 ft.) on the borders of Lanarkshire and Dumfriesshire, after a course of 10½ m., and Potrail Water, rising 3 m. farther W. in the same hilly country (1928 ft.), after running N.N.E. for 7 m., unite 3½ m. S. of Elvanfoot to form the Clyde, of which they are the principal headstreams, though many mountain burns in these upland regions are also contributory. The old rhyme that “Annan, Tweed and Clyde rise a’ out o’ ae hillside” is not true, for Little Clyde Burn here referred to, rising in Clyde Law (2190 ft.), is only an affluent and not a parent stream. From the junction of the Daer and Potrail the river pursues a direction mainly northwards for several miles, winding eastwards around Tinto Hill, somewhat north-westerly to near Carstairs, where it follows a serpentine course westwards and then southwards. From Harperfield, a point about 4 m. above Lanark, it assumes a north-westerly direction, which, roughly, it maintains for the rest of its course as a river, which is generally held to end at Dumbarton, where it merges in the Firth. Its principal tributaries on the right are the Medwin (16 m. long), entering near Carnwath, the Mouse (15 m.), joining it at Lanark, the South Calder (16 m.) above Bothwell, the North Calder (12 m.) below Uddingston, the Kelvin (21 m.) at Glasgow, and the Leven (7 m.) at Dumbarton. The chief left-hand affluents are the Elvan (8 m.), entering at Elvanfoot, the Duneaton (19 m.), joining a few miles above Roberton, the Garf (6½ m.) below Lamington, the Douglas (20 m.) above Bonnington, the Nethan (12 m.) at Crossford, the Avon (28 m.) at Hamilton, the Rotten Calder (10 m.) near Newton, and the Cart (1 m.), formed by the junction of the Black Cart (9 m.) and the White Cart (19 m.), below Renfrew.
The total length of the Clyde from the head of the Daer to Dumbarton is 106 m., and it drains an area estimated at 1481 sq. m. It is thus the third longest river in Scotland (being exceeded by the Spey and Tay), but in respect of the industries on its lower banks, and its sea-borne commerce, it is one of the most important rivers in the world. Near Lanark it is broken by the celebrated Falls, four in number, which are all found within a distance of 3¾ m. Bonnington Linn, the most graceful, 2 m. above Lanark, is divided into two parts by a mass of tree-clad rocks in mid-stream, and has a height of 30 ft. From this spot the river runs for half a mile through a rugged, red sandstone gorge till it reaches Corra Linn, the grandest of the Falls, where in three leaps, giving it the aspect of a splendid cascade, it makes a descent of 84 ft., which, however, it accomplishes during flood at a single bound. Almost ¾ m. below Corra Linn, Dundaff Linn is reached, a fall of only 10 ft. Farther down, 1¾ m. below Lanark, at Stonebyres Linn, reproducing the characteristic features of Corra Linn, the river descends in ordinary water in three leaps, and in flood in one bold drop of 80 ft. Within this space of 3¾ m. the river effects a total fall of 230 ft., or 611⁄3ft. in the mile. From Stonebyres Linn to the sea the fall is practically 4 ft. in every mile. The chief villages and towns on or close to the river between its source and Glasgow are Crawford, Lamington, New Lanark, Lanark, Hamilton, Bothwell, Blantyre and Uddingston. At Bowling (pop. 1018)—the point of transhipment for the Forth and Clyde Canal—the river widens decidedly, the fairway being indicated by a stone wall continued seawards as far as Dumbarton. Dunglass Point, near Bowling, is the western terminus of the wall of Antoninus, or Grim’s Dyke; and in the grounds of Dunglass Castle, now a picturesque fragment, stands an obelisk to Henry Bell (1767-1830), the pioneer of steam navigation in Europe.
As far down as the falls the Clyde remains a pure fishing stream, but from the point at which it begins to receive the varied tribute of industry, its water grows more and more contaminated, and at Glasgow the work of pollution is completed. Towards the end of the 18th century the river was yet fordable at the Broomielaw in the heart of Glasgow, but since that period, by unexampled enterprise and unstinted expenditure of money, the stream has been converted into a waterway deep enough to allow liners and battleships to anchor in the harbour (seeGlasgow).
Clydesdale, as the valley of the upper Clyde is called, begins in the district watered by headstreams of the river, the course of which in effect it follows as far as Bothwell, a distance of 50 m. It is renowned for its breed of cart-horses (specifically known as Clydesdales), its orchards, fruit fields and market gardens, its coal and iron mines.
2.The Firth.—From Dumbarton, where the firth is commonly considered to begin, to Ailsa Craig, where it ends, the fairway measures 64 m. Its width varies from 1 m. at Dumbarton to 37 m. from Girvan to the Mull of Kintyre. The depth varies from a low-tide minimum of 22 ft. in the navigable channel at Dumbarton to nearly 100 fathoms in the Sound of Bute and at other points. The Cumbraes, Bute and Arran are the principal islands in its waters. The sea lochs all lie on the Highland shore, and comprise Gare Loch, Loch Long, Loch Goil, Holy Loch, Loch Striven, Loch Riddon and Loch Fyne. The only rivers of any importance feeding the Firth are the Ayrshire streams, of which the chief are the Garnock, Irvine, Ayr, Doon and Girvan. The tide ascends above Glasgow, where its farther rise is barred by a weir. The head-ports are Glasgow, Port Glasgow, Greenock, Ardrossan, Irvine, Troon, Ayr and Campbeltown. In addition to harbour lights, beacons on rocks, and light-ships, there are lighthouses on Ailsa Craig, Sanda, Davaar, Pladda, Holy Isle, and Little Cumbrae, and at Turnberry Point, Cloch Point and Toward Point. The health and holiday resorts on the lochs, islands and mainland coast are numerous.
