Page:EB1911 - Volume 22.djvu/974

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.

distribution of drift over the protected area. They are constructed with a foundation of fascines and concrete, faced with brickwork or stone pitching. The result has been the formation of a gently sloping beach which reduces wave action; such loss, too, as is still occasioned by storms is speedily made good by natural accretion in moderate weather. The Blankenberghe groynes are too expensive a type for ordinary use. The beach at Bridlington, which rests on boulder clay, was rapidly disappearing owing to the increased scour due to the sea-walls. Accordingly, groynes (see figs. 11, 12) made

FIG. II.-Groynes at Bridlington.

of 14 ft. >< 9 in. X QlI'1.pltCl'l-pine piles, and II in. X 4 in. planking, were erected along the foreshore. The piles originally projected about 6 ft.; but, to prevent heaping up of sand to windward with

denudation to leeward, the planking was never raised more than two strakes above sand-level, fresh planks being added as the sand rose. The south-easterly gales are said to be the most erosive here, and prevalent during the Winter months; on this account the groynes were given an inclination of 10° south of east, that is 10° from the perpendicular. It may be doubted whether this was the best

angle, but the result has been very satisfactory. The cost of construction was from 125. 3d. to I8S. per lineal foot. The sand-banks at the entrance to Poole Harbour have been protected by groynes (see fig. 13) inclined at slightly varying

FIG. 12.-Enlarged

g cross-section of


FIG. 13.-Groynes for Protecting the Sand-banks enclosing Poole Harbour.

angles, some yielding better results than others. This is a good example of the important work which may be accomplished by groyning. Unprotected, a breach would soon have been effected in these sand-banks; with a double entrance to the bay the present deep channel would have silted up, and Poole Harbour would have been practically destroyed. It is evident that the efficacy of groynes in collecting drift is proportionate to the distance which they can be carried seawards, and that they should always be extended to out

low-water mark; whilst, by raising them only slightly above the



beach, the accumulation of drift to leeward is promoted, passage of drift over the obstruction being facilitated the scour of the waves diminished. By this means, and by gradually raising and extending the groynes as the drift accumulates, the general elevation of the beach can be secured. Déft generally travels in both directions along a coast, veering with the wind; thus the prevailing wind determines the preponderating travel of the drift. Groynes are usually constructed at right angles to the shore, but it is believed that increased benefit may be obtained by slightly inclining them to leeward of the prevailing wind. Some engineers have advocated the extension of groynes below low-water mark; and as wood when permanently submerged is specially liable, even when creosoted, to be attacked by the teredo and lirnnoria, the use of reinforced or ferro-concrete has been suggested as the most suitable material for submarine groyning. These suggestions, however, and many other current theories on groyning, require to be demonstrated by repeated experiments. For a useful bibliography of the subject see British Parliamentary Reports, Coast Erosion and the Reclamation of Tidal Lands, Cd. 3684, Appendix No. X. pp. 146-158. (L. W. V.~H.)

RECLUS, JEAN JACQUES ELISEE (1830-1905), French geographer, was born at Sainte-Foy la Grande (Gironde), on the 15th of March 1830. He was the second son of a Protestant pastor, who had a family of twelve children, several of whom acquired some celebrity either as men of letters, politicians or members of the learned professions. His education, begun in Rhenish Prussia, was continued in the Protestant college of Montauban, and completed at the university of Berlin, where he followed a long course of geography under Karl Ritter. Withdrawing from France in consequence of the events of December 1851, he spent the next six years (1852-57) visiting the British Isles, the United States, Central America, and Colombia. On his return to Paris he contributed to the Revue des deux rnondes, the Tour du monde and other periodicals a large number of articles embodying the results of his geographical work. Among other works at this period was an excellent short book, Histoire d'un ruisseau, in which he traces the development of a great river from source to mouth. In 1867-68 he published La Terre; description des phénomenes de la vie du globe, in two volumes. During the siege of Paris, Reclus shared in the aerostatic operations conducted by M. Nadar, and also served in the National Guard, while as a member of the Association Nationale des Travailleurs he published in the Cri du Peuple a hostile manifesto against the government of Versaillesin connexion with the Communist rising of the 18th of March 1871. Continuing to serve in the National Guard, now in open revolt, he was taken prisoner on the 5th of April, and on the 16th of November sentenced to transportation for life; but, largely at the instance of influential deputations from England, the sentence was commuted in January 1872 to perpetual banish-1nent. Thereupon, after a short visit to Italy, he settled at Clarens, in Switzerland, where he resumed his literary labours, and, after producing the Histoire d'une rnontagne (a companion to Histoire d'un ruisseau), wrote nearly the Whole of his great work, La Nouvelle Géographie universelle, la terre et les hommes, IQ vols. (1875-94). This is a stupendous compilation, profusely illustrated with maps, plans, and engravings, and was crowned with the gold medal of the Paris Geographical Society in 1892. An English edition appeared simultaneously, also in 19 vols., the first four by E. G. Ravenstein, the rest by A. H. Keane. Extreme accuracy and brilliant exposition form the leading characteristics of all Reclus's writings, which thus possess permanent literary and scientific value. In 1882 Reclus initiated the “ Anti-Marriage Movement, ” in accordance with which he allowed his two daughters to marry without any civil or religious sanction whatever. This step caused no little embarrassment to many of his well-wishers, and was followed by government prosecutions, instituted in the High Court of Lyons, against the anarchists, members of the International Association, of which Reclus and Prince Kropotkin were designated as the two chief organizers. The prince was arrested and condemned to five years' imprisonment, but Reclus, being resident in Switzerland, escaped. After 1892 he filled the chair of comparative geography in the university of Brussels, and contributed several important memoirs to French, German and English scientinc journals. Among these may be mentioned “ The Progress of Mankind ” (Conternp. Rev., 1896); “ Attila de Gerando ” (Rev. Géograph., 1898); “ A great Globe ” (Geograph. Journ., 1898); “ L'Extréme-Orient ” (Bul. Antwerp Geo. Soc.,