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heir to the Crown had been increased by the expression in the life of the nation and his wide interests may be of his satisfaction at his son's union to an Englishwoman. illustrated by his establishment (1897) of the “Prince of On 6th July 1893 the broken thread was reunited by the Wales's Hospital Fund,” his devotion to the cause of marriage of the princess (popularly known as Princess Masonry (he was first elected Grand Master of the FreeMay) to the brother of the deceased prince, George masons of England in 1874), and his position as a Bencher Frederick, duke of York.
of the Middle Temple, where he also became (1887) The year 1894 was a busy one for the prince of Wales, Treasurer. It was on the occasion of his first appearance who became a member of the Royal Commission on the at “Grand Night," that the students were for the first Housing of the Poor, opened the Tower Bridge, attended time allowed to follow the Prince's example and to smoke the Welsh Eisteddfod and was duly initiated, and paid in Hall; and this was only one instance of the influence two visits to Russia—one on the marriage of the Grand in this respect which the Prince's taste for tobacco had Duchess Xenia, the other on the death of the Tsar, his on English society. brother-in-law. In 1896 he became first Chancellor of the On the death of Queen Victoria on 22nd January 1901, University of Wales, and his first act after his installation the question what title the new king would assume was at Aberystwith was to confer an honorary degree upon speedily set at rest by the popular announcement that he the princess. He had already been for some years a
would be called Edward the Seventh. The new reign trustee of the British Museum, and participated actively began auspiciously by the holding of a Privy Council at in its administration. On 22nd July 1896 the prince's St. James's Palace, at which the King announced his third daughter, Princess Maud, was married to Prince intention to follow in his predecessor's footsteps and to Charles of Denmark. The arrangements for the Queen's govern as a constitutional sovereign, and received the oaths Jubilee of 1897 depended upon the prince even more than of allegiance. On 14th February the King and Queen those of the corresponding celebration in 1887: he rode opened Parliament in state. Shortly afterwards it was on the Queen's right at the great procession to St Paul's, announced that the visit of the duke and duchess of York and as an Admiral of the Fleet presided at the naval to Australia, in order to inaugurate the new Commonwealth, review at Spithead, a spectacle unparalleled in the history which had been sanctioned by Queen Victoria, would be of the world. In July 1898 the prince had the misfortune proceeded with ; and on 16th March they set out on board to fracture his knee-cap while on visit to Baron Ferdinand the Ophir with a brilliant suite. The tour lasted till de Rothschild, but completely recovered from the effects of 1st November, the duke and duchess , having visited the accident. In December 1899, while passing through Australia, New Zealand, the Cape, and Canada, and on Brussels on his way to St Petersburg, he was fired at by a their return the King, on 9th November, created the duke miserable lad named Sipido, crazed by reading anarchist prince of Wales and earl of Chester. In the meanwhile literature. Fortunately, no injury was done.
Parliament had settled the new Civil List (q.v.) at It was the especial distinction of Albert Edward, prince £470,000 a year. On 22nd May the King had a narrow of Wales, to have been an ornament and support of the escape in Southampton Water, on board Sir T. Lipton's throne before he was called upon to fill it himself. This yacht Shamrock II. (which was to compete for the cannot be said of any of his predecessors except Edward America Cup). The yacht had her masts, spars, and entire the Black Prince. Most princes of Wales have either died spread of canvas carried away in a squall; but the King or attained the regal dignity too early to leave any con suffered no injury. The question of enlarging the Royal spicuous mark in history as princes. Since the days of title to include specific mention of the colonial empire had the Black Prince only two have enjoyed a popularity com been discussed during the year, and on 30th July Parliaparable to Prince Albert Edward's—Henry of Monmouth ment passed a Bill to enable the King to style himself and Henry, the son of James I. The glories of Henry V. “Edward VII, by the grace of God of the United Kinghave cast a veil over the irregularities of Prince Hal; and dom of Great Britain and Ireland, and of all the British the popularity of the Stuart Prince Henry arose in great Dominions beyond the Seas, King, Defender of the Faith, measure from his suppressed antagonism to his father, and Emperor of India.” The "Coronation was fixed for 26th the expectation that he would reverse the latter's policy. June 1902. Two days earlier, however, the King was The other two princes of Wales who have filled a con announced to be suffering from