RHONE (Fr. Rhône), the largest European river flow-ing directly into the Mediterranean, rises in the Swiss canton of Valais, passes through the Lake of Geneva, strikes across the line of the Jura, and turning southward through France falls into the Gulf of Lyons. It has a length of 447 miles according to Strelbitzky (505 according to other authorities), and its principal affluent the Saone has a length of 268 miles above the confluence, which is 200 miles inland. The drainage area of the whole river-system is 38,000 square miles, and the mean discharge at the river mouth is 60,000 cubic feet per second, the maximum being 428,840 cubic feet and the minimum 19,426.
The natives give the name of source of the Rhone (locally Rotten or Rodden) to three warm springs that rise in a circular stone basin near the Hôtel du Glacier du Rhône ; but the real beginning of the river is the well-known glacier. According to M. Gosset, a Swiss engineer, the Rhone glacier, which at present measures about 9 miles in length by about 3200 feet in width, is proved to have retreated 3028 feet between 1856 and 1881 and sunk upwards of 300 feet. In geological time the Rhone glacier filled the whole valley to a depth of 4800 feet and spread out over the Swiss plain now partly occupied by the Lake of Geneva. Obstructed by the Jura, it divided into two branches, one of which found its way (as the river does still) by the " écluse " between the Jura and the western Alps to deposit its erratic blocks on the heights in the neighbourhood of Lyons, while the othei branch, bending northward, widened out so as to distribute its burden at Freiburg, Bern, Soleure, and even Aarburg. In the first 30 miles from the foot of the glacier (5751 feet) to Brieg (2214 feet) the stream has a fall of 1 in 46 ; in the next 70 miles to Villeneuve it descends at the rate of 1 in 378. It passes between the Bernese and the Pennine Alps, receiving the tribute of 260 glaciers, of which the Aletsch is one of the most important. At Martigny, where it is joined by the Drance (a glacier-fed stream memorable for the terrible inundation of 1818 caused by the sudden bursting of the ice barrier by which its waters had been dammed back), the Rhone turns suddenly north-west, and below the defile of St Maurice (about 90 miles from its source) it enters the wide alluvial plain formerly occupied by the south-eastern arm of the Lake of GENEVA (q.v.), which has now retreated about 12 miles northward. The limpid character of the Rhone water as it issues from the south-western end of this great settling vat has become a commonplace of geographical illustration, and equally well-known is the contrast afforded at the confluence about a mile below Geneva between the current of the main river and that of its turbulent affluent the Arve, which has found no resting place in its 2000 feet descent by a course of 60 miles from the valley of Chamouni and the glaciers of Mont Blanc. It is the Arve that is mainly responsible for the dangerous inundations of the Rhone valley farther down ; while its volume is sometimes not more than 1235 per second,* at other times it pours into the Rhone (whose maximum at this point is 2000 cubic feet) no less than 24,700 cubic feet, sometimes causing the river to flow backwards towards the Lake of Geneva. To obviate the evils of their irregularity it has been proposed to divert the lower course of the Arve into the Lake of Geneva. The annual maximum of the Rhone at Geneva, according to observations between 1806 and 1880, occurs on the 7th of August. Since 1862 there has been an increase of high levels owing to the dyking of the river and the destruction of forests (see Plantamour, " Obs. limnimétriques," in Mém. de la Soc. de Genève, 1880). The defile or " écluse " by which the Rhone passes between Grand Credo, the terminal bastion of the Jura, and Mont Vouache, one of the Alps of Savoy, is com-manded by one of the great frontier fortresses of France, Fort de l'Écluse. About 5-J- mues farther down occurs the famous Perte du Rhône, a partially subterranean passage, now considerably modified by blasting.