CLYDEBANK,a police burgh of Dumbartonshire, Scotland, on the right bank of the Clyde, 6 m. from Glasgow. Pop. (1891) 10,014; (1901) 21,591. There are stations at Yoker, Clydebank, Kilbowie and Dalmuir, all comprised within the burgh since 1886, served by both the North British and the Caledonian railways. In 1875 the district was almost purely rural, but since that date flourishing industries have been planted in the differentparts. At Clydebank are large shipbuilding yards and engineering works; at Yoker there is some shipbuilding and a distillery; at Kilbowie the Singer Manufacturing Company have an immense factory, covering nearly 50 acres and giving employment to many thousands of operatives; at Dalmuir are the building and repairing yards of the Clyde Navigation Trust. The important Rothesay Dock, under this trust, was opened by the prince and princess of Wales in April 1907. The municipality owns a fine town hall and buildings. Part of the parish extends across the Clyde into the shire of Renfrew.
CNIDUS(mod.Tekir), an ancient city of Caria in Asia Minor, situated at the extremity of the long peninsula that forms the southern side of the Sinus Ceramicus or Gulf of Cos. It was built partly on the mainland and partly on the Island of Triopion or Cape Krio, which anciently communicated with the continent by a causeway and bridge, and now by a narrow sandy isthmus. By means of the causeway the channel between island and mainland was formed into two harbours, of which the larger, or southern, now known as Port Freano, was further enclosed by two strongly-built moles that are still in good part entire. The extreme length of the city was little less than a mile, and the whole intramural area is still thickly strewn with architectural remains. The walls, both insular and continental, can be traced throughout their whole circuit; and in many places, especially round the acropolis, at the N.E. corner of the city, they are remarkably perfect. Our knowledge of the site is largely due to the mission of the Dilettanti Society in 1812, and the excavations executed by C. T. Newton in 1857-1858; but of recent years it has become a frequent calling station of touring steamers, which can still lie safely in the southern harbour. The agora, the theatre, an odeum, a temple of Dionysus, a temple of the Muses, a temple of Aphrodite and a great number of minor buildings have been identified, and the general plan of the city has been very clearly made out. The most famous statue by the elder Praxiteles, the Aphrodite, was made for Cnidus. It has perished, but late copies exist, of which the most faithful is in the Vatican gallery. In a temple-enclosure C. T. Newton discovered a fine seated statue of Demeter, which now adorns the British Museum; and about 3 m. south-east of the city he came upon the ruins of a splendid tomb, and a colossal figure of a lion carved out of one block of Pentelic marble, 10 ft. in length and 6 in height, which has been supposed to commemorate the great naval victory of Conon over the Lacedaemonians in 394B.C.Among the minor antiquities obtained from the city itself, or the great necropolis to the east, perhaps the most interesting are the leadenκατάδεσμοι, or imprecationary tablets, found in the temple of Demeter, and copied in facsimile in the appendix to the second volume of Newton’s work. Peasants still find numerous antiquities, and the site would certainly repay more thorough excavation.
Cnidus was a city of high antiquity and probably of Lacedaemonian colonization. Along with Halicarnassus and Cos, and the Rhodian cities of Lindus, Camirus and Ialysus it formed the Dorian Hexapolis, which held its confederate assemblies on the Triopian headland, and there celebrated games in honour of Apollo, Poseidon and the nymphs. The city was at first governed by an oligarchic senate, composed of sixty members, known asἀμνήμονες, and presided over by a magistrate called anἀρεστήρ; but, though it is proved by inscriptions that the old names continued to a very late period, the constitution underwent a popular transformation. The situation of the city was favourable for commerce, and the Cnidians acquired considerable wealth, and were able to colonize the island of Lipara, and founded the city of Corcyra Nigra in the Adriatic. They ultimately submitted to Cyrus, and from the battle of Eurymedon to the latter part of the Peloponnesian War they were subject to Athens. In 394B.C.Conon fought off the port the battle which destroyed Spartan hegemony. The Romans easily obtained their allegiance, and rewarded them for help given against Antiochus by leaving them the freedom of their city. During the Byzantine period there must still have been a considerable population; for the ruins contain a large number of buildings belonging to the Byzantine style, and Christian sepulchres are common in the neighbourhood. Eudoxus, the astronomer, Ctesias, the writer on Persian history, and Sostratus, the builder of the celebrated Pharos at Alexandria, are the most remarkable of the Cnidians mentioned in history.
See C. T. Newton and R. P. Pullen,Hist. of Discoveries at Halicarnassus, Cnidus, &c.(1863).
See C. T. Newton and R. P. Pullen,Hist. of Discoveries at Halicarnassus, Cnidus, &c.(1863).