perityphlitis, and on 24th spicuous place in the public eye, Prince Frederick and June an operation was performed by Sir Frederick Treves. George IV., were neither dutiful nor popular. It was The Coronation was consequently postponed. On 27th reserved for the son of Queen Victoria to show what June the King was pronounced “out of immediate danger," strength an heir-apparent exemplary in the discharge of the and up to 1st July, when this volume was printed, he was duties of his station can bring to a monarchy, and how stated to be progressing favourably. important'a place, even with the most scrupulous abstin The grandchildren of King Edward VII. are—children of the ence from party politics, he can fill in the life of a self-prince and princess of Wales-(1) Prince Edward Albert Christian governing nation. He was a keen patron of the theatre, George Andrew, Patrick David, born 23rd June 1894 ; (2) Prince
Albert Frederick Arthur George, born 14th December 1895; (3) and made it his business to know and remember all the
Princess Victoria Alexandra Alice Mary, born 25th April 1897; distinguished men of the time in arts and letters. His
(4) Princo Henry William Frederick Albert, born 15th March thoroughly British taste for sport was as pronounced as 1899. Children of the duke and duchess of Fife—(1) Lady his inclination for most of the contemporary amusements
Alexandra Victoria Alberta Edwina Louise Duff, born 17th May
1891 ; (2) Lady Maud Alexandra Victoria Georgina Bertha Duff, of Society. The "Tranby Croft Case" (1890), in which
born 3rd April 1893. Sir William Gordon Cumming brought an unsuccessful libel action for having been accused of cheating at a
Edwardsville, capital of Madison county, Illinois, game of baccarat, caused some comment in connexion U.S.A., on Cahokia creck, at an altitude of 554 feet. It with the Prince's appearance in the witness - box on be
has three railways, the Wabash, the Toledo, St Louis, and half of the defendants. But it did him no disservice Kansas City, and the Chicago, Peoria, and St Louis. with the people to have twice won the Derby with his Population (1880), 2887; (1890), 3561 ; (1900), 4157 horses Persimmon (1896) and Diamond Jubilee (1900), Edwardsville, a borough of Lucerne county, and his interest in yacht-racing was conspicuously shown Pa., U.S.A., in the anthracite coal region, on the north at all the important fixtures, his yacht Britannia being branch of the Susquehanna river. The official name of one of the best of her day. In other respects his activity the post oflice is Edwardsdale. Population (1900), 5165.
Eel.—The common fresh-water eel belongs to a group plete development of the ovary. The invariable death of the fish of soft-rayed fishes distinguished by the presence of an in the same almost ripe condition leads to the conclusion that
under normal conditions the fish dies after the mature ova have opening to the air-bladder and the absence of the pelvic
been discharged. Grassi states that he obtained ripe male eels, fins. With its nearest relatives it forms the family Muræn
and ripe specimens of Muræna, another genus of the family, in dæ, all of which are of elongated cylindrical form. The the whirlpools of the Strait of Messina. A ripe female Muræna special peculiarities of the eel are the rudimentary scales has also been described at Zanzibar. Gravid female eels, i.e., buried in the skin, the well-developed pectoral fins, the
specimens with ovaries greatly enlarged, have been occasionally
obtained in fresh water, but there is no doubt that, normally, rounded tail fin continuous with the dorsal and ventral fins.
sexual maturity is attained only in the sea. Only one other species of the family occurs in British Until recent years nothing was known from direct observation waters, namely, the conger, which is usually much larger, concerning the reproduction of the common eel, or any species of and lives in the sea. In the conger the eyes are larger
the family. It was a well-known fact that large eels migrated
towards the sea in autumn, and that in the spring small transthan in the eel, and the upper jaw overlaps the lower,
parent eels of 2 inches in length and upwards were common on whereas in the eel the lower jaw projects beyond the the shore under stones, and ascended rivers and streams in vast upper. Both species are voracious and predatory, and feed
It was reasonable, therefore, to infer that the mature eels on almost any animal food they can obtain, living or dead. spawned in the sea, and that there the young were developed.
A group of peculiar small fishes were, however, known which The conger is especially fond of squid or other Cephalopods, while the eel is partial to carrion. The common eel occurs
were called Leptocephali, from the small proportional size of the in all the rivers and fresh waters of Europe, except those draining towards the Arctic Ocean, the Black Sea, and the Caspian Sea. It also occurs on the Atlantic side of North America. The conger has a wider range, extending from the western and southern shores of Britain and Ireland to the East Indian Archipelago and Japan. It is common in the Mediterranean.