The rocks forming the funnel come so close at one place that there is only a distance of about two feet from bank to bank, and a man of moderate height could stand with one foot on the French side and the other on the Savoy side and see between the beautiful river trembling as it were with rage and hastening to escape from the defile through which it is doomed to pass. A little way farther down the river has hollowed out a passage about 30 feet wide, which retains this width for a depth of from 30 to 35 feet, when it contracts considerably. At this depth a stratum of harder rock has resisted the action of the water, which, however, has scooped out beneath it almost as much as above it. Along each side of the ravine the harder rock projects for eight or ten feet like a cornice. At first the water is seen through the opening down the middle ; but farther on great masses of rock from the walls of the ravine have fallen down, and, resting on the double cornice, conceal the river for a distance of some 60 paces. "
During the summer floods the water filled the ravine far above the level of the fallen blocks, and the Perte du Rhône was no longer visible. The rocks through which the " perte " is cut belong to the Urgonian sub-division of the Cretaceous system,—the stratum which has been hollowed out being described as calcaire gris. Just below the ravine the Rhone is joined by the Valserine, whioh a little above Bellegarde passes through a " perte " of a similar character. Since 1871 the motive power of the main river has been utilized for the industries of Belle-garde ; a large tunnel 20 feet high and more than half a kilometre long brings the water from the south side of the perte to turbine wheels placed in the bed of the Valserine, and wire ropes transmit the power to the Bellegarde workshops on the plateau 400 feet above. Below Belle-garde the river is deflected southwards by the western chain of the Jura. It receives from the left the Usses, the Fiar (which drains the lake of Annecy), and the emissary of the Lake of Bourget, the largest of the purely French lakes, and then at the junction of the Guiers (from the Grande Chartreuse) it turns north-west round the southern end of the Jura. The Ain (118 miles long), which joins it from the right, is navigable in the direction of the current, and in its upper waters has a " perte " of some interest. Farther down the main river meanders for a time with shifting channels in a bed about two miles broad, but it gathers into a single stream before its junction with the Saône. This important confluent (the ancient Arar, which according to Caesar flows " incredibili lenitate ") has its source at Vioménil in the Vosges 1300 feet above the sea, and has been joined by the Doubs, which, rising in the district between the Jura and the Vosges, is famous for the beauty of its ripper gorges and for the waterfall (70 feet) known as the Saut du Doubs. Southwards from Lyons, where it is 530 feet above the sea, the united river continues to be still the "arrowy Rhone"; in the 61 miles from the Saône mouth to the Isère it falls 180 feet, in the 18 from the Isère to the Drome 56 feet, in the 38 from the Drome to the Ardèche 164, and in the 34 from the Ardèche to the Durance 88|-. Those affluents, all except the last from the Savoy and Maritime Alps, are in general of little importance, but at times become formidable torrents. The same is true of the much shorter streams which bring down the waters from the eastern slopes of the Cevennes. During the inundation of the 10th September 1857, which has been frequently exceeded, the three streams the Doux, the Érieux, and the Ardèche poured into the Rhone 49,000 cubic feet per second. At Fourques d'Arles, 25 miles from the sea, the river begins to form its delta, breaking up into two main branches, the Grand Rhône passing from Aries south-east towards the Gulf of Fos, and the Petit Rhône south-west towards the Little Cam-argue. With all its rapidity of current and mass of waters it is not able to keep a clear passage to the sea through its own alluvium, which, according to M. Reclus's estimate, has since the Gallo-Roman period added from 75 to 100 square miles to the area of its delta.
From the time that Marius caused his soldiers to excavate the Fosste Mariana? which have left the name of Fos to the bay already mentioned the endeavour to maintain a navigable channel inland from the sea has perplexed successive generations. Vauban himself declared " Les embouchures du Rhône sont incorrigibles. " The method of contracting and embanking a principal channel right out to sea failed, either because the embankments were not carried out far enough, or more probably because the tides of the Mediterranean are not sufficiently strong to aid in removing the alluvium. A canal constructed in 1802-1832 from Aries to Bouc (on the east side of the Gulf of Fos) proved too shallow for the new steam traffic. At length in 1863 a scheme brought forward by Hippolyte Pent in 1846 was adopted for the making of a canal, 11,480 feet long, 210 feet wide and 19J feet deep at low tide, from Tour St Louis on the left bank of the Grand Rhône to the Anse de Repos in the Gulf of Fos. The canal was completed in 1871, and the quays of the port of St Louis by the close of 1878, at a cost of 26,000,000 francs. Hostile critics main-tain that it will be possible to keep this channel open at the seaward end only by continual and costly dredging, but hitherto their fears seem exaggerated. The new port has been very success-ful, 1261 vessels (313,745 tons) entering in 1881 and 2317 vessels (448,757 tons) in 1882. The regulation of the river itself is still a problem. The rapidity of the current from Lyons downwards, the extremely shifting character of the channel, and the varia-tions that take place in the volume of water are the great obstacles to be overcome. Two mouths of the year are lost for navigation through floods or lack of water or fogs or ice. At present (1885) a scheme combining the two systems of régularisation and canaliza-tion is being carried out for the purpose of securing everywhere at low water a depth of 5 feet 3 inches.