CNOSSUS,Knossos, orGnossus, an ancient city of Crete, on the left bank of the Caeratus, a small stream which falls into the sea on the north side of the island. The city was situated about 3 m. from the coast, and, according to the old traditions, was founded by Minos, king of Crete. The locality was associated with a number of the most interesting legends of Greek mythology, particularly with those which related to Jupiter, who was said to have been born, to have been married, and to have been buried in the vicinity. Cnossus was also assigned as the site of the labyrinth in which the Minotaur was confined. The truth behind these legends has been revealed in recent years by the excavations of Dr Evans. As the historical city was peopled by Dorians, the manners, customs and political institutions of its inhabitants were all Dorian. Along with Gortyna and Cydonia, it held for many years the supremacy over the whole of Crete; and it always took a prominent part in the civil wars which from time to time desolated the island. When the rest of Crete fell under the Roman dominion, Cnossus shared the same fate, and became a Roman colony. Aenesidemus, the sceptic philosopher, and Chersiphron, the architect of the temple of Diana at Ephesus, were natives of Cnossus.
The Site.—As the excavations at Cnossus are discussed at length in the articleCrete, it must suffice here briefly to enumerate the more important. The chief building is the Great Palace, the so-called “House of Minos,” the excavation of which by Arthur Evans dates from 1900: a number of rooms lying round the central paved court, oriented north and south, have been identified, among them being the throne-room with some well-preserved wall paintings and a small bathroom attached, in the north-west quarter a larger bathroom and a shrine, and residential chambers in the south and east. The latter part of the palace is composed of a number of private rooms and halls, and is especially remarkable for its skilful drainage and water-supply systems.
In 1907 excavations on the south side of the palace showed that the plan was still incomplete, and a southern cryptoporticus, and outside it a large south-west building, probably an official residence, were discovered. Of special interest was a huge circular cavity under the southern porch into which the sub-structures of the palace had been sunk. This cavity was filled with rubbish, sherds, &c., the latest of which was found to date as far back as the beginning of the Middle Minoan age, and the later work of 1908 only proved (by means of a small shaft sunk through the débris) that the rock floor was 52 ft. below the surface. The first attempt to reach the floor by a cutting in the hill-side proved abortive, but the operations of 1910 led to a successful result. The cavity proved to be a great reservoir approached by a rock-cut staircase and of Early Minoan date.
In 1904-1905 a paved way running due west from the middle of the palace was excavated, and found to lead to another building described as the “Little Palace” largely buried under an olive grove. The first excavations showed that this building was on the same general plan and belonged to the same period as the “House of Minos,” though somewhat later in actual date (17th centuryB.C.). Large halls, which had subsequently been broken up into smaller apartments, were found, and among a great number of other artistic remains one seal-impression of special interest showing a one-masted ship carrying a thorough-bred horse—perhaps representing the first importation of horses into Crete. A remarkable shrine with fetish idols was also discovered. The sacred Double-Axe symbol is prominent, as in the greater palace. By the end of 1910 the excavation of this smaller palace was practically completed. It was found to cover an area of more than 9400 ft. with a frontage of more than 130 ft., and had five stone staircases. One object of special interest foundin the course of excavation is a black steatite vessel in the form of a bull’s head. The modelling is of a very high order, and the one eye which remains perfect is cut out of rock crystal, with the pupil and iris marked by colours applied to the lower face of the crystal.
The work of excavation in the palace has been complicated by the necessity of propping up walls, floors and staircases. In some instances it has been found necessary to replace the original wooden pillars by pillars of stone. Again in the “Queen’s Megaron” in the east wing of the Great Palace it was found that the exposure of the remains to the violent extremes of Cretan weather must soon prove fatal to them. It was therefore decided to restore the columns and part of the wall, and to roof over the whole area.
For recent excavations see R. M. Burrows,The Discoveries in Crete(1907); A. Mosso,The Palaces of Crete(1907); Lagrange,La Crète ancienne(1908); Dr. Evans’s reports inThe Times, Oct. 31, 1905, July 15, 1907, Aug. 27, 1908, and 1909 (Index); D. Mackenzie,Cretan Palaces.
COACH(through the Fr.coche, originally from the Magyarkocsi, an adjective from the Hungarian place named Kocs, between Raab and Buda,i.e.the sort of vehicle used there in the 15th century), a large kind of carriage for passengers (seeCarriage). As a general term it is used (as in “coach-building”) for all carriages, and also in combination with qualifying attributes for particular forms (stage-coach, mail-coach, mourning-coach, hackney-coach, &c.); but the typical coach involves four wheels, springs and a roof. The stage-coach, with seats outside and in, was a public conveyance which was known in England from the 16th century, and before railways the stage-coaches had regular routes (stages) all over the country; through their carrying the mails (from 1784) the term “mail-coach” arose. Similar vehicles were used in America and on the European continent. Thediligence, though not invariably with four horses, was the Continental analogue for public conveyance, with other minor varieties such as theStellwagenandEilwagen.
