~~ < « < A \ « . ALBERT R. MANN LIBRARY New York STATE COLLEGES OF AGRICULTURE AND HOME ECONOMICS AT CORNELL UNIVERSITY Cornell University Library SD 409.B87R 1880 “MT or, Records of the INTERNATIONAL FORESTRY EXHIBITION. a WORKS ON FOREST SCIENCE. By tae REV. J. ©, BROWN, LL.D. 0 Epmvgurcu : OLIVER & BOYD. Lowpon : SIMPKIN, MARSHALL, & CO., anp W. RIDER & SON. Montrean: DAWSON, BROTHERS. —_—__—_—____ I.—Introcuction to the Study of Modern Forest Hconomy. Price 5s. In this there are brought under consideration the exten- sive destruction of forests which has taken place in Europe and elsewhere, with notices of disastrous consequences which have followed—diminished supply of timber and firewood, droughts, floods, landslips, and sand-drifts—and notices of the appliances of Modern Forest Science success- fully to counteract these evils by conservation, planting, and improved exploitation, under scientific administration and management, Exrract FROM Prerace,—‘ At a meeting held on the 28th of March last year (1883), presided over by the Marquis of Lothian, while the assemblage was representative of all interests—scientific, practical, and professional—it was resolved :—‘‘ That it is expedient in the interests of torestry, and to promote a movement for the establishment of a National School of Forestry in Scotland, as well as with a view of furthering and stimulating a greater improvement in the scientific management of woods in Scotland and the sister countries which has manifested itself during recent years, that there should be held in Edin- burgh, during 1884, and at such season of the year as may be arranged, an International Exhibition of forest products and other objects of interest connected with forestry.” It was then moved, seconded, and agreed :—‘‘ That this meeting pledges itself to give its hearty co-opera- tion and patronage to the promotion of an International Forestry Exhibi- tion in Edinburgh in 1884; and those present resolve to give their best efforts and endeavours to render the Exhibition a success, and of such importance and general interest as to make it worthy of the name of International.” ‘It isin accordance with this resolution, and in discharge of obligations which it imposed, that this volume has been prepared.’ 2 II.—_The Forests of England; and the Management of them in Bye-gone Times. Price 6s. Ancient forests, chases, parks, warrens, and woods, are described ; details are given of destructive treatment to which they have been subjected, and of legislation and literature relating to them previous to the present century. Exrract From Prerace.—‘ Contrast with this [the paucity of works in English on Forest Science], the richness of Continental languages in literature on such subjects. I have had sent to me lately Ofversight of Svenska Skogsliteraturen, Bibliografiska Studicren of Axel Cnattingius, a list of many books and papers on Forest Science published in Sweden ; I have also had sent to me a work by Don José Jordana y Morera, Ingenero de Montes, under the title of Apuntes Bibliographico Forestale, a catalogue raisonné of 1126 printed books, MSS., &c., in Spanish, on subjects connected with Forest Science. ‘Tam at present preparing for the press a report on measures adopted in France, Germany, Hungary, and elsewhere, to arrest and utilise drift- sand by planting them with grasses and trees ; and in Der Huropaeische Flug-sand und Seine Cultur, von Josef Wessely General Domaenen- Inspecktor, und Forst-Academie-Direktor, published in Vienna in 1873, I find a list of upwards of 100 books and papers on that one department of the subject, of which 30, in Hungarian, Latin, and German, were published in Hungary alone. ‘ According to the statement of one gentleman, to whom application was made by a representative of the Government at the Cape, for infor- mation in regard to what suitable works on Forest Economy could be procured from Germany, the works on Forst- Wissenchaft, Forest Science, and Forst- Wirthchaft, Forest Economy, in the German language may be reckoned by cartloads. From what I know of the abundance of works in German, on subjects connected with Forestry, I am not surprised that such a report should have been given. And with the works in German may be reckoned the works in French. ‘In Hermann Schmidt’s Fach Katalogue, published in Prague last year (1876), there were given the titles, &c., of German works in Forst und Jagd-Iiteratur, published from 1870 to 1875 inclusive, to the 3lst of ~ Gctober of the latter year, amounting in all to 650, exclusive of others given in an appendix, containing a selection of the works published prior to 1870. They are classified thus :—General Forest Economy, 93 ; Forest Botany, 60 ; Forest History and Statistics, 50; Forest Legislation and Game Laws, 56; Forest Mathematics, 25 ; Forest Tables and Measurements, &c., 148; Forest Technology, 6; Forest Zoology, 19 ; Peat and Bog Treatment, 14; Forest Calendars, 6; Forest and Game Periodicals, 273 Forest Union and Year Books, 13; Game, 91; Forest and Game in. Bohemian, 44. In all, 652. Upwards of a hundred new works had been published annually. Amongst the works mentioned is avolume entitled Die Literatur der letzten sieben Jahre (1862-1872) aus 3 dem Gesammtgebiete der Land-und Forst-wirthschaft mit Einschluss der landw. Geweber u. der Jagd, in deutscher, franadsischer wu englisher Sprache Herausg. v. d. Buchandl, v. Gerold and Co., in Wein, 1878, a valuable catalogue filling 278 pages in large octavo. ‘ This volume is published as a small contribution to the literature of Britain, on subjects pertaining to Forest Science. ‘It is after due consideration that the form given to the work—that of a compilation of what has been stated in works previously published —has been adopted. III.—Forestry of Norway. Price 5s. There are described in successive chapters the general features of the country. Details are given of the geo- graphical distribution of forest trees, followed by discussions of conditions by which this has been determined—heat, moisture, soil, and exposure. The effects of glacial action on the contour of the country are noticed, with accounts of existing glaciers aud snow-fields. And information is supplied in regard to forest exploitation and the transport of timber, in regard to the export timber trade, to public instruction in sylviculture, and to forest administration, and to ship-building and shipping. Extract FRoM Prerace.—‘In the spring of 1877, while measures were being taken for the formation of an Arboretum in Edinburgh, I issued a pamplet entitled The Schools of Forestry in Hurope: a Plea for the Creation of a School of Forestry in connection with the Arboretum in Edinburgh. After it was made known that arrangements were being carried out for the formation of an International Exhibition of forest roducts, and other objects of interest connected with forestry, in Edin- Etat with a view to promoting the movement for the establishment of a National School of Forestry in Scotland, and with a view of furthering and stimulating a greater improvement in the scientific management of woods in Scotland, and the sister countries, which has manifested itself during recent years, the council of the Kast Lothian Naturalists’ Club resolved on having a course of lectures or popular readings on some subject connected with forestry, which might enable the members aad others better to profit by visits to the projected Exhibi- tion, and which should be open to the public at a moderate charge, The conducting of these was devolved upon me, who happened to be vice- president of the club. The following treatise was compiled from information then in my possession, or within my reach, and it constituted the basis of these lectures.’ 4 IV.—Finland: its Forests and Forest Management. Price 6s 6d. In this volume is supplied information in regard to the lakes and rivers of Finland, known as The Land of a Thousand Lakes, and as The Last-born Daughter of the Sea ; in regard to its physical geography, including notices of the contour of the country, its geological formations and indications of glacial action, its flora, fauna, and climate; and in regard to its forest economy, embracing a discussion of the advantages and disadvantages of Svedjande, the Sartage of France, and the Koomaree of India; and details of the development of Modern - Forest Economy in Finland, with notices of its School of Fores- try, of its forests and forest trees, of the disposal of its forest. products, and of its legislation and literature in forestry are given. Extract rrom Prerace.—‘I happened to spend the summer of 1879 in St. Petersburg, ministering in the British and American Chapel in that city, while the pastor sought relaxation for a few months at home. I was for years the minister of the congregation worshipping there, and I had subsequently repeatedly spent the summer among them in similar circumstances. I was at the time studying the Forestry of Europe ; and I availed myself of opportunities afforded by my journey thither through Norway, Sweden, and Finland, by my stay in Russia, and by my return through Germany and France, to collect information bearing upon the enquiries in which I was engaged. On my return to Scotland Icontributed to the Journal of Forestry a series of papers which were afterwards reprinted under the title Glances at the Forests of Northern Hurope. In the preface to this pamphlet I stated that in Denmark may be studied the remains of forests in pre-historic times ; in Norway, luxuriant forests managed by each proprietor as seemeth good in his own eyes; in Sweden, sustained systematic endeavours to regulate the management of forests in accordance with the latest deliverances of modern science; in Finland, Sartage disappearing before the most advanced forest economy of the day; and in Russia, Jardinage in the north, merging into more scientific management in Central Russia, and Aeéboisement in the south. This volume is a study of information which I then collected, together with information which I previously possessed, or have subsequently obtained, in regard to the Forests and Forestry of Finland.’ 7 Translation of Extracts from Letters from Dr A. Biomevist, Director of the Finnish National School of Forestry at Evois :—‘On my return from Salmos three weeks ago I had the great pleasure to receive your volume on the Forests and Forest Management in Finland. I return 5 you grateful thanks for the gift, and no less for publishing a description of the forestal condition of our country. It is with sentiments of true gratitude I learn that you had previously taken part in a work so important to our country as the preparation of a new edition of the New Testament in Finnish. Your descriptions of our natural scenery are most excellent and interestivg. Personally I feel most interest in your accounts of Koomaree. I value it much. and not less so your concurrent final conclusion in regard to the effects of the exercise of it in Finland,’ Translation of Statement by M, Dz La Gryz, in the Revue des Lauc et Férets of January 1884 :—‘In an address delivered some weeks since at a banquet of exhibitors in the French section at Amsterdam, M. Herisson, Minister of Commerce, expressed an intention to publish a series of small books designed to make known to French merchants foreign lands in a commercial point of view. If the Minister of Commerce wishes to show to our merchants the resources possessed by Finland, he need not go far to seek information which may be useful to them, they will be found in « small volume which has just been published by Mr John Croumbie Brown. ‘ Mr Brown is one of those English ministers, who, travelling over the world in all directions [some at their own cost], seeking to spread the Word of the Lord in the form of Bibles translated into all languages, know how to utilise the leisure left to them at times while prosecuting this mission. Some occupy themselves with physical science, others with archeology, some with philology, many with commerce ; Mr Brown has made a special study of sylviculture. He has already published on this subject many works, from amongst which we may cite these : Hydrology of South Africa ; The Forests of England ; The Schools of Forestry in Hurope ; Réboisement in France; Pine Plantations on Sand Wastes in France. ‘His last book on Finland is the fruit of many journeys made in that country, which he visited for the first time in 1833, but whither he has returned frequently since that time. Mr Brown gives narratives of his voyages on the lakes which abound in Finland, and his excursions in the immense forests, the exploitation of which constitutes the principal industry of the country. The School of Forestry at Evois has furnished to him much precise information in regard to the organisation of the service, and the legislation and the statistics of forests, which, added to what he had procured by his own observation, has enabled him to make a very complete study of this country, poetically designated The Land of a Thousand Lakes, and which might also justly be called The Kingdom of the Forest, for there this reigns sovereign.’ V.—Forest Lands and Forestry of Northern Russia. Price 6s 6d. Details are given of a trip from St. Petersburg to the forests around Petrozavodsk on Lake Onega, in the government of Qlonetz; a description of the forests 6 on that government by Mr Judrae, a forest official of high position, and of the forests of Archangel by Mr Hepworth Dixon, of Lapland, of the land of the Samoides and of Nova Zembla; of the exploitation of the forests by Jardinage, and of the evils of such exploitation; and of the export timber trade, and disposal of forest products. In connection with discussions of the physical geography of the region information is supplied in regard to the contour and general appearance of the country ; its flora, its forests, and the palaeontological botany of the regions beyond, as viewed by Professor Heer and Count Saporta ; its fauna, with notices of game, and with copious lists of coleoptera and lepidoptera, by Forst-Meister Gunther, of Petrozavodsk. Extract From Prerace.—‘In the spring of 1877 I published a brochure entitled The Schools of Forestry in Europe: a Flea for the Crea- tion of a School of Forestry in connection with the Arboretum in Edin- burgh, iu which with details of the arrangements made for instruction in Forest Science in Schools of Forestry in Prussia, Saxony, Hanover, Hesse, Darmstadt, Wurtemburg, Bavaria, Austria, Poland, Russia, Finland, Sweden, France, Italy, and in Spain, and details of arrange- ments existing in Edinburgh for instruction in most of the subjects in- cluded amongst preliminary studies, I submitted for consideration the opinion, ‘‘that with the acquisition of this Arboretum, and with the ex- isting arrangements for study in the University of Edinburgh, and in the Watt Institution and School of Arts, there are required only facil'- ties for the study of what is known on the Continent as Forest Science to enable these Institutions conjointly, or any one of them, with the help of the other, to take a place amongst the most completely equipped Schools of Forestry in Europe, and to undertake the training of foresters for the discharge of such duties as are now required of them in India, in our Colonies, and at home.” ‘This year has seen world-wide arrangements for an International Exhibition of forest products and other objects of interest connected with forestry in Edinburgh, *‘In the interests of forestry, and to pro- mote a movement for the establishment of a School of Forestry in Scot- land, as well as with a view of furthering and stimulating a greater im- provement in the scientific management of woods in Scotland and the sister countries which has manifested itself during recent years.” _ ‘The following is one of a series of volumes published with a view to introduce into English forestal literature detailed information on some of the points on which information is supplied to students at Schools of Forestry on the Continent ; and to make better known the breadth of study which is embraced in what is known there as Forstwissenscaft, or Forest Science,’ , 7 VI.—French Forest Ordinance of 1669; with Historical Sketch of Previous Treatment of Forests in France. Price 4s. The early history of forests in France is given, with de- tails of devastations of these going on in the first half of the seventeenth century; with a translation of the Ordi- nance of 1669, which is the basis of modern forest econo- my; and notices of forest exploitation in Jardinage, in La Methode a Tire et Aire, and in La Methode des Comparti- ments, Extract From Prerace.—‘ “ The Celebrated Forest Ordinance of 1669 :” Such is the character and designation generally given at the present day to the Ordinance in question. It is known, by reputation at least, in every country on the Continent of Europe; but, so far as is known to me, it hasnever before been published in English dress. It may possibly be considered antiquated ; but, on its first promulgation, it was welcomed, far beyond the bounds of France, as bringing lite to the dead ; and I know of no modern system of Forest Exploitation, based on modern Forest Science, in which I cannot trace its influence. In the most advanced of these—that for which we are indebted to Hartig and Cotta of Saxony—I see a development of it like to the development of the butterfly from what may be seen in the structure of the chrysalis ; and thus am I encouraged to hope that it may prove suggestive of bene- ficial arrangements, even where it does not detail what it may be deemed desirable to adopt. ‘In my translation I have followed an edition issued with Royal ap- proval in 1753, with one verbal alteration to bring it into accordance with certain older approved editions, and with another verbal alteration to bring it into accordance with editions issued in 1699, 1723, 1734, and 1747.” Translation of notice by M. De La Grve for July 1883 in the Revue des Haux et Férets: ‘England, which with her immense possessions in India, in Canada, and in the Cape of Good Hope, is beyond all question a State rich in forests, has never up to the present time given to this ortion of her domains more than a very moderate share of her attention ; Bit for some years past public opinion is becoming alarmed, in view of the immense devastations which have been committed in them, and the forest question coming forward spontaneously has hecome the subject of numerous publications : amongst which, atter the excellent monthly collection, the Journal of Forestry and Estate Management, comes the Translation of the Ordinance of 1669, which has just been published by Mr John Croumbie Brown. ‘This translation of a monument of juris- prudence, well known in France, but which has never before been repro- duced in English, has furnished to Mr Brown an opportunity of giving a historical sketch of French Forest Legislation, and an exposition of the 8 different methods of exploitation followed in our country. Drawn from the best sources, and commented on with talent, these documents form an elegant volume, which the author has made the more complete by binding with it a summary of the treatise he has published on the Forests of England.’ VII. —Pine Plantations on Sand Wastes in France. Price ‘7s. In this are detailed the appearances presented by the Landes of the Gironde before and after culture, and the Landes of La Sologne; the legislation and literature of France in regard to the planting of the Landes with trees ; the characteristics of the sand wastes; the natural his- tory, culture, and exploitation of the maritime pine, and of the Scots fir; and the diseases and injurious influences to which the maritime pine is subject. Extracts From Prerace.—‘ The preparation of this volume for the press was undertaken in consequence of a statement in the Standard and Maik, a Capetown paper, of the 22d July 1876, to the effect that in the estimates submitted to Parliament £1000 had been put down for the Cape Flats, it was supposed with a view to its being employed in car- rying out planting operations as a means of reclaiming the sandy tracts beyond Salt River. ‘This volume was originally compiled in view of what seemed to he required at the Cape of Good Hope, It has been revised and printed now, as a contribution towards a renewed enterprise to arrest and utilise eand-wastes which stretch from Table Mountain to the Hottentot Holland Mountains; and additional information is forthcoming if it should be desired.’ VIII.—Reboisement in France; or, Records of the Re- planting of the Alps, the Cevennes, and the Pyrenees, with Trees, Herbage, and Bush, with a view to arresting and preventing the de- structive consequences of torrents. Price 12s. In this are given a réswme of Surell’s study of Alpine torrents, of the literature of France relative to Alpine tor- rents, and of remedial measures which have been proposed for adoption to prevent the disastrous consequences fol- 9 lowing from them—translations of documents and enact- ments, showing what legislative and executive measures have been taken by the Government of France in connec- tion with réboisement as a remedial application against destructive torrents—and details in regard to the past, present, and prospective aspects of the work. Extract From PrErace.—‘ In a treatise on the Hydrology of South Africa I have given details of destructive effects of torrential floods at the Cape of Good Hope and Natal, and referred to the measures adopted in France to prevent the occurreuce of similar disastrous floods there. The attention of the Legislative Assembly at the Cape of Good Hope was, last year, called by one of the members of the Assembly to the importance of planting trees on unproductive Crown lands. On learn- ing that this had been done I addressed to the editor of the Cape Argus a communication, of which the following is a copy :— ‘“T have before me details of destructive effects of torrents which have occurred since I left the Colony in the beginning of 1867. Towards the close of that year there occurred one, the damage occasioned by which to roads and to house property at Port Elizabeth alone was estimated at from £25,000 to £30,000. Within a year thereafter a similar destructive torrent occurred at Natal, in regard to which it was stated that the damage done to public works alone was estimated at £50,000, while the loss to private persons was estimated variously from £50,000 to £100,000. In the following year, 1869, a torrent in the Western Province occa- sioned the fall of a railway bridge, which issued in loss of life and loss of property, and personal injuries, for one case alone of which the rail- way proprietors were prosecuted for damages amounting to £5000. In Beaufort West a deluge of rain washed down the dam, and the next year the town was flooded by the waters of the Gamko; and the next year, 1871, Victoria West was visited with a similar disaster. Such are the sums and the damages with which we have to deal in connection with this question, as it affects the case; and these are only the most remarkable torrents of the several years referred to. I have spoken of millions of francs being speat on réboisement in France, and some may be ready to cry out, ‘ Nothing like such an expenditure can be under- taken at the Cape!’ Perhaps not; but the losses occasioned by the torrents seem to amount at present to about a million of francs in the year, This falls in a great measure on individuals, that would fall on the community ; and the community in return would benefit by water rétained to fertilize the earth, instead of being lost in the sea, and by firewood and timber being grown where now there is none. These are facts well deserving of consideration in the discussion of the expediency of planting Crown lands with trees.” ‘Towards the close of last year, 1874, still more disastrous effects were produced by torrential floods, According to the report given by one of the Colonial newspapers, the damages done could not be esti- mated at much less than £300,000. According to the report given by 10 another, the damage done to public works alone was estimated at £350,000,—eight millions, seven hundred and fifty thousand francs. And my attention was called anew to the subject. “On addressing myself to M. Faré, Director-General of the Administra- tion of Forests in France, there was afforded to me every facility I could desire for extending and verifying the information I had previously col- lected in regard to the works of réboisement to which I have referred. Copies of additional documents were supplied to me, with copies of works sanctioned by the Administration, and arrangements were made for my visiting and inspecting, with every assistance required, the works begun and the works completed ; and thus I have been enabled to sub- mit a much more complete report than it would otherwise have been in my power to produce, ‘While the compilation I have prepared owes its publication at this time to the occurrence of the inundations of last year at the Cape of Good Hope, the publication has been undertaken in the hope that in other countries besides South Africa the information may be turned to practical account.’ Translation of extract from letter to the author by M. ALEXANDRE SuRELL, Jngenieur des Ponts et Chausses, chairman of the Compagnie des Chemins des Fer du Midi et du Canal lateral a la Garonne, and author of Kiude sur les Torrents des Hautes-Alps, Ouvrage Couronne par ? Academie des Sciences en 1842 :—‘ You are rendering an eminent service to society in calling the attention of serious thinkers to the subject of réboisements and gazonnements. It is a vital question affecting our descendants, specially in southern climates, there are useful truths which have to be diffused there, and you have fulfilled this duty amongst your country- men, , ‘In France public opinion, long indifferent, is now sufficiently en- lightened on the question, and much has been done. ‘I have been able to establish in the course of a recent journey that, throughout a great part of Switzerland, in Styria, in Carinthia, and in the Tyrol, the same phenomena which have issued in the desola- tion of our French Alps are beginning to produce the same effects. There have been recognised a number of extinct torrents which had originated in the destruction of the forests. If people go on sleeping, and the administration or the communes do nothing to arrest the evil, posterity will have a sad inheritance devolved upon it. : ‘You have given, with very great clearness, a résumé of what I have done in France, be it by my works, or be it by my workings, for the re- generation of our mountains,’ Translation of extract from letter by the late M. Ernest Cézanne, Jn- genicur des Ponts et Chausses, Représentant des Hautes Alpes a P Assemblée Nationale, and author of Une Suite to the work of M. Surell. § The post brought to me yesterday your very interesting volume on Réboise- ment. Lat once betook myself to the perusal of it 3 and I am surprised that a foreigner could digest so completely such a collection of our French documents drawn from so many diverse sources, The problem 11 of réboisement and the regeneration of the mountains is one of the most in- teresting which man has to solve, but it requires time and money, and with the authorities and political assemblies, technical knowledge which is as yet but very sparingly possessed. It is by books so substantial as yours, sir, that public opinion can be prepared to face the importance of this great work.’ IX.—Hydrology of South Africa; or Details of the Former Hydrographic Condition of Cape of Good Hope, and of Causes of its Present Aridity, with Suggestions of Appropriate Remedies for this Aridity. Price 10s. In this the desiccation of South Africa, from pre-Adamic times to the present day, is traced by indications supplied by geological formations, by the physical geography or the general contour of the country, and by arborescent pro- ductions in the interior, with results confirmatory of the opinion that the appropriate remedies are irrigation, arboriculture, and an improved forest economy: or the erection of dams to prevent the escape of a portion of the rainfall to the sea—the abandonment or restriction of the burning of the herbage and bush in connection with pastoral and agricultural operations—the conservation and extension of existing forests —and the adoption of measures similar to the réborsement and gazonnement carried out in France, with a view to prevent the formation of torrents, and the destruction of property occasioned by them. M. Jules Clavé, of world-wide reputation as a student of Forest Science, wrote in the Revue des Deux Mondes of Ist May 1882 :— [Translated.] ‘Since the first travels of Livingstone, the African continent, hitherto inacessible, has been attacked on all points at once. By the north, and by the south, by the east, and by the west, hardy explorers have penetrated it, traversed it, and have dragged from it some of its secrets, ‘[ravellers have paid tribute and done their work in opening up a path; it is now for science and civilisation to do theirs, in studying the problems which present themselves for investigation ; and in drawing in the current of general circulations the peoples and lands, which appear as if destined to stand outside; and in causing ta 12 contribute to the increase of social wealth the elements of production previously unknown. Thus are we led to receive with interest works which can throw a new light on the condition of regions which may have been known fora long time, and which make known the conditions oftheir prosperity. It is under this title that the work of the Rev. J. C. Brown on the Hydrology of South Africa appears deserving of notice ; but it is so also from other points of view. Mr Brown, after a previous residence in the colony of the Cape, whither he had been sent in 1844 as a missionary and head of a religious congregation, returned thither in 1863 as Professor of Botany in the College of South Africa, and he remained there some years. In both of these positions he had occasion to travel through the colony in all directions, and had opportunities to col- Ject most valuable information in regard to its physical geography. Mr Brown on going out to the Cape knew nothing of the works which had for their object to determine the influence of forests on the climate, on the quantity of rain, and on the river-courses in Europe ; he had never heard mention of the work of M. Surell on the torrents of the Alps, or of that of M. Mathieu on forest meteorology, nor of those of M. Domontzey, Costa de Bastelica, and so many others on the subject of réboisement ; and yet in studying by himself, and without bias, the climatic condition of South Africa, he came to perceive that the dis- turbances in the regularity of the flow of rivers within the historic period should be attributed in a large measure to the destruction of forests ; and he meets in agreement on this point the savants whose names have been mentioned. We have thought it might not be with- out interest to readers of the Revue to have in the lines of Mr Brown a collection of phenomena which, in their manifestation at any speci- fied point are not less due to general causes, the effects of which may be to make themselves felt everywhere where there may be existent the same conditions than to aught else.’ And there follows a lengthened article in illustration. X.—Water Supply of South Africa, and Facilities for the Storage of it. Price 18s 6d. In this volume are detailed meteorological observations on the humidity of the air and the rainfail, on clouds, and winds, and thunder-storms; sources from which is derived the supply of moisture which is at present available for agricultural operations in the Colony of the Cape of Good Hope and regions beyond, embracing the atmosphere, the rainfall, rivers, fountains, subterranean streams and reser- voirs, and the sea; and the supply of water and facilities for the storage of it in each of the divisions of the colony 18 —in Basutoland, in the Orange River Free State, in Griqualand West, in the Transvaal Territory, in Zululand, at Natal, and in the Transkei Territory. Extract From Prerace.—‘ Appended to the Report of the Colonial Botanist at the Cape of Good Hope for 1866 was an abstract of a Memoir prepared on the Hydrology of South Africa, which has since been embodied in a volume which has been published on that subject, and an abstract of a Memoir prepared on Irrigation and its application to agricultural operations in South Africa, which embraced a Report on the Water Supply of the Colony ; its sources, its qnantity, the modes of irrigation required in different circumstances, the facilities for the adop- tion of these in different districts, and the difficulties, physical and other, in the way of works of extensive irrigation being carried out there, and the means of accomplishing these which are at command. ‘In the following volume is embodied that portion of the Memoir which related to the water supply, and the existing , facilities for the storage of this, with reports relative to this which were subsequently received, and similar information in regard to lands beyond the Colony of the Cape of Good Hope, which it has been sought to connect with the Colony by federation, or otherwise ; and the information relative to irrigation has been transferred to a Report on the Rivers of the Colovy, and the means of controlling floods, of preventing inundations, of regulating the flow of rivers, and utilising the water by irrigation otherwise. ‘In the series of volumes to which this belongs its place is immedi- ately after that on the Hydrology of South Africa, which contains details of the former hydrographic condition of the Cape of Good Hope, and of causes of its present aridity, with suggestions of appropriate remedies for this aridity ; and it has been prepared to show that, not in a vague and general use of the terms, but in strict accordance with the statement, the severe, protracted, and extensive droughts, and destructive floods and inundations, recorded in the former volume, find their counterpart in constantly alternating droughts and deluges in every district of the Colony,—and that, in every so-called division of it, notwithstanding the deluges, there were protracted sufferings from drought, and, notwithstanding the aridity, there is a supply of water at command, with existing facilities for the storage of the superabundant supply which at present proves productive of more evil than good.’ Statement by Reviewer in Huropean Mail :—‘ Dr Brown is well known at the Cape, for in the exercise of his duties he travelled over the prin- cipal part of it, and much, if not indeed the substance, of the bulky volume before us, has been before the Cape public in the form of Reports to the local Government. As these reports have been commented upon over and over again by the local press there is little left for us to say beyond the fact that the author reiterates his opinion that the only panacea fox the drought is to erect dams and other irrigation works for the storage of water when the rains come down. There can be no doubt 14 that this is sage and wholesome advice, and the only question is, who is to sustain the expense? Not long ago, somewhere about the time that Dr Browa was prosecuting his labours, it will be remembered that General Wynard said that ‘‘Nature had furnished the cups if only science would take the trouble to make them secure.” It is but to repeat an oft-told story that with a good supply of water South Africa would be une of the finest of nature’s gardens, and would be capable of producing two crops a year, in addition to furnishing fodder for sheep and cattle. The question of the water supply for irrigation and other purposes has been staved off year after year, and nothing has been done. It is not too much to say, however, that the question must make itself felt, as it is one of the chief factors in the ultimate prosperity of South Africa. The author is evidently in love with his subject, and has con- tributed a mass of facts to Hydrology which will be useful to all coun- tries of an arid character.’ XI.—Forests and Moisture; or Effects of Forests on Humidity of Climate. Price 10s. In this are given details of phenomena of vegetation on which the meteorological effects of forests affecting the humidity of climate depend—of the effects of forests on the humidity of the atmosphere, and on the humidity of the ground, on marshes, on the moisture of a wide expanse of country, on the local rainfall, and on rivers—and of the correspondence between the distribution of the rainfall and of forests—the measure of correspondence between the distribution of the rainfall and that of forests—the distri- bution of the rainfall dependent on geographical position, or determined by the contour of a country—the distribution of forests affected by the distribution of the rainfall—and the local effects of forests on the distribution of the rain- fall within the forest district. Extracts FRoM Prerace.—‘ This volume is one of a series. In the first of the series—a volume entitled—published last year, Hydrology of South Africa ; or, Details of the Former H. ydrographic Condition of the Cape of Good Hope and of Causes of its recent Aridity, with Sugges- tions of appropriate Remedies for this Aridity, ‘This volume, on the effects of forests on the humidity of the atmos- phere and the ground, follows supplying illustrations of the reasonable- ness of the suggestion made in regard to the conservation and extension of forests as a subordinate means of arresting and counteracting the deseccation and aridity of the country,’ oe oe 15 Extracts rrom Letters to the author from the late Hon. George P. Marsh, Minister of the United States at Rome, and author of The Harth as Modified by Human Action :—‘I am extremely obliged to you for a copy of your Réboisement in France, just received by post. I hope the work may have a wide circulation. . . . Few things are more needed in the economy of our time than the judicious administration of the forest, and your very valuable writings cannot fail to excite a powerful influence in the right direction. . . . ‘I have received your interesting letter of the 5th inst., with the valuable MSS. which accompanied it. I will make excerpts from the latter, and return it to you soon. I hope the very important facts you mention concerning the effect of plantations on the island of Ascension will be duly verified. . . . ‘I put very little faith in old meteorological observations, aad, for that matter, not much in new. So much depends on local circumstances, on the position of instruments, &c.—on station, in short, that it is only on the principle of the tendency of some to balance each other that we can trust to the registers of observers not known to be trained to scientific accuracy. Even in observatories of repute, meteoro- logical instruments are seldom properly hung and guarded from dis- turbing causes. Beyond all, the observations on the absorption of heat and vapour at small distances from the ground show that thermometers are almost always hung too high to be of any value as indicating the temperature of the stratum of the atmosphere in which men live and plants grow, and in most tables, particularly old ones, we have no information as to whether the thermometer was hung five feet or fifty feet from the ground, or whether it was in any way protected from heat radiated from near objects,’ Extract Lerrer from the late Professor Henry, of the Smithsonian Institution, Washington :—‘ The subject of Forest Culture and its in- fluence on rainfall is, just at this time, attracting much attention in the United States. At the last meeting of the American Association for the advancement of science a committee was appointed to memorialise Con- gress with reference to it. Severalof the Western States Governments have enacted laws and offered premiums in regard to it. The United States Agricultural Department has collected statistics bearing on the question, and we have referred your letter to that establishment. ‘The only contribution that the Smithsonian Institution has made to the subject is that of a series of rain-fall tables, comprising all the obser- vations that have been made in regard to the rainfall in the United States since the settlement of the country ; a copy of this we have sent to your address. ‘It may be proper to state that we have commenced a new epoch, and have, since the publication of the tables in question, distributed several hundred rain gauges in addition to those previously used, and to those which have been provided by the Government ia connection with the signal service.’ These notices and remarks are cited as indicative of the importance which is being attached to the subject discussed. 16 Exrract rrom Lerrer to the author from Lieut.-Col. J. Campbell Walker, Conservator of Forests, Madras, then Conservator-in-Chief of Forests, New Zealand; author of Report on State Forests and Forest Management in Germany and Austria:—‘I am in receipt of yours, along with the notices of your works on Forestry, by book post. I think very highly of the scope of the works, and feel sure that they ae similar works will supply a want much felt by the Indian forest officers, ‘It contains many important data which I should have vainly sought elsewhere, and it will be regarded by all competent judges as a real substantial contribution to a knowledge of the existing surface, and the changes which, from known or unknown causes, that surface is fast undergoing.’ Copies of any of these Works will be sent post-paid to any address within direct Postal communication with Britain, on receipt by Dr Joun C. Brown, Haddingten, of a Post-Office Order for the price. REBOISEMENT IN FRANCE: OR, RECORDS OF THE REPLANTING OF THE ALPS, THE CEVENNES, AND THE PYRENEES WITH TREES, HERBAGE AND BUSH, WITH A VIEW TO ARRESTING AND PREVENTING THE DESTRUCTIVE CONSEQUENCES AND EFFECTS OF TORRENTS. COMPILED BY JOHN CROUMBIE BROWN, LL.D., Formerly Government Botanist at the Cape of Good Hope, and Professor of Botany in the South African College, Capetown, Honorary Vice- President of the African Institute of. Paris, Fellow of the Royal Geographical Society, Fellow of the Linnean Society, dc. SECOND ISSUE. LONDON: C, KEGAN PAUL & CO., 1, PATERNOSTER SQUARE. 1880. PREFACE. Tue following treatise owed its origin, and the first issue of it to a desire which I felt to show that it is quite practicable to prevent, or to moderate inundations at the Cape of Good Hope, such as occasionally occur there, destroying property of great value. for some years I held the appoint- ment of Government Botanist in that Colony, and there saw something of the appearance of these inundations, and the serious consequences following. Of both I have given details in a volume, entitled “ Hydrology of South Africa ; or, Details of the former hydrographic condition of the Cape of Good Hope, and of causes of its present aridity, with suggestions of appropriate remedies for this aridity.”