The ovaries of the eel resemble somewhat these of the salmon in structure, not forming closed sacs, as in the majority of Teleostei, but consisting of lamine exposed to the body cavity. The laminæ in which the eggs are produced are very numerous, and are attached transversely by their inner edges to a membranous band running nearly the whole length of the body-cavity. The majority of the eels captured for market are females with the ovaries in an immature condition. The male eel was first discovered in 1873 by Syrski at Trieste, the testis being described by him as a lobed elongated organ, in the same relative position as the ovary in the female, surrounded by a smooth surface without laminæ. He did not find ripe spermatozoa. He discovered the male by examining small specimens, all the larger being female. Jacoby, a later observer, found no males exceeding 19 inches in length, while the female may reach a length of 39 inches or more. Dr Petersen, in a paper published in 1896, states that in Denmark two kinds of eels are distinguished by the fishermen, namely, yellow eels and silver eels. The silver eels are further distinguished by the shape of the snout and the size of the eyes. The snout in front of the eyes is not flat, as in the yellow eels, but high and compressed, and therefore appears more pointed, while the eyes are much larger and directed outwards. In both kinds there are males and females, but Petersen shows that the yellow eels change into silver eels when they migrate to the sea. The sexual organs in the silver eels are more developed than in the yellow eels, and the former have almost or entirely ceased to take food. The male silver eels are from 111 to 19 inches in length, the females from 16.1 to about 39 inches. It is evident, therefore, that if eels only spawn once, they do not all reach the same size when they become exually mature.
The male conger was first described in 1879 by Hermes, who obtained a ripe specimen in the Berlin Aquarium. This specimen was not quite 23 feet in length, and of the numerous males which have been identified at the Plymouth Laboratory, none exceeded this length. The large numbers of conger above this size caught for the market are all immature females. Female conger of 5 or 6 feet in length and weighing from 30 to 50 lb are common enough, and occasionally they exceed these limits. The largest recorded was 8 feet 3 inches long, and weighed 128 1b.
There is every reason to believe that eels and conger spawn but once in their lives, and die soon after they have discharged their generative products. When kept in aquaria, both male and female conger are vigorous and voracious. The males sooner or later cease to feed, and attain to the sexually mature condition, emitting ripe milt when handled and gently squeezed. They live in this condition five or six months, taking no food, and showing gradual wasting and disease of the bodily organs. The eyes and skin become ulcerated, the sight is entirely lost, and the bones become soft through loss of lime. The females also after a time cease to feed, and live in a fasting condition for five or six months, during which time the ovaries develop and reach great size and weight, while the bones become soft and the teeth disappear. The female, however, always dies in confinement before the ova are perfectly ripe and before they are liberated from the ovarian tissue. The absence of some necessary condition, perhaps merely of the pressure which exists at the bottom of the sea, evidently prevents the com
Leptocephali. (By kind permission of J. & A. Churchill.) head. The first of these described was captured in 1763 near Holyhead, and became the type of L. Morrisii, other specimens of which have been taken either near the shore or at the surface of the sea. Other forms placed in the same genus had been taken by surface fishing in the Mediterranean and in tropical ocean currents. The chief peculiarities of Leptocephali, in addition to the smallness of the head, are their ribbon-like shape and their glassy transparency during life. The body is flattened from side to side, and broad from the dorsal to the ventral Like the eels, they are destitute of pelvic fins, and no generative organs have been observed in them (see Fig. above).
In 1864 the American naturalist, Gill, published the conclusion that L. Morrisii was the young or larva of the conger, and Leptocephali generally the young stages of species of Murænidæ. In 1886 this conclusion was confirmed from direct observation by Yves Delage, who kept alive in a tank at Roscoff a specimen of L. Morrisii, and saw it gradually transformed into a young conger. From 1887 to 1892 Professor Grassi and Dr Calandruccio carried on careful and successful researches into the development of the Leptocephali at Catania, in Sicily. The specimens were captured in considerable numbers in the harbour, and the transformation of L. Morrisii into young conger, and of various other forms of Leptocephalus into other genera of Murænidæ, such as M[urcena, Congromurcna, and Ophichthys, was observed. In 1894 the same authors published the announcement that another species of Leptocephalus, namely, L. brevirostris, was the larva of the common eel. This larval form was captured in numbers with other Leptocephali in the strong currents of the Strait of Messina. In the metamorphosis of all Leptocephali a great reduction in size
The L. brevirostris reaches a length of 8 cm., or a little more than 24 inches, while the perfectly-formed young eel is 2 inches long or a little more.