The driving of coaches with four horses was a task in which a considerable amount of skill was required,1and English literature is full of the difficulties and humours of “the road” in old days. A form of sport thus arose for enterprising members of the nobility and gentry, and after the introduction of railways made the mail-coach obsolete as a matter of necessity, the old sport of coaching for pleasure still survived, though only to a limited extent. The Four-in-hand Club was started in England in 1856 and the Coaching Club in 1870, as the successors of the old Bensington Driving Club (1807-1852), and Four-Horse Club (1808-1829); and in America the New York Coaching Club was founded in 1875. But coaching remains the sport of the wealthier classes, although in various parts of England (e.g.London to Brighton, and in the Lake district), in America, and in Europe, public coaches still have their regular times and routes for those who enjoy this form of travel. The earliest railway vehicles for passengers were merely the road coaches of the period adapted to run on rails, and the expression “coaching traffic” is still used in England to denote traffic carried in passenger trains.
Of coaches possessing a history the two best known in the United Kingdom are the king’s state coach, and that of the lord mayor of London. The latter is the oldest, having been built, or at least first used, for the procession of Sir Charles Asgil, lord mayor elect, in November 1757. The body of this vehicle is not supported by springs, but hung on leather straps; and the whole structure is very richly loaded with ornamental carving, gilding and paint-work. The different panels and the doors contain various allegorical groups of figures representing suitable subjects, and heraldic devices painted in a spirited manner. The royal state coach, which is described as “the most superb carriage ever built,” was designed by Sir William Chambers, the paintings on it were executed by Cipriani, and the work was completed in 1761. During the later part of Queen Victoria’s reign it was hardly ever seen, but on the accession of Edward VII. the coach was once more put in order for use on state occasions. The following is an official description of this famous coach:—
“The whole of the carriage and body is richly ornamented with laurel and carved work, beautifully gilt. The length, 24 ft.; width, 8 ft. 3 in.; height, 12 ft.; length of pole, 12 ft. 4 in.; weight, 4 tons. The carriage and body of the coach is composed as follows:—Of four large tritons, who support the body by four braces, covered with red morocco leather, and ornamented with gilt buckles, the two figures placed in front of the carriage bear the driver, and are represented in the action of drawing by cables extending round their shoulders, and the cranes and sounding shells to announce the approach of the monarch of the ocean; and those at the back carry the imperial fasces, topped with tridents. The driver’s foot-board is a large scallop shell, ornamented with bunches of reeds and other marine plants. The pole represents a bundle of lances; the splinter bar is composed of a rich moulding, issuing from beneath a voluted shell, and each end terminating in the head of a dolphin; and the wheels are imitated from those of the ancient triumphal chariot. The body of the coach is composed of eight palm-trees, which, branching out at the top, sustain the roof; and four angular trees are loaded with trophies allusive to the victories obtained by Great Britain during the late glorious war, supported by four lions’ heads. On the centre of the roof stand three boys, representing the genii of England, Scotland and Ireland, supporting the imperial crown of Great Britain, and holding in their hands the sceptre, sword of state, and ensigns of knighthood; their bodies are adorned with festoons of laurel, which fall from thence towards the four corners. The panels and doors are painted with appropriate emblematical devices, and the linings are of scarlet velvet richly embossed with national emblems.”See the BadmintonDriving, by the duke of Beaufort (1888); Rogers’sManual of Driving(Philadelphia, 1900); and “Nimrod’s”Essays on the Road(1876).
“The whole of the carriage and body is richly ornamented with laurel and carved work, beautifully gilt. The length, 24 ft.; width, 8 ft. 3 in.; height, 12 ft.; length of pole, 12 ft. 4 in.; weight, 4 tons. The carriage and body of the coach is composed as follows:—Of four large tritons, who support the body by four braces, covered with red morocco leather, and ornamented with gilt buckles, the two figures placed in front of the carriage bear the driver, and are represented in the action of drawing by cables extending round their shoulders, and the cranes and sounding shells to announce the approach of the monarch of the ocean; and those at the back carry the imperial fasces, topped with tridents. The driver’s foot-board is a large scallop shell, ornamented with bunches of reeds and other marine plants. The pole represents a bundle of lances; the splinter bar is composed of a rich moulding, issuing from beneath a voluted shell, and each end terminating in the head of a dolphin; and the wheels are imitated from those of the ancient triumphal chariot. The body of the coach is composed of eight palm-trees, which, branching out at the top, sustain the roof; and four angular trees are loaded with trophies allusive to the victories obtained by Great Britain during the late glorious war, supported by four lions’ heads. On the centre of the roof stand three boys, representing the genii of England, Scotland and Ireland, supporting the imperial crown of Great Britain, and holding in their hands the sceptre, sword of state, and ensigns of knighthood; their bodies are adorned with festoons of laurel, which fall from thence towards the four corners. The panels and doors are painted with appropriate emblematical devices, and the linings are of scarlet velvet richly embossed with national emblems.”
See the BadmintonDriving, by the duke of Beaufort (1888); Rogers’sManual of Driving(Philadelphia, 1900); and “Nimrod’s”Essays on the Road(1876).
1The idea of “driving” was responsible for the use of the term “coach” and “coaching” to mean a tutor or trainer, for examinations or athletic contests.
1The idea of “driving” was responsible for the use of the term “coach” and “coaching” to mean a tutor or trainer, for examinations or athletic contests.