* And in the preface to the former issue of this treatise, I had occasion to state—I have before me details of destructive effects of torrents which have occurred since I left the Colony in ‘the beginning of 1867. Towards the close of that year there occurred one, the damage occasioned by which to roads and to house property at Port Elizabeth alone was estimated at from £25,000 to £30,000. Within a year thereafter a similar destructive torrent occurred at Natal, in regard to which it was stated that the damage done to public works alone was estimated at £50,000, and the loss to private persons was estimated variously from £50,000 to £100,000. In the following year, 1869, a torrent in the Western Province occasioned the fall of a railway bridge, which issued in loss of life and loss of property, and personal injuries, for one case alone of which the railway proprietors were prosecuted for damages amounting to £5000. In Beaufort West a deluge of rain washed down the dam, and the next year the town was flooded by the waters of the Gamka; and the next year, 1871, Victoria West was visited with a similar disaster. Such are the sums and the damages with which we have to deal in connection with this question, as it affects the case ; and these are only the most remarkable torrents of the several years referred to. “ Towards the close of last year, 1874, still more disastrous effects were produced by torrential floods. According to the report given by one of the Colonial newspapers, the damages done could not be estimated at much less than £300,000. According to the report given by another, the damage done to public works alone was estimated at £350,000,—eight millions, seven hundred and fifty thousand francs. And my attention was called anew to the subject. : * London: C, Kegan Paul & Co. hy PREFAOH, “ Torrents have proved destructive on the continent of Europe by washing away fertile soil, by undermining houses and fields, and whole villages and towns, and causing their fall, by burying fields and vineyards and towns in the debris thus produced, and swept away, and by producing extensive inundations of lower lying level lands, drowning man and beast, and burying, washing away, or otherwise destroying the labour of years, and I would briefly advert to the remedial measures which have been adopted. “ One of the means employed to avert destruction when it was threatened, was the erection on the river-bed of protecting walls, and of advanced structures, to determine the current, and of continuous slopes to regulate its rapidity and force, and of combined and modified forms of all of these appliances, which manifested great art and skill, ingenuity, and power. It would be exaggeration to say they proved in every case an utter failure, but this would only be an exaggeration of what was the fact, which was, that in very many cases they failed to avert the evil, and in not a few cases they were carried away before the torrent like chaff before the wind, while the torrent seemed to laugh a loud and hollow laugh at the silliness of. man’s device. “To prevent the destruction of land by inundations, the more promising measure of raising embankments based or founded on the dry land was adopted, and the river was thus chained within its bed, with only liberty of action within a limited space beyond. But what did the river do? It silted up its-bed, and thus raised itself, and attempted to overflow the embankment. The danger was perceived in time, and the embankments were raised to a higher elevation. The river quietly repeated the silting up of its bed, which was met by a repeated addition to the embankment. This was done again and again. It was a continuous struggle between dead matter and living mind, carried on for years—for generations,—both refusing to give in. Meanwhile, as in the case of the River Po, not only the embankments, but the silted-up bed of the river was elevated consider- ably above the level of the country lying on one side and on the other, an aqueduct of earth overtopping and threatening with destruction houses and trees, and man and beast alike. Then it was a desperate and a deadly struggle, which many saw it would have been well it had never been entered on, while others looked on and said, It is evident that that is not the way in which the evil.is to be averted. Meanwhile the struggle was continued, until a breach was at length effected in the embankment, and the river oured forth its torrent, inundating the country far and wide. “While this contest was going on, the study of torrents in the Alps revealed the form of the bed of these to be a large somewhat semi-circular funnel-shaped basin, from the rainfall in which the waters were collected,— a channel more or less elongated, along which the waters flowed,—and a fan-shaped bed of deposit corresponding to the delta of a river, the whole being like to a river-bed reduced or contracted in length ; it showed, further, that these torrents were to be met with in all stages of progress, from incipient information, throughout various stages of activity, to final extinction ; it showed that in forest-covered mountain regions there were none; that in denuded mountain ranges they were numerous, and some- times very destructive; that, where they were extinct, the forest had extended itself till it covered the basin and lined the banks of the channel ; that, where they were in a state of progressive extinction, the forests were progressively extending themselves; and that this extension of the forest was apparently the cause or occasion of the extinction of the torrent. PRRFACE. ¥ “ From what had thus been observed the inference was drawn that by artificial plantation the gradual extinction or the subjection of the torrent ‘to control might be effected—and numerous facts which had been long known were recalled to give their testimony in confirmation of the correct- ness of the inference drawn. Rain falling on a metallic roof rushes off, while the same rain falling on a thatched roof trickles down in drops; from the bared ground the rain runs off in streamlets long before it runs off in a similar way from the grass-field or the thicket; and the more the phenomena of percolation and drainage was studied, the more manifest did it become that vegetation retarded the flow and prevented the rush of water, retained it to moisten the soil, and extinguished the torrent, requiring the river to take days and weeks to carry away what the torrent carried away in hours, and thus securing something like a permanent flow in what had become a dry channel, filled occasionally from bank to bank with a destructive torrent, converting the lion into a lamb. And now Millions of francs are being spent on the work of planting trees, and herb- age, ang a with a view to preventing torrents and inundations destroying e land. When the first issue of this volume took place, the inundation which had proved so destructive to Toulouse was engaging the attention of the General Directory of Forests in France, who were satisfied that they had the means of preventing the recurrence of such a catastrophe if they only had the money necessary for carrying out the necessary reboisement and gazonnement of the mountains; and the works have been carried on with more or léss energy ever since. Amongst other important and interesting models exhibited by the Forest Administration at the Exposition Universelle of 1878, were models, and charts, and drawings of works of reboisement of mountains; and in the Budget for 1880, provision has been made for the work being carried out with still increasing energy. An application was made to the Chamber for a credit of about four millions of francs, well nigh £164,000, a million of francs or £111,667 above what had been asked for 1879, for the execution of such works. In making this application the Administration stated that after the disasters occasioned in 1875, by the overflowing of the Garonne and the Herault, and their affluents, the Minister of Finance and the Minister of Public Works gave assurance that measures would be concerted between the departments over which they respectively presided, to be taken with a view to prevent the recurrence of such calamities. They stated that many surveys which were subsequently undertaken had been completed, but in the absence. of funds the works of reboisement had not been begun. That, subsequently the Minister of Public Works had solicited their co-operation to enable him to give a specification of works actually called for in Savoie. That information supplied by the engineers of roads and bridges showed that the four torrents of Saint Martin, the Grillaz, the Pousset, and Saint Julien, all of them afiluents of the Arc, were causing every year great destruction, which it was of importance should be arrested without delay. That according to information in possession of the Administration, the execution of the works in Savoié alone would absorb more than a million of francs. The Budget Committee of the Chamber in reporting on the application, submitted a detailed statement of what had been done, and the results, vi PREFACE. giving tabulated statements as well as details, showing how effectually reboisement had arrested torrents, and showing further, that for the comple- tion of the works in the Alps, in the Cevennes, and the plateau of Central France, and in the Pyrenees, there would be required 148 millions of francs, upwards of six millions sterling, and 72 millions more, upwards of three millions sterling, for the purchase of land. And they unanimously recom- mended that a credit for the whole amount applied for should be granted. “We are all,” say they in the concluding sentence of their report, “deeply impressed with the thought—better far spend a million in rebotsement than have to give such a sum to sufferers from inundations.” The credit applied for was unanimously granted by the Chamber, together with a grant made sua sponte of 5000 francs to be employed in developing roads, to facilitate the exploitation of communal forests, the effect of which it was anticipated might .be to raise the average value of 360,000 hectares, or 900,000 acres of forests, from five francs to fifty francs per hectare. And in view of the importance of employing forest engineers of superior attainments in the works of rebotsement in Savoie and in the basin of the Garonne, 50,600 francs, about £2,110, in addition to the credit for the material work was granted. If such sums tell of the great expense at which these works are being executed, they tell of the importance attached to the execution of them, and of the perfect confidence which is felt in their immediate efficiency, and in their ultimately proving remunerative of the outlay. I have retained the terms reboisement and gazonnement, because I know of no equivalent English terms by which they can be replaced. Both in India and in America the former term at least has been adopted ; and I believe it will soon be naturalised among the English speaking population on both sides of the Atlantic. JOHN C. BROWN. Happinaton, 10th December, 1879. PREFACE. In a treatise on the Hydrology of South Africa I have given details of destructive effects of torrential floods at the Cape of Good Hope and Natal, and referred to the measures adopted in France to prevent the occurrence of similar disastrous floods there. The attention of the Legislative Assembly at the Cape of Good Hope was, last year, called by one ‘of the members of the Assembly to the importance of planting trees on unproductive Crown lands. On learning that this had been done I addressed to the editor of the Cape Argus a communication, of which the following is a copy :— My last communication shows, I consider, no lack of interest on my part in whatever may tend to secure the conservation and improved management of the forests of the Colony ; but important as I consider the fact that attention is being given by the Legislature to a suggestion by the Conservator of forests at the Zitzikamma, having this for its object, 1 attach still more importance to the faet that attention is being called in the Legislative Assembly to the question of the expediency of planting Crown lands with trees. In several other countries the same work has been begun ; and the evils against one or more of which they are seeking in these countries to protect themselves by planting trees by the million, are all of them already to be met with at the Cape, and many of them are to be met with there at the same time and in the same place, all mustering in full force, while elsewhere in many cases it is only the anticipation and dread of some one or other of them, or the partial prevalence of them, which has prompted to the precautionary measure. At the Cape, through- out extensive districts, we meet with want of fuel, multitudes being driven to the use of mist in cooking food, and multitudes more numerous being unable to obtain even this; winds powerful, if not terrific, sweep over the land, with hail and tempest ; droughts, long-continued droughts, alternate with deluges of rain and’ thunderstorms ; heat by day in some districts is succeeded not unfrequently by frosty nights ; locusts and voetyangers remind one of what is written of Judea, “‘ That which the palmerworm hath left hath the locust eaten, and that which the locust hath left hath the cankerworm eaten, and that which the cankerworm hath left hath the caterpillar eaten ;’ and then, when it is least expected—the sky unclouded, the sun or the moon shining in its brightness,—down comes a river, carrying all before its wave. : 4 il PREFACE. These are evils, the dread of one or other, or of some combination of which, is prompting many elsewhere to labour like men chained to the pumps of a vessel foundering at sea, in the hope that they may yet avert what they fear; and the measures adopted by them are similar to those to which reference has been made. My ears still ring with the echoes of Reboisement, and the corresponding terms applied to the operation of planting or replanting forests where they have been destroyed ; and I cannot but hope that the means thus employed, if adequate to avert the dreaded evil, might prove to some extent an appropriate remedy for the evil where it exists. I say nothing at present of what may have brought about the present state of things. I admit the importance of the consideration of this in discussing in full the subject ; but it is enough for me, and it will probably be deemed enough by many of your readers, that I am satisfied J am giving safe advice in saying,—Look to what men are doing elsewhere! Wishing to give unity and completeness to my communication, I shall at present refer only to what is being done to bridle torrents by planting trees, knowing that the torrents of the Colony have been destructive both of life and property to avery great extent, and that almost every year has its doleful renewal of such calamities. . Torrents have proved destructive on the continent of Europe by washing away ‘fertile soil, by undermining houses and fields, and whole villages and towns, and causing their fall, by burying fields and vineyards and towns in the debris thus progiset, and swept away, and by producing extensive inundations of lower lying evel lands, drowning man and beast, and burying, washing away, or otherwise destroying the labour of years. Your readers will know to what extent the parallel holds, and to what extent it fails, in the destructive effects of torrents at the Cape, or in the districts in which they reside. Having thus indicated the evil, I would briefly advert to thé remedial measures which have been adopted. One of the means employed to avert destruction when it was threatened, was the erection on the river-bed of protecting walls, and’of advanced structures, to ‘determine ‘the current, and of continuous slopes to regulate its rapidity and force, and of combined and modified forms of all of these appliances, which manifested great art and skill, ingenuity, and power. It would be exaggeration to say they proved in every case an utter failure, but this would only be an exaggeration of what was the fact, which was, that in very many cases they failed to avert the evil, and in not a few cases they were carried away before the torrent like chaff before the wind, while the torrent seemed to laugh a loud and hollow laugh at the silliness of man’s device. To prevent the destruction of land by inundations, the more promising measure of raising embanknients based or founded on the dry land was adopted, and the river was thus chained within its bed, with only liberty of action within a limited space beyond. But what did the river do? It silted up its bed, and thus raised itself, and attempted to overflow the embankment. ‘The danger was perceived in time, and the embankments were raised to a higher elevation. The river quietly repeated the silting up of its bed, which was met by a repeated addition to the embankment, This was done again and again. It was a continuous struggle between dead matter and living mind, carried on for years—for genera- tions,—buth refusing to give in. Meanwhile, as in the case of the River Po, not only the embankments, but the silted-up bed of the river was elevated consider- ably above the level of the country lying on one side and on the other, an aqueduct of earth overtopping and threatening with destruction houses and trees and man and beast alike, Then it was a desperate and a deadly struggle, which many saw it would have been well it had never been entered on, while others looked on and said, It is evident that that is not the way in which the evil is to be averted. Meanwhile the struggle was continued, until a breach was at length effected in the embankment, and the river poured forth its torrent, inundating the country far and wide. While this contest was going on, the study of torrents in the Alps revealed th form of the bed of these to be a large somewhat semi-circular Uiauel stapad basin, from the rainfall in which the waters were collected,—a channel more or PRGFACE. ii less elongated, along which the waters flowed,—and a fan-shaped bed of deposit corresponding to the delta of a river, the whole being like to a river-bed redueed or contracted in length; it showed, further, that these torrents were to be met with in all stages of progress, from incipient formation, throughout various stages of activity, to final extinction ; it showed that in forest-covered mountain regions there were none; that in denuded mountain ranges they were numerous, and sometimes very destructive; that, where they were extinct, the forest: had extended itself till it covered the basin and lined the banks of the channel ; that, where they were in a state of progressive extinction, the forests were progressively extending themselves; and that this extension of the forest was apparently the cause or occasion of the extinction of the torrent. From what had thus been observed the inference was drawn that by artificial plantation the gradual extinction or the subjection of the torrent to control might be effected;—and numerous facts which had been long known were recalled to give their testimony in confirmation of the correctness of the inference drawn. Rain falling on a metallic roof rushes off, while the same rain falling on a thatched roof trickles down in drops; from the bared ground the rain runs off in streamlets long before it runs off in a similar way from the grass-field or the thicket ; and the more the phenomena of percolation and drainage was studied, the more manifest did it become that vegetation retarded the flow and prevented. the rush of water, retained it to moisten the soil, and extinguished the torrent, requiring the river to take days and weeks to carry away what the torrent carried away in hours, and thus securing something like a permanent flow in what had become a dry channel, filled occasionally from baak to bank with a destructive torrent, converting the lion into a lamb. And now millions of franes are being spent on the work of planting trees, and herbage, and bush, with a view to preventing torrents and inundations destroying the land. It does not comport with my purpose to discuss details. I wish simply to open up the previous question, —Is it expedient to give consideration to this? It may be objected,—It would be a gigantic work by which anything could be done. to bridle the torrents of the Cape! It would; uo one knows that‘bettér'than I do ; and I think it probable that no one has any such conception of the magnitude. of the enterprize as [ have ; but it is by gigantic struggles that the capabilities of ,a people are developed. It may be objected,—It would require a gigantic expendi- ture! It would; but what is the cost of the destruction of property, to ay nothing of the destruction of life, which these torrents at present occasion ? i have before me details of destructive effects of torrents which have occurred sine I left the Colony in the beginning of 1867. ‘Lowards the close of that year there occurred one, the damage occasiuned by which to roads and to house property at Port: Elizabeth alone wus-estimated: at from £25;000 to £30,000. Within a year thereafter a similar destructive torrent occurred at Natal, in regard to which it was stated that the damage done to public works alone was estimated at £50,000, while the loss to private persons was estimated variously from £50,000 to £100,000. In the following year, 1869, a torrent in the Western Province occasioned the fall of a railway bridge, which issued in logs of. life and loss of property, and personal injuries, for one case alone of which the railway pro- _prietors were prosecuted for damages amounting to £5000. In Beaufort, West:a deluge of rain washed down the dam, and the next year the town was flooded by. the waters of the Gamka; and the next year, 1871, Victoria West was visited with a similar disaster. Such are the sums and the damages with which we have to deal in connection with this question, as it affects the case ; and these are only the most remarkable torrents of the several years referred to. I have spoken of millions of francs being spent on Reboisement in France; and. some may'be ready to cry out, “ Nothing like such an expenditure can be undertaken at the Cape!” Perhaps not ; but the losses occasioned by the torrents seem to amount at present to about a million of francs in the year. This falls in a great measure on individuals, that would fall on the community ; and the community in return would benefit by water retained to fertilize the earth, instead of being lost in the. sea,.and by firewood and timber ‘being grown-where now.there:is none. ‘These iv PREFACE. are facta well-deserving of consideration in the discussion of the expediency of planting Crown lands with trees, Towards the close of last year, 1874, still more disastrous effects were produced by torrential floods. According to the report given by one of the Colonial newspapers, the damages done could not be estimated at much less than £300,000. According to the report given by another, the damage done to public works alone was esti- mated at £350,000,—eight millions, seven hundred and fifty thousand francs. And my attention was called anew to the subject. On addressing myself to M. Faré, Director General of the Admini- stration of Forests in France, there was afforded to me every facility I could desire for extending and verifying the information I had previously collected in regard to the works of reboisement to which I have referred. Copies of additional documents were supplied to me, with copies of works sanctioned by the Administration, and arrange- ments were made for my visiting and inspecting, with every assistance required, the works begun and the works completed ; and thus I have been enabled to submit a much more complete report than it would otherwise have been in my power to produce. While the compilation I have prepared owes its publication at this time to the occurrence of the inundations of last year at the Cape of Good Hope, the publication has been undertaken in the hope that in other countries beside South Africa the information may be turned to practical account. It may prevent misapprehension if I state that I do not for a moment suppose that the measures adopted to control Alpine torrents are measures to be adopted in their entirety, and without modification, to control all torrential floods. I profess only to supply information in regard to what has been done in certain definite circumstances; and thus to place the practical hydraulic engineer, who may have to prescribe for special cases which may be somewhat analogous, in possession of the information I happen to have collected in regard to what has been done in France, leaving him to turn this to practical account as he may. I may add, it was not until twenty years after the publication of the work by M. Surell, which is considered to be the work which gave rise to the operations now being carried on in France, that these operations were commenced ; and this was upwards of sixty years after similar views had been published by Fabre. And in view of this fact, I shall not be surprised, nor shall I be discouraged PREFACE. v in endeavouring to develope the resources and agricultural capabilities of Southern Africa, though nothing should be done in my life-time towards carrying out my suggestions in regard to the application of remedial measures to prevent the occurrence of devastating torrential floods. I am quite aware that time is required for information to permeate any community, and that this is more especially the case where the population is sparse and pre-occupied with pastoral and agricultural operations. To meet this disadvantage as far as I can, I have made arrange- ments similar to those made in regard to the treatise on the Hydrology of South Africa, for copies being transmitted to any Post Office in the world accessible by the Book Post from Britain, And in anticipation of what may be done at some future time to employ plantations of trees as a means of preventing the occurrence and the destructive effects of torrential floods at the Cape of Good Hope, I may here put on record that appended to Report of Colonial Botanist for 1868 are—(1) A memoir on the Conservation and Extension of Forests as a means of counteracting disastrous consequences following the destruction of Bush and Herbage by fire; (2) A Letter to Rev. W. Stegman, Adelaide, on the spread of the Rhinoster Bush; (3) A letter to Mr Hayward, Swellendam, on the planting of trees by water- courses. Appended to Report of Colonial Botanist for 1865 are— (1) A letter to J. F. J. Wrensch, Esq., Secretary to Divisional Council of district of Albert, on trees deemed suitable for culture in that and similar districts; (2) A letter to J. H. L. Schumann, Esq., Aberdeen, South Africa, on trees deemed suitable for culture in the Karroo and Sweet veldt; (3) A letter to E. L. Layard, Esq., on trees suitable for culture at Cape l’Agulhas and other districts exposed to a strong sea breeze ; (4) A letter to Dr Mueller (Baron von Mueller) Government Botanist and Director of Melbourne Botanic Garden, relative to shrubs and trees used at the Cape for fences, avenues, and burying- grounds; (5) A letter to Walter G. Fry, Esq., Victoria Tannery, Bristol, relative to Tannin-yielding plants growing in the Colony. And appended to Report of Colonial Botanist for 1866 is—(1) A list of South African trees, shrubs, and arborescent shrubs, upon the natural history, or botanic character, or economic uses of which a report had been prepared ; (2) An abstract of memoir on the forests and forest lands of Southern Africa, with details of the extent and contents of the different forests of the Colony of the Cape, of Kaffir-land, of Natal, and of the regions beyond to the mouth of the Zambesi, and vi PREFACE, to a corresponding latitude on the West Coast, with the intermediate districts ; (3) An abstract of memoir on the Forest Economy of the Colony of the Cape of Good Hope; (4) An abstract of memoir on Arboriculture in South Africa, with details of what has teen done and of what might be done, in planting trees in the Cape Colony with notice of the Natural History of Australian and European trees which have been recommended by arboriculturists for plantation there. JOHN CROUMBIE BROWN. Happinaton, CONTENTS AND ARGUMENT, PAGE. PREFACE, . e : ‘ a | In this is stated the exigence existing in the Cape of Good Hope, and by inference existing elsewhere, for the adoption of measures similar to what have been co in France to avert the destructive effects of floods and inundations p. 1). IyTRoDUCTION, ; i : : 5 7 The application of the terms reboisement and gazonnement is stated ; illustrations of the evils which the operations so designated have been employed to remedy are given in citations descriptive of Devoluy and other places in the High Alps (p. 7); and in further illustration of the same there are cited cor- responding cases from Abyssinia, India, Switzerland, and Italy (p. 11); an ea is given of the fwhn, the wind occasioning the torrents of the Alps p. 13). é PART I.—Resvumst or Surety’s Srupy or ALPINE TORRENTS, . 15 States the position assigned to Surell’s work (p, 15). Section I.—The Phenomena of Alpine Torrents, . : . 15 Gives the distinguishing characteristics of rivers, of torrential rivers, of torrents, and of mountain streams; of different classes of torrents, of glacier torrents, and of torrents blane (p. 15) ; detailed information is given in regard to the beds of torrents, and the continuation of these in the ravines of the mountains, and in regard to the thalweg or inclination of the valleys, and to the operation of flowing water in the formation of these (p. 17); in regard to Bassing de re- ception, or basins drained by torrents (p, 21); to Canauax d'ecoulement, or water- courses; to Lits de dejection, or beds of deposit (p. 23); and in regard to torrential fleods of water ; to the occasion of these, and to the avalanche-like effects produced by them (p. 25). Section I].—Watural History of Alpine Torrents, . 2 It is stated that there may be seen in the Alps old beds of torrential deposit covered with vegetation of many years growth, which proves that the torrents forming them have long ceased to flow; and that such may be seen in various stages of advancement, indicating different periods of extinction of torrents of a former day (p. 30); that in view of these and other facts observed, the his- tory of a torrent may be considered as marked by three periods—that of the creation of the curve of the bed, that of the deepening and enlarging of this, but with the course inconstant, and that with this stable and fixed,— followed in the cases referred to by the extinction of the torrent (p. 33); that many torrents have originated from mountains, or mountain sides, having ben denuded by the clearing away of forests; and that they have owed their development to the combined operation of deluges of rain (p, 34), the nature of the soil, and the consequent contour of the country(p. 36)—the latter an effect as really as a cause of the flood (p. 38). 30 Section III.—Remedial Appliances to prevent the destructive conse- quences of Torrents, . ; . : . . Al What were sought to be prevented were inundations, the washing away of lands, and the ruin of fertile fields by the deposit on them of the detritus washed away (p. 41). Embankments were employed to prevent inundations, but without success (p. 44.) The other evils were not less serious, of which illus- Vv CONTENTS. : Ae aus Ie trations are given, and the remedies at first employed were retaining was, palisades, near of varied structure, and coffers, but the evi's still ee (p. 45). It having been observed by M. Surell that the origin of | arenes torrents might be traced to the destruction of forests, and that the extine of torrents was attributable to the extension of forests (p. 46), he laid an as established facts—(1), that the existence of a forest on a soil prevents ie 4 f na ; mation of a torrent there, and (2), that the destruction of forests leaves ar subject to become the prey of a torrent;‘and he recommended Dos appropriate remedies for the evils experienced, extensive properly ee plantation of trees, the exclusion of cattle from properly selected spots to a ‘ of the growth on these of herbage and bush, and in subordination to the re ing out of these measures such artificial structures of defence as mig’ called for,—which measures are detailed. PART Il.—Lirsrarvre RELATIVE To Anpine ToRRENTS, AND RE- MEDIAL MEASURES PROPOSED FOR ADOPTION TO PREVENT 5 THE DISASTROUS CONSEQUENCES FOLLOWING FROM THEM, ‘ Contains notices of treatises and proposals by Fabre, 1759 (p. 55); Lecreulx, 1804 (p. 59); Hericart de Thury, 1806 (p. 59); Ladoucette, 1834 (p, ao Dugied (p. 60), SURELL (p. 65), Delafont (p. 66), Jousse de Fontaniere (p. 6 . Labecke (p. 67), Chevalier (p. 69), Blanqui (p. 70), Bonville (p. 72), Belgran (p. 73), Valles (p. 74), Delbergue-Cormont (p, 75), Rozet (p. 78), Scipion Gras (p. 79), Breton (p. 82), Culmann (p, 84), Revue des Deux Mondes (p. 91), Mar- schand, who treats of the hydroseopicity, capillarity, permeability, and im- permeability of soil (p. 94), Cézanne, in a supplement to Htude des Torrents by Surell, with notices of phenomena referred by him to what he calls a torrential era following the glacial period in pre-Adamite times (p. 101) ; Costa de Bastelica, who treats of what he designates Torrentiality, or torrential phe- nomena, in contradistinction to the flow of limpid water, and alleges that by this may phenomena referred by Cézanne to glacial action be accounted for (p. 111) ; explains the phenomena of stones bounding in advance of a torrent wave (p. 117); discusses the extinction of torrents by bodsement (p. 118) ; by gazonnement (p, 121) ; and by barrages (p, 123) ; treats of Colmatage or warp- age in connection with these, and applies his views of torrentiality to ac- count for geological phenomena (p, 127). And thera is given a list of other works on the subject in French (p 129), in German (p. 132), and in Italian (p. 133), and quotations from works in English by Marsh (p. 134), Arthur Young (p, 136}, and Duile (136). PART II].—Lecisuative AnD Executive MmASURES TAKEN BY THE GoVERNMENT OF FRANCE, IN CONNECTION WITH REBOISEMENT AS A REMEDIAL APPLICATION AGAINST DESTRUCTIVE TORRENTS,. 137 In the 14th century edicts were issued and other means were employed to arrest the destruction of forests, as a means of arresting the destruction which was being wrought by torrents. These are referred to, and there are given translations of the text, and of copious extracts from the Act-Decree of the 4th Thermidor an XIII. relative to the torrents of the department of the High Alps (p. 188); Act of 16th September, 1806, and law of 16th September, 1807, relative to the execution of works required to prevent destructive effects of such torrents (p 140). The state of matters about the time of the publication of Mr Surell’s work, and for some years thereafter, till the destructive inundations in 1856 led to the issue ofa letter from the late Emperor Napoleon, desiring attention to be given to the cause or occasion of such inundations, with a view to the employment of appropriate remedies (p. 147) ; and there are yiven translations in whole of (1) the Report given in reply to the Emperor by the Minister of Finance, pub- lished 3rd February 1860 (p. 147); (2) Law founded thereon, promulgated on 28th July 1860 (p. 142); (3) Cireular in relation thereto, addressed to Con- servators of forests by the Director General of the Forest Administration on 17th August 1860 (p. 154); (4) Decree embodying the Statute of the Public Administration for the enforcement of the said Jaws issued 27th April 1861; (5) Cireular addressed to Conservators of forest by the Director General of the Forest Admin‘stration communicating explanations of said decree, issued 1st June 1861 (p. 163), Translations in whole or in part are given of (1) Resu né of First Annual Conference of Agents employed, instituted by Ministerial decision of 21st November 1861, and held on the 9th, 10th, and 11th December, at Valance for the region of the Alps, at Aurillac for the region of mountains in central France, and at Tarbes for the region of the Pyrenees (p, 171); (2) Report for 1861 CONTENTS. (p. 180); (3) Résumé of the Second of the Annual Conferences of forest agents specially charged with the replanting of mountains with woods in the different districts of France, instituted by Ministerial decision of 21st Nov. 1861. held on 8th September 1862, and days following, at Clérmont Fer- rand for the region of the mountains of central France; at the same date, at Carpentras for the region of the Alps; and on 15th Sep, and days following, at Foix for the region of the Pyrenees (p. 181); (4) Report for 1862 (p. 200) ; (5) Report for 1863 (p. 293) ; (6) Report for 1864 (p, 206) ; (7) Report for 1865-66 ; (8) Report for 1867-68. To meet difficulties arising out of popular opposition to the operations, a mixed com- mission was appointed to carry out in combination this law and a land-improve- ment act which had been passed at the same time, uhder the title Lot du 28 juillet 1860, relative & la mise en valeur des Marais et des Terres incultes appar- tenant aux Communes ; but this measure having failed to meet the case (p. 208), additional legislation was required; and there are given translations of (1) Exposé des Motifs, or reasons assigned for the legislation (p. 209); (2) The Supple- mentary Law of 8th June 1864, completing in regard to gazonnement the law of 28th July, in regard to the reboisement of the mountains (p.215); and (3) The Decree embodying the regulations of the Public Administration of the two laws of the 28th July 1860 and the 8th June 1861. in regard to the reboisement and gazonne- ment of the mountains (p, 2!6). In 1865 this law came into operation, and there is reported what was done in the years 1865 and 1866 (p. 223), Some delay had occurred in the opening of this report, and the Administration was enabled to embody in this a report of the success of the operation, as tested by extensive inundations which occurred in the autumn of 1866 (p, 224); and a report on the difference between the expense of the works of reboisement and works of gazonnement, and the cause or occasion of this difference (p. 239), In August 1866 there was issued by the Director-General of the Adminis- tration of Forests a circular containing instructions aud directions in regard to all matters pertaining to the work (p, 231), Aud with the report of operations in the years 1867 and 1868 was given a tabulated statement of the areas upon whic’ operations had been carried out in the several years which had elapsed from the publication of the law of 28th July 1860, with a statement of the expenditure involved (p. 231) PART IV.—Past, PRESENT, anD Prospective ASPECTS OF THE Work, ; ‘ Cuar. I.—Past History of Alpine Torrents, ; ; ; Information supplementary to what had been given in connection with the con- sideration of the literature of this subject is supplied in regard to the views of Marsh (p. 235), of Marschand (p. 236), and Gras (p. 237) in regard to the past history of torrents in France. Cuap. Il. —L£xisting Forests, s : ‘ 3 ‘ There is cited the testimony of Becquerel in regard to the extent of existing forests in France, and of Marschand in regard to the position of forests in the mountain ranges (p. 238). Cuap. II].—Laws Regulating the Reboisement Hffected and Measures Adopted, : : There is cited an abortive law submitted to the Chamber of Deputies in the Session of 1847, and in connection with a reference to the cause of its failure to effect anything is stated wherein the law of 1860 differed from it (p. 240); and there are enumerated and described the kinds of works by which the object of this law had been accomplished during the first decade of the operations carried on (p, 241), Cuap. IV.—Devastations occasioned by Torrents which it was sought to Arrest and Prevent, and Measures employed, . : ; Details are given to show, as was subsequently seen by the population of the moun- taius, that in the operations carried on they had a beneficiary interest as real as that of inhabitants of the valleys and of the plains, for which they considered that their interests were being eacrificed (p. 242); a brief but detailed descrip- tion of the measures employed is given (p. 249); and of the kinds of trees and bushes made use of in different situations (p. 254), and different localities (p. 256). Cuar. V.—Devastations and Restorations, . ‘i ‘ z In this chapter are given detailed information in regard to the work being carried on in different localities within the first decade, showing what was undertaken and what had been effected in different departments of France, embracing the following :— 234 234 238 239 242 257 vi CONTENTS. Szor. L—TZhe High Alps, . e p ‘ ‘ ' There is given the description of the state of devastation which moved Surell to act (p. 258), cited by the Director-General of the Forest Administration, with details of what had been effected in remedying the evil, given by M. Gentil in a report to Conseil General des Hautes Alpes in 1869 (p. 259), and a corres- ponding report given in 1868 by a commission appointed by that body (p. 260); and this is followed by details of what bad been the state of the valley of the Durance (p, 261), and of what had been done (p, 264), and with what results (p, 265). Szot. II.—Department of the Isére, ‘ ; : : There is given an account of Dauphiny and Provence by Marsh, based on a work by Charles de Ribbe (p. 267), and detailed information of what had been done in the périmétre of the Bourg-d'Oisans (p. 268). Szor. II].—Department of the Dréme, ; ; : i This department was formerly included in the Independent State of Dauphiny. There is detailed what had been done in the périmétre of Luc in the arrondisse- ment of Die (p 271). Szot, IV.—The Lower Alps, : : 5 . ‘ Details are given of what had been done in the périmétre of Labouret in the arrondissement of Digne (p. 272), aud notices of what had been effected by Jourdan, a simple forest warder (p. 274). Szor. V.—Department of the Ardéche in Central France, . ; Information in regard to this district is supplied in the words of M. Marsh, founded on statements by M. Mardigny (p. 275), and corresponding information supplied by M. Cézanne (p. 278). Szor. VI.—Department of the Gard, : ‘ ; : mass are given of works undertaken and executed in the périmétre of Ponteils p. 279). Szor. VII.—Department of Lozére, . : é ‘ i The sad condition of the district, and the benefits of boisement are described as de- scribed by the prefect of Lozére (p. 280). Szor. VILII.—Department of the Loire and of Haute Loire, ; The practicability of improving the basin of the Loire by boisement, as described by M. Cézanne (p. 283). Szor. IX.—Department of Herault, : ‘ : Details are given of works executed in the périmetre of Riols (p. 284). Szor. X.—TZhe Pyrenees, . : The French Pyrenees are deseribed by Weld (p. 285-291), and there is reported tha reboisement in périmetre of Bareges (p. 297). Szct. XI.—Department of Aude, . : ‘ : Details are given of operations in the périmbtre of l'Argente-Double (p. 307), Cuap. VI.—Local Feeling and Public Opinion in regard to Reboise- ment, : 7 . . . 2 : There is given information in regard to proceedings in different sessions of the Conseil Général of the High Alps (p, 312), to change of tone after 1865 (p. 313) to testimony of M. Sequinard, Conservator of Forests in the district (p. 314), to testimony of commissioners appointed by the Conseil Général (p. 316) to proceedings in the Conseil Généraux of other departments (p. 317), to testimony of M. Faré, Director General of the Administration of Forests (p. 318), aud of the National Assembly (p. 319). , Cuap. VII.