The Italian naturalists have also satisfied themselves that certain pelagic fish eggs originally described by Raffaele at Naples are the eggs of Murænidæ, and that among them are the eggs of
Conger and Anguilla. They believe that these eggs, although free church contains monuments by Flaxman. Within the in the water, remain usually near the bottom at great depths, and parish are the Royal Indian Engineering College on Cooper's that fertilization takes place under similar conditions. No fish
Hill, the hill celebrated in Sir John Denham's eggs of the kind to which reference is here made have yet been
poem, 1642, obtained on the British coasts, although conger and eels are so
the Royal Holloway College for Women, the Holloway sanaabundant there. Raffaele described and figured the larva newly
torium for the treatment of mental ailments, and a cottage hatched from one of the eggs under consideration, and it is evident hospital ; also the field of Runnymede, where King John that this larva is the earliest stage of a Leptocephalus.
signed Magna Carta, and (partly in Berkshire) Virginia See “The Eel Question,” Report U.S. Commissioner of Fisheries for 1879. Washington, 1882.-CUNNINGHAM, “Reproduction and
Water, a large artificial lake in the south of Windsor Development of the Conger,” Journ. Mar. Biol. Assn. vol. ii. Great Park. Area of parish (with Englefield), 7786 acres. PETERSEN, Report Dan. Biol. Station, v., 1894.—GRASSI, Quart. Population (1881), 8692; (1901), 11,894. Journ. Nic. Sci. vol. xxxix., 1897.
(J. T. C.)
Egin (Armenian, Agn, “the spring”), an important Eger, the chief town of the government district of town in the Memuret el-Aziz viláyet of Asiatic Turkey the same name in Bohemia ; connected by rail with Nurem- (altitude, 3300 feet). It is picturesquely situated in a berg, Prague, Vienna, Reichenberg, &c. Population (1890),
theatre of lofty, abrupt rocks, on the right bank of the 18,658; (1900), 23,665, almost exclusively German (esti- Western Euphrates, at the point where the Kharpútmated at 91 per cent. Roman Catholic, 6 per cent. Pro
Erzingan road crosses the river by a wooden bridge. The testant, and 3 per cent. Jewish). There is a garrison of stone houses stand in terraced gardens and orchards, and 1069 men. Latterly Eger has been very prominent on the streets are mere rock-ladders. The population numbers account of its strong Pan-Germanic sentiment. The town 10,000 (Moslems 6000, Armenians 4000). Egin was is exceptionally interesting from its ancient buildings, settled by Armenians who emigrated from Van in the collection of historical relics of Wallenstein, &c. There is
11th century with Senekherim. On 8th November 1895 a considerable textile industry, together with the manu many Armenians were massacred. facture of shoes, machinery, brewing, milling, &c. The inhabitants of the district are still distinguished from Egorievsk, a district town of Russia, government the surrounding population by their costumes, language, and 74 miles north-east of Ryazan, connected by branch manners, and customs.
line (14 miles) with the Moscow to Ryazañ main line. Its
cotton mills (yielding over £500,000 a year) and other Egham, a town and railway station in the Chertsey factories give occupation to 6000 persons. It has important parliamentary division of Surrey, England, on the Thames, fairs for trade in grain, hides, &c., exported. Population, 21 miles west by south of London by rail. The parish 20,000.
GEOGRAPHY AND STATISTICS.
their colour from the overlying Nile deposit, and are of
considerable thickness. A boring made in 1886 for the THE salient physical features of Egypt may be grouped Royal Society at Zagazig attained a depth of 375 feet
as follows, each division having its own characteristic without reaching rock, and another, recently sunk near features, due essentially to the geological structure of Lake Abukir (close to Alexandria) by a company, reached the country S(1) the Delta, (2) the Trough or “Rift” a depth of 405 feet with the same result. Numerous other Valleys, (3) the Desert Plateaux, (4) the mountainous borings to depths of 100 to 200 feet have given similar region in the east and north-east. The Nie must also results, showing the Nile deposit to rest generally on these be considered separately.