COAHUILA,a northern frontier state of Mexico, bounded N. and N.E. by Texas, U.S.A., E. by Nuevo León, S. by San Luis Potosi and Zacatecas, and W. by Durango and Chihuahua. Area, 63,569 sq.m.; pop. (1895) 237,815; (1900) 296,938. Its surface is a roughly broken plateau, traversed N.W. to S.E. by several ranges of mountains and sloping gently toward the Rio Grande. The only level tract of any size in the state is the Bolsón de Mapimí, a great depression on the western side which was long considered barren and uninhabitable. It is a region of lakes and morasses, of arid plains and high temperatures, but experiments with irrigation toward the end of the 19th century were highly successful and considerable tracts have since been brought under cultivation. In general the state is insufficiently watered, the rainfall being light and the rivers small. The rivers flow eastward to the Rio Grande. The climate is hot and dry, and generally healthy. Stock-raising was for a time the principal industry, but agriculture has been largely developed in several localities, among the chief products of which are cotton—Coahuila is the principal cotton-producing state in Mexico—Indian corn, wheat, beans, sugar and grapes. The Parras district in the southern part of the state has long been celebrated for its wines and brandies. The mineral wealth of the state is very great, and the mining industries, largely operated with foreign capital, are important. The mineral products include silver, lead, coal, copper, and iron. The mining operations are chiefly centred in the Sierra Mojada, Sierra Carmen, and in the Santa Rosa valley. The modern industrial development of the state is due to the railway lines constructed across it during the last quarter of the 19th century, and to the investment of foreign capital in local enterprises. The first Spanish settlement in the region now called Coahuila was at Saltillo in 1586, when it formed part of the province of Nueva Viscaya. Later it became the province of Nueva Estremadura under the Spanish régime, and in 1824, under the new republican organization, it became the state of Coahuila and included Texas and Nuevo León. Later in the same year Nuevo León was detached, but Texas remained a part of the state until 1835. The capital of the state is Saltillo; Monclova was the capital from 1833 to 1835. Among the more important towns are Parras (pop. 6476 in 1900), 98 m. W. by N. of Saltillo in a rich grape-producing district, Ciudad Porfirio Diaz, and Monclova (pop. 6684 in 1900), 105 m. N. by W. of Saltillo, on the Mexican International railway.
COAL.In its most general sense the term “coal” includes all varieties of carbonaceous minerals used as fuel, but it is now usual in England to restrict it to the particular varieties of such minerals occurring in the older Carboniferous formations. On the continent of Europe it is customary to consider coal as divisible into two great classes, depending upon differences of colour, namely,brown coal, corresponding to the term “lignite” used in England and France, andblackorstone coal, which is equivalent to coal as understood in England. Stone coal is also a local English term, but with a signification restricted to the substance known by mineralogists as anthracite. In old English writings the terms pit-coal and sea-coal are commonly used. These have reference to the mode in which the mineral is obtained, and the manner in which it is transported to market.
The rootkolis common to all the Teutonic nations, while in French and other Romance languages derivatives of the Latincarboare used,e.g.charbon de terre. In France and Belgium, however, a peculiar word,houille, is generally used to signify mineral coal. This word is supposed to be derived from the Walloonhoie, corresponding to the medieval Latinhullae. Littré suggests that it may be related to the Gothichaurja, coal. Anthracite is from the Greekἄνθραξ, and the termlithanthrax, stone coal, still survives, with the same meaning, in the Italianlitantrace.
It must be borne in mind that the signification now attached to the word coal is different from that which formerly obtained when wood was the only fuel in general use. Coal then meant the carbonaceous residue obtained in the destructive distillation of wood, or what is known as charcoal, and the name collier was applied indifferently to both coal-miners and charcoal-burners.
The spelling “cole” was generally used up to the middle of the 17th century, when it was gradually superseded by the modern form, “coal.” The plural, coals, seems to have been used from a very early period to signify the broken fragments of the mineral as prepared for use.
Coal is an amorphous substance of variable composition, and therefore cannot be as strictly defined as a crystallized or definite mineral can. It varies in colour from a light brown in the newest lignites to a pure black, often withPhysical properties.a bluish or yellowish tint in the more compact anthracite of the older formations. It is opaque, except in exceedingly thin slices, such as made for microscopic investigation, which are imperfectly transparent, and of a dark brown colour by transmitted light. The streak is black in anthracite, but more or less brown in the softer varieties. The maximum hardness is from 2.5 to 3 in anthracite and hard bituminous coals, but considerably less in lignites, which are nearly as soft as rotten wood. A greater hardness is due to the presence of earthy impurities. The densest anthracite is often of a semi-metallic lustre, resembling somewhat that of graphite. Bright, glance or pitch coal is another brilliant variety, brittle, and breaking into regular fragments of a black colour and pitchy lustre. Lignite and cannel are usually dull and earthy, and of an irregular fracture, the latter being much tougher than the black coal. Some lignites are, however, quite as brilliant as anthracite; cannel and jet may be turned in the lathe, and are susceptible of taking a brilliant polish. The specific gravity is highest in anthracite and lowest in lignite, bituminous coals giving intermediate values (see Table I.). As a rule, the density increases with the amount of carbon, but in some instances a very high specific gravity is due to intermixed earthy matters, which are always denser than even the densest form of coal substance.