—Present Position and Prospects of the Enterprise, , There are cited anticipations by M. Surell (p, 321), description of the present by M. Cezanne (p. 323), and details by M. Gentil of what has been effected (p. 324). Conclusion, : There is given an account of the inundation of Toulouse 329 and of Hi y (p. 337), and Port Elizabeth in South Africa, as tase B a phase orn rons commen a aan ae reboisement may meet, and the first men- ioned, the inundation of Toulouse, is studied in the ligh steered Ge aa3) ij @ light of what has been 257 267 271 272 275 279 280 284 285 307 311 320 328 INDEX OF AUTHORITIES CITED IN ADDITION TO OFFICIAL DOCUMENTS EMBODIED IN THE COMPILATION. Antoine d'Abadie, page 11, Battivilla, 133. Becquerel, 238, Belancier, 129. Belgrand, 78, 129, 181. Berlepsch, 183, Blanqui, 70, Bonville, 72. Breton, 82,103, Broignard, 74. Caimi, 133. Castellani, 183. Cereni, 183. Cézanne, 79, 81, 82, 84, 85, 86, 90, 101, 181, 146, 208, 234, 286, 240, 248, 244, 249, 257, 261, 263, 274, 283, 312, 314, 323, 327. Champien, 74. Chevalier, 61. Chevandier de Veldrom, 209. Colegnon, 129. Colomb, 108. Cérnoy, 127. Costa de Bastelica, 111, 235, 266. Culmann, 81, 84, 89, 115. Daily News, 331. Darcy et Bazin, 129. Delafont, 66. Belbergue-Cormant, 75, Dugied, 35, 60. Duile, 132, 136. Dumont, 129,145. Dupuit, 130. Eastern Province Herald, 339. Escher, 89. Fabre, 55. Fairbairn, 336. Faré, 231,318. Fargue, 130. Fossombroni, 133. Foutnie, 180. Frank Hausen, 251. Gentil, 324. Gauloes, 332. Graeff, 130. Gras, 79, 237, 243. Guide Joanne, 87. Hagen, 131. Hall, 334. Hericart de Thury, 59, 97. Heyer, 132. Jamieson, 106. Journal des Debats, 333, 346, 348, Jousse de Fontaniere, 10, 66 Kloden, 1382. Krantz, 180. Labecke, 67, Labuissiere, 91, 274. Ladoucette, 60, 67, 75, 77, 242. Lamairesse, 180. lLavignot, 74. Laydeker, 224, 229, Lecreulx, 59. L’Moine, 131. Léonce de Lavergne, 262. Lombardini, 79. Lorentz, 256. Lorgna, 133. Mague, 74, 147, 289. Malézieux, 130. Mangon, 130, Marschand, 13, 94, 132, 236, 238, 248, 251. Mardigny, 74, 257. Marsh, 8, 11, 29, 70, 72, 73, 74, 78, 114, 134, 187, 146, 235, 245, 267,275. Martins, 106, 108, Monestier- Savigonot, 130. Montleussant, 60, 266. Morell, 11. Morgue, 10. Muller, 133. Nadault de Buffon, 130. Nanquette, 256. Palissy, 78. Paoli, 183, Parade, 256. Partiot, 180, De Paasy, 130. Picol, 130. Philips, 338. Plocq, 130. Poirée, 130. Rapport au Conseil Provincial de Luxemburg, 180. Rappen, 183. Reclus, 248. Ribbe, 74, 266. Rosa, 133. Rozet, 74, 78. Sache, 95. Schlangenweit, 11. Scipion Gras, 79, 237, 243. Sequinard, 314, Spectator, 849, Standard, 331. Streffleur, 131. Surell, 7, 15, 54, 58, 59, 63, 65, 77, 114, 141, 257, 263, 321. Tallon, 319. Tartini, 133. Thurmann, 96. Times, 330, Tray, 75. Valles, 74. Van den Brinken, 133. Venez, 87. Vigan,130. Vicaire, 154, 163, 171, 180, Von Arrentin, 131. Von Berg, 132. Von Zaltinger, 131, Weld, 285, 296. Wessely, 133. Young, 72, 136. Zanotti, 133, REBOISEMENT IN FRANCE, INTRODUCTION. Ont of the striking features of the scenery of. extensive districts in the High Alps is that presented by numerous ravines, of greater or less depth and extent, furrowing the mountains, created by mountain floods, These are the Torrents of the High Alps. In the creation of these much valuable land, and in some cases houses and fields, have been undermined, precipi- tated into the water-course, and washed away; and land not less valuable hps been devastated by being covered with the detritus. The most efficacious means of preventing the formation of torrential floods have been found to be what are designated reboisement and gazonnement,—the former being the replanting with woods lands in the districts formerly covered with forests which have been denuded of these, the latter the creating of a dense turf of herbage and bush upon adjacent ground. Evils similar in kind but differing in degree are not unknown in several newly-settled lands. The success with which these remedial operations have been carried out in France may commend them as appropriate appliances to remedy these evils; and the magnitude of the evil which is being combated and remedied in France may be considered as calculated to ' speak encouragement to those who are called to meet only lesser forms of the evil. Under this impression I would here cite details which have been given of the form and magnitude which the evil had assumed, and in which it has been attacked with success. The first I shall cite relates to the Dévoluy. Of this valley Surell writes,—‘“ The Dévoluy forms to the west of the department of the High Alps an elongated valley, divided into two parts by a little col and circum- scribed by elevated mountain chains. It is entered by five passages, which are gorges or cols which the horrors of the locality make impracticable for passage during a part of the winter. The mountains are bare,—eaten up by the flocks and by the sun ; they are without shade and without verdure. The bases of the mountains are almost deserts, having been ruined by the Ceposit of material dejected from ravines, The aspect of this miserable country is oppressive to the soul: one would say of it, It is smitten with death. The pale and uniform colour of the soil, the silence which weighs on the fields, the hideous spectacle of these mountains flayed by the waters 8 INTRODUCTION. and falling into disintegration, and everything about them, announces a miserably ruined, decrepitated land, which does not appear even to struggle against, or resist, or resent its destruction. The unchanging serenity of the sky, which anywhere else would be a trait of beauty, adds here to the melancholy sadness of the country. I shall go over step by step the errors of man which have brought about this state of things. “Everything concurs to show that in ancient times this country was wooded. There are dug up from its peat bogs buried trunks of trees— monuments of ancient vegetation. In the frame-work of old houses are seen pieces of enormous timber such as is not now to be found in the district. Many localites completely bare still bear, even to-day, the name of wood. One of these valleys (that of Agnéres) is called, in old deeds, Comba-nigra, on account of its thick forests. By these evidences, and many others, are confirmed the traditions of the district, which are, on this point, unanimous. “There, as in all the High Alps, the destruction of the forests began on the flanks of the mountains, and thence descended little by little towards the depths of the valleys, and ascended to the highest accessible peaks. Then came the late Revolution which caused to fall the remainder of the woods which had escaped the first devastation. This last destruction was accomplished under the eyes of some of the present population, and all the old men remember what the forest was in a former day.” He adds in a note :—“ And many have told me that they have lost flocks of sheep straying in the forests of Mount Auroux, which covered the flanks of the mountain from La Cluse to Agnéres. These flanks are to-day as bare as my hand.” 1 “ And,” he resumes, “ there, after the destruction of the forests, have come also the grubbing up of roots and the pasturing of flocks. They grubbed up the grounds nearest to the dwelling-places. Theylet the flocks go freely every- where, wherever it was inconvenient or impossible to transport the ploughs. This proceeding, begun centuries ago, accelerated by the Revolution, has produced its inevitable fruits, and the inhabitants suffer sorely to-day from the improvidence of their fathers. “The first evil to be noticed is the extreme rarity of woods. The communes are burdened with the purchase, at great expense, of the possession of distant forests. It requires in certain localities, as for instance at Saint Etienne, thirteen hours of fatiguing work to convey, on the back of a mule, a load of wood across the fearful precipices, and this without reckoning the time occupied in felling and cutting. Other communes, for example La Cluse and Saint Disdier, have preserved woods which, with the greatest economy, might suffice to meet their wants, but they are not more happy ; and this fact makes it apparent that the forests have a function to fulfil here other than simply that of satisfying the daily wants of the inhabitants. For, first the clearances, then the plough and the flocks, have so dissipated the vegetable soil that there now remains no more of it than a thin bed formed by the disintegration of the rock which underlies it, and which now protrudes through it on all hands. Such is the mobility of this ground that it is washed away by the slightest showers and leaves an arid bottom in the place of cultivated fields. Every storm gives rise to a new torrent.” In confirmation of this it is stated by Marsh in his treatise on The Eart as Modified by Human Action,—“No attentive observer can frequent ie INTRODUCTION, 9 southern flank of the Piedmontese Alps or the French province of Dauphiny for half-a-dozen of years without witnessing with his own eyes the forma- tion and increase of torrents. I can bear personal testimony to the conver- sion of more than one grassy slope into the bed of a furious torrent by the baring of the hills above of their woods.” And Surell goes on to say,— There can be shown here torrents, which have not been in existence for three years, which have destroyed the finest parts of the valleys. Whole villages have been almost carried away by ravines formed in a few hours; and the greater part of the torrents have not as yet received a name. Often the wild waters, flowing in broad sheets over the surface of the ground, without bed, without ravine, without torrent, have sufficed to soak and ruin whole districts which have been abandoned for ever. “One may see also dispersed here and there on the brows of many hills (revers), traces of old fields and of old estates, the bounds of which are still marked out by thick dry stone-walls, but which no man has been near for along time. Such are to be seen on the rising grounds of Agnéres, and on the col of the Noyer. One can with difficulty imagine anything more dis- tressing and more significant than the sight of these ruins; they have written on the brows of hills (revers) of the Dévoluy the future destiny of all the French Alps. And here again come into view proofs which do not admit of any doubt in regard to the destructive influence of flocks. Some communes, dreading the future, have enclosed some quarters, as the mountain of Chaumette, quartier de Maniboux, quartier de Lierravesse, quartier de Auroux, near Saint Etienne. Immediately vegetation had again gained possession of the soil, the herbage, bushes, and shrubs have spread with wonderful rapidity, and formed what are called dlanches in the country. Whole forests have sprung up on the soil of the forests which were destroyed at the Revolution, but which the inhabitants, now inspired with a better feeling, have subjected to a regular course of forest management. Finally, on the same mountain brows (revers ) enclosed portions assume, by the end of two years, appearances different from that of those given up to the sheep. The latter are bare and cut into ravines ; the former are covered with vege- tation, the soil is consolidated, and the ravines, carpeted with tufted plants, look like cicatrices occasioned by wounds, which are under the benignant influence of a topical application. In the two quarters—the exposure, the slopes, the soil are the same ; the mere fact of putting them ex reserve has determined the difference. What can be objected to such facts? Are they not conclusive? Do they not give the clue to the system to be followed to put at last a stop to these calamities always increasing ? “To resume, we see here always the same effects resulting from the same causes. Let us follow them a little further and we find them become still more saddening. “The country is being depopulated day by day. Ruined in their cultiva- tion of the ground the inhabitants emigrate to a great distance from this desolated land, and, contrary to the general custom of mountaineers, many never return. There may be seen on all hands cabins deserted or in ruins, and already in some localities there are more fields than labourers. “The precarious state of these fields discourages the population. They abandon the plough and invest all their resources in flocks. But these flocks expedite the ruin of the country, which would be destroyed by them alone. Every year their number diminishes in consequence of want of 10 INTRODUCTION. pasture-grounds. The number of sheep which was 53,000 twenty years ago are now only 36,000. One commune, Saint Etienne, which supported 25,000 sheep fifteen years ago, supports no more than 11,000 now. Thus the inhabitants, who sacrifice all their soil for the flocks, will not even leave this last inheritance to their descendants. “Thus may one see clearly whither tends this fatal chain of causes and effects, which commences with the destruction of the forests and ends in suffering and misery for the population, condemning man also to share the ruin of the soil which he devastated. “ All these facts have been lately recounted by M. Morgue, the present Prefect of the High Alps, in a memoir which treats specially of this unhappy valley. ‘The history of Dévoluy,’ says he, in closing his memoir, ‘will be that of the High Alps before five centuries have passed if the indifference of the Legislature go on, if the recklessness of the Administration continue, and if nothing occur to arrest the cupidity of the communes.’ We may place side by side with these words those of a former Prefect of the Low Alps, M. Dugied, in a memoir on the subject. ‘Such,’ says he, ‘are the causes of the sad condition of the department. One may affirm with certainty that, of a remedy be not speedily applied, ere long the population wm the upper portion will go on diminishing, and that with a rapidity which can only be accounted for by that which went on before. I do not know if I deceive myself, but I believe it is possible to remedy the evil ; and-I believe, moreover, that it is high time to set about this. Wait a quarter of a century and perhaps it will be too late, because the best grounds which exist on the mountains furrowed by the storms may then have been carried away by the floods.’” In accordance with the forebodings of Surell were the following forebod- ings of M. Jonsse de Fontaniétre, Inspector of Forests, embodied in a memoir, Sur la degradation des foréts dans les arrondisements d’ Lmbrun et de Briancon, “From all that has been said the conclusion may be drawn that the department of the High Alps is the one, in all France, in which the cultivators of the land are most menaced in their fortunes, and that they will be compelled, and that sooner than they dream of, to abandon the places which were inhabited by their forefathers; and this solely in con- sequence of the destruction of the soil, which, after having supported so many generations, is giving place, little by little, to sterile rocks. “Tt is the destruction of forests which will be the principal cause of the calamity. The torrents, becoming more and more devastators of the country, in consequence of the destruction of these, will bury under their deposits extensive grounds which will be lost for ever to agriculture. The hills, denuded of their vegetable soils, will no longer admit of the infiltra- tion of water. Then sources of streams and rivulets will be exhausted, and the drought of the summers not being moderated by their irrigation all vegetation will be destroyed. = , . “The destructive elements thus give birth one to another, and it is only necessary to notice what is going on to-day to foretell what will infallibly come to pass some ages hence—when the forests shall at last have entirely disappeared—fuel and water, the two first necessaries of life, will then fail from these desolated countries. “The cupidity of the inhabitants, and the tenacity with which they hold to old usages, admit of no hope that any moral conviction in regard to their future will so impress them as to lead them to submit willingly to a tem- INTRODUCTION, i porary sacrifice. It is for the Administration, more enlightened than they on the state of things and on the consequences which are coming, to meet the evil by legislation appropriate to the requirements of the country.” Varied is the tone in which like forewarning was given by different fay- seeing men, who gave their attention to the subject, about the time in which these forebodings were published. : To one unacquainted with the facts of the case such forebodings of evi may appear extravagant. To one knowing something of these facts they appear legitimate and true; and to one who has seen the region in some of its aspects they seem to be not unreasonable. But the truth is not always truth-like, and to remove any lingering incredulity I may state that the torrents of the High Alps are equalled and even exceeded by torrents seen elsewhere. The traveller, Antoine d’Abadie, who was almost frozen to death in climbing the Wosho,—a mountain of Abyssinia, 5060 métres, upwards of 16,000 feet, above the level of the sea, gives the following picture of what he witnessed :—‘ Sometimes we would be going on in all security under a serene sky, when a native, hearing a strange noise at a distance, which quickly increased, would cry out with all his might, The torrent! and with all haste clamber up upon the nearest height. Thirty seconds would not have elapsed when the bottom of the valley totally disappeared under a sheet of water, which swept away with it trees, blocks of rock, and even wild beasts. These torrents, formed in a moment, exhaust themselves in the course of the same day, and leave no trace of their passage but debris of all sorts and pools of muddy water retained here and there in the clefts and hollows.” M. d’Abadie relates that one day he arrived at a spot just a little too late to see in all its grandeur one of these sudden inundations. He found only a native, looking with a dumfoundered air on the wet ground. “Good morning,” said-the traveller. ‘‘ What has happened to you? Where are our drms? Can aman like you stand there without lance or buckler 2” “Good morning,” answered the African, “and health be yours! The torrent has carried off my lance, my buckler, my camel, and all my possession ; my wife, and my children. Wretched me! Wretched me!” Such are the torrents of Abyssinia. The brothers Schlangenweit, writing of the energy of the torrents of the Himalayas, state it as their belief that they will cut gorges through that lofty chain wide enough to admit the passage of currents of warm wind from the south, and thereby modify the climate of the countries lying to the north of the mountains. Morell, in his Scientific Guide to Switzerland, mentions that about an hour from Thusis, on the Spluegen road, “ opens the awful chasm of the Nolla, which a hundred years ago poured its peaceful waters through smiling meadows protected by the wooded slopes of the mountains. But the woods were cut down, and with them departed the rich pastures—the pride of that, valley—now covered with piles of rock and rubbish swept down from the mountains.” And he goes on to say,—‘‘ The result is the more to be lamented as it was entirely compassed by the improvidence of man in thinning the forest.” Marsh, citing a pamphlet published at Brescia in 1851, entitled Dellu Inandaciont del Mella nella notte del 14 al 15 Agosto 1850, says,—“ The 12 INTRODUCTION. recent changes in the character of the Mella—a river anciently so remark- able for the gentleness of its currents that it was specially noticed by Catullus as flowing molle flumene—deserves more than a passing remark. This river rises in the mountain chain east of Lake Iseo, and traversing the district of Brescia, empties into the Oglio after a course of about seventy miles. The iron-works in the upper valley of the Mella had long created a considerable demand for wood, but their operations were not so extensive as to occasion any very sudden or general destruction of the forests, and the only evil experienced from the clearings was the gradual diminution of the volume of the river. Within the last thirty years the superior qualities of the arms manufactured at Brescia has greatly enlarged the sale of them, and very naturally stimulated the activity of both the forges and of the colliers who supply them, and the hill-sides have been rapidly striped of their timber. Up to 1850 no destructive inundation of the Mella had been recorded. Buildings in great numbers had been erected upon its margin, ' and its valley was conspicuous for its rural beauty and for its fertility. But when the denudation of the mountains had reached a certain point, avenging nature began the work of retribution. In the spring and summer of 1850 several new torrents were suddenly formed in the upper tributary valleys, and on the 14th and 15th of August in that year a fall of rain, not heavier than had been often experienced, produced a flood which not only inundated much ground never before overflowed, but destroyed a great number of bridges, dams, factories, and other valuable structures, and what was a far more serious evil, swept off from the rocks an incredible extent of soil, and converted one of the most beautiful valleys of the Italian Alps into a ravine almost as bare and barren as the savagest gorge of Southern France. The pecuniary damage was estimated at many millions of francs ; and the violence of the catastrophe was deemed so extraordinary, even in a country subject to similar visitations, that the sympathy excited for the sufferers produced in five months voluntary contributions for their relief to the amount of nearly 200,000 dollars, or £40,000.” The rendering of Job xiv. 18-19 in the Vulgate is,— “ Mons cadens definit, et saxum transfertur de loco suo ; lapides excavant aquae et alluvione paullatim terra consumiture.” “ The mountain crumbling down comes to an end ; and the rock is removed from its place; the waters undermine the stones ; and by inundation little by little the land is laid waste.” This is accurately descriptive of the action of the torrent, and this the author of the pamphlet has prefixed as a motto to his narrative. By Mr Marsh it is stated,—‘ The recent date of the change in the character of the Mella is contested, and it is possible that though the extent of the revolution is not exaggerated, the rapidity with which it has taken place may have been.” From such independent testimony inregard to similar phenomena presenting themselves elsewhere, it may be seen that there is nothing incredible in the published reports of the state to which the High Alps had been brought before the operation of reboisement was commenced with a view to arrest the evil. It is with a view of promoting the adoption of a similar remedy for cor- responding evils manifesting themselves in other lands that this compilation has been made, Anticipating that the aridity and limited average rainfall INTRODUCTION. 13 on some lands, on which the remedy would not be inappropriate, may be considered a satisfactory reason for delay, I may state that I admit without hesitation that to produce such torrential flows as has been seen in the Alps the quantity of rain falling there must be very great; but I must add that the effect of the rainfall on water-courses depends more on its dis- tribution over time and space than on its average annual amount, and that orages, or storms of rain, constitute one of the peculiar meteorological phenomena of the High Alps. M. L. Marchand, Garde General dés Foréts, says on this subject,—“ When the torrential rains of the Alps are made a subject of study it is soon seen that they are all of them occasioned by a particular wind called the fehn. These winds are generally violent, and present almost always the character of orages, or storms of rams ; it follows that great quantities of rain are poured down upon the soil ; and to this may be attributed disasters sometimes coming upon spots which seemed to be placed in the best possible situation and circumstances to bear the most persistent rains. “ The fehn is a wind which blows from the south, often with extraordinary force ; it is peculiar to the Alps, and is felt throughout their whole extent. Having climbed over Italy where it is no other than the siroco, the following are its chief characteristics :—It comes from the south, but its direction is modified at every step, either by mountain chains or by valleys. Its origin is still a subject of discussion : according to some it originates in the Sahara, according to others it originates in the Gulf of Mexico. It gives to the sky a strangely-marked, peculiar, heavy, whitish aspect ; and the rain falls on the second or third day following its appearance. “The wind arrives on the Mediterranean coast loaded with vapour ; it there encounters that immense calcareous simi-circular wall of the Maritime Alps, and it scales their higher slopes ; but in consequence of their covering of forests, and the great heat concentrated by them, in doing so it only attains a higher temperature. It is rarely the case that the moisture is condensed or precipitated on these countries which it rapidly traverses ; but it cools by degrees as it mounts the Maritime Alps, and on reaching the upper basin of the Var and its affluents it deposits an enormous quantity of water ; then it continues to advance northwards to French Comté, before reaching which latitude it has lost much of its force. “Tf a glance be cast over a map of the Southern Alps, it may be observed that from Mount Viso there part off great chains running perceptibly from east to west ; the fahn comes by the valleys of the basin of the Var, or of the upper sources of the Durance, it strikes upon the first chain parting from the col of the Pas-de-la-Cavale, or of the Grandes-Communes, taking a deviation to the north of Digne. _ It is against this chain that the first great storms of rain dash themselves. The clouds in passing over these mountains seek the cols or lower parts, and they arrive in the valley of the Ubaye by the openings of Grange-Commune, of Enchastrayes, of the Col d’Allos, of the Lawerq, of the Bas, and in fine, by the great passage of the mountains of the Seyne. “The fehn forces a passage for itself into the valley of the Durance ; goes up this throughout its whole length; it makes its way also by some cols of the chains which separate this valley from that of the Ubaye, and more especially by those which are opposite Embrun. “Tf now the forest chart of the country spoken of and the chart of the fohn be compared, it will be seen that the mountains of Seyne have been 14 INTRODUCTION. cleared of woods, and that the whole southern upper slope of the valley of the Ubaye is devoid of forests; in a word, that all the parts which bear the direct attacks of the fwhn—those which arrest it—force it to ascend them, and to pour upon them masses of water, are all of them almost entirely cleared of woods. Here we have no longer, as is the case above Menton, a tropical sun to warm the soil; the wind has cooled down as it rose higher from the sea, and is obliged with fatal effect to precipitate in the form of rain the moisture it has borne thither ; and at that place where the forests are an absolute necessity, and where the most considerable quantities of water fall, there it is that they have completely disappeared. “This sammary is incomplete, but it may suffice to render intelligible the general course of the orages, or storms of rain in the Alps, and the intensity of these on certain parts, which are generally those at which the fehn is compelled to rise considerably or to change its direction. The celebrated torrent of Riou-Bordoux, near Barcelonette, in face of the opening at Allos, is exactly so situated. The portion of the Alps situated below the department of the Isére almost completely relieves the jwhn of its humidity, and this is the classic region of the orages. “The fehn does not confine itself to the production of torrential rains ; it is not less terrible in its action on the snow, and on the glaciers. As has been stated it blows sluggishly and warm for one, two, or three days before the rain appears ; if at this time the ground be covered with snow this is not slow to melt rapidly, and absorbing a great quantity of water it becomes like a sponge ; then supervenes the rain which expedites the process and brings on a kind of débdcle, or breaking up, and the water arrives in great quantities in the valleys. If the rain do not supervene the action of the fohn may suffice to cause all the snow to melt and to produce great conse- quent disasters.. Tn 1856 the inundations of the valley of Barcelonette had no other cause of production ; the maximum of the flood was attained under a magnificent sky, and all the water came from the melting of the snow which covered the mountain. In Switzerland the terrible inundations of 1868-had in general a double origin—with warm continuous rains were com- bined the melting of the glaciers, It is always in the spring, or with the first snows of October, that the latter torrents are to be dreaded if the mountains be not covered with glaciers ; where this is the case the danger is constant. “The feehn sometimes produces general rains over the whole of the.country over which it blows, but sometimes only looal oruyes, or storms of rain. This can easily be accounted for when it is considered that the contour of the Alps:admits of one current of air passing up a valley to be in its cause and in its effects quite independent of a current passing up a neighbouring valley, though they have had a common origin,—and that a difference in ‘the cooling of the currents of air may occasion a precipitation of rain in one valley. while the neighbouring valleys, being warmer, are enjoying a cloudless sky.” Thus can the immense quantities of water poured down by these torrents be traced to their source, and thus can the immensity of the quantity of water producing these devastations be accounted for. The inquiry ‘brings into view the fact that it is the temporary deluges of rain, and not the mean average annual rainfall, which occasion the torrential floods of the Alps. And there are countries in which the mean average annual rainfall may be very small, when an orage, equalling or exceeding any inthe Alps occulring once in a decade, may prove not less destructive than any torrent in-that’ torrent-ravaged region. PART L RESUME OF SURELL'S STUDY OF THE TORRENTS OF THE HIGH ALPS. OF numerous treatises on subjects connected with the natural history, and the arrest or control of torrents in France, that by M. Surell appears to have been that which has done most to give the direction to remedial operations which has been pursued thus far with the happiest results. There were writers before him who anticipated him in some of his sugges- tions, and there are writers of the present day who have suggested more advanced operations ; but that the work of Surell to which I have referred had the effect [ have indicated seems to be proclaimed by all. This work, entitled Htude sur les Torrents des Hantes-Alpes, was printed by order of the Minister of Public Works, and published in Paris in 1841. Theauthor-had been engaged in engineering work on the High Alps, and his first intention was to prepare a few notices of matters connected with engineering for insertion in the Annales des Ponts et Chaussées ; but becoming interested in the subject, and being encouraged by the Prefect of the district, he was led to make a study of water-courses and every thing connected with them. In the sequel I adhere not closely the order in which the several subjects noticed are discussed by him ; but to some extent I follow that order, while the division adopted is my own. Section 1.—The Phenomena of Torrents in the High Alps. M. Surell, to give precision to his treatise which relates to torrents alone, classifies the water-courses of the High Alps as—ruisseaux, or mountain streams ; torrents ; rivieres torrentials, or torrential rivers ; and rivers: and states what he reckons the distinguishing characteristics of these. He refers also to glacier streams, and to what are known as torrents blancs, to point out wherein they differ from what are known as torrents. In what are called torrents blancs the agency of water is scarcely perceived ; it is in operation, but it occupies a very subordinate position ; in torrents it is the one commanding power, acting with apparently resistless force. From the glaciers there proceed currents of water, and by them are formed deposits of stones and rubbish, known as moraines, which might be mistaken for beds of deposit formed by torrents ; but these have character- istics all their own by which they may be easily destinguished from those, The rutsseaux, or mountain streams, are formed of a body of water, small in comparison with the torrents of which he treats, and may form cascades but not torrents, though they may become feeders of these. He describes the rivers of the High Alps, of which he enumerates four, as flowing in wide valleys enclosed-by elevated ranges of mountains or of hills, : 16 RESUME OF SURELL'S STUDY OF and as forming larger bodies of water which, when swollen, continue so for a time more or less protracted ; the slope of their fall is constant throughout long stretches, and does not exceed 15 millimeters per metre, or a fall of 15 in a thousand. They are in many places characterised by a water- course in a level bed of very great breadth, a small portion of which only is taken up by such a water-course, and this is liable to be forsaken and left dry, while the waters flow in another channel which they have formed for themselves, to be again changed for another, and that again after a time for another ; by which constant changes there is frequently occasioned a great waste of land, and this, if cultivated, must be cultivated at the risk of the whole being swept away—crop and soil together. Elsewhere he mentions that traces of the former existence of ancient lakes are frequent in these mountains, and that it is the constant rule for a water-course, whatever may be the class to which it belongs, when it enters one of these basins, to change its bed when traversing it ; but while this happens once and again, perchance, with others of the different kinds of Alpine water-courses which he has enumerated, it occurs so constantly as a general feature of all the rivers, repeating itself unceasingly throughout the whole of their course, while in the other forms of water-course its occur- rence is only occasional and as it were accidental, that he considers this one of the permanent and specific characteristics of the rivers. Torrents, on the contrary, is a name given to what may be called a dry water-course, along which a tiny stream may be generally seen to flow, but which from time to time is filled with a rushing, roaring, resistless flood. They generally traverse very short valleys, which cut up the moun- tains into buttress-like projections. Their fall throughout the greater part of their course exceeds six centimétres per métre, and it is never less than two centimétres per métre, or two in the hundred. Changes in the slope of their fall succeed one another very closely ; and there is given as a charac- teristic of them that they constantly, if they have not previously done so to a great extent, undermine the sides of their course at one place, and sweep away the debris and deposit it at another, and subsequently change their course above the place at which the deposit has been made,—giving occasion for the same process being again repeated at some other spot. By the rapid fall, the rapid succession of changes in the degrees of this, and their destructive effects, they are distinguished from rivers, and also ‘feomn torrential rivers, in the technical classification of water-courses adopted. Of torrential rivers, rivieres torrentiales, in the High Alps, Surell enumerates five, but he intimates that there are many more. They are affluents to the principal rivers. The valleys in which they flow are less extensive and more compressed, and they cut up the mountain range into spurs and lesser chains. Variations in the slope of their fall succeed each other more closely than do those of the rivers. They do not change their courses as do these, or they do so but little. Their fall is greater, but it does not exceed six centimétres per métre, or six in the hundred. "The have not the characteristics or specific characters assigned to rivers : naithee do they present the characteristics or specific characters assigned ‘to torrents ; they present characteristics of both with characteristics peculiar to them. selves ; and they are classed apart that the field may be clear for the stud of what are known specifically as torrents. roe While the distinctions thus drawn between torrents and other wat : ean : mae er- courses is maintained in the treatise, it is stated that the different forms TORRENTS OF THE HIGH ALPS, 17 may be considered as passing, by intermediate gradations, into one another, and that the same body of water may in one part of its course appear in one of these forms, and in another part of its course it may appear in another. The torrents thus specified he classifies under three heads, those of each category presenting characteristics by which they may be distinguished from the others. Torrents of the first class take their departure from a col in the mountains and flow through a valley. Those of the second class flow from the mountain-top and follow the line of greatest declivity. Those of the third class take their origin from the flank of the mountain at some distance below the summit. Of these also there are intermediate varieties, and varieties assimilating them to some of the other forms of water-courses. The first class approxi- mate in some of their features to those of torrential rivers ; in the second class all the characteristics of the torrent are prominent, and to this type most of the torrents in the High Alps are conformed ; and the third class often show ravines, with all the secondary characteristics of these. The washing away of earth, and stones, and blocks of rock being one of the constant effects of torrents in the High Alps, and the deposits of the detritus presenting certain constant features whereby they may be distin- guished at a glance, not only from the moraines of a glacier, but from the shot-heap of a land-slip, and from all other earthen mounds whatever, Surell has fixed upon the bed of deposit as the most characteristic indica- tion of the previous action of a torrent, and makes the study of these beds of deposit, or hits de déjection, the point of departure in his study of torrents. ; Of these torrents, he says, in the introduction to his work, “ The depart- ment of the High Alps presents us with water-courses of a singular form. There is given to them in the locality the name of torrents, but with the term, as thus used there, there are associated peculiar characteristics which do not manifest themselves in the torrents of other countries. “The sources of the torrents are hid in the recesses of the mountains, thence they descend to the valleys, on arriving in these they spread themselves out over an immensely extended convex bed, the convexity of which establishes a marked distinction between these torrents and most other water-courses, “Tn these the waters always flow in a hollow which encloses them in such a way that a section of the ground in a direction perpendicular to their course would give a curve concave towards heaven, the lower portion of which was occupied by the waters. In the torrents, on the contrary, when they reach the plain, a similar section would show a curve convex towards heaven, and the waters confining themselves in their course on the summit of this. With the water flowing in a slight depression on the summit of a convex torrent bed, it may be imagined that there can be but little stability in the current ; and such is the case. The most trifling rise or swelling of the torrent throws the water out of the depression, and it is scattered right and left, flowing away in streams which, however, still follow the line of the course of the bed. “ This instability renders the torrents very damaging, for they are ever breaking bounds at new points, and subjecting to their ravages immense areas of ground. Beds of torrents are to be seen exceeding 3000 métres, B 18 RESUMA OF SURELL’S STUDY OF or about two miles, in breadth. It never happens, indeed, that a torrent covers at any one time the entire surface of this; but in going now here, now there, it threatens continually every part of it, and after some floods every part may be found to bear traces of its passage. Such are the torrents when they debouch into the valleys. “When they are traced up into the mountain passes they are seen to bury themselves in between steep cleft banks, which rise to the greatest heights, and thus form deep gorges. These banks, constantly undermined at the base, give way, and in their fall drag with them cultivated fields and adjoining dwellings. When this water-course is traced up to the sources of the torrents, the ground there is seen to be spread out like an amphitheatre. Tt forms a sort of funnel, open to the sky, which receives waters from the rains, from the snows, and from the thunder-storms, and precipitates them rapidly into the gorge.” By this gorge, as by the neck ofa funnel, the water is drawn off and precipitated into the water-course opening upon the let de déjection, or bed of deposit. In giving additional details of the principal peculiarities or characteristics of torrents, he says elsewhere, ‘‘ When one casts an eye over a map of the High Alps he- sees a country furrowed with innumerable water-courses, which are spread over the ground in a kind uf confusion. It is an aspect presented by all mountainous countries. Perhaps here the confusion is more manifest because of the little regularity in the arrangement of the mountain chains. These run in many different directions. They constantly cross each other’s lines, break into each other, and disturb the straight line of the valleys. From these frequent intersections results a certain disorder which has for a long time engaged the attention of geologists, but no satis- factory explanation of the production of which has been produced. All the larger water-courses flow into the Durance, the Buéch, and the Drac, whereby are formed three distinct basins marked out by these rivers.” In a note, it is mentioned that by one author, to whom I shall afterwards have occasion to refer—M. de Ladoucette, author of a work entitled Historie, Topographie, Antiquités, Usages, Dialects, des Hautes Alpes—there are reckoned five distinct basins; and by another, M. Hericart de Thury, there are reckoned eight ; but the number might be increased indefinitely by considering every valley a basin. The three basins spoken of receive, he says, all the water-courses of the department with the exception of some insignificant streams which flow to the west. And he goes on to say, “ When the three rivers named are followed beyond the boundary of the department they all three are seen to discharge their waters into the Rhone, the first retaining its name to the confluence, the other two previously losing theirs. And thus it appears that all the water-courses of the department of the High Alps belong to the great basin of the Rhone, one of the five great basins of France. Each of the three basins is traversed by a great valley. which rises by insensible degrees to the col, or neck, in the mountain where it originates. It receives secondary valleys, into which descend other valleys smaller still, which may again be seen subdivided ina similar pein oe a ier like NaC indefinitely subdivided, of whic e secondary valleys are the branch i rinci r Sieee Gained y 'Y es, while the principal y alley “All of these valleys, whatever be their comparative magnitude, their relative rank, or their position, are watered or drained by a stream which indicates the thalweg or direction of the inclination of the valley ; and if we TORRENTS OF THE HIGH ALPS. 19 look horizontally across the sweep of this thalweg we see in most cases a curve, evidently continuous, the inclination of which rises,—or, if the expression be preferred, a curve the tangent of which, by degrees, approxi- mates the vertical as we approach the neck. : “The curve is convex towards the centre of the earth, and it may be remarked that the changes in the tangent are more rapid towards the neck than towards the base. In other words, the radii of the curve diminish in approaching the neck. “ This configuration,” says he, “is remarkable. Why should the bed of the water-courses be disposed in the form of a continuous curve? Why is this curve convex? Why does the curvature vary more rapidly above? The answer is—All these peculiarities are combined in the exact curve which best suits the flow of a liquid the volume of the current of which increases with the length of the distance gone over. And he asks,—Does it not seem that the forms which are so perfectly adapted to the laws regulating the movement of water can be themselves but consequences of these laws ? If it be supposed that the thalwegs have been brought into the state in which they are now seen by the same general cause, whatever it may have been, which created the mountains, why have they such regular forms, while the outlines of the summits, which, according to the hypothesis, would have been formed at the same time as they, show only capricious lines ? By what chance, in an infinitude of possible forms, have they taken exactly such an one as the waters would have themselves created had they not found it already made? It is in these circumstances reasonable to conclude that a regulated cause has operated in the formation of the thalwegs, whilst the summits have been left to themselves; and it is equally reasonable to attribute this to the action of the waters as the cause. “Tt is true that this supposition attributes to the waters a prodigious power, very different from the effects which they produce daily before our eyes, and therefore it is necessary fully to understand the manner in which they have been able to act in the formation of the curve of their bed, or in other words that of the thalweg. “ When we trace attentively the course of the Durance it is seen that the valley successively expands and contracts in such a way as to produce a succession of basins separated by connecting straits. These basins are elongated in the line of the river’s course. The bottom of them is very level, and exhibits a clear and well-defined junction with the base of the enclosing mountain, giving to it an appearance suggestive of its having been in some measure reduced to level by water.” According to a generally received opinion, such elliptical basins are the basins, now filled up, of ancient lakes, and it may be that for a time the place of the river was occupied by a succession of such lakes or sheets of water appearing at different successive levels, communicating with each other by waterfalls or rapids, through which the waters then poured from the lakes, successively passing, as it were, from mill-race to mill-race. Little by little the beds or basins have been silted up, the rocks by which they were separated have been hollowed down, and the waters have at length come to flow in a united bed, and over continuous slopes. We have in our own day an example of such action in the consecutive lakes in the north of the United States, which seem destined to be lost one day in the River St Lawrence, and numerous illustrations of the same thing may be seen in Finland in all directions throughout the country. 