In the beginning of the present century even passenger boats used to be hauled up the river by towing ropes, and when steam was introduced it was found that the vessels had to be specially constructed to make head against the current. The laying of a continuous chain all the way from Lyons to Aries is impracticable through the shifting character of the bed ; but several methods have been adopted to overcome the difficulties of the ascent. Thus some boats advance by means of long jointed levers which catch into the ground. Or a steel wire cable with one of its ends fixed at a given spot is unwound as a steam tug descends the stream and then the tug with its convoy of boats makes its way up again by simply winding in. Or two tugs are employed, the first going in advance of the other so far that the cable wdiich it pays out takes a sufficient hold of the bottom to enable the second to haul by it. Or, lastly, Dupuy de Lome's system is adopted, by which the boat grips the river bottom by means of two continuous chains perpetually sunk in front and emerging behind. The Saône is much more easily dealt with than the Rhone. It is navigable as far up as Port-sur-Saône, and a system of movable dams and sluices has been established to secure a depth of 6 to 7 feet at low water.
The basin of the Rhone communicates with the Loire by the Canal du Centre (joining the Saône at Chalons), with the Seine by the Burgundy Canal (joining the Saône at St Jean de Losne), with the Rhine bj^a canal (1783-1834) which passes from the Saône at Saint Symphorien to the Doubs, and finally ends at Strasburg, and with the Meuse and the Belgian system by a canal (Canal de l'Est) constructed since 1875 from the Saône to the Moselle.
See Boissel, Voy. pitt. et navigation exécutée sur une partie du Rhône réputée non-navigable, 1795, and works on the liver by Hippolyte Peut (1846), Surell (1847), Desjardins (1866), Adrian German (1872), and De la Rochette. Also Lentlieric, Les villes mortes du Golfe de Lyon, 1875, and a paper in Rev. des Deux Mondes, 1880; Blerzy, Torrents, fleuves, et canauxde la France, 1878. (II. A. W.)
Footnotes
A sketch of M. Gosset's remarkable labours is given in the Alpine Journal, 1878-80.
A sketch of M. Gosset's remarkable labours is given in the Alpine Journal, 1878-80.
3 See the annual Observations hydromêtriques suisses sur le bassin du Rhône issued by the Bureau fédéral des travaux publics.
A large-scale profile of the upper Rhone accompanies Gerlach's paper " Die Penninischen Alpen " in Mém. de la Soc. Helv., 1869.
3 See the annual Observations hydromêtriques suisses sur le bassin du Rhône issued by the Bureau fédéral des travaux publics.
2 See Faisan and Chantre, Monographie géologique des anciens glaciers et du terrain erratique de la partie moyenne du bassin du Rh&ne, 1880. See also the map illustrating Auguste Jaccard's paper in Bull, de la Soc. Vaucloise, Feb. 1885.
4 Professors Paul Chaix and Plantamour, on one occasion in March, found the volume of the Arve as low as 812 cubic feet per second, and that of the Rhone 1612.
De Saussure, Voyage dans les Alpes (1780-1796), ii. 90 sq.
See the elaborate papers, with maps and sections, by Renevier in Mém. de la Soc. Helvétique, 1855 ("Mem. Geol. sur la Perte du Rhône et ses environs"), and in Bull, de la Soc. Géologique, 1874-5, 3d ser. vol. iii.
See Reclus, Nouv. Geogr. Univ., "La France," p. 215.
See "La Saut du Doubs," in Tour du Monde, 1880.