Coal is never definitely crystalline, the nearest approach to such a structure being a compound fibrous grouping resembling that of gypsum or arragonite, which occurs in some of the steam coals of South Wales, and is locally known as “cone in cone,” but no definite form or arrangement can be made out of the fibres. Usually it occurs in compact beds of alternating bright and dark bands in which impressions of leaves, woody fibre and other vegetable remains are commonly found. There is generally a tendency in coals towards cleaving into cubical or prismatic blocks, but sometimes the cohesion between the particles is so feeble that the mass breaks up into dust when struck. These peculiarities of structure may vary very considerably within small areas; and the position of the divisional planes or cleats with reference to the mass, and the proportion of small coal or slack to the larger fragments when the coal is broken up by cutting-tools, are points of great importance in the working of coal on a large scale.
The divisional planes often contain small films of other minerals, the commonest being calcite, gypsum and iron pyrites, but in some cases zeolitic minerals and galena have been observed. Salt, in the form of brine, is sometimes present in coal. Hydrocarbons, such as petroleum, bitumen, paraffin, &c., are also found occasionally in coal, but more generally in the associated sandstones and limestones of the Carboniferous formation. Gases, consisting principally of light carburetted hydrogen or marsh gas, are often present in considerable quantity in coal, in a dissolved or occluded state, and the evolution of these upon exposure to the air, especially when a sudden diminution of atmospheric pressure takes place, constitutes one of the most formidable dangers that the coal miner has to encounter.
The classification of the different kinds of coal may be considered from various points of view, such as their chemical composition, their behaviour when subjected to heat or when burnt, and their geological position andClassification.origin. They all contain carbon, hydrogen, oxygen and nitrogen, forming the carbonaceous or combustible portion, and some quantity of mineral matter, which remains after combustion as a residue or “ash.” As the amount of ash varies very considerably in different coals, and stands in no relation to the proportion of the other constituents, it is necessary in forming a chemical classification to compute the results of analysis after deduction of the ash and hygroscopic water. Examples of analyses treated in this manner are furnished in theAnthracite.last column of Table I., from which it will be seen that the nearest approach to pure carbon is furnished by anthracite, which contains above 90%. This class of coal burns with a very small amount of flame, producing intense local heat and no smoke. It is especially used for drying hops and malt, and in blast furnaces where a high temperature is required, but it is not suited for reverberatory furnaces.
The most important class of coals is that generally known as bituminous, from their property of softening or undergoing an apparent fusion when heated to a temperature far below that at which actual combustion takes place.Bituminous coals.This term is founded on a misapprehension of the nature of the occurrence, since, although the softening takes place at a low temperature, still it marks the point at which destructive distillation commences, and hydrocarbons both of a solid and gaseous character are formed. That nothing analogous to bitumen exists in coals is proved by the fact that the ordinary solvents for bituminous substances, such as bisulphide of carbon and benzol, have no effect upon them, as would be the case if they contained bitumen soluble in these re-agents. The term is, however, a convenient one, and one whose use is almost a necessity, from its having an almost universal currency among coal miners. The proportion of carbon in bituminous coals may vary from 80 to 90%—the amount being highest as they approach the character of anthracite, and least in those which are nearest to lignites. The amount of hydrogen is from 4½ to 6%, while the oxygen may vary within much wider limits, or from about 3 to 14%. These variations in composition are attended with corresponding differences in qualities, which are distinguished by special names. Thus the semi-anthracitic coals of South Wales are known as “dry” or “steam coals,” being especially valuable for use in marine steam-boilers, as they burn more readily than anthracite and with a larger amount of flame, while giving out a great amount of heat, and practically without producing smoke. Coals richer in hydrogen, on the other hand, are more useful for burning in open fires—smiths’ forges and furnaces—where a long flame is required.
The excess of hydrogen in a coal, above the amount necessaryto combine with its oxygen to form water, is known as “disposable” hydrogen, and is a measure of the fitness of the coalGas coal.for use in gas-making. This excess is greatest in what is known as cannel coal, the Lancashire kennel or candle coal, so named from the bright light it gives out when burning. This, although of very small value as fuel, commands a specially high price for gas-making. Cannel is more compact and duller than ordinary coal, and can be wrought in the lathe and polished.
Table I.—Elementary Composition of Coal(the figures denote the amounts per cent).
These properties are most highly developed in the substance known as jet, which is a variety of cannel found in the lower oolitic strata of Yorkshire, and is almost entirely used for ornamental purposes, the whole quantity produced near Whitby, together with a further supply from Spain, being manufactured into articles of jewellery at that town.