20 RESUME OF BURELL’S STUDY OF There may be reckoned up on the Durance very distinct forms of five of these ancient lakes, extending from the neck of Mont-Genéve, where its source is, to the boundary of the department. Vestiges of the same phenomenon are to be seen in the valleys of the Grand Buéch, and of the Petit Buéch. They are to be seen, again, in the valley of the Drac, and in that of the Romanche. In general, all the great valleys of the department present similar traces. Some of these lakes existed within historical times, and we may remark, in fine, that the same appearances have been observed in a great many other places, and on all sorts of rivers. In this, then, we find a general mode of action, of which traces are constantly reproduced in a certain kind of valleys, to which may be attri- buted not only the formation of the valleys but also the formation of their thalwegs, which two things are, he states, distinct and different. There are, he remarks, valleys which seem to have been created solely by the erosion effected by waters flowing at first in a simple depression in the soil ; other valleys seem to have originated in dislocations of the soil opening clefts into which the waters have afterwards precipitated themselves. But in valleys of both formations the action of the waters has invariably been the same, and it has produced the same results. Thrown upon an irregular surface of soil, they have followed at first the line of the greatest inclina- tion ; then they have modified this. Whilst this was going on there has been thus formed the most stable curve of the bed; under the double influence of the friction of the waters tending to reduction to a minimum, and the resistance offered by the soil tending to a maximum: this curve, thus formed, is the thalweg. Thus are brought together and harmonized a great many facts, the explanation of all of which are embodied in one formula—vague it may be— but unique, general, and of universal applicability. If the valleys be studied in their topographical aspect several laws may be discovered, covered by this regulated appearance, which seem to be entirely the result of chance. Amongst these are two beautiful laws evolved by Brisson, which may be verified here in most of the necks of the moun- tains. I adduce only one illustration of each. The first is supplied by the col of the Lauteret, situated between two water-courses, parallel and flowing in opposite directions—La Romanche and La Guisanne. The other is supplied by the col of the Bayard, situated in the district where the Drac and the Durance, after they have both flowed from east to west, separate,—the one directing its course towards the north, the other towards the south. A high- way which passes from the second basin into the first shows distinctly the thalweg passing by the col from the one into the other. By this notice of the action of water in flood we are prepared for entering upon the more special study of torrents. In the torrent, or what, in accordance with the English applicati that term, may be called the torrent-bed, there are aalieaslie eon distinct parts,—the basin drained by the torrent or funnel-shaped hollow from which the waters are collected, called the bassin de réception ; the gorge and channel by which the waters are carried off from this funnel- shaped basin, called the canal d’écoulement ; and the deposit of detritus at the lower extremity of this, called the lit de déjection. To this last great importance is attached, as by detritus borne down b torrents many fruitful fields have been buried under a layer of debrig under TORRENTS OF THE HIGH ALPS. 21 which they have been lost for ever; in view of this next in importance is reckoned the ravages committed by the flood in undermining enclosing banks, and thus bringing down fields and houses to be washed away and added to the deposit of debris; and M. Surell, after having traced the evil to its source, returns to treat of the several parts of the torrent in what would probably be considered by some of my readers an inverted order,— treating first of this bed of deposit, next of the channel, next of the basin drained, and next of the flood creating the torrent. I find it more convenient for my purpose to reverse somewhat the order in which I bring forward his views, following that which I have adopted in enumerating these different parts of the torrent. Looking at a bed of deposit, or lt de déjection, such as is often seen in the Alps, the question suggests itself,-Whence has come this detritus? Deep as may be the channel of the torrent, the canas d’écoulement, this alone could not have supplied such a mass of material as is generally found con- stituting a let de déjection. A study of the outline and soil of the bassin de réception, or basin drained by the torrent, with the information previously obtained, supplies the information desired. This is generally more or less of a funnel-shaped basin ; the angle of inclination formed by its sides may be acute, very acute, or it may be obtuse, very obtuse,—but the resemblance to the sides of w funnel is marked ; the curve may be more or less irregular, and the arc may be more or less nearly complete, but there it is, more or less distinctly perceptible. Here we have discovered what may have been both cause and effect of what we have seen,—an effect of the rapid rush of water, a cause of the increased fall, and of the increased flow, and increased velocity of flow, and thus of the increased ravages and increased deposit and devasta- tion occasioned by the torrent ; and here we have found what may have been the quarry whence most of the material deposited at the outlet of the gorge may have been obtained. It is optional with any one to prosecute the enquiry thus suggested by himself alone, or to do so with the help of others who have gone over the ground before him. It isa matter to which Surell has given careful considera- tion. He has given as the result of his observations and thoughts that in order to the formation of these deposits there must have been in operation a great erosive force, acting on ground susceptible of erosion ; and seeing these meet in the flow of the torrent of water, and in the character of the soil over which it flows, he attributes all the phenomena to the meeting of a copious rainfall and a friable soil, so situated that a rapid flow of the water and a consequent erosion of soil must follow; and I have cited in detail his exposition of the whole contour of the region being attributable to some such aqueous operation. To follow him in his application to bassins de réception of the law thus evolved, it may be desirable to bear in mind that he speaks of three distinct forms of torrents, designated respectively torrents of the first, second, and third classes, The distinction is based entirely upon the position which their bassins de réception occupy in the mountains,—the first proceeding from a col or neck in the mountain range, the second from the mountain brow, the third from the mountain flank,—this difference of position to a great extent determining the differences seen in the aspect they present. In torrents of the first kind, in which everything appears on the largest 22 RESUME OF SURELL’S STUDY OF scale, the basin embraces vast ridges of mountains, and the outline may be traced on an ordinary map. The gullet is prolonged towards the lower art of the channel, forming a valley or rather a narrow gorge deeply embanked by the flanks of the mountains, and the length of which is often more than two leagues. It supplies, says Surell, the very best example I could give of valleys opened up or created by the action of the waters alone. In this gorge the hills are very abrupt, and minceo par les pieds, cut away at the base, and cut up by a great many ravines. They rise frequently more than 100 métres, or 335 feet, above the bed. At different distances they are cut into by secondary torrents, which are lost above in the rami- fications of the contour of the mountains, and they each bring into the gorge the waters collected from a part of the basin. These mountains furnish to the torrents a large portion of the matter carried away and deposited in the bed of dejection, and from their sides come the large blocks which fall here and there into the bed of the torrent. He mentions that in the bassins de réception, or basins drained by torrents, of the first order, there are often seen on the sides of the mountains enormous blocks of stone, which sometimes fall into the beds of the torrents and are then carried far by the rush of waters. In some cases there may be seen standing in a vertical position, in the middle of a slope, what looks like an artificial obelisk; such are almost always capped by some such large block, which one would almost say had been placed there by the hand of man. It is to this block, says Surell, that the obelisk owes its formation. Originally the block lay on the surface of the slope. In this position, when there came a sudden heavy fall of rain, and the water was rushing away in little streamlets on the face of the mouutains, this stone presented a solid and indestructible obstacle which divided a current turning it off to the right and to the left. It may easily be conceived that in this manner it would protect the portion of the slope immediately beneath it, on which it rested ; this then would remain untouched and undisturbed, while the ground around it was being dug into and carried away. At last it would come to pass that the portion of the soil which had thus managed to keep itself above the level of the parts washed away, forming at first a ridge or a block of earth with a sharp angle, which became thinner and thinner by the action of time and atmospheric disintegrating influences, took the figure of a well-defined obelisk, standing out clearly from the slope. These obelisks are known by the inhabitants of the country under the designations demoiselles, or young ladies, and nonnes, or nuns. They may be seen on the mountains of the torrent of the "Graves, of that of Crevoux, of Rabioux, of Grenoble, of that near Briangon, etc., etc. The throat or gullet widens upward at the spot where it joins the funnel, and this sometimes takes the figure of a col denuded of its covering of earth, which assumes the form of an amphitheatre before the embouchure of the gullet. At other times the col forms what is called a pastoral mountain—a name given to mountains appropriated to the flocks—furrowed by innumerable currents, which there spread themselves out in the form of the foot of a goose. The torrents of Rabioux and of Mauriand may be taken as types of such, and so may the torrent of Bachelard, abutting on the col d’Allos, in the Lower Alps. These vast depressions being situated in the higher parts of the mountains, the water supply during the greater portion ‘of the year can only fall in the shape of snow. In this state it is not dispersed, or is but little dispersed ; it is retained, it accumulates, and if TORRENTS OF THE HIGH ALPS. 23 the warmth of spring supervene without a gradual preparation there is poured forth in the course of a few days the-mass of water accumulated during months. This may be considered one of the principal causes of the violence of certain floods. He cites the torrents which proceed from the Col Izoard towards Arvieux, to which reference has already been made, as presenting the most complete and perfect type of the gullet of a bassin de réception. There, as has been stated, more than sixty torrents, within less than 3000 métres, or two miles, precipitate into the depth of the gorge the debris torn from the two flanks of the mountain. In the torrents of the second kind the basin, instead of being cut out on the cols of the mountains, is formed by an indentation of their summits, and is hollowed out in their revers, It is in this kind of basin that it is easiest to trace the disposition to assume the funnel shape so characteristic of these basins, as the eye can take into one glance the entire course of the torrent, all the points of which are depicted before it. The torrent of Merdinal, at Saint-Crépin, may be cited as a type. Lastly, in the third kind the basin is reduced to a kind of large bog, hollowed out by some ravine, and which in the country often bears the name of combe, as for instance the Combes of Puy-Saniere, the torrent of Combe-Barre, the torrent of Comboye. It receives no affluents or feeders, and it collects little more, if any, than the waters which fall in the same enclosure as the depression. It is always dug out in the flanks of the mountains and below their summit; but it tends to grow, and it creeps up little by little towards the summit, which it reaches at. last. This process goes on with greater rapidity in grounds subject to rapid disintegration, and thus is formed in the long run many of the torrents of the second kind. And one can, in many cases, follow the progress and the different phases of the formation of these, from their nascent condition on to their complete development. Below the basin of reception, and in continuation of the gullet, is a region in which there is neither any more downfall of earth nor is there as yet any deposit. This is designated the canal découlement. Of the three parts of the torrent this is the least marked by characteristics, and almost always the least extended. It is the longer the more gentle are the changes of inclina- tion inits bed And this is the reason why it is generally pretty lengthened in torrents of the first kind ; it becomes shorter in those of the second ; and lastly, in those of the third, it reduces itself almost to a vanishing point. The canal d écoulement is always contained between mountains well defined. In fact, when there are no mountains the slope does not suffice to prevent the torrent from spreading itself out; and in doing this it would lose velocity and it would cease to be. The canal @écoulement is the only part of the course in which the torrents do little damage. Unhappily it is the least extensive. It is here bridges should be located. If we could artificially prolong this channel to its confluence with the river, maintaining throughout its slope, its section, and its course, we would stop the ravages. And this is the problem in the embankment of torrents, The its de déjections, or beds of deposit, at the mouth of the torrent next demand attention. The aspect of many of these is suggestive at first sight 24 RESUME OF SURELL'S STUDY OF of a vast ruin, and several torrents have obtained their names from a per- ception of this resemblance. Thus is it with the torrent dela Ruine, at Lantaret, the torrent de la Ruinasse, at Monestier, and the torrent de Ruinance, on the Lower Alps. The deposit is a heap of pebbles and of blocks of stones, scattered over a vast extent of ground—an arid region devoid of culture, of vegetation, and even of vegetable soil—and it suggests to the mind the idea of some great catastrophe having occurred. In sight of this enormous mass of debris, one finds it difficult to perceive or admit that it can be the work of the paltry thread of water—a mere streamlet—which is seen oozing through among the rocks. Examined more carefully, it is seen that these heaps, which seem scattered there in so much disorder, are disposed in accordance with mathematical laws. The general outline of elevation is that of a very much flattened hillock ; the outline of shape is that of a half-expanded fan extending from the mouth of the gorge and leaning on the mountain like a buttress. Projecting lines, which mark on the surface of this cone the lines of greatest declination, are arranged very regularly, following the gentle slopes, which bend inwards a little towards the bottom, but maintain withal a perfect continuity,—all taking their departure from the mouth of the gorge forming the apex of the cone. Further on they diverge somewhat further horizontally, with an outline so distinct that if made with a ruler it could scarcely have been more so, and thus is completed the resemblance first suggested—that of an expanded fan, the joint of which is represented by the mouth of the gorge, and the scales of the fan by these rays, somewhat raised towards the middle, as is the back of an ass, and presenting an appearance such as may be supposed to have been produced by the natural slope of a semi-fluid or viscous body flowing out of the mountain and escaping by the gorge. The whole aspect of the mound is so peculiar that it reveals from a great distance the existence of a torrent before any other indication has been seen to awaken a suspicion that such may be there. It stretches often more than three-quarters of a league in breadth, and its height above the level of the valley may exceed 70 métres, or 230 feet. Nothing can better prove the force of these torrents in action than those immense deposits formed entirely of what has been ejected by them. When one looks, says M. Surell, at the slope presented by these beds of deposits at the water level, following with the eye the central ridge of the cone-shaped group of these, he may perceive them to manifest the following three laws, which may be seen regulating the deposit beds of all torrents reproducing the same or similar effects everywhere with the greatest con- stancy :—(1) The longitudinal profile forms a continuous curve convex towards the centre of the earth,—that is to say, to express the fact in other terms, that the slope becomes less, diminishing in proportion as it goes down towards the river; (2) The changes in the declivity of the fall are more rapid towards the top than towards the bottom ; (3) The declivity of the fall, or slope, varies with the nature of the deposits. It is never under 2 centimétres per métre, nor above 8 centimétres—2 and 8 in the 100; and it is constant for all the torrents of the same locality, and which have their origin in the same mountain range. It is then shown by the author that that curve is the natural result of the action of the flood; and he proceeds to discuss the causes and the con- sequences of the formation of these beds of debris deposited by them. TORRENTS OF THE HIGH ALPS. 25 Two distinct causes concur in the formation of these deposits. First, the torrents proceeding from a confined channel in the mountain come into a valley, in which, being all at once deprived of the side support of sustaining banks, they diffuse themselves, losing velocity and depth. And then the passing from the steep declivity of the mountain to the gentle declivity of the plain proves a second and an additional cause of loss of velocity and of depth. The two causes are distinct and altogether independent of each other, and importance is attached to this circumstance. The tendency is to form a continuous curve from the canal d écoulement, corresponding to the angle of stability. Where this has been done the first cause alone will make additions to the bed. Where this limit of slope has not been created deposits will be continued in virtue of the operation of the second cause. From which it follows that some torrents may be confined by artificial structures, but not others; and that in the former case, other things being equal, the effects will be probable in proportion as the diminished slope may be continuous with that from the gorge, as this continuity is a presump- tive proof that the curve of the bed has been definitely taken to such an extent that the dejected matters have reached the limit of their slope, which is to them in the circumstances the angle of stability. Detailed information is given in regard to the effect of the current in giving to the bed of déjection its peculiar form, with such variations as have been noted, and in regard to the effect of this upon the current. There are next described the materials brought down by torrents—clay, gravel, shingle, and blocks of stone. The laws regulating the deposit of these are noticed ; and the injuries which are thus done are detailed. Every thing connected with the phenomena of the bassin de réception, the canal d’écoulement, and the lit de déjection, having been discussed, attention is given to the phenomena of the flood of water by which the damage and devastation are occasioned. This he traces to two sources—first, the ‘melting of snow towards the beginning of June, and second, storms of rain occurring towards the end of summer. Those occasioned by the latter are by far the most awful, and by far the most injurious In general, says he, the rain of such a storm gives rise to a much more terrible swelling of the torrents than does the melting of the snow. Rains are rare in these mountains ; but when they do fall they fall in tremendous showers, like waterspouts. Their action is instantaneous and cannot be foreseen. The snows never melt so suddenly and quickly as come the deluges of rain, and they produce more prolonged but less sudden swellings of the torrents. Besides this, they may be foreseen and anticipated, for ‘they come at known times. The torrent de l’Ascension owes its pame to the regularity with which it flows about the time of Ascension day. And the melting of the snows produces a general swelling of the torrents and rivers, which causes all to overflow at the sametime. The swellings caused by storms of rain are local ; one torrent becomes furious, while another quite near to it remains dry. The time of the melting of the snow is that for the highest floods in all the water-courses in all the department ; and for all, without exception, the time for low-water is towards the end of autumn. The phenomena which accompany the swelling of torrents are very varied. It may be said that each torrent in its manner of flooding has something which is peculiar to itself, and which is not found in any of the others, It must be so, for all the torrents have not the same distribution of slopes; 26 RESUME OF SURELL’S STUDY OF and the same thing may be observed in all rivers, each of which has a character of its own. Sometimes the swelling occurs gradually ; the waters rise ; clear at first, they become more and more turbid, and then throwing their strength into their velocity, rolling along stones which strike each other with a dull sound, they end at last by overflowing their banks, and then begin the ravages and additions to the deposit in the bed de déjection. At other times they come suddenly, and all at once is seen instead of water the black lava-like flow of stones, the slow progression of which has nothing like to the flow of liquid. ~ At other times, again, we find the torrent falls like thunder. It is announced by a rumbling roar in the interior of the mountain range, and at the same time a furious wind escapes from the gorge. These are the precursory signs. In a few instants the torrent appears in the form of an avalanche of water, rolling before it a heaped-up mass of blocks of stones. This enormous mass forms a moving barrier, and such is the violence of the impulse that the stones may be seen leaping before the waters become visible. The hurricane which precedes the torrent is accompanied by effects still more surprising. It makes stones fly in the midst of a whirlpool of dust ; and there have been seen sometimes on the surface of a dry bed blocks moving as if propelled by some supernatural force. \. All these statements, incredible as they may appear, are attested by a host of cases. I quote some of these, but I shall afterwards have occasion again to call attention to the subject. “Tn 1837 several carriers, and at the same time a Conductuer des Ponts et Chaussées, were stopped during a storra at the place where the torrent La Couche crosses the highway, No. 94. The torrent was then dry. All at once a whirlpool of dust descended along the river-bed, and before their eyes some lumps of stone cleared the road at a bound. “Tn 1821 the roadway of the bridge at Boscodon was swept away by a blast of wind coming with fury from the gorge of the torrent. Immediately the waters arrived, tearing along between the abutments of the dismantled bridge. This event occurred within ten minutes after the Prefect of the Department had passed, and under the eyes of a great number of country people engaged in harvest work in the field above. The Prefect, question- ing the fact, caused several of these people to appear before him, when he questioned them, and held'a kind of formal inquiry, which established all the details which have been reported. “At Guillestre, in 1836, there was a frightful overflow of the stream Rif-Bel, which flows through the middle of the market-town. Several persons were standing near a bridge, listening to the noise made in the mountain, when an enormous stone was, without apparent cause, thrown te their feet, more than 4 métres, 13 feet, above the bed of the stream. “The torrent of the Moulettes, which threatens the market-town of Chorges, overflows every year, and it gives every time an opportunity of verifying facts of the kind stated. In July 1838, a little rain having fallen on the summits of the mountain, this drew some of the inhabitants on to the embankment to see the torrent. Soon the blast of wind—the avant- courtier of what was coming—made the stones roll with such violence that all these people, drawn thither by curiosity, drew back in haste. In a moment the embankment which they had just quitted fell down as it were so to speak, under their heels. It was a massive wall built of stone and TORRENTS OF THE HIGH ALPS. 27 lime, 2 métres or nearly 7 feet thick, and 5 métres or 17 feet in height. The breach, extending 25 métres or 83 feet in length, fell with a crash which was heard more than 3000 métres or 2 miles off. It raised a cloud of dust through which was seen the lava-like stream making straight for the town.” Another case, which shows how sudden these irruptions are, was this :— “Tn 1837 the village des Crottes was encroached upon by a small torrent of the third kind, which no one had ever feared. In an instant the cellars and the tortuous streets of the village were inundated with mud and blocks of stone. A great many cattle were smothered. With difficulty many people escaped with life, and a child perished in a stable.” The following additional facts, relative to the avalanche form taken by the torrents, are given :—“ At the bridge over the little torrent-stream of Chaumateron, in June 1838, the road-labourer heard the precursory sound. Aware of the danger he moved away. He had gone but a step or two when he saw coming the torrent tumbling over itself. It threw itself in one mass over the bridge and broke it. The elevation of the roadway of the bridge above the radier plate was 5 métres or 17 feet. “The village of Saint-Chaffrey is traversed by a small torrent. The bassin de réception is hollowed out of a bed of gypsum. It flows over a steep declivity at the foot of solid banks, but not very high. At every rise or swelling of the torrent it comes tumbling over itself like a ball, 8 métres or 25 feet in height, and a portion of the hemisphere appears above the banks. It is formed of liquid thickened with gypsum, and brings in its train a great current of water, which tears along with violence, but following ordinary laws. With these examples (says he) I stop. They might be multiplied indefinitely, for they are renewed every year.” My purpose in citing these details is, first, to make my readers acquainted with the facts stated ; next, to give confidence in the man who could bravely grapple with the question,—How shall such torrents be bridled and tamed ? and beyond this, to give confidence in the application, to what may be con- sidered as the torrents of a mill-lead in comparison with these, of measures deemed, and proved by recorded results, to be sufficient to prevent so much as the formation of torrents so irresistible in their might as these. To this I have referred in the introduction, and I refer to it again. My fear, as stated then, is that to many the statements will appear incredible, and that thus the end and object I have in view will fail to be accomplished. Statements of fact, far surpassing what may have come under the experience or observation of a reader, may arouse suspicion in regard to much besides what may be stated in connection with what thus startles, and may call forth resistance to the truth advanced. The rise of such incredulity may perhaps be prevented, if I shew that these statements are in accordance with what has been stated by others of what has come under their observation else- where. To those who are conversant with the literature of the subject there is nothing startling in such statements. Theories may be questioned, but the facts are accepted. I shall afterwards have occasion to cite at some length the statements made by M. de Mardigny in a Mémoire sur les Inondations des Rivieres de UArdéche ; here I cite only one. Of the tributaries of the Ardéche he tells that they often hurl into the bed of that river “‘enormous blocks of rock, which this river in its turn bears onwards and grinds down at high-water, so that its current rolls only gravel at its confluence with the Rhone.” 98 RESUME OF SURELL’S STUDY OF The expression “enormous blocks of rock” may seem vague; I can be more explicit. Coaz reports that at Renkenberg, on the right bank of the Vorder Rhein, in the flood of 1868, a block of stone, computed to weigh nearly 9000 ewt., was carried bodily forwards—not rolled—by a torrent a distance of three quarters of a mile. Coaz, Die Hochwasser im 1868, p. 54, cited by Marsh, by whom also is cited the following statement from Die Oecsterreichischen Alpenlinder und thre Forste, by Joseph Weasley, a work published in Vienna in 1853 :—* The terrific roar, the thunder of the raging torrents, proceeds principally from the stones which are rolled along in the bed of the stream. This movement is attended with such powerful attri- tion that, in the Southern Alps, the atmosphere of valleys where the lime- stone contains bitumen has, at the time of floods, the marked bituminous smell produced by rubbing pieces of such limestone together.” Occasionally it happens that after a temporary suspension of the flow, the torrent of water, and mud, and stones, burst forth afresh. These explosive gushes of mud and rock appear to be occasioned by the caving-in of large masses of earth from the banks of the torrents, which dam up the stream, and check its flow until it has acquired volume enough to burst the barrier, and carry all before it. In 1827, such a sudden irruption of a torrent, after the current had appeared to have ceased, swept off forty-two houses, and drowned twenty-eight persons in the village of Goncelin, near Grenoble, and buried with rubbish a great part of the remainder of the village. From these statements it will be seen that similar phenomena have occurred elsewhere ; and we may thus be prepared to follow Surell in his study of the phenomena reported by him. “There are,” says he, “in these irruptions an action like to that of the avalanches. The inhabitants of the district designate them by this term ; it is not a mere figure of speech ; there is in reality an identity of cause, as there is a similitude in the effects. When a great mass of water suddenly pours into the gullet of a bassin de réception, resting on a very steep slope, and confined in a deep gorge, this mass no longer flows in accordance with the peaceful rules of hydrostatics. It rises behind to a great height, rolls over on itself, and thus descends the gorge with tremendous rapidity—far beyond that of the regular current of water which is flowing before it towards the bottom. It must then overtake in succession all the points of that current; it absorbs all its waters, which it hurries along with itself, and which it assimilates to its own mass. In this course its volume swells in proportion to the distance traversed, and when it debouches in the valley it arrives charged with the whole mass of water which was contained in the bed of the torrent from its birth to its exit from the gorge. It is in reality the whole mass of the torrent heaped up and concentrated simultaneously in a single wave. This phenomenon is identically that of the avalanche, with only this difference, that the water, fluid in the first case, is in the atate of snow in the second. By this explanation may be understood the short duration of certain floods,—for instance, an hour after the catastrophe at the bridge of Chaumateron, mentioned above, the bed was dry as it was before “ Another fact, not less singular, is that of the hurricane which precedes the torrent. Let us try also to explain this. All the examples of a hurri- cane which I have been able to collect relate to those floods following storms of rain during the close heats of summer. Let us suppose that in one of those sultry days, so common at this season in this part of the Alps a thunder-shower, storm of rain, or water-spout falls on the bassin de réception ; TORRENTS OF THE HIGH ALPS. 29 there is immediately poured a great mass of cold air over the whole extent of this region. This, specifically heavier than the rest of the atmosphere, can neither rise nor spread out, because it is imprisoned in a kind of funnel, which constitutes always the form of the basin. It escapes then by the gorge, following the line of greatest declivity, as every fluid must, and is precipitated to the bottom of the medium of lesser density. The phenomena of this efflux becomes in every respect similar to that of water. “But there are causes which must prodigiously accelerate the velocity. The column of water carries with it a great volume of air incorporated with it, which it pours with violence into the gullet. At the same time it does not cease to press with all its weight on the volume of air, which has been engulfed in the gorge as in a closed channel. There is there, then, a double action, the force of which is extreme ; one may form some idea of it by com- paring it to that exercised by the trombes d'eau, which serve as blast-engines to the works established in the mountains. It is necessary to imagine the air escaping by the gorge of the mountains as by the nozzle of the bellows of a gigantic forge, and then there will be no wonder that it produces the effects I have described, which are all the consequences of excessive rapidity.” This may require some explanation or illustration, Marsh, citing Wanderungen durch Silicien und die Levant, by G. Parthey, a work published in Berlin in 1834, gives the following singular instance of unforeseen mischief, following from an interference with natural arrange- ments, which may be considered a natural illustration of the application of force referred to by Surell in his allusion to the application to blast- furnaces of what is called a trombe d@eau:—“ A land-owner at Malta possessed a rocky plateau sloping gradually towards the sea, and terminating in a precipice forty or fifty feet high, through natural openings in which the sea water flowed into a large cave under the rock. The proprietor attempted to establish salt-works on the surface, and cut shallow pools in the rock for the evaporation of the water. In order to fill the salt-pans more readily he sank a well down to the ocean beneath, through which he drew up water by a windlass and buckets. The speculation proved a failure, because the water filtered through the porous bottoms of the pans leaving little salt behind. But this was a small evil compared with other destructive consequences which followed. When the sea was driven into the cave by violent west or north-west winds it shot a jet d’eau through the well to the height of sixty feet, the spray of which was scattered far and wide over the neighbouring gardens, and blasted the crops. The well was now closed with stones, but the next winter’s storm hurled them out again, and spread the salt spray over the grounds in the vicinity as before. Repeated attempts were made to stop the orifice, but at the time of Parthey’s visit the sea had thrice burst through, and it was feared the evil was without remedy.” Something similar to this is the action referred to by Surell. The analogy holds only in the compression of air by the pressure of water following upon it quicker than it can escape, and the force developed by its elasticity where space is found for its subsequent expansion. M. Surell enters into several computations to determine the rapidity of the flow of torrents, from which it appears that while the flow of the most rapid rivers does not exceed 4 métres, or 13 feet, per second, both calcula- tions and observations shew the flow of these torrents to be sometimes about 14:21 métres per second—nearly 15 métres, or 50 feet,—which ig the 30 RESUME OF SURELL’S STUDY OF velocity of a strong wind. Applying this to a torrent through 4 canal 8 métres, or 27 feet in breadth, and 2 métres, nearly 7 feet in depth, he shews that it gives a flow of 228-48 cubic métres per second, while the Garonne gives only a flow, in the ordinary state of the river, of 150 cubic métres, and the Seine of 130 cubic métres, per second ; and thus is the brief duration of the flow of a torrent accounted for. The calculation is founded on a formula given in D’Aubuisson Hydraul—(p. 133), in which, representing the fall per métre by Pp, the section of the body of water by s, the perimetre mouille, or circumference of the wheel, by c, the velocity =51 square P 8 +C. It is founded on the observation that in such rapid currents the resistance to the flow is proportional to the square of the velocity ; and extencing the computations to determine the size of blocks of stones which may be carried down by such torrents, he shews that such a torrent as is supposed is capable of moving a stone of the heaviest kind equivalent to a cube of 5°15 métres. But referring to the circumstance that a torrent 2 métres, or 7 feet in depth, could not act on such a block over the whole of its side, he shews that this will give only an equivalent of 2°74 cubic métres ; and then he states that, in accordance with this, it is not rare to find blocks of 20 cubic métres near slopes of 6 centimétres per métre ; and that in the last preceding irrup- tion of the torrent of Chorges the waters left on the bed de déjection a hundred blocks of 30 cubic métres, and some even which measured upwards of 60 cubic métres. Section IL—Watural History of Torrents in the High Alps. The most striking and characteristic feature of torrents—understanding by that term what in English would be called the bed of the torrent—is, according to M. Surell, the deposit known technically as the lit de déjection, though this can only be considered a product of the flow of water by which that bed of the torrents is produced, for, if the waters had not carried off the material deposited, then there could have been no deposit; and by this are supplied indications of the comparative age or antiquity of many torrents now extinct. Often, says M. Surell, are we struck, in passing through the department, with the appearance of a flattened mound, situated at the opening of a gorge, presenting a fan-shaped surface with very regular slopes,—it is the bed de déjection of an ancient torrent. “Sometimes careful continued observation is requisite to the discernment of the original form, concealed as this is by massive trees, by cultivated fields, and often even by houses and towns. But when it is examined with care, and looked at under different aspects, the outline so characteristic of beds de déjection comes out at last most clearly, and it becomes impossible to mistake it. Along this mound flows a little streamlet which proceeds from the gorge, and peacefully traverses the fields. It is this which has ormed the ancient torrent, and in the depth of the mountain may be dis- covered the old basin de réception, recognisable also by its form. “ These extinct torrents, if such a phrase may be used, are More numerous than one at first thought would expect. When once the key to be employed in the search has been obtained, and attention is directed to them, creat numbers are discovered, oe TORRENTS OF THE HIGH ALPS. 31 “The site of the market town of Savines may be adduced, amongst others, as a very remarkable example of this kind of formation. The whole town, along with a part of its fields, stands on a bed of ejected deposit, the breadth of which exceeds 1500 métres, upwards of a mile, covering fields once of great fertility. The nature of this ground is no more doubtful than is its origin. It has been excavated to its greatest depth in digging foundations and in sinking several of the wells in the town ; and the drains of a highway lately put in order have disembowelled it in all directions. Below that town the Durance has cut out a channel and bed on some banks more than 70 feet in height, which forms a sort of natural cutting across the bed. It surmounts and overlooks the whole place, and towards the west, at the extremity of the town, there flows the stream by which all the deposits have been produced ; this is confined between high banks adorned with meadows, and flows deep down in its own earlier alluvial deposits. “Tt is thus open to the day on all sides, and may be studied with the greatest ease. Everywhere it is composed of rolled stones, agglutinated by a lime-like mud. This pudding-like matter is spread in regular beds parallel to the curvature of the surface. It becomes harder and coarser as we get further down, and ends in forming a very compact mass. As to the characteristic form, it may be distinguished from a distance, especially on the east side. The town is built on the highest portion, and the fields lie scat- tered around it. In the background rises the mountain, Le Morgon, in which the basin of reception is covered or buried now under black forests of firs. “It may be remarked that the extinction of this torrent, although of a very old date—dating as it does from a time beyond the memory of man —must nevertheless have occurred after the first establishment of human habitations in this mountain range, for hearth-stones and lumps of charcoal have been disinterred from great depths in the pudding-like mass. These fragments show that men had been then in the locality while, anterior to historical times, the torrent in full action was making this bed of deposit ; and the name of the stream seems to indicate that the stream must have retained its violent character till times less remote from our own.” In a note it is stated it is called Branajfet, which seems to be a corruption of Bramafam, Howling Hunger, a name already mentioned as common to many torrents; and it seems as if in losing its violence it had lost also the name which spoke of it. “The details mentioned leave no doubt in regard either to the fact or to the interpretation put upon it; and they are applicable, not to a single isolated case, but to an order of things which is quite general, the examples of which are widespread, and would each of them furnish materials for observations precisely similar. Names are given in a note of several, with references to more. It must therefore be admitted as an established fact, that the violence of torrents is not of interminable duration, but that it may be arrested—be it by the accomplishment of a definite effect, or be it that the torrent has been brought under some influence by which it has been stifled. “The torrents which present these features are probably the most ancient. To render this conjecture more probable, I proceed by a bound to the opposite end of the scale. We find villages standing in the place where torrents in full action debouch from the mountains. Thus is it with Les Crottes, and with the market-town of Chorges. It is most probable that these towns were built where they stand before the torrents by which they 32 RESUME OF SURELL’S STUDY OF are now