yellow sands, which provide a constant though not a very The Delta.—The delta of the Nile occupies a triangular large supply of good water; near the northern limits of the area north of Cairo, measuring 100 miles from south to delta this cannot, however, be depended on, since the well north, and having a width of 155 miles on the shore of water at these depths has proved on several occasions to the Mediterranean between Alexandria on the west and be salt. The surface of the delta is a wide alluvial plain Port Said on the east. Beyond these two points the low sloping gently towards the sea, and having an altitude of hills of the desert form the coast-line, while between them 29 feet above it at its southern extremity. The only the low sandy shore of the delta, slowly increasing by the
inequalities are the mounds, formed of ruined mud-brick annual deposit of silt by the river, is a barren area of sand dwellings, which mark the site of ancient towns, or on which hills and salty waste, land, except in a few parts where the present towns and villages stand, occupying often the reclamation has already made progress.
Southwards the same site as their predecessors of earlier times. Its limits quality of the soil rapidly improves, and becomes the most east and west are determined by the higher ground of the fertile part of Egypt. This area is watered by the Damietta deserts, to which the silt-laden waters of the Nile in flood and the Rosetta branches of the Nile, and by the network time cannot reach. of canals which, beginning at Cairo and the Barrage, The Valleys.—The valleys, which are a remarkable intersects the whole delta and extends castwards through feature of the country, are those occupied respectively by the Wadi Tumilat as far as Suez. The soil of the delta is the Nile, the Gulf of Suez, and the Gulf of Akaba, and a dark grey fine sandy soil, becoming at times almost a stiff each of these is a rift-valley determined by the subsidence clay by reason of the fineness of its particles
, which consist of a narrow belt in the neighbourhood of a line of fracture almost wholly of extremely small grains of quartz with a on the earth's surface. In the Gulf of Suez, certainly, an few other minerals, and often numerous flakes of mica. upward movement is still in progress, as salines along the This deposit varies in thickness, as a rule, from 55 to 70 coast are still being formed as the land rises; but in the feet, at which depth it is underlain by a series of coarse Nile Valley north of Assuan this is more difficult to and fine yellow quartz sands, with occasional pebbles, or determine, though certain slight local earthquake shocks, even banks of gravel, while here and there thin beds of which occasionally occur, seem to point to the fact that clay occur. These sand-beds are sharply distinguished by that movement has not wholly ceased. The trough so
formed has been filled by deposits of coarse and fine sand by the occasional rain, are ceaselessly at work, and produce and gravel, containing numerous fragments of igneous the successive plateaux, dotted with small isolated hills and rocks, which underlie the present Nile mud deposit, as in cut up by valleys (wadis), which occasionally become deep the Delta ; and similarly, also, deep borings have reached ravines, thus forming the principal type of scenery of these no rock-floor up to the present. At Beni Suef, with the deserts. From this it will be seen that the desert in Egypt Tertiary limestone plateaux of the desert 3 miles distant, is mainly a rock desert, where the surface is formed of 400 feet of sands and clays were penetrated without any disintegrated rock, the finer particles of which have been sign of rock, and at Medinet el Fayum a boring of 450 carried away by the wind; and east of the Nile this is feet gave the same result.
almost exclusively the case. In the western desert, howEntering Egypt proper, a little to the north of the Second ever, those large sand accumulations which are usually Cataract, the Nile flows through a valley in sandstone beds associated with a desert are met with. They occur as of Cretaceous age as far as latitude 25° N., and throughout lines of dunes formed of rounded grains of quartz, and lie in this part of its course the valley is extremely narrow, rarely the direction of the prevalent wind, usually being of small exceeding 2 miles in width. At two points, namely, breadth as compared with their length; but in certain Kalabsha and Assuan (First Cataract), its course is inter areas, such as that lying south-west and west of the Oases rupted by outcrops of granites and other crystalline rocks, of Farafreh and Dakhleh, these lines of dunes, lying which have been uncovered by the erosion of the overlying parallel to each other and about half a mile apart, cover sandstone, and to-day form the mass of islands, with immense areas, rendering them absolutely impassable exnumerous small rapids, which have been described not very cept in a direction parallel to the lines themselves. East accurately as cataracts; no good evidence exists in support of the Oases of Baharieh and Farafreh is a very strikof the view that they are the remains of a massive barrier, ing line of these sand dunes; rarely more than 3 miles broken down and carried away by some sudden convulsion. wide, it extends almost continuously from Moghara in From latitude 25° N. north wards for 518 miles the valley the north, passing along the west side of Khargeh Oasis is of the “rift-valley” type, a level depression in the lime to a point near the Nile in the neighbourhood of Abu stone plateau, enclosed usually by steep cliffs, except where Simbel in Nubia—having thus a length of nearly 550 the tributary valleys drained into the main valley in early miles. In the northern part of this desert the dunes lie times, when there was a larger rainfall, and which now about N.W.