When coal is heated to redness out of contact with the air, the more volatile constituents, water, hydrogen, oxygen, and nitrogen are in great part expelled, a portion of the carbon being also volatilized in the form of hydrocarbonsCaking coals.and carbonic oxide,—the greater part, however, remaining behind, together with all the mineral matter or ash, in the form of coke, or, as it is also called, “fixed carbon.” The proportion of this residue is greatest in the more anthracitic or drier coals, but a more valuable product is yielded by those richer in hydrogen. Very important distinctions—those of caking or non-caking—are founded on the behaviour of coals when subjected to the process of coking. The former class undergo an incipient fusion or softening when heated, so that the fragments coalesce and yield a compact coke, while the latter (also called free-burning) preserve their form, producing a coke which is only serviceable when made from large pieces of coal, the smaller pieces being incoherent and of no value. The caking property is best developed in coals low in oxygen with 25 to 30% of volatile matters. As a matter of experience, it is found that caking coals lose that property when exposed to the action of the air for a lengthened period, or by heating to about 300° C., and that the dust or slack of non-caking coal may, in some instances, be converted into a coherent coke by exposing it suddenly to a very high temperature, or compressing it strongly before charging it into the oven.
Lignite or brown coal includes all varieties which are intermediate in properties between wood and coals of the older formations. A coal of this kind is generally to be distinguished by its brown colour, either in mass or inLignite.the blacker varieties in the streak. The proportion of carbon is comparatively low, usually not exceeding 70%, while the oxygen and hygroscopic water are much higher than in true coals. The property of caking or yielding a coherent coke is usually absent, and the ash is often very high. The specific gravity is low when not brought up by an excessive amount of earthy matter. Sometimes it is almost pasty, and crumbles to powder when dried, so as to be susceptible of use as a pigment, forming the colour known as Cologne earth, which resembles umber or sepia. In Nassau and Bavaria woody structure is very common, and it is from this circumstance that the term lignite is derived. The best varieties are black and pitchy in lustre, or even bright and scarcely to be distinguished from true coals. These kinds are most common in Eastern Europe. Lignites, as a rule, are generally found in strata of a newer geological age, but there are many instances of perfect coals being found in such strata.
By the term “ash” is understood the mineral matter remaining unconsumed after the complete combustion of the carbonaceous portion of a coal. According to Couriot (Annales de la société géologique de Belgique, vol. xxiii.Ash of coal.p. 105) the stratified character of the ash may be rendered apparent in an X-ray photograph of a piece of coal about an inch thick, when it appears in thin parallel bands, the combustible portion remaining transparent. It may also be rendered visible if a smooth block of free-burning coal is allowed to burn away quickly in an open fire, when the ash remains in thin grey or yellow bands on the surface of the block. The composition of the ashes of different coals is subject to considerable variation, as will be seen by Table II.
The composition of the ash of true coal approximates to that of a fire-clay, allowance being made for lime, which may be present either as carbonate or sulphate, and for sulphuric acid. Sulphur is derived mainly from ironSulphur in coal.pyrites, which yields sulphates by combustion. An indication of the character of the ash of a coal is afforded by its colour, white ash coals being generally freer from sulphur than those containing iron pyrites, which yield a red ash. There are, however, several striking exceptions, as for instance in the anthracite from Peru, given in Table I., which contains more than 10% of sulphur, and yields but a very small percentage of a white ash. In this coal, as well as in the lignite of Tasmania, known as white coal or Tasmanite, the sulphur occurs in organic combination, but is so firmly held that it can only be very partially expelled, even by exposure to a very high and continued heating out of contact with the air. An anthracite occurring in connexion with the old volcanic rocks of Arthur’s Seat, Edinburgh, which contains a large amount of sulphur in proportion to theash, has been found to behave in a similar manner. Under ordinary conditions, from1⁄8to1⁄4of the whole amount of sulphur in a coal is volatilized during combustion, the remaining3⁄4to7⁄8being found in the ash.
Table II.—Composition of the Ashes of Coals.
The amount of water present in freshly raised coals varies very considerably. It is generally largest in lignites, which may sometimes contain 30% or even more, while in theWater in coal.coals of the coal measures it does not usually exceed from 5 to 10%. The loss of weight by exposure to the atmosphere from drying may be from ½ to ¾ of the total amount of water contained.
Table III.—Composition of Fuels (assuming Carbon = 100).
Coal is the result of the transformation of woody fibre and other vegetable matter by the elimination of oxygen and hydrogen in proportionally larger quantity than carbon, so that the percentage of the latter elementOrigin of Coal.is increased in the manner shown in Table III., given by J. Percy, the mineral matter being also changed by the removal of silica and alkalis and the substitution of substances analogous in composition to fire-clay. The causes and methods of these changes are, however, not very exactly defined. According to the elaborate researches of B. Renault (Bulletin de la Société de l’Industrie minérale, 3 ser. vol. xiii. p. 865), the agents of the transformation of cellulose into peaty substances are saprophytic fungi and bacterial ferments. As the former are only active in the air while the latter are anaerobic, the activity of either agent is conditioned by variation in the water level of the bog. The ultimate term of bacterial activity seems to be the production of ulmic acid, containing carbon 65.31 and hydrogen 3.85%, which is a powerful antiseptic. By the progressive elimination of oxygen and hydrogen, partly as water and partly as carbon dioxide and marsh gas, the ratios of carbon to oxygen and hydrogen in the rendered product increase in the following manner:—
The resulting product is a brown pasty or gelatinous substance which binds the more resisting parts of the plants into a compact mass. The same observer considers Boghead coal, kerosene shale and similar substances used for the production of mineral oils to be mainly alteration products of gelatinous fresh water algae, which by a nearly complete elimination of oxygen have been changed to substances approximating in composition to C2H3and C3H5, where C : H = 7.98 and C : O + N = 46.3. In cannel coals the prevailing constituents are the spores of cryptogamic plants, algae being rare or in many cases absent. By making very thin sections and employing high magnification (1000-1200 diameters), Renault has been enabled to detect numerous forms of bacilli in the woody parts preserved in coal, one of which,Micrococcus carbo, bears a strong resemblance to the livingCladothrixfound in trees buried in peat bogs. Clearer evidence of their occurrence has, however, been found in fragments of wood fossilized by silica or carbonate of lime which are sometimes met with in coal seams.