threatened made their appearance ; for, on the one hand, these towns are very ancient—Chorges, for instance, dates certainly from before the commencement of the Christian era ; on the other hand, the two torrents which now severally threaten these towns cannot have acted long with the energy which they at present manifest. Their slope is abruptly broken at the issue of the gorge ; their bed of dejection is not yet regularly formed, and that of Chorges has risen 6 métres, or 20 feet, in the course of the last fifteen years. “Tf this process had been going on at the same rate for only a thousand years the market-town would have been buried long ago under a mountain of deposit. That of Crottes, again, is a large ravine, which has only within the last few years given occasion for disquietude. There are cases yet more conclusive in regard to the comparatively recent formation of some torrents which can be adduced. A church in the valley of Dévoluy is threatened by a torrent which flows directly towards the building, and is only kept in check by an embankment constructed about twenty years ago; and we cannot suppose such an edifice, the construction of which seems to have been attended to with all care, to have been erected in the very mouth of the torrent! The style of its ornamentation is that of the beginning of the thirteenth century. We know well with what precautions Christian archi- tects have surrounded their edifices, and we infer that this torrent did not exist when this church was built in the thirteenth century, and if so there have been torrents formed in historic times. And, without quitting this same district of the Dévoluy, we can cite examples of formations of a still more recent time. In this district completely organized torrents have been developed under the eyes of the population of the present day. Several have not yet even received names, and they commit already fearful ravages. “In travelling through other localities like observations may be made. Recent torrents are ploughing out for themselves their courses on all hands. Everywhere new cases are surging up, which prove the abundance and the rapidity of these formations ; and one is soon brought to a stand in con- sternation before this accumulation of facts, which present a bad omen for the future of the country.” In a note it is added,—“ Immediately in front of the esplanade of Embrun is seen a mountain cut by a number of torrents of the third kind. They grow, so to speak, under the very eyes of the town. One of them, called Piolet (petit lit), which was only a little ravine about thirty years ago, when it received this name, has become a large and perfect torrent. The mountain, which extends from Orciéres to the valley of Champoléon, on the right bank of the Drac, is being ravaged by such a number of torrents that it seems as if it must be swallowed up in a mass by the river. These torrents are for the most part recent, and the old men of the country have seen them born, and seen them develope themselves to their present magnitude.” “Thus does it appear that torrents may be formed in our own day ; several are of an age quite recent, and besides these, as if not to leave a single link in the chain of ages awanting, there are torrents existing which, judging by their form, their appearance, and their effects, may be placed as inter- mediate in age between the extinct torrents, and the torrents still in full activity. These are not yet confined within a stable course in the middle of the deposits ; but they overflow-only a small part of their bed. The rest is covered with cultivated spots, woods, and houses, and seems to have been TORRENTS OF THE HIGH ALPS, 33 abandoned by the torrent from time immemorial. And torrents in all stages of the transition, which begins in the establishment of the extreme limit of the slope, and ends in complete extinction, are met with. Stability begins, generally, first to show itself towards the extremities of the bed, and vegetation establishes itself there, advances, and ends in invading the whole surface of the deposit.” Names of several torrents, illustrating what is said, are given. These observed facts are followed up by M. Surell with reflections on the age of the torrents themselves. Specifying and detailing the peculiar charac- teristics of three recognised forms of torrents, and generalizing the whole, he concludes,—‘‘ The action of torrents may thus be divided into three periods, corresponding to three different ages of growth and development and having each an end to accomplish, and distinct effects which they severally produce. ‘“‘The first period embraces the creation of the curve or general sweep of the bed of the torrent. “In the second period the curve or sweep is determined, created, fixed, but the course or channel is not yet fixed ; and it is changec from time to time as if by accident, but all in accordance with law. “ Finally, the third period is that of a stable régime. The course or channel as well as the curve is permanent, or as permanent as manhood is in comparison with childhood and youth. “But many things remain yet to be explained. “ Why do extinct torrents, when they are confined within banks of their own deposits, plough up the very slopes over which they themselves immediately before flowed without having strength to scoop out of it a bed for themselves? The reason is a very simple one. In proportion as the torrent was becoming extinct the waters became more and more limpid. They took then on the same slopes a greater velocity than that which they had when they came charged with alluvial matter, and they then could scoop out where they had previously been depositing. “By what cause, again, are new torrents produced? One cannot at all see why waters which have respected a district during long ages should begin to attack such district now, if all things continue as they were. Those causes which operate to produce a new torrent ought to have formed it from the first day of the creation of the mountains. How could the district of itself change its form or nature 1 “Tt is evident that foreign influences must have interfered, which have modified the primitive conditions. ‘We are thus brought into contact with a new order of facts which demand attention.” It is then stated that when we examine grounds, in the midst of which are torrents of recent origin, we find them always devoid of trees and of every kind of robust vegetation ; and when, in some other localities, we look to revers, the sides of which have been recently deforested, we see them to be cut bya great many torrents of the third class, which aparently could only have been formed within a few years before; and extended observations bring under consideration a great many corresponding facts. “There exist many revers formed by the detritus of the vertical rocks which generally crown the summits of the mountains. In these mobile soils vegetation takes root with power, and vigorous forests of larch and firs have clothed the sides of the mountains. But the axe, little by little, has deci- mated the trees ; the fellings, made without plan, have opened across the forest large open spaces running with the slope of the revers, this arrange- Cc 34 RESUMA OP BURELL'S STUDY OF ment being that which renders exploitation most easy. Now, wherever the woods have been cleared in this manner, at the place of each clearance the vegetable soil has been carried away by the waters; a furrow is formed there, of little depth at first, but which digs away more and more, extends itself upwards, enlarges itself, and soon constitutes a complete torrent, In the intermediate stripes, where the trees have been spared, it is seen to be altogether different. There—with the same soil, under the same exposure, under the same slope, and this often very steep,—the ground has been held firm, and the contour has been respected by the waters. In going over the forest we often traverse thus a succession of zones, the differences of which are striking. We may even catch sight of intermediate shades, which fill up the contrast. We see nascent ravines in parts where the stumps thickly standing bear testimony to a recent destruction of trees. We see completed torrents in other parts, where the indications of the ground, and the inform- ation given by the inhabitants, bear testimony to trees having been destroyed in times more remote. We are thus well assured that we are not taking the effect for the cause, when we affirm that it is the destruction of trees in the clearance which has formed the ravine, and not the ravine which has formed the clearance.” As is the case with the gorges, so does it appear to be the case with the bassins de réception. There is no question in regard to the fact that the effect of such a conformation of the basin drained by a torrent, as has been described, is to bring a large body of water, falling over a great extent of surface, to concentre in the orifice of the gorge ; but the allegation of Surell is that the form of the basin is itself the product of the long-continued violent action of waters, collected first in a recess of the mountains, and flowing over a soil of little compactness and cohesion ; and he accounts for the absence elsewhere of certain characteristics of the torrents of the High Alps by stating that, where the ground presents more resistance, and where the climate is less rigorous, there may be formed only brooklets and moun- tain streams. Similar torrents are not met with in the Vosges, in the Cévennes, or in the Auvergne. In the Lozére there are vallats which are not without characteristic features of torrents of the third class, such as are of frequent occurrence between Briangon and the Monestier, and along the Guissanne ; but these, through their weakness, scarcely resemble true tor- rents, though, compared with vallats, they are torrents of great energy. The torrents of the Pyrenees, generally called Gaves in the district, are very rapid water-courses in deep cuttings, often losing themselves in sub- terraneous canals, but they should be classed with mountain streams or torrential rivers. And no torrents are met with in the mountains of La Corse, or in those of the Jura, But torrents similar to those of the High Alps are found in a portion of the mountains of the department of the Isére of the Dréme, and of the Lower Alps, which belong to the same formation. A chapter is devoted to the consideration of cli influence, and another to the effects attributable t¢ geological formations of the locality. In regard to climate, he shows that the elevation them into the region of snow. When this accumulates all winter over an extensive area, and under the powerful rays of spring melts in great quanti- ties all at once, the process being often accelerated by the arrival of warm matal or atmospheric o the character of the of the High Alps brings TORRENTS OF THE HIGH ALPS, 35 southerly winds, so much so that sometimes in two days’ time the breaking up is finished and the whole of the snow has disappeared, this is one powerful cause of disintegration more energetic there than elsewhere ; but it is trifling compared with others,—in illustration of which he refers to the clear blue sky of the High Alps, a district in which fogs, and mists, and long-continued drizzling rains are unknown, though these are throughout a great extent of France the normal characteristics of the atmosphere during six months of the year. ‘“ Nothing,” says he, “ can equal the purity of the air, the unchanging serenity of the heavens, there. But this dryness of the air and this cloudless sky are dearly purchased, for the rains, if less frequent, are the more tremendous.” M. Dugied, author of a Memoire entitled Projet de boisement des Basses Alpes, to which I shall afterwards have occasion to refer more in detail, says, in writing of this,—* It is thus that it comes to pass that the Alps are sometimes months, sometimes years, without rain. Then all at once the clouds gather as if from all points of the horizon, pile themselves up as if pressed by opposing winds, and empty themselves in torrents which sweep * away everything in their course.” M. Surell says,—“ It is an admited fact that the quantity of water which falls annually in a mountainous country—other things being equal—is greater than in the country of the plains. It is also an admitted fact that the quantity is augmented as we approach the tropics. It follows that there ought to fall here a quantity of rain equal at least to what falls in the same time in Paris. But while the fall in Paris is distributed over a period of six months, here the whole quantity is used up in some few rain-storms.” This makes all the difference ; and thus, to some extent, is the soil made more mobile than it is elsewhere, and of this the following illustration is ven :— ae There is a transition point very remarkable where the climate changes all at once from that of Provence to that of the north; it is the col du Laterat. In proportion as we rise towards this neck, in ascending the valley of the Durance, and then that of the Guisanne, its affluent, we see the serenity of the heaven disturbed, and rainy days become more and more frequent. When the neck is passed, and we penetrate into the gorge of Mallaval, dug out by the Romanche, in following this water-course into the country called the Oysan, which is a portion of the department of Isére, there the change of climate is complete. The rains are extremely frequent, and instead of falling in what seem like thunder-plumps they are prolonged, and fall continuously as drizzling rain. The air is almost constantly moist, and loaded with clouds. One sees the mists creeping over the sides of the mountains, to catch upon the projecting rocks, and often to envelope the valley completely. In word, we have entered the climate of the north, the same as prevails at Grenoble, and which differs in a striking manner from that of Embrun, where fogs are a phenomenon almost unknown. “From this difference in the climate follow corresponding differences in the action of torrents. The mountains which enclose the valley of the Romanche present in many parts the same kind of ground as do those of the basin of Embrun; it is a flaky, black, calcareous earth, remarkable for its excessive friability. But this same soil, which in the Embrunais is furrowed by a multitude of formidable torrents, shows in the Oysans only a few torrents, almost effaced, without energy, and in no repect to be compared with those, In the latter country the mountains are seen clothed on the steepest slopes 36 RESUME OF SURELL'S STUDY OF and covered with vegetation over all their height ; and although they may be stripped of trees, they are scarcely furrowed by a few thread-like streams. In the Embrunais, on the contrary, where the forests have disappeared from the sides of the mountain, these never fail to become the prey of the torrents. “Such is the hygrometric action of the climate. There, where the soil is constantly bathed in a humid atmosphere, the summits carpet themselves with verdure, and the torrents have no more aliment. Here, where the air is always dry, vegetation proceeds with more difficulty, and the storms of rain sweep from the surface the soil to the extent to which vegetation has fixed it there. “Thus the moisture of the climate impedes the action of torrents in two ways equally effective ; first, it makes the rain storms more rare and less violent ; secondly, it renders the soil more fixed by covering it with more vigorousvegetation ; it diminishes thus as by one stroke two causes of erosion. “Tf there still remain any doubt as to the active part played by the climate in the production of torrents, I would cite a general observation which has been made for a long time in these mountains :—When one traverses the valleys running east and west, or the reverse, he sees that the slopes on the north side are generally wooded, or carpeted with vegetation, whilst those which look towards the south are denuded and arid. He sees, at the same time, that the former are much less cut up with torrents than the latter ; and the contrast is often such that he sees the one slope horribly disfigured by torrents over against another on which there exists not one, as, for instance, in the valley of Orcieres, in the Vallonise. “ Now it is evident that such a difference in the whole character of two slopes, which are almost always formed of the same banks of earth, cannot be explained but by the influence of the exposure. And how does the exposure act but by moderating in the slopes directed to the north the effects of the noon-tide sun? They protect for a longer time the snow, retain more humidity, are protected from the scorching winds of the south, enjoy all the advantages of shade and coolness, d&c. All these effects combine and actually submit these slopes to climatal influences different from those which act on the opposite slopes, although they may both be situated under the same atmosphere.” Enumerating the geological formations of the High Alps, he shows that the most abundant are comparatively recent formations, many of them so friable that they crumble through exposure to the sun’s rays, without the super-added action of either frost or moisture; that limestones presenting all the appearance of great hardness, and selected on this account for enrochements, were found to be reduced to earth in two years; that others were not only liable to be disintegrated, but, efflorescing with what seem crystals of alum, lose at once their coherence and their chemical constitu- tion. And the torrents are found to abound in the mountain chains of unstable mineral composition ; they are more rare and less formidable in mountains of more compact constituents ; and in mountains of primitive rock they are altogether absent. Nowhere are torrents more furious or mere numerous than in the valley ‘of Embrun, extending over the whole land from Gap and Tallard to the village of St Crepin. Throughout the whole of this basin the base of the ‘mountain is of a slaty limestone, manifesting in a high degree the character given above. It is in this formation that innumerable ravines TORRENTS OF THESHIGH ALPS. 37 cut into the dry and bluish-tinted hills, which give to the mountains of Embrun their peculiar aspect. These hills are crumbled to such an extent that in trying to climb them one sinks often to the knees in the detritus, And this valley is situated in what may be called the point of intersection of the atmospheric and geological causes of the formation of torrents. To the north we travel over similar formations, but under a different atmo- sphere ; to the south we travel under a similar atmosphere but come upon soil of a different character,—and in both directions the number of the torrents is diminished, as are also their effects. Other illustrations of the same fact are given. Studying thus the natural history of torrents, he attributes their appear- ance to the simultaneous operation of several causes in combination. There appears to be (1) a geological cause—the nature of the soil; (2) a topo- graphical cause—the superficial aspect assumed by the country ; ; and (3) a meteorological cause—the rainfall in the locality. And the question next raised is—Is the second of these seen in the existence and form of the bassin de réception, or basin drained by the torrent, to be considered a primary, or only a secondary cause of the torrent ? Surell maintains it is a secondary cause—itself a consequence, effect, or product of that to which it ministers. Were it otherwise, he says, in order to this being the case, it would be necessary that the cause which created these mountains should have moulded and shaped at one stroke these basins, according to the characteristic figure which they present to-day ; it would be necessary that this form, shape, and outline should have preceded all the action of the waters collected from them ; that these, from the first, should have found all the ground so moulded and prepared for them; and that they should have produced, from the first day, all the phenomena which they continue till to-day to present before us. But it is impossible, says he, to admit such a supposition. The bassins de réception are evidently the result of the violent and long-continued action of the water collected at first in a simple recess of the ground, and flowing over a soil deprived of coherence and consistency. What proves this decidedly is the presence of the larger lits de déjection, which have been formed entirely and exclusively at the expense of the lower-lying lands, whence the torrents issue. Every day, moreover, we see the bassins de réception increasing in magnitude. These effects follow on with such rapidity that a limited number of years should have sufficed to have produced enormous modifications in the original outline of the land. We have then only to carry back, so to speak, into olden times the action going on to-day under our eyes, supposing that present phenomena are the continuation of an action begun some centuries ago, and the digging out of the basin finds a ready explanation. And he refers to the facts already cited, that there are torrents of quite recent formation ; that new ones are being formed constantly ; and that these then aid in the formation of basins in the midst of grounds in which there was nothing of the kind previously existing. He goes on to say,—‘ I know well that I may seem to have exaggerated this action when there is considered the vast extent presented by the basins of certain torrents, and the profound depths of their declivities forming veritable valleys. But there should be taken into account, on the other hand, and at the same time, the enormous cubical contents of the deposits produced by them, which can have been obtained only from the erosion of x 38 RESUME OF SURELL’S STUDY OF such basins; and at the same time it should be recollected that the cubical measurement of these is still far from representing all the mass of material which the torrent has drawn away from the mountain, since a portion of this has been swept into the river, which has widely dispersed it far away. By an effort of thought let us transport the mountain formed by (this deposit to the upper part of the torrent ; let us throw this into the hollow constituting the basin ; let us add to this all that has been carried away by. the river, and we shall not be far from having filled up those deep excava- tions which we hesitated just now to attribute to the digging away of the waters, And we may come in this way to comprehend that there is no ex- aggeration in alleging that the whole valley of the torrent, from its birth to its junction with the ¢halweg, is the work of the waters alone,” Of the correctness of this view there are numerous corroborative indica- tions or proofs referred to ; and as the result of the whole of these observa- tions the natural history of many of the torrents in the High Alps appears to have been this: a deluge of rain such as is brought by the fwhn, falling on an exposed bare spot of greater or lesser extent on the col, or the summit, or the flank of a mountain, has washed away soil and formed thus a hollow basin with an outlet on its lower-edge, the water flowing off by this has made a little runnel carrying away, along with the earth washed out of the hollow, earth which impeded its progress; and as more and more fell into the runnel, through the undermining of its tiny banks, carrying this off also and depositing the detritus, whenever a reduced inclination of the ground reduced the velocity of the flow, and forming thus and there a tiny bed of deposit. But the operation—the process thus begun—goes on widening deepening, extending the basin drained, and the gorge or channel; and adding to the deposit, increasing both its depth and extent, till they have each of them attained the fearful aspect they now present. But there have been similar torrents in the same region in former times —which are now as innocuous as the extinct voleano—they too, to borrow the term, have become extinct; and the brushwood and trees growing on the bed of deposit tell by their age that these torrents have been extinct long. And while the its de déjection are now covered with vegetation, and in some cases with fields, and houses, and towns, the basin and the gorge have also been covered with forests. May not this have been the cause of the extinction? The more closely and the more extensively the subject is studied the more manifest does it appear that it must be so. Thus may it have been in the olden time. In more modern times the destruction of trees has preceded the formation of torrents; and the spread of the forests seems to have preceded the extinction of those of an older creation. This is in accordance with everything that is known in regard to the action of ‘trees in promoting the infiltration, retention, and percolation of water ‘through the soil, and subsoil, on which they grow. With the light thus obtained, we are enabled to trace back the natural history of the existing torrents to the destruction of herbage and trees formerly growing on the bare and exposed spots, from which these torrents have originated,—a destruction of which in some cases historical records direct us to the time in which it occurred; while in other cases it has occurred within the memory of the present inhabitants of the district, The student of physical phenomena may meet occasionally with what TORRENTS OF THE HIGH ALPS, 39 seems paradoxical facts, which do not appear to be in accordance with the law he thinks he has discovered. A modification of that law may, in some instances, be necessary to enable him to embrace by it all the facts of the case; but there may be other instances in which a more comprehensive view of the matter may show that the apparently paradoxical fact, so far from vitiating, establishes the law. Thus is it here. It is mentioned by M. Surell that there may be named a good many rivers which were navigable formerly, but are no longer so on account of the condition of their lower stream ; this may seem to be inconsistent with the general law which has just been propounded, but the study of the phenomena presented by some torrents supplies a solution of the paradox. To cite a case in point, the revers on the left bank of the Durance, from Savines to the river Ubage, is formed, it has been stated, by a succession of beds of dejection belonging to ancient torrents, which became extinct after atime. The whole district was covesed with forests, but these have been cleared away in a great measure, and the torrents resumed their ravages. Many rivers have attained to the state of stability, in the same way that many torrents have done so—by the spread of vegetation over the whole area of the grounds, through the midst of which their waters flow. If this vegetation were destroyed by any means, the soil being again left free, the stability would be interrupted, and devagation would be recommenced by the rivers, with effects similar to those connected with the devastations of the torrents. So that the undesirable change which has taken place in the per- manent flow of some rivers may be attributed to the denudation of their basin. This explanation, he says, has been frequently given, but without power to adduce direct proof of its correctness. But now the rekindling of extinct torrents by deforesting operations supplies the desiderated demonstration of an analogous fact. It may be considered, in some sorts, a special experi- ment on a small scale under exaggerated conditions, to render the effects more striking and more quickly produced. And thus may we obtain, from what has been termed the study of these torrents, information which may be turned to practical account in dealing with torrential floods in other lands, and in other circumstances, The peculiar characteristics of the torrents of the High Alps, consequent on the combination of atmospherical influences on the mineral composition of the mountains, seems at first to place them apart from all other analogous water-courses. But the study of these has revealed the homology which subsists and seems to run through the whole of these, making it appear that in the torrents of the High Alps we have only one excessive develop- ment of what is common to all,—which, having arrested the attention of Surell, has enabled him by this excessive development to study it without difficulty in all its details, and to show in them what may be seen ina degree less manifest, and it may be less developed, but not the less really existent, in all mountain streams, and to show that rivers also are only homologues of these. Comparing rivers with torrents, he finds and shows that the law of development of both is the same, marked by the same three stages, posses- sing the same characterestics, attained in the same way, the most stable in their course, having attained this stability after and by means of similar devagations, or changes of channel. And he goes on to say,— When we consider the wide-stretching valleys in which flow the Rhine, the Nile, we Mississippi, and the greater part of the large rivers which diversify the 40 RESUME OF SURELL’S STUDY OF surface of the globe ; when we observe that the bottom of these valleys is flat, levelled by the waters, and entirely formed by their alluvial deposits ; when, going back to the most ancient historic times, we see in Egypt, in China, in India, é&c., the first societies of men, descending little by little from the heights, occupied in struggling against the inconstancy.and the tremendous overflowings of these rivers,—may we not believs that all these courses have had, during a long course of centuries, changes in their channels such as those which the Durance exhibits now? But, gradually, the field of these devagations has been confined, as is seen so distinctly mn the case of torrents, and like these they have ended in being confined within their present banks. The Durance, on the contrary, is still existing in its second stage—that of instability—-which has succeeded to the first, charac- terized by a succession of lakes,.and to which in course of time a period of stability will gradually succeed.” And inferring that the most stable rivers of to-day have passed through an epoch of change, of course corresponding to the sevond period of torrents, he goes on to say,— In the study of these same rivers there have been collected a multitude of observations which show that they have had in a former age to open their thalweg, and to create their slopes the samme as we have said has been done by the Durance, and the same as we see being done under our eyes by the torrents in the interior of the continents ; they furrowed continents, they filled up basins, and the traces of these phenomena are still very apparent. In approaching these as they cast there immense deltas—ever enlarging deltas—on which sites for entire kingdoms have been found, which deltas constitute true beds of dejection. Thus have these rivers at a certain epoch of their existence acted as the torrents have done in the first period of their history.” : And he goes on to say,‘ Resuming this discussion, I will undertake to show in the action of torrents a faithful and miniature image of that which passed or will pass in all rivers in general. “In all I see three consecutive stages, succeeding each other in the same order, and dividing their existence into three distinct periods—First, a period of corrosion and elevation, which prepares the bottom of the thalweg and puts throughout its course the slopes in equilibrium with the resistance of the soil and the friction of the waters. It has for its end to determine the longitudinal profile of the water-course. “Second, a period of devagation, when the rivers seek that form and those bendings of the course which correspond to the greatest stability (for the rectilineal course is not the most stable, since it does not necessarily lead the current over those points where the bank is most solid and least likely to be changed). In this the action of the waters is confined to going hither and thither on the same level without perceptibly carrying away or eleva- ting the bottom ; it is the liquid mass which displaces itself rather than the soil. The result of this stage is to fix the laying out of the line of the course, or, if the expression be preferred, to determine the plan of it. " Third, in fine, a period of permanence, when the waters may overflow their banks but ever return again to their place in an unchanging bed. “The violence of torrents in the first period has been seen There ought to be the same in the first period of rivers; and this analogy ma i : ; y Serve to explain the formation of those alluvial deposits spread out in such a m in the greater part of extensive valleys. If it be true that the errs have been elevated successively in the midst of convulsions of which nothing TORRENTS OF THE HIGH ALPS. 41 can give us an idea, the waters have necessarily found in this chaos the matter of these enormous alluvial deposits. The rivers were acting at that time as our torrents do now—that is as these torrents do which have for their basins of reception entire chains of mountains, and which precipitate themselves across a soil newly disturbed and susceptible of being washed away, quite otherwise than that of our Alpine hills. Many hypotheses have been proposed to explain the origin of the Alpine pudding-like deposits. Along the Durance banks of these are met with which rise to upwards of 100 métres, or 330 feet, above the actual level of the waters. But the dejections of extinct torrents are, relatively to the trifling streamlets which now furrow them, deposits still more surprising, and of an appearance more inexplicable ; we are, nevertheless, well assured that they are the work of these streamlets in the first period of their action. Why then may it not be the same in regard to the puddings being the work of rivers in a period in every respect similar ? “T point out these things in passing, not daring to stop to develope and to follow out the views they suggest. This would take me too far away from my subject. Everyone can understand that a mass of water rolling over the soil must act in the same way and conform to the same laws, whether it form a torrent or constitute a great river. Now, as we see formed before our eyes the bed of torrents, we may infer that the bed ef rivers has been created in the same manner. And this presumption is accordingly confirmed by the study of such rivers as show traces of their action in bye- gone times in the soil of the valley they have formed.” In more than one of the British Colonies, and in other newly settled lands—using that phrase as applicable to the immigration and settlement of more highly-civilized nations than the native tribes—and in lands which have not been so colonized, are rivers in some of the earlier forms of development referred to. Now, dry channels, or channels threaded by a tiny stream, and now filled from bank to bank—a mighty rushing flood— carrying all before it, undermining banks and washing away the debris, the analogues of the torrents studied by M. Surell, having like them their bassin de réception—one of immense extent—covering it may be thousands of square miles, and embracing numerous secondary basins drained by affluents, a thunder-shower falling in any one of which may produce a torrential flood,—having their canal d’ écoulement, their water-course through which the waters roll their flood along towards the sea, and their lit de déjection, or bed of deposit, though this it may be is in the ocean-bed near to, or remote from, the shore, contributing in the former case to augment the bar which bars the river’s mouth. And it may be inferred that the application of like’ remedies may produce like effects. What bridles the torrent like a young lion in its fury may bridle the torrential river subject only occasionally to fits of rage. Section III.—Remedial Appliances to prevent the Destructive Consequences of Torrents. The natural history of torrents is suggestive of a most efficient remedy, but it is only of late years that it has been applied, and for its adoption we are indebted greatly to the study of these torrents by Surell, though he was 42 RESUME OF SURELL’S STUDY OF not the first to advocate its application, Until the natural history of these torrents was studied and made known special applications were in use, but a remedial cure seems not to have been attempted. What was tried was to prevent inundations, and the washing away of lands, and the deposit of detritus on fertile land. What is now being done is to extirpate the occasion of these. In the low-lying plains, at some distance from the mountains, it was the destructive effects of inundations which commanded attention ; in the Alps it was the ravages of torrents on the land which did this. “The torrent which dashes a great. body of water over very steep slopes (says Surell) undermines and eats away with fury the base of the banks, These fall in, and little by little pull down towards the bed the adjoining property, which is finally engulfed by the waters. As the banks are generally very deep their fall brings in its train effects the results of which extend far from the spot. All the surrounding land is disturbed. Some portions undermined subside, others slip, others break away, leaving deep crevices. Along the two banks of the torrent may be seen large chinks or rents running parallel to the bed. These subsidences, these rents, and this disturbance spread from place to place, repeat themselves to incredible distances, and end by including the whole sides of the mountain within the range of the effects. There are many quarters which can be named which the erosion of torrents have made so unstable that it has become impossible to build upon them. On the left bank of the torrent Les Moulettes there may be seen houses belonging to the village of Les Andrieux, which have been rent at a distance of more than 800 métres from the bed. On the highway, No. 91, opposite Les Ardoisiéres, we have an example of a consi- derable revers of a mountain eaten away by the Romanche and tormented by continual movements of the soil. The instability of the soil has com- pelled many families to abandon cottages situated at a great distance from the river. One could scarcely comprehend that that could be the cause of movements so remote, if the analogy of facts and other evidences had not proved it to be so in a manner the most irresistible.” Numerous cases are referred to in a note followed up with the remark,— “T have thought it right to multiply citations, because the cause of these movements has been often misapprehended, and notably so in the case last mentioned. The inhabitants attribute it to some particular character of the ground. Having under their eyes only the case of their own locality, they are not aware that it is a phenomenon quite general and common to all torrents.” He specifies movements of the soil in the mountain of Saint Sauveur, over against Embrun, brought about by the torrent of Vachéres, and by a great many other torrents of the third class, similar movements in the district of Vabries, mined by the torrent Crevoux on the left bank, and in the district of Villard Saint André, by the same torrent on its right bank ; it is stated that this ground had become more mobile subsequently to the formation of a canal for irrigation ; accounts are given of simiiar movements attributable to the torrent of Sainte-Marthe, near Caleyéres, in connection with which it is stated that there was there a mill apparently on the point of being engulfed, and of movements attributable to the torrent Merdanel, above Chadenas ; and it is stated that very violent movements have been observed in the portions of the Diveset, of Labéoux, of the Rabioux, of TORRENTS OF THE HIGH ALPS. 43 Boscodon, of the Ruisseauioux (Lauterat), dc. dc, And he goes on to say, —There are whole villages built in bassins de réceptions which are threat- ened to be engulfed in this manner by the torrents, Every year the torrent acquires more of the ground, and the village abandons to it several cottages. These facts demonstrate the encroaching march of these water-courses. Little threatening at first, they increase in size, they extend themselves, and soon they reach the habitations built without mistrust at a great distance from their banks. There was, before the thirteenth century, on the borders of the Ralioux, near to Chateaureux, a monastery inhabited by the Benedictines. At a later period the monks deserted it through fear of its being engulfed, and now one sees the ruins suspended in the middle of the river's bank. “There are threatened with a similar fate the village of Lacluse, by the Labéoux (Dévoluy); that of the Hitres, by the Mauriand; that of the Arvieux, by the Moulettes ; the hamlet of the Marches, and the hamlet of the Maisonnasses, by the torrent Rousensasse, on the right bank of the Drac (Champsam).” Having specified these as villages or hamlets exposed to a fate similar to that of the Benedictine Monastery, whose history is given, he goes on to say, — Most frequently the undermining of the soil is done gradually, and this action is the more slow and the more regular in proportion to the extent ot the region. The great mass of ground deadens the movements, and impresses them with a kind of continuity. But at other times also the soil detaches itself suddenly, as if through the effects of a blow. It is thus that in the valleys of the Dévoluy, some years ago, a fragment of the mountain Auroux, covered with cultivated fields, precipitated itself, in one block, into the gorge of the torrent Labéoux. The commotion occasioned by this frightful fall was felt at a considerable distance in the village Lacluse, and the inhabitants attributed it to an earthquake. The cause was no other than erosion by the torrent, which had sapped the base of the ground. “This may demand some explanation. ; ‘“‘Many lands are formed of parallel banks, disposed in flat layers and raised up on great inclinations. Often an interposed bed, more soluble or less tenacious, is decomposed or disintegrated by infiltration. Ifit happens at the same time that the under banks be attacked by the current at the foot, an enormous weight of ground finds itself suspended over an abyss ; the force of adhesion being weakened, it no longer suffices to keep together this mass and to attach it to the body of the mountain ; it is then detached in a mass, and it slides over the surface of the decomposed bed as on an inclined plain. One may indeed see similar land-slips frequently occurring in the limestones of the lias formation, which decompose with the greatest facility, and which often present a schistose stratification ; this kind of ground extensively prevails here. In other cases the grounds have been formed of the debris of the upper parts of the mountains; they compose a rough mass without stratification, and most frequently without consistency, covering the stratified nucleus of the mountain, and forming on its surface beds of great thickness, It rarely happens that a bassin de réception does not contain within its circuit a large strip of this quite recent formation, for it is into the scooped out parts that the debris have had to roll and rest, And one may easily see that the erosions which take place in such grounds, when they attack the foundation of very high banks, must force the soil to detach itself in great masses; and the fractures will take the form of 44 RESUME OF SURELL’S STUDY OF immense prisms, in accordance with laws similar to those regulating land- shoots (pousée des terres). So that it is in the abundance of certain kinds of grounds, and in the composition of the soil itself, that we find the secret of the principal power of these torrents. “And this is the evil to be met.” With these destructive effects of the torrents are conjoined the devastat- ing effects of the deposit of debris covering up fertile soil with barren sand, and gravel, and stones,—and, in some places, overwhelming not only cultivated ground, but houses and property not less necessary for the maintenance of the life of man, his wealth, and his comfort. M. Surell brings under consideration the several defensive appliances which had been employed in the bed of the torrent to prevent those destructive effects, and describes the respective merits of these. The first of these brought under consideration is a wall built along the base of banks in danger of being undermined; and the impotency and inefficiency of such a defence is exposed. The