-S.E., but farther south incline more towards carry off the occasional rainstorms that burst on the the meridian, becoming at last very nearly north and desert. The average width of the cultivation is about south. 10 miles, of which the greater part lies on the left bank Oases.—In the western desert lie the five large oases of of the river; and outside this is a belt, varying from a Egypt, namely, Siwah, Baharieh, Farafreh, Dakhleh, and few hundred yards to 3 or 4 miles, of stony and sandy Khargeh, occupying depressions in the plateau or, in the ground, reaching up to the foot of the limestone cliffs, which case of the last three, large indentations in the face of the rise in places to as much as 1000 feet above the valley. escarpment formed by the Lower Eocene and Upper This continues as far as latitude 29° N., after which the Cretaceous Limestones. Their fertility is due to a plentiful hills that close in the valley become lower, and the higher supply of water furnished by a sandstone bed 300 to 500 plateaux lie at a distance of 10 or 15 miles back in the feet below the surface, whence the water rises through desert. The fertile province of the Fayum, on the left bank natural fissures or artificial boreholes to the surface, and of the Nile and separated from it by 6 miles of desert, sometimes to several feet above it. These cases were seems to owe its existence to movements similar to those known and occupied by the Egyptians as early as 1600 which determined the valley itself. Surrounded by Tertiary B.C., and Khargeh rose to special importance at the time of limestone strata on the north, west, and south, the boring the Persian occupation. above mentioned met with no representatives of these beds The Mountainous Region.—The mountainous part of in the 450 feet which were penetrated. Lying in a basin the country is that occupied by the crystalline rocks in the sloping in a series of terraces from an altitude of 65 feet southern part of Sinai, and the belt occupying the western above sea-level in the east to about 140 feet below sea shore of the Gulf of Suez and Red Sea, where the principal level on the north-west, at the margin of the Birket-el-Kerun, peaks rise to heights of 6000 and 7000 feet. Owing to this province is wholly irrigated by a large canal, the Bahr the slight rainfall, and the rapid weathering of the rocks Yusef, which, leaving the Nile at Deirut in Upper Egypt, by the great range of temperature, these hills rise steeply follows the western margin of the cultivation in the Nile from the valleys at their feet as almost bare rock, supporting Valley, and at length enters the Fayum through a gap in hardly any vegetation. In some of the valleys, wells or the desert hills by the XIIth Dynasty pyramids of Lahun rock-pools filled by rain occur, and furnish drinking-water and Hawara.
to the few Arabs who wander in these hills. Farther south, The Desert Plateaux.-Speaking generally, Egypt con where the rainfall is greater, the valleys are more fertile, sists of a broad plateau of sedimentary rocks, lying on the and support considerable numbers of camels, sheep, and western side of a band of crystalline rocks which occupy goats. the southern part of the peninsula of Sinai and the western The Egyptian Nile.—The Nile (q.v.) enters Egypt side of the Red Sea from latitude 29° N. southwards. In proper a little to the north of the Second Cataract, and the north, where beds of Upper Tertiary age occur, the between there and the First Cataract has a length of 200 desert plateaux are comparatively low, but from Cairo miles and a slope of 1500 From this point to the southwards, as the Eocene limestones come in, they rise to Barrage at the apex of the Delta the length is 605 miles 1000 and even 1500 feet above sea-level. Formed mostly and the slope 13 doo, and thence to the sea, by either the of horizontal strata of varying hardness, they present a Rosetta or Damietta branch, is 145 miles more. The Nile series of terraces of minor plateaux, rising one above the is at its lowest at Assuan at the end of May, then rises other, and intersected by small ravines worn by the slowly until the middle of July, and rapidly throughout occasional rainstorms which burst in their neighbourhood. August, reaching its maximum at the beginning of SepThe weathering of this desert area is probably fairly rapid, tember; it then falls slowly through October and November. and the agents at work are principally the rapid heating At Cairo the lowest level is reached about the middle of and cooling of the rocks by day and night, and the erosive June, after which the rise is slow in July and fairly rapid action of sand-laden wind on the softer layers; these, aided in August, reaching the maximum at the beginning of