The subsequent change of peaty substance into coal is probably due to geological causes,i.e.chemical and physical processes similar to those that have converted ordinary sediments into rock masses. Such changes seem, however, to have been very rapidly accomplished, as pebbles of completely formed coal are commonly found in the sandstones and coarser sedimentary strata alternating with the coal seams in many coalfields.
The variation in the composition of coal seams in different parts of the same basin is a difficult matter to explain. It has been variously attributed to metamorphism, consequent upon igneous intrusion, earth movements and other kinds of geothermic action, greater or less loss of volatile constituents during the period of coaly transformation, conditioned by differences of permeability in the enclosing rocks, which is greater for sandstones than for argillaceous strata, and other causes; but none of these appears to be applicable over more than limited areas. According to L. Lemière, who has very fully reviewed the relation of composition to origin in coal seams (Bulletin de la Société de l’Industrie minérale, 4 ser. vol. iv. pp. 851 and 1299, vol. v. p. 273), differences in composition are mainly original, the denser and more anthracitic varieties representing plant substance which has been more completely macerated and deprived of its putrescible constituents before submergence, or of which the deposition had taken place in shallow water, more readily accessible to atmospheric oxidizing influences than the deeper areas where conditions favourable to the elaboration of compounds richer in hydrogen prevailed.
The conditions favourable to the production of coal seem therefore to have been—forest growth in swampy ground about the mouths of rivers, and rapid oscillation of level, the coal produced during subsidence being covered up by the sediment brought down by the river forming beds of sand or clay, which, on re-elevation, formed the soil for fresh growths, the alternation being occasionally broken by the deposit of purely marine beds. We might therefore expect to find coal wherever strata of estuarine origin are developed in great mass. This is actually the case; the Carboniferous, Cretaceous and Jurassic systems (qq.v.) contain coal-bearing strata though in unequal degrees,—the first being known as the Coal Measures proper, while the others are of small economic value in Great Britain, though more productive in workable coals on the continent of Europe. The Coal Measures which form part of the Palaeozoic or oldest of the three great geological divisions are mainly confined to the countries north of the equator. Mesozoic coals are more abundant in the southern hemisphere, while Tertiary coals seem to be tolerably uniformly distributed irrespective of latitude.
The nature of the Coal Measures will be best understood byconsidering in detail the areas within which they occur in Britain, together with the rocks with which they are most intimately associated. The commencement of the Carboniferous period isSequences of carboniferous strata.marked by a mass of limestones known as the Carboniferous or Mountain Limestone, which contains a large assemblage of marine fossils, and has a maximum thickness in S.W. England and Wales of about 2000 ft. The upper portion of this group consists of shales and sandstones, known as the Yoredale Rocks, which are highly developed in the moorland region between Lancashire and the north side of Yorkshire. These are also called the Upper Limestone Shale, a similar group being found in places below the limestone, and called the Lower Limestone Shale, or, in the north of England, the Tuedian group. Going northward the beds of limestone diminish in thickness, with a proportional increase in the intercalated sandstones and shales, until in Scotland they are entirely subordinate to a mass of coal-bearing strata, which forms the most productive members of the Scotch coalfields. The next member of the series is a mass of coarse sandstones, with some slates and a few thin coals, known as the Millstone Grit, which is about equally developed in England and in Scotland. In the southern coalfields it is usually known by the miners’ name of “Farewell rock,” from its marking the lower limit of possible coal working. The Coal Measures, forming the third great member of the Carboniferous series, consist of alternations of shales and sandstones, with beds of coal and nodular ironstones, which together make up a thickness of many thousands of feet—from 12,000 to 14,000 ft. when at the maximum of development. They are divisible into three parts, the Lower Coal Measures, the middle or Pennant, a mass of sandstone containing some coals, and the Upper Coal Measures, also containing workable coal. The latter member is marked by a thin limestone band near the top, containingSpirorbis carbonarius, a small marine univalve.
The uppermost portion of the Coal Measures consists of red sandstone so closely resembling that of the Permian group, which are next in geological sequence, that it is often difficult to decide upon the true line of demarcation between the two formations. These are not, however, always found together, the Coal Measures being often covered by strata belonging to the Trias or Upper New Red Sandstone series.
The areas containing productive coal measures are usually known as coalfields or basins, within which coal occurs in more or less regular beds, also called seams or veins, which can often be followed over a considerable length of country without change of character, although, like all stratified rocks, their continuity may be interrupted by faults or dislocations, also known as slips, hitches, heaves or troubles.