second consists of stone erections or wears raised across the bed of the torrent, to create an artificial fall diagonal to the torrent’s course, diverting it away from the ground _ which it is desired to protect ; such erections, it is stated, operate beneficially, and do so in two different ways,—they retain the bed of the torrent, and they diminish the velocity of the torrent for some distance above them. The first action prevents the sweeping away of the ground, the second deadens the violence of the current, thus not only preventing erosion, but destroying the cause of erosion. And details of their structure, of the extent of some, and of beneficial results which have followed the erection of them, are given. References are also made to fascinages, structures of fascines, or bundles of bushes, and to pallissades clayonnées, or stockades of wicker work, which are successfully employed elsewhere—but not there, In another chapter are discussed the defences employed in the valleys. Amongst the mountains, as has been intimated, the evil against which protection is sought is the erosion, and subsidence, and destruction of the ground ; in the valleys the evils to be guarded against are those resulting from the deposit of the debris of the mountain in places where it does harm. Of the magnitude of these evils illustrations are given; and the defences employed are classified under two heads,—epis, blocks or piles, and longitu- dinal dams. The effects of a single epi, and of a line of these placed diagonally across a portion of the stream, are described, as are also the structure and effect of dams, and the structure and effect of a third defence consisting of a combination of the two. A chapter is then devoted to the more full discussion of endiguements, the designation given to embank- ments designed for the defence of one bank of a river, the designation encaissement, or enclosing banks, being applied to structures designed for the simultaneous defence or protection of both banks. In regard to these effects, it is stated that, whenever in the bed of a water-course a resisting obstacle to the flow of the water presents itself— be it the projection of a rock, be it the bluff side of a mound or hillock, or be it an artificial obstruction—two effects manifest themselves. (1) The current is directed towards the obstacle and maintains this flow; t3} The current is thence reflected and directed against the opposite bank. The hurtful consequence of this reaction is constant, and it is so serious that it TORRENTS OF THH HIGH ALPS, 45 has called for special legislation ; and to this legislation on the subject a chapter is devoted. The legislation referred to is embodied in the Déecret du 4 Thermidor an XIII. relatif aux torrents du department des Hautes Alpes. Itis given in full in an appendix to the work, with much additional information in regard to the subject; and in the text is given a succinct account of the working of the law, with illustrations in justification of the same. From this it appears that when a new bank of a certain extent is ravaged by a torrent, the proprietors meet together and constitute a syndicat, or court, a requisition is addressed to the prefect, he commissions a civil engineer, officially connected with the department, intrusted with. the construction and conservation of roads and bridges—ingenieur des ponts | et chaussées,—to examine the ground, and, if it be necessary, to report the. works proper for the defence of the bank. F The work is executed in accordance with the adjudication ; the engineer superintends the construction, and sanctions the delivery of it; and the expense is borne by those interested, shared according to a scheme of division prepared by the syndic. A translation of the decreet will be given in the sequel. Attention is next given to the different modes of constructing the defences—(1) Levée en Perré ; (2) Walls built with lime; (3) Drystone walls ; (4) Chevalets ; (5) Coffres. The first is employed by preference in longitudinal embankments; the three last mentioned are rarely employed but in the construction of épis ; lime-built walls are employed in both forms of defence ; the chevalet is a wooden erection of three pieces of timber stuck into the ground, apart below, meeting above, and sustained by a fourth piece stuck into the ground behind them, meeting them at the apex of the angle formed by them ; coffres are quadrangular structures of timber, the interior of which is filled with stones; the levée en perré is an embankment of earth faced with stone. A chapter is devoted to the consideration of a form of embankment called Dique éperonné or spurred embankments. Another is devoted to the consideration of the encaissement or confining of torrents, the outline to be given in the encaissement in section, the direc- tion to be given to the axis of the course, and the declination to be given to it. This is followed by a chapter devoted to the consideration of different systems of defence which have been proposed ; and three ehapters which follow are occupied with the condition of roads swept by these torrents, details of what measures are requisite to remedy existing evils, and of measures to be adopted in erecting bridges over the torrents. These constitute the third part or division of the work. The ground being thus cleared, M. Surell proceeds, with a view to the adoption of less objectionable and more appropriate remedial applications, to bring under consideration the causes of the formation and of the violence of the torrents, and with this the fourth part of the work is occupied. In discussing the foreign influences which have modified the primitive condition of the Alps, and produced definite effects on the formation or extinction of torrents, he gives prominence to the influence of forests, In successive chapters he discusses the influence of forests on the formation of torrents, and the influence of forests on the extinction of torrents, the decay 46 RESUMA OF SURELL’S STUDY OF of forests, and the influences of forest clearings and pasturage,—following the whole with a chapter devoted to illustrations and applications of the warning to be derived from the case of Dévoluy, which I have previously cited, The whole tone and spirit of these chapters produces an impression that the exposition of the view given is not only the result of a prosecution of the study of the subject, but probably an exposition of what first gave to him a clue to the discovery of all he subsequently discovered in regard to the natural history of torrents, and the appropriate measures for extinguishing them and preventing their ravages. I have often pictured him to myself as one day plodding along, gradually ascending a mountain valley, in the discharge of his professional duties, hig thoughts being at other times full of the subject of torrents and their numerous phenomena, but on this occasion thinking on anything but these. When, standing for a moment to rest and wipe away the sweat from his brow, looking back he sees what he cannot but perceive is an old torrent deposit—a veritable (it de déjection—though overgrown now with shrubs and herbs, with here and there cottages, and cottage gardens, and cotter’s fields. There it is! He feels he cannot be mistaken, Who would have thought to see it there and see it thus? But there is the cone-like forma- tion, the fan-like expansion spreading from the outlet of the gorge! Here is food for thought, and he goes on his way rejoicing. He comes upon a lesser Lit de déjection of recent formation ; how like and yet how different ! Here all is desolation; there all was clothed in living green, and the opening beyond showed a young and vigorous growth of trees. But stop! May not this have had something to do with the extinction of the torrent, and that more as cause than as effect? This is something to be thought about—I leave to others to follow out the train of thoughts thus begun. I find no difficulty in doing so till I picture to myself Surell master of the whole subject in all its details, and it is with these, his matured views, irrespective of the way in which they have been attained, that we have here to do. Writing on the influence of forests, or of the absence of forests, on the formation of torrents, he says,—‘‘ When we examine the lands in the midst of which are scattered the torrents of recent origin, we see them to be in every case stripped of trees and of all kinds of arborescent vegetation. On the other hand, when we look at mountain slopes which have been recently stripped of woods, we see them to have been gnawed away by innumerable torrents of the third class, which evidently can only have been formed in later years. “See then a very remarkable double fact: everywhere where there are recent torrents there there are no more forests ; and wherever the soil has been stripped of wood recent torrents have been formed ; so that the same eyes which have seen the forests felled on the slope of a mountain have there seen incontinently a multitude of torrents.” The names of numerous mountains and torrents, illustrative of both allegations, are given. “The whole population of this country may be summoned to bear testi- mony to these remarks, There is not a commune where one may not hear from old men, that on such a hill-side, now naked and devoured by the waters, they have seen formerly fine forests standing, without a single torrent. “ Observations which are reproduced so often, and with characteristics so constant, can we explain as simply the result of chance? Do they not force TORRENTS OF THE HIGH ALPS. 47 us to admit that forests exercise a powerful influence on the production of torrents, whether it be by standing on the soil they defend it against their approach, or, obliterated by the hand of man they leave to them an open field which they are not slow to devastate ? ' “Tt is of importance to establish the fact of this influence by direct and positive proofs. Here we are almost embarassed by the very amount of evidence. It should be known that this influence manifests itself here in so many varied circumstances, in such a variety of forms, and with such a force of truth, that assuredly not one man throughout the whole country would dare to dispute it. It is only necessary to spend one day traversing these mountains to be struck with an infinity of facts fitted to produce conviction in opposition to theemost rooted prejudice to the contrary. All of those who know the country can have, on this point, but one opinion. All the observations on this matter which have been published are of one accord, and the authors have had no other trouble than to verify the public opinion, nor other merit than to express by the pen that which has been for many ages in all mouths and in all minds.” In face of a belief so universal, so little disputed, and so indisputable, one finds himself at a loss when he tries to reduce it to a kind of demon- stration ; he knows not how to select one from so great a number of cases, which corroborate one another, and the force or power of which lies in their cumulation ; and he thus writes on the influence of forests on the extinction of torrents :—‘‘ In examining the basins drained by great extinct torrents, there are almost always found there forests, and often dense forests. There may be observed also, along wooded rever's, a number of small torrents of the third class, which appear as if stifled under the mass of vegetation, and are completely extinct. Now this second observation, which can be verified by a multitude of examples, supplies a demonstration of a fact of which the first only permitted us to entertain a suspicion in a vague way :—it is, that the forests are capable of briuging about the extinction of a torrent already formed. Indeed, it is impossible to admit that the small torrents, dug for the most part in mobile and friable ground, can have died of themselves, so to speak, in their very birth, and through the effect alone of that equili- brium to which reference has already been made. “ Stability cannot establish itself so speedily on beds which are scarcely formed, and in the midst of lands which offer still so much food for erosion by the waters ; it is a work which demands time, and which is never entirely consummated until the mountain has been gnawed away to the quick, and to its last ridge. “ Amongst the great number of extinct torrents, the basins of which are wooded, there are some the forests of which have been subjected to the commune régime, and have fallen in part under the axe of the inhabitants, Very well, the result of this destruction of trees has been to rekindle the viclence of the torrents, which only slumbered. There have been seen thus peaceful streams give place to furious torrents, which the fall of the wood had re-awakened from their long sleep, and which vomited forth new masses of déjection on beds of deposit, which had been cultivated without suspicion from time immemorial. This is what has been remarked more especially after the excessive destruction of woods which followed the first years of the Revolution ; the devastations of many great torrents only date from this epoch. It is from this time that the torrent of Merdanel has advanced towards the village of Saint Crépin, the inhabitants of which are to-day 48 RESUME OF SURELL’S STUDY OF within a little of being ruined. The same observation has also been made on the Lower Alps. We may cite as an example of what has been said the whole of the revers which are situated on the left bank of the Durance, from Sabines to the river Ubaye. It is formed exclusively by a succession of beds of dejection belonging to ancient torrents, which had been extinguished after having gnawed away a great portion of the mountain of Morgon. The whole of this district was covered with forests, which have been cut up with clearings, and which continue to be impoverished still further every day. The torrents also have commenced their devastations, and, if the destruction of woods be continued with the same recklessness, this revers, fertile to-day, will speedily be ruined, as so many others have been. _“ This last fact completes all that need be said in regard to the influence of forests. In seeing these show themselves almost everywhere on the body of extinct torrents, one may suppose that these had first died, and that the woods had then seized upon them when the extinction had been completed, and when the soil of the neighbourhood, become stable, permitted vegetation to develope itself in safety : the forest would then only have been one of the effects of the extinction of these, instead of being the cause of it. But then the destruction of the woods would only have restored things to their pri- mitive state, and the torrent ought to have been able to continue extinct after the taking away of the woods as it was before their appearance there ——and this is exactly what does not happen. It has sufficed to clear away the woods to see the devastations immediately reappear. It must be then the forests which, by their permanent appearance on the soil, hindered the devastations, and it is the forests, in taking possession of the soil, which have again caused them to cease—and the extinction of the torrents is so completely their work that it begins, continues, and disappears with them, the effect ceasing immediately with the cause. ; “One sees by this that the action of forests is not confined to preventing the creation of new torrents, but that it is sufficiently energetic to destroy torrents already formed. One sees also that the injurious result of the removal of woods is not only to open everywhere the soil to new torrents, but that it augments the violence of those which exist, and resuscitates those which appear completely extinct. We may then sum up the influence which forests exercise on torrents already formed in two facts, parallel to those which sum up tbeir influence on lands where the torrents have not yet appeared. (1.) The presence of a forest on a soil prevents the formation of a torrent there. (2.) The destruction of forests leaves them subject to become the prey of torrents. Nor is there in this any thing for which we may find it difficult to account. “ When the trees fix themselves in the soil the roots consolidate this, inter- lacing it with a thousand fibres ; their branches protect it, as would a buckler against the shock of the heavy rains ; and their trunks, and at the same time the suckers, brambles, and that multitude of shrubs of all kinds which grow at their base, oppose additional obstacles to the eurrents which would tend to wash it away.<.The effects of all this vegetation is thus to cover the soil, in its nature mobile, with an envelope more solid and less liable to be washed away. ~ Besides, it divides the currents and disperses them over the whole surface of the ground,)which keeps them from going off in a body in the lines of the thalweg and meeting there, which would be the case if they flowed freely over the smooth surface of a denuded ground. Finally, it TORRENTS OF THE HIGH ALPS. Ad absorbs a portion of the waters which are imbibed in the spongy humus, and so far it diminishes the sum of the washing away forces. (“It follows from this that a forest, in establishing itself on a mountain, actually modifies the surface of the ground,)which alone is in contact with atmospheric agents, and all the conditions find themselves then modified as they would be if a primitive formation had been substituted for a formation totally different. Whence it is not more astonishing to see the same soil alternately cut up or free from torrents, according as it is despoiled or clothed with forests, than it is astonishing to see torrents cease when we come to primitive formations, or reappear suddenly on friable limestone. “In accordance with this we find—first, the development of forests brings about the extinction of torrents ; second, the destruction of forests redoubles the violence of torrents, and may even cause them to reappear. And nothing is more easy than to explain these new actions. It will be remembered what are the causes which call forth and maintain the violence of torrents: it is, on one hand, the friability of the soil ; and, on the other, .the sudden concentration of a great mass of water. Now, we know already that the forests render the soil less liable to be washed away ; we know also that they absorb and retain a portion of the rainfall, and prevent instan- taneous concentration of the portion whieh they do not absorb. Conse- quently they destroy both the one and the other cause. They prolong the duration of the flow, and they render the floods at once more prolonged, less sudden, and less destructive. “Tt may be understvod from this how forests, in invading the bassins de réception, may have contributed powerfully to stifle certain torrents. Whilst the waters were creating for themselves the most convenient slopes, the forests were retaining the soil which was ready to go, was rendering it more solid, was consequently diminishing the mass of earth washed away, and above all was opposing itself to the concentration of currents. They were augmenting all the resisting, all the existing, obstacles, and were diminish- ing all the motive powers ; and they were coming thus to hasten by a double efficacy that epoch of stability in which the force of the waters would find itself in equilibrium with the resistance of the soil. There is one circum- stance which ought to render their triumph still more speedy,—it is, that the torrent, in proportion as it is enfeebled, abandons to them a soil more and more stable and favourable to vegetation, in such a way that this augments every day their forces in proportion as the torrent loses force. In fact, if the expression may be allowed, it is reinforced by the effect. “ By this I do not mean to say that the torrents can never become extinct of themselves. That would be in contradiction to what I have said, and at the same time to facts observed, for there are examples of torrents being extinguished without the presence of forests, and solely through the erosion of the mountains—as, for,instance, the torrent of Saint Joseph, near Mones- tier. But I say that the forests expedite the accomplishment of this effect, and that they can produce it where the other circumstances are not yet producing it. “Thus nature, in summoning forests to the mountains, places the remedy side by side with the evil. She combats the active forces of the waters ; to the invasions of the torrents she opposes the aggressive conquests of vegeta- tion. On those mobile revers she spreads a solid layer which protects them against external attack, somewhat in the manner that a facing of stone protects an earthen embankment. It is worthy of remark, that the little D 50 RESUME OF SURELL’S STUDY OF cohesion of limestones, which is opposed to the fixing of grounds, which renders them so mobile, and draws torrents thither, is precisely the quality which renders them favourable to the development of vegetation. The game cause which multiplies the torrents ought then to multiply also the robust forests, and to cause productiveness to succeed in the long run to barrenness, and stability to disorder. Not that, strictly speaking, there can be in nature anything otherwise than orderly, for there is nothing which is not subject to the rule of immutable laws, but in popular phrase the term disorder has also its meaning. “One is struck with the illustrations of the observation which has just been made in going over certain forests in these mountains. One sees the vegetation doubling its profusion and energy in grounds torn by ravines, and crumbling on all hands, as if it were mustering its last efforts to retain a soil escaping from it. To cite one example: in the forest of Boscodon may be seen the vigour and tenacity of the vegetation contending against a friable soil composed of schist, tufa, and gypsum. It is, in fact, the lands which are the most mobile which are at the same time the most fertile, and the hard rocks on which vegetation has no hold, brave also the effort put forth by all the causes of destruction. The mountains, if they were abandoned quite naked to external influences, would soon be levelled or cut up into bits, and they would offer to man nothing but a heap of cleft rocks, unculti- vated and uninhabited. “Tt is vegetation which prevents this ruin; and as there can be no vegetation without water, it is on the mountains that nature has poured out the water in the greatest profusion. We have already called attention to the remark, that there falls more rain on the mountains than on the plains. The mountains attract and retain the clouds []. Snows and glaciers crown their summits as immense reservoirs, whence trickles out a perpetual moisture, and whence flow innumerable streamlets which fertilize their sides, and distribute fertility, from brow to brow, down to the very depth of the valleys. Thus, the waters which are the most energetic means of destroying the soil are at the same time the most active in its conservation. In drawing on vegetation, they preserve the soil against their own attacks, and the more they have of power to destroy, the more vegetation they cause to spring up to preserve. It is in this way that nature imposes on all her forces moderators which counterbalance them and keep them from acting always in the same way ; and this must end in bringing everything to a state of restored peace.” And dwelling on the thought of self-adjusting provision for the natural extinction of torrents, he thus, in something like a burst of enthusiasm, gives expression to his feelings in view of the thorough and efficient way in which torrents had naturally become extinct, and the contrast thus pre- sented to the puny endeavours of man to restrain their ravages : the natural and the artificial ; God’s way of doing it, and man’s way of doing ; the work of God and the work of man ; and the results : success, perfect and complete ; and success, partial and imperfect ! ; “Let us go back for a moment,” says he, ‘and compare these effects of vegetation with those exercised by the different systems of defence hitherto devised. The result of defences like that of vegetation is to arrest the ravages of torrents ; and how powerless appear all embankments by the side of those great and powerful means which nature employs when man TORRENTS OF THE HIGH ALPS. 51 ceases to oppose her, and when she patiently prosecutes her work through- out a long series of ages! All our paltry works are nothing but defences, as their name indicates ; they do not diminish the destructive action of the waters, they only keep it from spreading beyond a certain boundary. They are passive masses opposed to active forces ; obstacles, inert and decaying, opposed to living powers, which always attack, and which never decay. Herein is seen all the superiority of nature, and the nothingness of the artifices devised by man. “1 make not here a barren comparison. I wish to let it be seen that it is better to bridle the torrents than to erect at great expense masonries and earthworks, which will always be, whatever may be done, expensive palliatives, better adapted to conceal the plague than to eradicate it. Why then does not man ask assistance of those new powers, the energy and efficacy of which are so clearly revealed to him? Why does he not command them to do yet again, and that under the directions of his own genius, that which they have already done in times long gone by on so many extinct torrents, and that under the prompting of nature alone ?” With the views thus expressed he proceeds to discuss more thoroughly the measures to be adopted for opposing, counteracting, subduing, and taming tor- rents. He argues that the continued application of such measures of defence as have been referred to must necessarily fail ; and he alleges that prevention —not cure—must be attempted. This, says he, resolves itself into two distinct problems—(1) To prevent the formation of new torrents, and (2) To arrest the ravages of torrents already formed. But the remedy proposed by him, as applicable to both, is the same— namely, the extension of vegetation, “ All the facts which have been adduced,” says he, “carry with them the conclusion to which they lead, and it would be superfluous to go back upon them. It is vegetation which is the best means of defence to oppose to torrents.” And starting with this idea, the two problems resolve themselves into the discussion of the pro- ceedings to be followed to throw the greatest possible mass of vegetation either on to the lands threatened with torrents in the future, or on to lands surrounding existing torrents. “Tn doing this, art,” says he, “should confine herself to imitating nature, to mastering its forces, and skilfully to opposing one of these to another, All that we are about to undertake nature has already done before us in time past, and she does it over again to this very day under our eyes when- ever we leave her free to work. We are assured, then, beforehand of success, since all we have to do, to a certain extent, is to recommence experiments already made, and the success of which has been complete. Whence also it follows it is no longer a system of defence we have to seek, but a system of extinction.” As a preliminary measure, he argues the reservation, by legislative enact- ment, of certain portions of the soil ; and a limitation or restriction of the number of the flocks and herds within what the reproductive vegetable power of the district can sustain. He recommends that the land to be defended against the ravages of the torrents should then be marked out by tracing, on each bank of the torrent, a continuous line, following all the windings of its course, from the highest point of its commencement to its issue from the gorge. “The strip of land comprised between each of these lines, and the summit of the mountains, would constititute (says he) what I 52 RESUME OF SURELL’S STUDY OF would call a zéne de defense, enclosed against flocks and herds, The zones of the two banks, following the outline of the basin, would meet in the hei ghts, and would begird the torrent like a girdle. The breadth, varying with the slope and with the consistency of the soil, would be about 40 métres, or 130 feet, below, but it would increase rapidly as the zone rose on the mountain ‘side, and it would end in embracing a space of 400 or 500 metres, or from a quarter to a third of a mile. «This outline would require to follow, not only the principal branch of the torrent, but also the different secondary torrents which degorge into the first ; following then the ravines which each of the secondary torrents receives, and going on thus, from branch to branch, it would go on to the birthplace of the last threadlet of water. In this way the torrent would find itself begirt thoughout the most minute of its ramifications, These zones of defence, in penetrating the bassin de réception, will be enlarged ; while, on the other hand, as the ramifications are in this part more multiplied and more approxi- mated, it will come to pass that neighbouring zones will join and even over- lap each other, and their outlines will be.lost in a common region, which will eover the whole of this part of the mountain, without leaving there a void space. The zones of enclosure being thus determined, the first part of the operation is finished. But this is in some respects only the outline of the periphery of the work which is to be done. “We have next to do with what may be the most active and prompt means of drawing veretation over the whole surface of this enclosure. For this purpose it should-be sown and planted with trees ; where it may be impossible to raise trees at once, the growth of shrubs, bushes, and thorns should be stimulated ; but on the height, where the zones include the whole extent of the bassin de réception, it is a forest which must be created. The best adapted kind of trees must be selected ; recourse must be had to all modes of procedure, indeed, even to modes of procedure which have yet to be discovered, and which go beyond experience. The work must be done any way and every way ; and the end aimed at in these works ought to be to cover the bassin de réception by a forest which will every day become more dense, and which, extending itself step by step, will end in spreading even into the most hidden depths of the mountain. 5 “ Tf the vegetation thus developed over the zones of defence be protected against flocks, if it be protected against the depredations of the inhabitants, if it be tended, maintained, stimulated by all means possible, it will ulti- mately envelope all the parts of the torrent by a very dense thicket, and thereby will be realized two effects at once, both of them equally salutary. “First, this will arrest the waters which trickle down the surface of the soil, and will keep them from entering the torrent ; or, if it do not prevent them doing this, it will at least retard them, and we know that this result ig in every way a happy one. From the time this is done the torrent will only receive the waters which fall vertically from the sky into its bed ; and this will diminish its volume in the same proportion as the proportion which exists between the extent of the general basin of the mountains and that of the stringently reduced opening presented by this bed. From a considera- tion of the great difference in extent of these two surfaces may be under- stood how great should be the reduction of the body of waters thus effected. And next, the ground of these zones can be no more washed away by the rains, and swept away by the torrent, and thereby will be diminished so far the mass of deposited matter, It is true, it may indeed be swallowed up little TORRENTS OF THE HIGH ALPS. 53 by little if the foot of the banks be undermined by the waters, but this constitutes another point to be attended to, and one to which I shall attend immediately, and on which, until I do so, I crave for a moment a suspension of judgment. “To return, I give in one word the effect of these arrangements. I may say that the torrent will find itself placed in the same conditions as if it issued from the bosom of a deep forest, which wiJl surround it in all its windings, and in which it will be as if it were drowned. Elsewhere I have described the results to which such a condition of things gives birth. It may be remembered as the forest struggling with the water ends in extin- guishing the torrent, the same effects will reproduce themselves here, and it is unnecessary to repeat them. “ By the same analogy it may be understood that the vegetation advancing always, and gaining each day upon the ground, should descend on the banks and carpet them almost to the bottom of the bed, as has happened in exten- sive torrents; but the giving of permanence to the banks is a result of too great importance to be left thus to the caprices of the soil, and of the free will ofnature. We come thus to a third department of the work. It is one in which it is especially necessary to redouble care and to multiply devices. “To draw the vegetation over the banks they should be cut with small canals of irrigation derived from the torrent. These will impregnate with fertilizing humidity the land now rent and dry; they will break also the slope of the declivities, and serve to render them more stable, and soon they will disappear under the tufts of various plants brought to light by the water. “The formation of these canals being extended ultimately to the summit of the bank, the water will thence penetrate the zones of enclosure and fertilize their soil, It is in the retention of the water, and in the possibility of opening everywhere and multiplying almost indefinitely provision for this, that rests in reality the whole future of the work. “Tn fine, I pass to the fourth phase of the work, which is also the last. Whilst all these plantations retain the grounds through which the torrent flows, the undermining may be prevented by the construction of artificial barrages, oY wears. “We thus borrow from existing systems of defence that which is most efficacious in them ; but in doing this how greatly have we ameliorated the circumstances in which we set to work ! “Indeed, we shall find in the plantations, everywhere where it is thought fit to establish these works, the best material for their construction. The young trees will supply stakes, prunings and bushes will supply facines. We can then construct the barricades of facines, or the wicker palisades recommended by Fabre. These works will cost little for manufacture, the materials will cost absolutely nothing. They will be cheap ; and they do not present the dangers which accompany walls of masonry. Onecanthen multiply them everywhere without any inconvenience, and almost without expense. “ These barricades will be like the completement of the works of extinction ; they will serve to defend certain banks till the vegetation has reclothed them over all their extent, and till the torrent itself shall have lost the greater part of its violence. They can be employed also to stop up the secondary ravines, to intercept the little ramifications, to fill up small holes ; in fine, to lead over the surface of the soil, and thus completely efface those innumerable streamlets divided like the hair-like fibres of a root, which are really and indeed the root of the evil. 54 RESUME OF SURELL’S STUDY OF “ Behold the work completed ! “In recapitulating what has been said it will be seen that it resolves itself into four parts—first, the tracing of zones of enclosure ; second, the covering of these with trees ; third, the extension of vegetation over the banks ; and fourth, the construction of barricades of facines, of brushwood, or of wicker-work. “One thing remains yet to be adverted to. I must speak for a moment of the order in which the work should be advanced. This order, far from being arbitrary, is an element of first importance, and a most essential element of success. I have already so often, in the course of this work, brought forward the necessity of attacking the torrents at their source that I believe it to be unnecessary to dwell uponit now. Thus, then, it is in the highest parts that the works should be first undertaken, thence to be extended to the parts of a lower level. Not only should a commencement be made by planting the bassin de réception before giving attention to the lower zones, but even in this basin the commencement should be made in its highest ramifications. One should go above the last traces of the bed, up to the abrupt slopes furrowed with ravines which the waters form and deform with each storm of rain,—it is there that the first works should be established ; one should afterwards—but only afterwards—carry them lower, but making sure first that the parts left are quite consolidated.” A chapter is devoted to the discussion of the practicability of carrying out such measures ; and another to the consideration of the legal difficulties in the way of this being done. In a résumé of the work proposed, he concludes his recapitulation, saying, —“The definite result of the whole will be the creation of forests; the whole work may be summed up in one sentence :—Reclothe with woods the more elevated parts of the mountains. If it be true, that forests exercise an influence on the climate, the effect of this extended mass of new woods will be to render the showers of rain less heavy, the rain-storms more rare, and the whole atmosphere more moist and more showery ; the climate will then, by insensible degrees, be changed at the same time as the surface of the soil ; and thus the two causes of torrents will be destroyed at one and the same time, and a general result will have been obtained while seeking at first only to remedy a particular evil.” But, he goes on to say, the work of reclothing the heights with wood will not of itself render unnecessary the construction of dams and wears; and he proceeds to indicate the application of embankments, which would meet the requirements of the case with which he had to do—the prevention of ravages by torrents. The question of expense is then discussed ; reasons are adduced to show that the expenses should be borne by the State. And, in a recapitulation and conclusion, the various measures proposed are reviewed and defended against such objections as it was thought possible might be brought against them. Such is an analysis of the Study of the torrents of the High Alps, to which may be traced the commencement of the works of reboisement and gazonnement which are now being carried on, on a gigantic scale, in the Alps, the Cevennes, and the Pyrenees. But it is by no means the only work advocating such measures ; and I proceed to supply information in regard to other works, treating of the same subject, published before and after this work of Surell’s, PA LT. LITERATURE RELATIVE TO ALPINE TORRENTS, AND REMEDIAL MEASURES PROPOSED FOR ADOPTION TO PREVENT THE DISASTROUS CONSEQUENCES FOLLOWING FROM THEM. Tue subject treated so exhaustively by Surell has commanded the attention of many besides him. In 1797 was published an Essai sur la theorie des torrents et des rivieres, by M. Fabre, an engineer referred to by M. Surell, who had made these his study. The following are translations of some of his propositions relative to them, and to appropriate remedies for them. “144. The destruction of the woods which cover our mountains is the primary cause of the formation of torrents. “The reason is apparent. These woods, be they timber forests or be they high coppice, intercept by their foliage and by their branches a considerable portion of the water falling in- rains and in thunderstorms. The remaining portion, which they could not retain, falls only drop by drop at intervals sufficiently long to let them have time to filtrate into the earth. On the other hand, the bed of vegetable earth, which goes, on increasing annually, imbibes a considerable quantity of these waters. In fine, tufts of herbage and bush break and destroy at their origin the torrents which might have been formed notwithstanding all these obstructions. The woods being destroyed, the waters of a storm no longer meet with any- thing in their fall to intercept them. They cannot, by reason of their abundance, be absorbed by the ground as they fall. They flow over the surface, and meeting no more tufts which might have broken and divided their courses, they form torrents, as has been said. “145. The clearings on the mountains are the second cause of the formation of torrents. “ We have shown that a torrent will be formed with so much the more facility in proportion as the matters which compose the mountain shall have less tenacity. Now the clearings, in rendering the earth friable and mobile, have diminished this tenacity; and thus they have favoured the formation of torrents. “One may see from this how ill-advised and inconsiderate was the law given under the ancient régime, which authorised clearings, provided there ' were constructed at intervals walls of support to keep the earth on the slopes of mountains. It was not seen that in a great many countries the people confined themselves to raising two or three crops on a clearing, and that they then abandoned it. It was natural, this being the usage, that the sustaining walls, coming to cost more than the crops would repay, would not be constructed ; and this is just what has happened. But there has already resulted from this, and there will result from it in the future, frightful disasters, as we shall now see. 56 LITERATURE ON TORRENTS. “146. The first disaster produced by the two causes of which we have just spoken is the ruin of our forests. “Tf there had existed wise laws, and these had been carefully executed, we should have had now building timber in such quantity as to permit of exportation. We should also have had in abundance wood for carpentry and fire-wood. It is felt that both of these things are essentially necessary in a well organized state. But they fail us to such a degree that in a great number of communes there is not even fire-wood. The evil has been long felt, and the necessity of remedying this is urgent. “147, The second disaster is the destruction in a great many places of the bed of vegetable soil with which our mountains were covered. “This bed would otherwise have produced abundant pasturage for the sheep, but, carried away by the storms and torrents, there remains at present on these mountains only a naked and dry rock. From this results necessarily a diminution of the small number of cattle which France might have been able to support if these pasturages had continued to exist. “148. The third disaster is the ruin of the domains which le upon the rivers. “We have seen that the swellings of the torrents were stronger in proportion as the mountains were less wooded and more impoverished. These swellings are then greater now, through the operation of the two causes mentioned above, than otherwise they would have been. They ought, therefore, to cause, and they do really cause, much more havoe to the domains along their course than they otherwise would have caused. “On the other hand, we have seen that it might happen, as it has in effect happened too often, that the torrents in issuing from their bed or channel would cover adjacent domains situated at the foot of the mountains with deposits, which absolutely alters their nature. Now, this never happened until that by the operation of the two causes mentioned above the torrents were formed. “149. The fourth disaster is the drainage, experienced in the navigation of the rivers, by the divisions in the water-courses, which are the consequents of great floods, “150. The fifth disaster consists in the strifes and contentions, between the proprietors on opposite banks of the river, to which the divisions in these water- courses give rise, “151. The sixth disaster results from the deposits which they make at the mouths of the streams, which often intercept the navigation.” Each of these three statements is illustrated in detail. “152. In fine, the seventh disaster consists in the diminution of the sources which feed the streams and the rivers (n their ordinary state. “We have seen that springs, the sources of streams, are formed from the rains which filtrate through the earth and meet in the subterranean reser- voirs, whence they escape by minute channels, and make their appearance at the surface of the ground. Novw, if the mountains be despoiled of their bed of vegetable earth, and there remain only the bare rock, it is evident that the water of the rains will no longer filtrate through the soil, but will flow quite superficially ; thence it follows, that as the fountains diminish so must the rivers which they feed; and a time will come when even the rivers which at present are navigable will cease to be so. True, indeed, that time is still distant, but sooner or later it will arrive if the cause whol produces this effect be not destroyed.” FABRE’S ESSAI. 57 With these views M. Fabre urged then the planting of trees, or the rebvise- ment of the mountains, and the protection of these throughout their growth. He thus states his opinion:—“ We have said that the destruction of the woods which were covering the mountains, was the primary cause of the formation of the torrents. To destroy the effect, the cause must be exterminated. Therefore, if there be still vegetable earth on the mountains, it will be well to leave these to become clothed again with wood, by leaving them in fallow, and with a view to the same end, it may be well to remove every- thing which might damage the young trees. For this reason, most rigidly should be carried into execution the laws relating to the. prohibition of goats, for it is known that the tooth of this animal is murderous to young trees. It is not less essential to provide for the conservation of existing woods, since these woods, which have kept the torrents hitherto from being formed, are to us a sure guarantee that they will prevent the formation of them in the future. “Clearings are the second cause of the formation of torrents. It is necessary, then, that after having been too extensively tolerated by the ancient laws, these should be restricted within prescribed limits. In con- sequence, we consider, that in this respect, they should be conformed to the following rules :—First, a clearing ought never, under any pretext whatever, to be permitted on the slope of a mountain, which has less than three of a base for one of vertical height, z.e. a slope of one in three. “ Second, the clearance might be permitted on one of less declivity, but only under the restrictions we are about to state. “ Third, the clearance ought never to be authorised, but on the verge, or in transverse horizontal strips, or on a level, or what is nearly such. “ Fourth, in this case the strips of fallow should be separated from one another by other strips, likewise horizontal or level, left uncultivated, on which the wood should be -permitted to grow. “ Fifth, these uncultivated strips should be made to take the place of the sustaining walls, prescribed by the law previously spoken of. It appears that they should not be less than five toises, or thirty feet, in breadth, to enable them, in case of need, to destroy a torrent which might be formed on the strip of fallow above it. “ Sixth, the breadth of the strips of fallow should be only five ovses, or thirty feet, where the slope.of the mountains may be one in three; but it appears that it may be increased with the diminution of the slope, ‘until a slope is arrived at, which leaves no cause of fear of the formation of torrents, in which case the breadth may be unlimited. “Seventh and lastly, the clearings should in no case be permitted without the authorization of the respective municipal authorities, and after the specification and plan, which shall have been previously made by a public official of what is proposed in each commune. “ Every one must see that by some such regulation we may escape for the future all the disasters produced by arbitrary clearings, almost always ill- arranged, both as they affect the interests of the community and those of the individual, Nature is only the more active when aided by human industry, and so in cases in which it is wished to hasten on, on certain moun- _tain slopes, the increase of woods, it would often not be bad to sow acorns and beech-nuts, or seed of any species of trees which may be presumed to be proper to the localities. There is more than one country where they are-quite accustomed to do so, E 58 LITERATURE ON TORRENTS. “There are cases where there remains so little earth on the mountains as to lead one to conclude that wood will there make but little increase ; such grounds may be laid with turf, and sown with seeds of plants which may be deemed most proper for the localities. The superficial tissue formed of turf will be an obstacle to the formation of torrents, and by this means besides will be created useful pasturage. “These are the means of preventing the formation of torrents on the mountains. It remains for us to see those which must be employed to destroy, when the thing is possible, the torrents already formed.” The views advanced by M. Fabre have never, so far as I know, been subverted ; and by subsequent studies of the phenomena many of them have been confirmed. But it has been objected that the subject was not one which admitted of being discussed in such precise propositions as those in which he invested his views—that some of his propositions were based on deduction rather than founded on an induction of fact—and that, in the absence of facts, adduced to establish or support his deductions, there was an element of uncertainty thus introduced into his conclusions, which prevented them being made the ground of extensive practical undertakings, involving great expenditure, until they had subsequently been verified by renewed observations of facts systematically conducted. This circumstance makes the work more valuable to any one desirous of studying the subject in all its aspects. It is a work to which Surell often appeals, as a work the value of which was indisputable, and as the only work going to the root of the matter in discussing a subject not exactly the same but one nearly allied to that to which he was giving attention. And he mentions that Fabre had himself announced, that no work on the subject had previously been published, praying that the imperfections of his work might be borne with in view of the novelty of the matter. Surell speaks of Fabre as an engineer who had occupied himself with this study, and he says of the work by him, that it contains a complete des- cription of torrents, with just, and often ingenious, remarks on their action ; but he states that he considered the form of aphorism in which his obser- vations are couched a defect, exposing them to the objections I have cited. He states further that it is clear, from many passages, that the torrents seen by M. Fabre were not those of the High Alps, which were those which were the subjects of his own study, though they were similar to them in many respects ; and that his theory, when applied to them, was not always borne out by the phenomena presented by them, or did not cover these: that it was evidently based on the observation of torrents, which devastated the South of Provence, and more especially the torrents of the Var, where he was Ingénieur en chéf. But all of these considerations make his observations and conclusions the more valuable to any, who may be studying the subject, with a view to the discovery of remedial measures, appropriate to countries very differently situated from the ravaged and devastated regions of France. We find in Fabre and Surell, men of different casts of mind, belonging to different generations, following their professional pursuits in districts far apart and differently situated, propounding doctrine essentially and substantially the same. With regard to the deficiency of observations as a foundation of M. Fabre’s counsels, such observations were greatly desiderated by him; he stated that no work on the subject had been published, and he craved that LEOREULK AND H&RICART DE THURY. 59 the defects of his work should be excused in view of the novelty of the subject of which it treated. In 1804 there were published Reserches sur la formation et Vexistence des ruisseaux, des rivieres, et torrents, by M. Lecreulx. The design of this publi- cation was to refute the views advanced by Fabre ; but it has been alleged that apparently the author did not know the kind of water-courses to which Fabre in his work had a reference. On this point M. Surell writes—‘“I searcely know whether Lecreulx meant positively to dispute the position that woods have an influence on the production of torrents. In attacking Fabre on this point all that he does is to bring to light his complete ignorance of the kind of mountains and of the kind of water-courses which Fabre had specially before him. Lecreulx had always before his mind the case of the Vosges, which comes up in every page of his book. I know the Vosges well, and I can affirm that these mountains no more resemble the High Alps than the German patois, spread over several of the valleys, resembles the provingal dialect which is here the general language of the country.” In 1806 appeared a Ptomographie des cours @eau du Département des Hautes Alpes, by M. Héricart de Thury, in which are pencilled rapid sketches of the geological characters of the beds of the water-courses of the Department, and his work supplies data valued by students of the country, seeking to discover the cause or occasion of the ravages which these water- courses make, and a remedy for the evil. He reckons eight distinct basins or river valleys in the High Alps. Surell reckons three, but this affects not the facts recorded: it resolves itself into a mere question of judgment in regard to the best division to be made. The views are in accordance alike with those advanced ten years before by Fabre, and thirty years later by Surell. Of the vicinity of Embrun he writes,—“ In this magnificent basin Nature, has been quite prodigal of her blessings. The inhabitants have enjoyed her favours with their eyes shut ; they have slept on in the midst of her beauties. Ungrateful for all, they have inconsiderately carried the axe and the fire into these forests which shade the steep mountains—the ignored source of their riches. Soon were these emaciated peaks ravaged by waters, torrents swelled and precipitated themselves with fury on the plains; they have cut down, torn away, and undermined the foundations of the mountains ; grounds of great extent have been carried off ; others have been entombed ; these have been covered with rocks, those show nothing but stones and gravel. The ravages are still going on ; no obstacle is opposed to their fury—soon in Crevoux, Boscodon, Savines, and all the country around, the torrents will have utterly destroyed all this fine basin, which but lately would have borne comparison with all possessed by the richest countries—with the most fertile and the best cultivated of them all.” The warning was sounded in vain. It was drowned in the roar of cannon carrying into other lands devastation, and death, and mourning, and woe ; but after the men of that generation had mostly died away, and another generation had taken their place, the subject was again brought under consideration. In the Annales des Ponts et Chaussées, for 1833, 2d Semestre, is a paper by 60 LITERATURE ON TORRENTS. M, Montleuisant, entitled Mote sur les Deséchements, les Endiguements, et les Frrigations, which is:‘not without its bearing on the subject im hand. And about the same time a Memoir.by M. Delborgue Cormant, Ingénieur en chéf des Ponts et Chaussées, on erabankments. In 1834 appeared a second edition of a work previously published—His- toire, Topographic, Antiquites, Usages, Dialects, des Hautes Alpes—by J. C. F. Ladoucette, who had been prefect of the department, and who had been eulogised as the best prefect the High Alps ever had had. A statue of him erected in Gap speaks of the high estimation in which his labours for the good of the department were held. By him the number of basins, or river- valleys, in the High Alps is reckoned five, while by M. Héricart de Thury they had been reckoned eight, and by M. Surell they were afterwards, as we have seen, reckoned to be three; but, as has been stated, such enumera- tions are mere matters of judgment in regard to what are entitled to be considered separate basins, and to be entitled to this designation. This work did not contribute much information in addition to what was previously known on the particular aspect of the subject which connected it with forest science. It was otherwise with another work by one who had also held the office of prefect, a memoir, entitled Projet de boisement des Basses Alpes présenté a S. £., lé ministre secretaire d'etat de Interieur, par M, Dugied, ex-préfet de ce département. The following is a translation of a statement of his views :— “More than half of the department of the Low Alps is covered with arid and unproductive soils. These are increased by numerous torrents, which, descending there into the fertile valleys, complete the ruin of the country. ““ Two causes have contributed more especially to bring about this sad state of things,—the destruction of forests on the one hand, and on the other the rage for clearing land by grubbing up the roots, and herbs, and bush. It is high time to apply remedies, for later to remedy the evil will have be- come impossible. i “To bring about a restoration of the department, three measures should be adopted—(1) To prevent additional grubbing, and to restore to the grubbed lands their primitive consistency ; (2) To plant the summits and sides of mountains with trees; (3) To enclose the torrents. We shall remark on each of these three measures in succession. “ First Measure.—Grubbings may be prevented by enforcing the ordinance of 1667, which pronounced a penalty of 3000 francs against all those who should grub ground free of wood on declivities. And grubbed lands may have their primitive consistency to some extent restored by compelling the proprietors to convert them into artificial meadows, be it by the power of the tribunals, or be it by administrative action. (The author cites an experiment, from which it appears that sowing the grounds with sainfoin, Hedysarum Onobrychis, had completely consolidated a land previously sub- jected to extensive waste). “ Second Measure.—lt follows, from statistical estimates, which have been prepared, that the area ofthe ground in the Low Alps, which we may hope to replant with trees with success, amounts to 150,000 hectares. It may be accomplished by each year taking of this surface from two to three thousand hectares, say 1200 acres, which it might be required of the pro- prietors of the soil to replant. But here there presents itself more of a difficulty. First, the great subdivision of the properties which will toultiply the cases of resistance, and the little revenue which the pro- DUGIED’S PROJET DE BOISEMENT. 61 prietors of each will draw from the plantations during the earlier years of their growth. And, secondly, it is the case that the gross expense of the plantations, will not on all grounds be compensated by proportionate future products. “ These difficulties are very serious, and they cannot be overcome but by one expedient, the intervention of the State. This may consist, lst, in premiums given to the planters ; 2nd, in the gratuitous distribution of seeds ; and 3rd, in a remission of taxes in favour of the planters. “ A premium should be granted to every proprietor whose sowings have been successful. ©The verification of this must be made by a commission, and the success stated in a minute addressed by this commission to the prefect. The value of the premium might be 20 francs per hectare, and it should be paid by the State conjointly with the department, the State paying three-fourths and the department one-fourth of the amount. Thus, on the supposition of two thousand hectares being sown annually, the department would disburse each year in prizes 10,000 francs, and the public treasury would disburse in the same way 30,000. . . . Thegrounds on which I propose that the department should not pay more than 10,000 francs a year are, (1) that the department is far from being rich ; (2) that it will not recover payment of the sums it furnishes, whilst the Government will recover all its advances ; and (3) in a word, that without such advances on the part of the Government, there is no reason to hope that the operation will ever be carried out. No doubt the department will derive very great advantages from the work ; but the sacrifices which it will make to contribute to the success will not be the less real sacrifices.” . . . M. Surell says,— “ This, which was a weighty reason at the time when M. Dugied wrote these lines, has become, since the law of the 10th May, an absolute necessity.” M. Dugied goes on to say, “The second mode of intervention, consisting in the gratuitous supply of seeds, should be wholly at the expense of the State. Let us suppose that there are sown 2000 hectares annually, and that they are divided, in regard to kinds of trees, in the following way : 600 hectares in acorns ; 600 in beech ; 800 in firs and pines—in all, 2000 hectares. The whole expense of the seeds, carriage included, should be about 23,400 francs. The expense would rise to 35,100 francs if there should be sown 3000 hectares per annum instead of 2000. “The Administration, by delivering the seeds gratuitously, will have it in its power to determine that the different kinds of trees have been distri- buted with intelligence, and that each kind of soil has only received those for the growth of which it is best fitted. Declivities too steep should be sown with box trees and brooms, “The sowing will also require to be protected against cattle and against plunder. It will be necessary to secure a very active and very strict surveillance on the part of the forest officials, who may remain charged with watching the future forests ; their number should be augmented, their organization perfected, and at the same time their condition raised and their circumstances improved. “Tn conclusion, passing on to the third means proposed—the remission of taxes. Each proprietor, after an examination and approval of his sowings, at the end of five years might have a remission of taxes for the period of ten years. “Such are the sacrifices which impose themselves on the State to secure, by degrees, the reboisement of the mountains. 62 LITERATURE ON TORRENTS. “Third Measure.—This relates to the enclosing of the torrents by embankments. This enclosing should not be commenced until the forests shall have produced their effects—that is to say, in fifteen or twenty years after the first plantings. The engineers of roads and bridges should prepare the plans of the works to be executed. The expense should be borne by the proprietors interested, and by the State, which should assume the responsibility for half the outlay. The effect of the dykes should be at once to protect the river lands and to acquire new lands.” The author calculates that the enclosing of the Durance between Sisteron and the Pertuis des Mirabeau would cost at most from 4 to 5,000,000 francs ; and that the area of land acquired would be 10,000,000 square toises or fathoms, which would be worth, at the end of three years, at least 10,000,000 francs. The capital in this undertaking would thus be doubled at the end of three years. In a second division of the work, M. Dugied endeavours to show benefits resulting to the State from such undertakings, which might induce them to enter into this expenditure, doing it in such a way that the first expenses could not be in excess of the sums to be repaid. “The mortgage of the sums expended by the State,” he says, “ will resolve itself into an augmentation of the imposts to which should be subjected waste lands converted into forests. Strictly, and according to the rules adopted in the assessments of imposts, the augmentation should be for the advantage of the Department, and should lighten the manorial tax of the other proprietors. But it may be believed that the General Council will consent to the addition which may be made to the manorial contribution of the Department ; and it is on this augmentation, on the assumption of this consent, that we can base our calculations. “The contribution allotted to waste lands is upon an average twenty-two centimes per hectare ; that on forests is seventy-two centimes. When, then, a hectare of waste lands shall have been converted into forest, it will produce an augmentation of contribution equivalent to fifty centimes. It is this difference of fifty centimes which will constitute the funds for repayment. It must be observed that the fifty centimes will not be touched until ten years after the sowing, if the State have granted to the sowers a remission of taxation during this period of time. It must also be taken into account in the calculations that all the sowings will not be successful, and that a portion of the seeds delivered gratuitously by the Administration, and paid for by it, will have perished. It is supposed that the loss of sowings may be about a fifth of the whole. “From these data there can be formed tables which will give, year by year, a statement of the expenses, or of the returns, of the Government ; and it may be seen in this way that for a sowing of 20,000 hectares, the expenses of the Government at the end of ten years will have amounted to 534,000 francs, but that at the end of eighty-six years it will have recovered all these advances. Moreover, it will have acquired an annual bonus of 8000 francs, seeing that the contributions will continue to run on. “Tf one extends the calculations to 150,000 hectares (that is, to the whole of the area to be re-wooded), and if we suppose that the sowings will extend over fifty years, it will be found that the State will have recovered these advances at the end of one hundred and ten years, and that it will enjoy thenceforward an annual bonus of 60,000 francs. It follows from this that DUGIED’S PROJET DE BOISEMENT. 63 it is for the interest of the State to give to these operations the greatest extension possible. “Tt is also necessary that the State should recover the advances which it will have made for the construction of dykes. And it will find the means of liquidating the amount sunk in the work, first, in the profit calculated above, as resulting from the 50 centime augmentation of impost on the land as wooded, and further, in the proprietorship of a certain portion of the lands acquired. As it will have furnished the half of the expense to which the acquisition owes its existence, it is just that it should obtain possession of half of the lands acquired.” M. Surell says,— Such is the system developed by M. Dugied in his Memoir Sur le Boisement des Basses Alpes. This work produced no fruit. Tt did not for one moment stop the abuse. The Administration is not yet aroused from its indifference ; and the devastation of the torrents, and the miseries which this brings in its train, and the daily progressive ruin of the country, go on still, as in the past, before unpitying eyes. “The efforts of M. Dugied have been but little appreciated; and the country, in favour of which he was the first to raise his voice, has not been more just in regard to him than was the Administration of the Restoration which deposed him from the prefecture of the Basses Alpes, which he had not occupied more than a year, and where he would probably have rendered eminent services to the country. His-work has called forth ridiculing criticisms. They have referred the execution of his project to the Princes of the Arabian Night Entertainments. I must confess that the extravagancies of the project of M. Dugied has entirely escaped me. I only see in it an operation, sufficiently simple at bottom, which could not fail to develope, on a vast scale, what is practised every day by private parties ; an operation, the execution of which is evidently possible, and the expense of which has nothing surprising in it when I compare it with those which the Administra- tion entrusts every year to the engineer of the smallest arrondissement. Certainly, it would read as a romance, much more extravagant than the alleged palingenesique romance of M. Dugied, if one would turn over the leaves, mastering the same, of the report of the 120,000,000 francs worth of works executed every year, on all the bridges of France, under the Direction des pouts et chaussées! This speaks of the sea imprisoned in harbours, roads tunnelled through rocks, rivers confined by embankments or by bridges, lighthouses erected on rocks in the midst of tempests, canals trans- porting boats across the summit of mountains. I see in these works, works more difficult, more costly, and more marvellous by far, than the reboisement of some nooks of mountains. And if any come to discuss in the Chamber seriously, and like people who are ready to put hand to the work, the enormous budget of a milliard and a half, which certain economists tell us to be necessary for the establishment of a complete net- work of railways, what will be thought of this other prodigy, which was held to be only fabulous not mure than thirty years ago? When we shall have multiplied by ten, or by a hundred, the figures given by M. Dugied, we shall not yet have come to expenses like to those of a great number of our public works, which are ten times—or, for that matter, a hundred times —less useful, and which do not frighten us, accustomed as we are, for a long time, to open our purses for their execution. “Will any one undertake seriously to deny the possibility of the reboise- ment proposed by M. Dugied? . . The proofs which have established 64 LITERATURE ON TORRENTS. this possibility are too numerous, too palpable, for this. Everybody admits that the Alps were wooded long ago; and this is itself a proof that woods may yet be made to reappear there. The first forests which nature cast on these mountains had to clothe a soil more naked, more sterile, more irregular, than the actual soil of the present. And if vegetation has already triumphed a first time in this struggle against destructive agents, why should she succumb to-day? It will be said that she was assisted by time! It is so. But to-day she will be assisted by man, and that assistance, in my opinion, avails more than that of some four centuries. There are here and there, in the bed of the Durance, conquests over the waters made by the effort of nature alone ; but long ages have scarcely sufficed to ensure vegetation there, ‘and some portions of it remain eternally sterile. When man undertakes like conquests he finishes them in three years ; three years suffice for him to make fields to flourish on the very place where the waters rolled pebbles and barrens sands. This miracle is renewed every day, and under the eye of all. Is not this a more marvellous triumph than it would be that man should succeed in reforesting lands which, for the most part, have been covered with forests before. “Tf I wished to criticise the work of M. Dugied,” says he, “I would not bring against him such objections. But whilst entirely approving the basis and the end of the project, I would condemn some few details of execution. M. Dugied has comprised, under the designation of torrents, the Durance, the Verdon, the Cleone, which are rambling rivers, and on which the reboisement of the mountains could only have a detournée, and secondary influence in affecting the water-course. And in making the embankment of these water-courses a corollary of the plantation of forests, he has coupled together two distinct operations. From this it follows that his project is in some respects too ample and exaggerated, and at the same time in some measure defective. And this impression of vagueness is deepened when it is seen that M. Dugied does not attach to forests any action on the torrents other and beyond that effected by a climatal change. As this influence is rather uncertain, and very difficult to be cleerly demonstrated, one cannot understand how the author came to build on it such great expectations, and that he should make of reboisement a preliminary operation, without which the embankment of rivers would not be undertaken with success. “ But there is a point in which his project seems to me defective in its very foundation—it is this, he makes the execution of it to rest entirely on the gooodwill of the proprietors. If the enterprise be really a thing of public utility, as the author says it is—if it truly have the degree of importance and necessity which he attributes to it—how does he come to leave it at the mercy of the first peasant—stupid or stubborn—who wlll refuse to take part in it? It showed little knowledge of the spirit of the inhabitants of the country, to believe that a premium will suffice in every case to overcome the natural apathy, and above all, the obstinacy of such, if once they stubbornly determine not to give in to the undertaking. Now, this will certainly occur oftener than once, if it do not become even generally the case. The twenty francs of premium per hectare, which M. Dugied tenders to them, would not always appear to them a sufficient indemnity to com- pensate the trouble which the sowings might entail, and the loss of their pastures, of which M. Dugied says nothing, and of the numerous interferences which will follow from the operation. These works, besides, will not succeed but through the expenditure of sustained and intelligent exertions, PUGIED AND SURELL, 65 which the peasants will not make. They. will soun have invented a thousand artifices to gain the premiums, without having done anything to deserve them. “It is thus indispensable that the State undertake the charge not only of the expense, but also the execution of the works; and ex-appropriation or con- fiscation will furnish them with a legal means to bring down all possible resistances. “Tt seems that M. Dugied has recoiled from urging this, most possibly be- causé he was afraid of the expense; but I have shown that this will be some- what reduced. Besides, does not the State acquire every day for roads, and by the same means, fields far more costly than the waste lands of these moun- tains? And in that case the possession of the soil brings to her nothing, or at least procures for her only a change of advantages. Here it buys the lands at a low price, it exploits them, it gives them value, and by that means she increases her domain if she retains them in her own hands, or the revenue from the taxes if she restores them to the inhabitants.” Of this work of M. Dugied, Surell says,— It is the only memoir known to me which treats specially of the means to be employed to counteract and oppose the scourge of the torrents.” And he adds,—‘‘ What is proposed by M. Dugied is conceived in a comprehensive spirit ; but the characteristic peculiarities of the torrents are neither analysed nor described by him ; the work is addressed to those to whom the torrents are already perfectly known.” In 1841 appeared his own work, Etude sur les Torrents des Hautes Alpes, of which a résumé has been given in Part I. of this compilation. On my first perusal of this work, knowing as I did how much damage was done by torrential floods at the “Cape of Good Hope, my feeling was a desire that I could make the substance of it my own, and give forth anew the observations, and the reasonings, and conclusions of the author, for the information of my former compatriots in that Colony, and of others in other lands exposed to such torrential floods as there alternate with severe and long-continued droughts. But this was impossible ; and, moreover, I have often found excerpts from the work of an original ‘thinker far more satis- factory, and often far more suggestive, than any digest of it given by friend or foe. Often, on reading some such digest, I have felt disposed to cry out, Give me his own words, for no words can better tell what he says than the words he has himself used in the collocation of them which he has given ! but to do this was also impossible; and I have done what I consider most likely to be satisfactory at once to M. Surell and to students of the subject of which he treats, at the Cape or in other lands, in which the English language must be the medium of communication. The work was published by order of the Administration des Ponts et Chaussées. Public opinion was not then so advanced on the subject as to prompt to action, and his services were put in requisition for the carrying out of the system of railways, which seemed to demand more immediate attention. While rejoicing in his honours and usefulness as Ingénieur en chéf des Ponts et Chaussées, and Directeur des Chemins de fer du Midi, some regret may be felt by those who are alive to the importance of reboisement as a means of stifling torrents that scope was not found for his energies in originating and carrying out works such as he had advocated. After the work was out of print, many solicitations were addressed to him F 66 LITERATURE ON TORRENTS, to issue a new edition. But from this he shrunk. The state of things depicted by him had, to a great extent, ceased to be, his suggestions had been carried into effect, and a new state of things had come into being. But he was relieved of embarrassment by his comrade and friend, M. Cézanne, agreeing to prepare a supplemental volume, and the two were published conjointly,—the first volume, the Etude of M. Surell, in 1870, and the Supplement, by M. Cézanne, in 1872. The subjects of M. Surell’s study were chiefly these,—the phenomena of torrents and effects produced by them; the causes of their occurrence ; means of defence which had been employed to protect the land and its inhabitants against their ravages ; and measures which were more likely to prove efficient if they should be employed, which measures were plantations of trees, and herbage, and bush, over the area drained by them, combined with the erection, in subordination to this, of barrages, or wears, to control and regulate the flow, where this may be practicable and desirable. Previously to the publication of the original edition—but at what date I know not—there had been published a Memoire sur [état des foréts dans les Hautes Alpes, les causes de cet état, ses resultats et les moyens dy remedier, by M. Delafont. Of this M. Surell writes,—‘ All the causes of the destruction and disappearance of forests are thoroughly and carefully expounded in a memoir by M. Delafont, inspecteur des eaux et foréts—a memoir full of well-intentioned and wise statements, which only calls forth regret that it did not inspire the Adminstration with enlarged and bold views, which alone would be commensurate with the evil; for great evils call for great remedies.” “The sad results which I am about to point out,” says M. Delafont, “ are deplorable on all hands. All men who have not been blinded by ignorance, or whose heart has not been withered up by selfishness, give expression to the thought that it is high time to stop the progress, ever increasing, of so fearful a devastation. They lament over the evils without number which are occasioned by the deforesting of the mountains, and seem to call us to the protection of our forest wealth. These reflections, these prayers, I have often myself heard uttered with an energy which is inspired by the profound conviction of the existence of a great evil, and of the imperious necessity which there is to stop its course. Let us listen to the cries of distress of a population alarmed by the future before it.” And M, Surell refers to this, and other statements by M. Delafont cited by him, as supplying evidence that he had himself in no way exaggerated the evil in what he said in his Etude sur les Torrents. While the work of M. Surell’s was passing through the press, he received a copy of a Memozre sur la dégradation des foréts dans les arrondissements @Embrun, et de Briancon, which the inspector of forests, in these two arrondissements, M. Jousse de Fontaniére, had shortly before addressed to the Administration, Of this he says,—“This work—prepared by a man most competent for the work, and devoted to his duties, who, after having struggled for a long time against the innumerable difficulties of his service, succumbing under the trial, took measures at last to demand aid—should have had the effect of securing the attention of the State to the frightful future to be anticipated in this department.” And he cites the following as a specimen of the out-spoken faithfulness of MEMOIRE BY JOUSSE DE FONTANIERE. 67 the author,—“ From all that has been said, it is concluded that the depart- ment of the High Alps is the one of all France in which the cultivators are most threatened in théir fortune, and that they will be compelled, sooner than is supposed, to abandon the places which were inhabited by their fore- fathers, and this as a consequence of the destruction of the soil, which, after having supported so many generations, has given place, little by little, to sterile rocks. “The destruction of the forests will be the principal cause of this calamity. The disappearance of these from the mountains will give up the soil to the action of the waters, which will sweep it away into the valleys ; and then the torrents, becoming more and more devastating, will bury under their alluvial deposits extensive grounds, which will be for ever with- drawn from agriculture. “The crusts, denuded of their vegetable soil, no longer permitting the infiltration of the waters, these will flow away rapidly on the surface of the ground. Then the springs will dry up; and the drought of summer being no longer moderated by their irrigations, all vegetation will be destroyed. “The elements of destruction growing thus one out of another, we have only to observe what passes to-day to predict what will infallibly come about some ages hence. When the forests shall have entirely disappeared, fuel and water, the two primary necessaries of life, will be awanting in these desolated countries. “The cupidity of the inhabitants of these mountains, the tenacity with which they keep to old customs, do not permit a hope that a moral conviction of this desolating future will strike their thoughts so strongly as to lead them to make some temporary sacrifice ; it is, therefore, for the Administra- tion, more enlightened in regard to the state of things, and to their con- sequences, to meet the evil by laws most appropriate to the requirements of the country.” Ladoucette, in his Histoire, Topographie, Antiquités, Usages, Dialectes des Hautes Alpes, already cited, says the peasant of Dévoluy “ often goes a distance of five hours, over rocks and precipices, for a single [man’s] load of wood ;” and that “ the Justice of Peace of that Canton had, in the course of forty-three years, but once heard the voice of the nightingale.” Now the desert and the solitary plain begins there anew to flourish like a rose, and the inhabitants to rejoice with joy and singing ; and there is heard the shout of children playing in the streets—a change brought about by reboisement and gazonnement, confirming the conclusion that the destruction of trees and herbage had been the occasion of the desolation. In regard to the valley of Embrun, where a corresponding improvement has been brought about by similar means, Héricart de Thury, who has also been already cited, wrote in 1806,—“ In this magnificent valley nature had been somewhat prodigal of its gifts, Its inhabitants have blindly revelled in her favours, and fallen asleep in the midst of her profusion.” And Becquerel, in his work Des Climats, mentions also that it was once remark- able for its fertility. What it became, through the ravages of torrents, after the destruction of its trees, Surell has shown. M. Surell cites, as in accordance with his views in regard to the influence of the climate on the formation and violence of torrents, the following remarks by Labéche, in his treatise on Geology. Writing of the geology of the Alps, M, Labéche says,—“ A difference in the climate ought to produce 68 LITERATURE ON TORRENTS. other visible changes, as well in the superincumbent rocks as in those that were of an older formation. It is probable that the more a climate was warm, and approached that of the tropics, the greater would be the evapor- ation, and the quantity of rain; greater also would. be the intensity of power of certain meteoric agents ; consequently, according to this hypothesis, the different deposits ought to present indications of the influence of such climates, more marked in proportion as the epoch in which they were formed was more remote from the present. Ifrains, like to those of the tropics, have fallen on high mountains such as the Alps—even supposing that many of them had an elevation less than that of these—these rains would produce effects very different from those which we see now in the same countries ; one may see that these would form all at once torrents of which the actual inhabi- tants of these mountains have no idea ; such volumes of water would sweep away quantities of detritus far greater than those which the actual torrents of the Alps carry away, the volume of which, however, is pretty considerable, “Thus, though admitting the correctness of this hypothesis in this, it is necessary always to take into account the differences produced on the sur- face of the earth by the action of meteoric agents, the which is more power- ful as the climate is more warm. One ought especially to give attention to this, when from the observation of a series of the layers of the same district it appears evident that the temperature, under the influence of which they were formed, has gradually diminished. Let us examine now to what degree vegetation can, in warm climates, counterbalance the power of dis- integration, and transport which atmospheric agents possess. It appears that, all other circumstances being equal, the more warm a climate is, the more vigorous is the vegetation which it produces. The question then comes to this: Does the vegetation protect the soil against the destructive action of the atmosphere? It is impossible to answer this otherwise than in the affirmative. If we want proofs of this fact we shall find them in the artifical mounds, or barrows, which are so common in many parts of England ; they had been exposed in that climate to the action of the atmosphere for about 2000 years; and yet they have not undergone, in their form, any perceptible change, although they have, during at least a considerable portion of that time, only been covered by a light layer of turf. If now it is admitted that the vegetation protects, to some extent, the ground which it covers, it follows that the stronger the vegetation is the more efficacious is the protection which it affords, and as a consequence the ground is always defended from the destructive action of the atmosphere in proportion to the need it has of such protection. Without this providential law of nature the softer rocks of tropical regions would be speedily carried away by the waters, and the soil would no longer be able to sustain vegetables or animals ; for, although in many tropical regions we meet with vast extents of land which present the appearance of sterile deserts, but which one sees suddenly start to life after two or three days’ rain, and cover themselves, as by enchantment, with a beautiful verdure, we should bear in mind that the roots of the briskly vivacious plants from which moisture causes to be produced so vigorous a vegetation—and even those of the annual plants which have passed away, of which the seeds produce leaves so verdant— interlace themselves in such a way in the soil that they oppose a consider- able resistance to the destructive power of rain. In the Savannahs of America it is frequently the case that there is little vegetation, and there they experience considerable disintegration, LABECHE AND MICHEL CHEVALIER. 69 “T have by no means the intention to infer from what has been said that the disintegration of soil is not generally greater under the tropics than in temperate climates ; it has been my desire simply to establish that in both cases the soil receives, from the vegetables which cover it, a pro- tection proportionate to the destructive influence to which it is exposed. Let’ us suppose that there should occur in England one of those rainy seasons so common under the tropics. No doubt.great extents of land would be washed away, and the barrows, of which we have already spoken, would quickly disappear. If, on the contrary, there fell there only the same quantity of rain which we have every year in the climate of England, we would find scarcely any traces of vegetation in the low-grounds, for the water produced by it would be insufficient to sustain tropical plants, and while it tended to disintegrate the soil, it would be so speedily evaporated that its destructive action would be scarcely perceptible. The quantity of rain and the vegetation are proportionate to one another; nevertheless, the disintegra- tion of the soil increases with the quantity of rain, and the force of many meteoric agents, in such a way that, other things being equal, the greater the rainfall the greater is the destruction of the soil ; and consequently, the warmer the climate, the more considerable is the disintegration of the mountains. “In tropical regions, parasitical and creeping plants are seen in all directions, growing wherever it is at all possible to do so, and with such luxuriance as to render the forest almost impassable. The forms and the leaves of trees, and of such plants, are admirably adapted to resist great rains, and to protect the innumerable creatures which, in the rainy season, come to seek a shelter under their foliage. The noise which the tropical rains make in falling on these forests strikes strangers with astonishment ; it is heard at distances which would be almost incredible to the inhabi- tants of temperate regions ; and the rain, thus deadened and broken in its fall, is speedily absorbed by the soil ; whereas, where it flows into hollows, it produces torrents, which every one must confess are rather impetuous, and cause great ravages.” M. Michel Chevalier, in his work entitled Des Interets Matériels de la France, writes thus :—“ Besides the works executed in the river-bed, there are other measures which, according to men of experience, would exercise a salutary influence on the navigability of natural water-courses, and which concern even canals, as to feed these recourse must be had to rivers and to the smallest streams. I wish to speak specially of the replanting of moun- tains which have been so improvidently despviled of their woods, and abandoned in their nakedness by a culpable indolence, or even by a fatal one, descending to niggardly interests, which the law does not recognize, but on the contrary resents, have hindered the forests from reproduction by the effort of nature alone. The rains and the snows, when they fall on the bald heights, flow away or evaporate with the greatest rapidity ; in place of maintaining brooks and rivers, on the rich levels, by which boatmen may profit, and on which the proprietors of river-banks may felicitate themselves, they produce there sudden floods, inundatious which suspend navigation, devastate pro- perties, covering them with gravel, and sometimes cating into them and carrying them away ; then, after these floods, there follow soon low waters, which only stop at distant points and for a short time after some storm, Through reckless deforesting our temperate countries are thus being agsimi- 70 LITERATURE ON TORRENTS. lated to southern regions, where there are nothing but torrents during the spring and autumn, imperceptible threads of water in the midst of an ocean of sand during the summer, and never smooth unmanageable rivers. The business is now to restore the soil of France to the primitive forests. Amongst the deforestings effected within the last fifty years there is much which will be permanently profitable to the country. Deforesting is a conquest of man over nature ; woods ought to disappear from the plains, and there to give place to cultivation. But, unhappily, we do not find in the valley alone ground furrowed by the plough, or lands furnishing pasturage and grass ; they have plucked up the trees of sterile cantons, where wood alone should grow ; they have imprudently given up to the axe the sides and the summits of our mountains; then the régime of the profitless pastures, freed from all surveillance, together with a vicious administration of public and private forests, have hindered the reproduction of wood after the felling ; and the carelessness of the agents of the State in the communes have shut their eyes to the most destructive abuses. To-day the communes and the State possess thousands—millions of hectares of nominal forests, where there is just as much vegetation as there is in the steppes of Tartary, or in the desert of Sahara, The sowing ordered by the laws, or by the regulations, have been rendered illusory through the amount of the grants which were allotted to them, and a mockery through the bad faith which has too often presided over their execution, We are assured that oftener than once, and that I may say at a time not very remote from the present, the lessees of the fellings of the woods have sown sand instead of seed. About twenty years ago the evil came to a head ; then the Administration established the Forest School at Nancy, which furnished workmen capable and active, and men of integrity. In 1837 the minister of finances proposed to stimulate the zeal of subaltern agents by an improved treatment, which placed them above misery, and protected them from temptation. All these improvements of the officials are doubtless to be commended, but they will be productive of little effect so long as there is not inserted in the budget a chapter in support of replanting. With a million devoted every year to sow and plant well-selected kinds of trees on the plots occupied by the forests, which would appear always to rebel against cultivation, the State would create in twenty or thirty years an immense eapital, spread over the vast brows of the Pyrenees, of the Alps, and of the Vosges; as well as on the shores of the lands where they have applied, only on a Lilliputian scale, the ingenious and economic process of the savant Bremontier. In time of peace this would be an inexhaustable provision for twenty branches of industry, and notably for that in iron, which will never be wrought cheaply in France until wood shall be more abundant. In time of war this would be a resource of more ready avail than that of new taxes.” In the Memoires de ? Academie des Sciences Morales et Politiques for 1843 there appeared a Memoire swr les Populations des Hautes Alpes, by M. Blanqui, an eminent political economist, from which the following passage is cited and translated by the Hon. George P. Marsh, in his valuable work entitled The Earth as Modified by Human Action :—*TI do not exaceerate.” says Blanqui. “When I shall have finished my description and designated localities by their names, there will rise, I am sure, more than one voice from the spots themselves, to attest the rigorous exactness of this picture of their wretchedness. I have never seen its equal even in the Kabyle villages BLANQUI'S MEMOIRE, val of the province of Constantine ; for there you can travel on horseback, and you find grass in the spring, whereas in more than fifty communes in the Alps there is absolutely nothing. “The clear, brilliant, Alpine sky of Embrun, of Gap, of Barcelonette, and of Digne, which for months is without a cloud, produces droughts interrupted only by diluvial rains like those of the tropics. The abuse of the right of pasturage and the felling of the woods have stripped the soil of all its grass and all its trees, and the scorching sun bakes it to the consistency of porphyry. When moistened by the rain, as it has neither support nor cohesion, it rolls down to the valleys, sometimes in floods resembling black, yellow, or reddish lava, sometimes in streams of pebbles, and even huge blocks of stone, which pour down with a frightful roar, and in their swift course exhibit the most convulsive movements. If you overlcok from an eminence one of these landscapes furrowed with so many ravines, it presents only images of desolation and of death. Vast deposits of flinty pebbles, many feet in thickness, which have rolled down and spread far over the plain, surround large trees, bury even their tops, and rise above them, leaving to the husbandman no longer a ray of hope. One can imagine no sadder spectacle than the deep fissures in the flanks of the mountains, which seem to have burst forth in eruption to cover the plains with their ruins. These gorges, under the influence of the sun which cracks and shivers to fragments the very rocks, and of the rain which sweeps them down, pene- trate deeper and deeper into the heart of the mountain, while the beds of the torrents issuing from them are sometimes raised several feet in a single year, by the débris, so that that they reach the level of the bridges, which, of course, are then carried off. The torrent-beds are recognized at a great distance, as they issue from the mountains, and they spread themselves over the low grounds, in fan-shaped expansions, like a mantle of stone, sometimes ten thousand feet wide, rising high at the centre, and curving towards the circumference till their lower edges meet the plain. “Such is their aspect in dry weather. But no tongue can give an adequate description of their devastations in one of those sudden floods which resemble, in almost none of their phenomena, the action of ordinary river-water. They are now no longer overflowing brooks, but real seas, tumbling down in cataracts, and rolling before them blocks of stone, which are hurled forward by the shock of the waves like balls shot out by the explosion of gunpowder. Sometimes ridges of pebbles are driven down when the transporting torrent does not rise high enough to show itself, and then the movement is accompanied with a roar louder than the crash of thunder. A furious wind precedes the rushing water and announces its approach. Then comes a violent eruption, followed by a flow of muddy waves, and after a few hours all returns to the dreary silence which at periods of rest marks these abodes of desolation. “The elements of destruction are increasing in violence. The devastation advances in geometrical progression as the higher slopes are bared of their wood, and ‘ the ruin from above,’ to use the words of a peasant, ‘helps to hasten the desolation below.’ “The Alps of Provence present a terrible aspect. In the more equable climate of Northern France, one can form no conception of those parched mountain gorges where not even a bush can be found to shelter a bird— where, at most, the wanderer sees in summer here and there a withered lavender—where all the springs are dried up—and where a dead silence, 92 LITERATURE ON TORRENTS, hardly broken by even the hum of an insect, prevails. But if storm bursts forth, masses of water suddenly shoot from the mountain heights into the shattered gulfs, waste without irrigating, deluge without refreshing the soil they overflow in their swift descent, and leave it even more seared than it was from want of moisture, Man at last retires from the fearful desert, and I have, the present season, found not a living soul in districts where I remember to have enjoyed hospitality thirty years ago.” And in another connection it is said by Mr Marsh,—“ It deserves to be specially noticed that the district here referred to, though now among the most hopelessly waste in France, was very productive even down to so late a period as the commencement of the French Revolution. Arthur Young, writing in 1789, says,—‘ About Barcelonette, and in the highest parts of the mountains, the hill-pastures feed a million of sheep, besides large herds of other cattle ;’ and he adds,—‘ With such a soil’and in such a climate, we are not to suppose a country barren because it is mountainous. The valleys I have visited are, in general, beautiful.’ He ascribes the same character to the provinces of Dauphiny, Provence, and Auvergne, and, though he visited, with the eye of an attentive and practised observer, many of the scenes since blasted with the wild desolation described by Blanqui, the Durance and a part of the course of the Loire are the only streams he mentions as inflicting serious injury by their floods. The ravages of the torrents had, indeed, as we have seen, commenced earlier in some other localities, but we are authorized to infer that they were, in Young’s time, too limited in range, and relatively too insignificant to require notice in a general view of the provinces where they have now ruined so large a proportion of the soil.” But the voice of warning fell on deaf ears. It was like a voice crying in the wilderness—not the voice spoken of by the Hebrew seer, powerful as was that which had said,—“ Let there be light,” and which like it brought about its own accomplishment—but a voice crying in the wilderness, as that expression is generally understood. Inundations in 1840, and others occurring in 1846, caused some attention to be given to the subject, and measures were about to be adopted, with a view to prevent the continued occurrence of such catastrophes, when the Revolution of 1848 took place, and forests were sacrificed right and left to provide funds required to meet the national expenditure of the day. But on the establishment of the empire the subject again commanded attention. And within the last twenty years several works, in this department of the literature of forest science, have followed each other in quick succession. “In 1853, ten years after the date of Blanqui’s memoir,” says Marsh, “M. de Bonville, prefect of the Lower Alps, addressed to the Government a report in which the following passages occur :— “*Tt is certain that the productive mould of the Alps, swept off by the increasing violence of that curse in the mountains, the torrents, is daily diminishing with fearful rapidity. All our Alps are wholly, or in large pro- portion, bared of wood. Their soil, scorched by the sun of Provence, cus up by the hoofs of the sheep, which, not finding on the surface the grass they require for their sustenance, gnaw and scratch the ground in search of roots to satisfy their hunger, is periodically washed and carried off by melting snows and summer storms. “¢] will not dwell on the effects of the torrents. For sixty years they DE EBONVILLE AND BELGRAND. 73 have been too often depicted to require to be further discussed, but it is important to show that their ravages are daily. extending the range of devastation. The bed of the Durance, which now in some places exceeds a mile and a quarter in width, and, at ordinary times, has a current of water less than eleven yards wide, shows something of the extent of the damage. Where, ten years ago, there were still woods and cultivated grounds to be seen, there is now but a vast torrent; there is not one of our mountains which has not at least one torrent, and new ones are daily forming. *«* An indirect proof of the diminution of the soil is to be found in the depopulation of the country. In 1852 I reported to the General Council that, according to the census of that year, the population of the department of the Lower Alps had fallen off no less than 5000 souls in the five years between 1846 and 1851. «Unless prompt and energetic measures are taken, it is easy to fix the epoch when the French Alps will be but a desert. The interval between 1851 and 1856 will show a further decrease of population. In 1862 the ministry will announce a continued and progressive reduction in the number of acres devoted to agriculture ; every year will aggravate the evil, and in half a century France will count more ruins, and a department the less.’ “Time has verified the predictions of De Bonville. The later census returns show a progresssive diminution in the population of the departments of the Lower Alps, the Isére, Drome, Ariége, the Upper and the Lower Pyrenees, Lozére, the Ardennes, Doubs, the Vosges, and, in short, in all the provinces formerly remarkable for their forests. This diminution is not to be ascribed to a passion for foreign emigration, as in Ireland, and in parts of Germany and of Italy ; it is simply a transfer of population from one part of the empire to another,—from soils which human folly has rendered unin- habitable, by ruthlessly depriving them of their natural advantages and securities, to provinces where the face of the earth was so formed by nature as to need no such safeguards, and where, consequently, she preserves her outlines in spite of the wasteful improvidence of man.” Mr Marsh adds in a foot note,—“ Between 1851 and 1856 the population of Languedoc and Provence had increased by 101,000 souls. The augmenta- tion, however, was wholly in the provinces of the plains, where all the principal cities arefound. In these provinces the increase was 204,000, while in the mountain provinces there was a diminution of 103,000. The reduction of the area of arable land is perhaps even more striking. In 1842 the department of the Lower Alps possessed 99,000 hectares, or nearly 245,000 acres, of cultivated soil. In 1852 it had but 74,000 hectares. In other words, in ten years 25,000 hectares, or 61,000 acres, had been washed away, or rendered worthless for cultivation, by torrents and the abuses of pasturage.—Ciave, Etudes, pp. 66, 67.” In the Annales des Fonts et Chaussées for 1854 is a paper by M. Belgrand, entitled De [Influence des Foréts sur Cécoulment des eaux pluviales, cited by Mr Marsh as containing notices of remarkable floods occurring in different rivers in France. The Loire, above Rouen, has a basin of 2417 square miles, and in some of its inundations it has delivered 9500 cubic yards per second, which is 400 times its low-water discharge. And he gives a list of eight floods of the Seine, occurring within the last two centuries, in which it has delivered 3000 cubic yards per second, or 30 times its low-water G 74 LITERATURE ON TORRENTS, discharge. Such is the vastness of the body of water rapidly poured into the rivers by torrents or storms of rain, by which torrents are occasioned. In 1857 appeared Etudes sur les Inondations, leur causes et leur effets by M. F. Vallés, in which he makes several comments on the observations of Belgrand, relative to the rainfall in 1852 at Vozelay, in the valley of the Beuchat, and at Avallon, in the valley of the Grenetiére. And in the Annales Forestiéres, for the December of the same year, appeared a paper, entitled Les Inondations et le livre de M. Valles, by A. F. D. Héricourt. “The udometric measurement of Belgrand, discussed by Valles, consti- tute,” says Marsh, “ the earliest, and in some respects the most remarkable, series known to me of persevering and systematic observations bearing directly and exclusively upon the influence of human action upon climate, or, to speak more accurately, on precipitation and natural drainage. The conclusions of Belgrand, however, and of Valles, who adopts them, have not been generally accepted by the scientific world, and they seem to have been, in part at least, refuted by the arguments of Héricourt, and the observations of Cantegril, Jeandel, and Belland.” These will be found quoted in Comptes Rendus aU Academie des Sciences, 1861. In 1856 appeared a pamphlet, published in Paris, entitled Moyens de Jorcer les torrents des Montagnes de rendre une partie du sol qwils ravagent, by UM. Rozet, to which I shall afterwards have occasion to refer more in detail. And in the course of this year—whether before or after the appear- ance of M. Rozet’s pamphlet I have not been able to ascertain—renewed inundations supplied a befitting opportunity for the Emperor to call the attention of the nation to the subject. In the following year (1857) was published La Provence au point de vue des Bois des Torrents, et des Inondations, par Charles de Ribbe. Some of the facts, historical and statistical, embodied in this work are embodied in a notice of Dauphiny and Provence, by Marsh, which will afterwards be cited. In a work by Maurice Champion, entitled Les Inondations en France depuis le VIme Siecle jusyaéa nos jours, a work in six volumes, published in Paris, 1858-1864, are narrated the ravages of many inundations which have devastated extensive districts. And in an erudite and able work by Alfred Maury, entitled Les Foréts de la Gaule et de Vancient France, published in Paris in 1857, is collected an immense amount of statistical detail, on the extent, the distribution, and the destruction of the forests of France. By help of these the student in this department of Forest Science can carry back his studies to times that are past. In 1858 appeared Htude sur les Phenomenes et la Legislation des Eaux au point de vue des Inondations, par A. Monestier Lavignot. The same subject is discussed in a Rapport sur les Plantations de la Solonge, by M. A. Broignard, de l'Institut, which appeared in Annales Forestiéres, Tom. X.; and in a report to the Emperor by His Excellency M. Magne, the Minister of Finance, relative to the planting of mountain ranges with trees, which appeared in the Moniteur of February 3, 1860. This will afterwards be given in full. : In this year (1860) was published a Memoire sur les Inondations des Rivieres de VArdéeche, by M, de Mardigny ; and in the year following (1861) LADOUCETTE AND DELBERGUE-CORMANT. 75 appeared a pamphlet, published in Paris and Toulouse, entitled Ftudes sur le Reboisement des Montagnes, par Paul Tray. During the years which followed much information was collected through enquiries made by the Government, the substance of which was embodied in documents issued in connection with the legislation which was now employed to give effect to the suggestions which had been made, and the results were to some extent embodied in that legislation; and a good deal more was learned in connection with practical operations which were being carried on, which was embodied in reports of operations and reports of conferences held by appointment of the Administration by the officials and others employed in the work, which were published by the Administration. Translations of most of these documents will afterwards be given. But it may be mentioned here that to meet public opinion it was deemed expedient, as the work advanced, to give more attention to gazonnement than was done in the commencement of the operations begun. In the citations which have been made from works previously published, one section only of the literature of Forest Science—that relating specially, if not exclusively, to the influence of forests on torrents—has been laid under contribution. In regard to that I may say, in a word, that the French literature in this department of Forest Science is saturated with the idea that vegetation is the natural protection of the ground from the consequences of meteorological disturbances, occasioned by the destruction of forests by which a meteorological equilibrium, favourable to agricultural operations, had been established, and which may be re-established by the restoration of sylvan clothing to the mountains; and the same idea permeates much of the literature of France on subjects allied to that to which I have referred. But, while primary importance was attached to reboisement and to gazonne- ment, mechanical appliances, such as Surell sought to combine, when necessary, with the extension of vegetation as a means of bridling, and stifling, and controlling torrents, did not fail to command the attention of those who were interested in the struggle, which was the more necessary that there are destructive torrents produced by the melting of snow, and the rapid melting of glaciers, or by débdcles, the breaking up of icy barriers confining waters, in situatioas in which rebotsement and gazonnement are impracticable, and therefore as a remedy inapplicable ; and there are other torrents of which the same thing, or something similar, may be alleged in regard to these appliances. There is given by M. de Ladoucette an exposition of a scheme of embank- ment proposed by M. Delbergue-Cormant, Ingénieur en chéf des Ponts et Chaussées. The following is a translation of the memoir by M. Delbergue- Cormant, cited by him :—“ There are two kinds of torrents, principal and secondary. The first are easily distinguished,—they always flow in the principal valleys; thus the Durance, the Guil, the Deux-Briich, the Drac, é&c., are principal torrents. “The second descend from the lateral mountains of the valley, and come often at an angle more or less approaching 90°, to increase the principal ‘torrent, which occupies the depth of the valley; it follows from this that the torrents of Sarrazin, of Boscodon, are secondary torrents. The means employed hitherto to control the principal torrents are to enclose them by 76 LITERATURE ON TORRENTS. banks faced with stones. I have shown in another memoir that one may obtain the same results more economically ; but wishing to occupy myself at present only with secondary torrents, I confine myself to this. ‘Before proposing means of preventing or of repairing the ravages which the secondary torrents make, it is necessary to know these torrents, and for this purpose to take them up at their birth, to examine them in their course, and in following them in the increase of their bed of deposit year by year to show the enormous extent of the damage which they may have occasioned. It is certain that a secondary torrent does but little or no evil so long as it is shut up between steep banks. It is when it leaves the lateral mountains to enter into the valley that it begins its ravages. Let us examine how this comes about. “So long as the waters of a torrent are confined within steep banks they roll on in a great body, drawing on with them not only gravel, but even enormous rocks, Scarcely have they left the mountain, when, not being sustained and kept together by the banks, they divide themselves into a thousand little currents; and then, so far from drawing on rocks, they scarcely roll gravel along, and as their force diminishes more and more they scarcely bear along to the principal torrents some grains of sand. This explains perfectly the form taken by the deposits formed by secondary torrents. At the departure from the mountain this form is that of a portion of a cone, the summit of which corresponds to the point where the torrent comes out from the mountain. In effect, the waters, in quitting the mountain, have still an acquired force which permits them to roll the rocks on to some dis- tance ; in the second instance, this force being diminished, they deposit the rocks and carry forward only stones ; in the third instance, their force being still further diminished, they abandon the stones and then carry on the gravel. Thus, then, is formed a first deposit, which will be less and less considerable in proportion to its distance from the mountain. In a second flood of the torrents the waters get freely away, and the deposits of sand and of gravel will increase less, always in this following a slope. In fine, the increase may become so inconsiderable that the sides of the cone recede from the mountain ; then the torrent divides itself into two currents, and soon there comes to pass, at each of these two currents, what had occurred with the principal currents. Thus the fertile lands of the valley may disappear under the heaps of stone and of sand ; as these torrents are greatly multi- plied, there will come a day that their deposits, spreading out till becoming conjoined, a whole valley will become sterile, and will not be able longer to support its inhabitants. “We have seen that the secondary torrents do not deposit the gravel and stones which they carried from the mountain ; but when their waters are no longer confined by the banks—when they enter the valley—they spread themselves over a great surface, and thus lose their force 5 they cannot carry further the stones and the gravel, and these they abandon at a greater or less distance from the mountain. This indicates to us the course to be followed in order to control these torrents at their embouchure, and to prevent them covering the land with gravel. “T would propose, then, in accordance with this principle :—First, to dig a bed for the torrent in the deposit which has penetrated to the exit from the mountain ; second, to give little breadth to this bed, but great depth, in order that the waters may be there confined as they are in the natural bed which the torrent has dug for itself in the mountain, and that they may MEMOIRE BY DELBERGUE-CORMANT. 7 continue to sweep on the stones and gravel ; third, to carry the gravel which is dug out from these cuttings to some distance from the edge, to form of them two embankments parallel to the new bed ; fourth, to widen the entry of the new bed at the end towards the mountain, in order to collect the waters, and to strengthen by large stones these widened portions; fifth, to plant the embankments with willows, and other trees which grow quickly ; sixth, to take care to clear away the obstructions which may form them- selves in the new bed after each eruption of the torrent. “One may see that there is no need of any building to confine these secondary torrents, and that the inhabitants of each village, with their shovels, their pick-axes, and some wheel-barrows, may secure the territory from the ravages. It is much to be desired, that being enlightened in regard to their true interest, they should lose at last that indifference which keeps them alike from preventing their ruin, and from repairing it. “Tt may be observed that it is not necessary that the new bed be dug throughout all its length in asingle campaign. It suffices to begin at the foot of the mountain, and to end off the open part in any year, by a more gentle declivity than that of the deposit of the ravine, to give an outlet to the waters. Thus the inhabitants would do wrong to excuse themselves by an alleged impossibility of doing all the work at one time. Further, neighbouring communities could mutually help one another. “ The advantages which the communes would derive from this work are considerable ; for, not only would they not have to fear new invasions of the torrent, but the sides of the torrent, not being now exposed to the waters, wight be usefully cultivated, by watering them with waters of the torrent which might be derived from the upper portion of it.” The scheme proposed resolves itself (he says) simply into digging for the torrent a straight canal through the centre of the deposit, and maintaining this canal by constant clearings. According to M. Ladoucette, whatever may be the precautions proposed by the author for strengthening the hills by means of plantations and cuttings like to continuous dykes, they will never present sufficient resistance to erosion ; still less will they hold out against the undermining effects of the flood. It is mentioned by M. Surell, that the clearing out of torrents is always a difficult operation, on account of the great size of the stones, and the hardness of the mud in which they are imbedded ; and that this work, which demands great waste of muscle, and entails great expense, produces no durable result. The smallest flood suffices to overturn all, and to throw the bed of deposit into its previous disorder. Something similar or analogous to the proposal of M. Cormant was carried into execution by M. de Ladoucette, who caused a trench to be cut ina straight line from the gorge of the Durance. He employed in this work the prisoners confined in the central house of Embrun, to the number of five hundred, and the work, prosecuted with energy, was completed in a month ; but in the course of the next month there came a flood, and all was destroyed. This scheme attributes all the ravages of torrents to the irregularity of their beds ; and proposes, as a simple and sufficient remedy, to give to them a straight bed. Surell alleges that the scheme confounds cause and effect ; and that torrents do not spread themselves hither and thither because they have not a straight bed ; but they have not a straight bed because, con- tinually depositing matter, they are forced to spread themselves hither and thither. 78 LITERATURE ON TORRENTS, M. Cormant might justly claim to be allowed to say, in defence of his suggestion, that had the artificial bed been of a magnitude to contain the whole flood, as was evidently requisite, the success might have been complete, In 1856 appeared, as has been already mentioned, the pamphlet of M, Rozet, entitled Moyens de forcer les Torrents des Montagues de rendre une partie du sol quils ravagent, to which reference has already been made. “He proposes,” say Marsh, “to commence with the amphitheatres in which mountain torrents so often rise, by covering their slopes and filling their beds with loose blocks of rock, and by constructing at their outlets, and at other narrow points in the channels of the torrents, permeable barriers of the same material promiscuously heaped up, much according to the method employed by the ancient Romans in their northern provinces for a similar purpose. By this means, he supposes, the rapidity of the current would be checked, and the quantity of transported pebbles and gravel—which, by increasing the mechanical force of the water, greatly aggravate the damage by floods—much diminished. When the stream has reached that part of its course where it is bordered by soil capable of cultivation, and worth the expense of protection, he proposes to place along one or both banks, according to circumstances, a line of cubical blocks of stone or pillars of masonry three or four feet high and wide, and at the distance of about eleven yards from each other. The space between the two lines, or between a line and the opposite high bank, would, of course, be determined by observation of the width of the /swift-water current at high floods. As an auxilliary measure, small ditches and banks, or low walls of pebbles, should be con- structed from the line of blocks across the grounds to be protected, nearly at right angles to the current, but slightly inclining downwards, and at convenient distances from each other. Rozet thinks the proper interval would be 300 yards, and it is evident that, if he is right in his main principle, hedges, rows of trees, or even common fences, would in many cases answer as good a purpose as banks and trenches or low walls. The blocks or pillars of stone would, he contends, check the lateral currents so as to compel them to let fall all their pebbles and gravel in the main channel—where they would be rolled along until ground down to sand or silt—and the transverse obstructions would detain the water upon the soil long enough to secure the deposit of its fertilizing slime. Numerous facts are cited in support of the author’s views, and I imagine there are few residents of rural districts whose own observation will not furnish testimony confirmatory of their soundness.” He says,—“ The plan of Rozet is recommended by its simplicity and cheapness as well as its facility and rapidity of execution, and is looked upon with favour by many persons very competent to judge in such matters. It is, however, by no means capable of universal application, though it would often doubtless prove highly useful in connection with the measures now employed in south-eastern France.” And he adds, in a foot-note,—“ The effect of trees and other detached obstructions in checking the flow of water is particularly noticed by Palissy in his essay on Waters and Fountains, p. 173, edition of 1844. ‘There be? says he, ‘in divers parts of France, and specially at Nantes, wooden bridges where, to break the force of the waters and of the floating ice, which might endamage the piers of the said bridges, they have driven upright timbers into the bed of the rivers above the said piers, without the which they HTUDES BY SCIPION GRAS, 79 should abide but little. And in like wise, the trees which be planted along the mountains do much deaden the violence of the waters that flow from them.’ Lombardini attaches great importance to the planting of rows of trees transversely to the current on grounds subject to overflow.—Hsame degli Studi sul Tevere, § 53, and Appendice, §§ 33, 34.” In 1857 there appeared, in the Annales des Ponts et Chaussées and in the Annales des Mines, Etudes sur les Torrents des Hautes Alpes, by M. Scipion Gras, ingénieur des mines. Of this work the following analysis is given by M. Cézanne, in his supplement to the work of Surell :—‘‘ After having defined torrents the author divides their course into four parts—bassin de réception, canal de réception, lit de déjection, and lit d’écoulement. M. Scipion Gras distinguishes amongst torrents at the bed of deposit four classes, according to the character of the basins drained by them. The study of the laws in accordance with which solid bodies are swept away by floods leads him to the conclusion that there are two distinct modes of operation —transport en masse and transport partiel—the former effected by floods of great body and strength, the second by floods of a medium character. These different operations produce contrary effects upon the bed of deposit ; the great floods, as they exhaust themselves, deposit over this a layer of clay and gravel, over or through which the waters spread themselves in thin sheets ; the lesser floods, on the contrary, dig down into the bed of deposit and plough in it a channel for themselves, after having conveyed thither the more comminuted materials referred to.” Upon which M. Cézanne remarks that M. Gras does not occupy himself much with the basin drained by the torrent, the special subject of study by him being torrents the basins of which are not susceptible of being planted ; and impressed with the evils resulting from the dejection of detritus, he seeks to modify the natural advance of the bed of gravel, and discusses the two methods generally employed to effect this, characterized respectively by the employment of dykes and of barrages, or embankments and barriers. He expresses himself very decidedly in favour of barrages, and he thus sums up his opinion on the point :—“ In short, the first proceeding (l’endiguement ), ag a means of suppressing a bed of deposit, is often impracticable, or at least the success of it is dubious ; when it does succeed, it only carries the mischief elsewhere. It is, then, one which is very defective, and which ought to be abandoned. “ There remains the second course of proceedure ; we have demonstrated its practicability, as applicability to all torrents, and its freedom from the drawbacks attaching to the first. And here begins the most important part of our task.” This quotation (says Cézanne) is characteristic of the method of procedure of M. Gras, which is pre-eminently systematic; he observes natural pheno- nema with great accuracy and precision ; he then proceeds to distinguish, to classify, and finally to bring all his energy to bear upun a single and exclusive system. “But,” says M. Cézanne, “ the consideration of nature inspires one with a dislike and opposition to all systematic formulas. It may be well to run down embankments, and extol barriers ; but it is not less the case that there are circumstances in which the practical man will see at a glance that there embankments are better adapted to meet the case than are barriers, And it is necessary, in a study of this kind, to avoid all 80 LITERATURE ON TORRENTS, special pleading in support of the absolute superiority of one system or of another, and to confine remarks to showing clearly in what circumstancs either of them should be preferred. “M. Gras being so decidedly in favour of the exclusive use of barrages, or barriers, in reference to the two different categories of floods established by him, recommends, according as it may be desired to effect a complete or a partial retention of gravel, the construction of submergible barriers in the latter case, and insubmergible barriers in the former. “The latter, insubmergible—so designated, although actually overflowed by the torrent, and expected and intended to be so at times, and it may be frequently—belong to a class of embankments which have been long in use. Erected in some favourable position in the gorges, they are designed to effect a deposit of gravel directed up the river. If the reservoir designed for this deposit be very considerable, if the transport be slow, it may tell effectively for some distance below for several years. “ Submergible barrages constitute, strictly speaking, the system which M. Gras claims the credit of originating. This system is based on a very delicate analysis of the effect of floods, which shows that high waters only acquire their full force in a narrow channel in which they are confined. If they be allowed or compelled to spread themselves out, their force is diminished, and the larger materials which were being borne along by them are deposited. To compel them to do this—to spread themselves out—it is only necessary to raise, on a widening of the bed, a horizontal sill, which cannot be washed away, worn down, or furrowed ; the waters, then, not being able to concentrate themselves in any place at a lower depth than that of the whole sill, spread themselves in a sheet over the sill, and a deposit up the river follows as a consequence. “ After a great flood, such as may be of occcasional but comparatively rare occurrence, floods of lesser magnitude, which are much more frequent, go over this deposit anew, and do on a lesser scale what the greater flood has done on a greater, excepting that such large blocks as could only be carried along by a great flood will remain in the places above the barrier in which they had been left. And the effect of the whole will be, that great floods will be less disastrous, the work done by them being effected by a great number of floods, the consequences of which are innocuous. “Tt is not necessary that these barrages should be of great height, ‘nor, consequently, of great solidity ; it isenough that their upper surface sustain the friction of the pebbles carried down by the flood, and that their base can sustain the slight water-fall which they occasion. “From this it may be seen,” says M. Cézanne, “ that the system of oper- ations proposed by M. Scipion Gras is the very opposite of the course formerly followed, in so far as formerly, when a dam or barrier was to be erected, a narrow depth in the bed of the current was selected, that the structure being short there might be given to it, at little expense, the thick- ness necessary to enable it to resist the violent action of the water. He recommends to select expansions in the bed of the current, and even proposes to erect, on the cones of dejection, works of the same kind, which he calls barrages radiers. To secure the plain of Bourg d’Oisans, in the basin of the former lake Saint Laurent, against ravages by the Romanche and the Vénéon, which debouche each by a different gorge, he proposes the erection of such barriers, spread out horizontally, the length of which should be not less than 763 métres, or 2500 feet, upon which he supposes that the TUDES BY SCIPION GRAS. 81 two torrents, uniting their floods, will pour out the mass of water ina regular sheet, 32 centimétres, or 12 inches, in fall.” Of this locality it is mentioned elsewhere by M. Cézanne, that in 1157, after a storm of rain, two torrents of the Oisans, which look directly across from one bank to the other of the Romanche, the Vandaine and the Infernay, raised a barrier across the principal valley ; a lake formed itself immediately behind this dam, which was known under the name of the Lake Saint Laurant, because the storm had burst on the day of St Laurant. This lake stood for sixty-eight years, but in the night between the 14th and 15th September 1219 the barrier gave way, the waters laid waste the lower parts of the valley, and two towns, Vozille and Grenoble, were almost entirely destroyed. Since the thirteenth century onwards there has often been a threatening of the formation again of this barrier, but in despite of this there has sprung up, in the dried basin of the Lake Laurant, the Bourg d’Oisans, which M. Gras proposed thus to protect. M. Cézanne states in detail objections to which the measure was deemed by him to be open; and referring to two practical applications which had been made of the system proposed by M. Gras—one on the Roise, near Grenoble, the other on the Riou-Bourdoux, in the Lower Alps—he cites observations made by Professor Culmann, who visited the former some three years after the publication of the memozre, and reported of it thus :—“ At the time of our visit (October 1860), we found that a strong débdcle had just passed over a barrage, and that a great mass of rubbish had been stopped behind the upper barrier. The little wooden bridge a little above it had evidently had too weak a channel, and it was carried away, and the barrier itself could not resist more. . . . “ Tt is clear that the work had maintained its resistance until the deposit above it had attained the top of its slope, and that so soon as blocks of even small size began to roll over the inclined plane the links of the binding chains, formed of iron bars ‘02 métre, or four-fifths of an inch, in thickness, yielded to the shock and opened.” “ Beyond this,” says M. Cézanne, “ M. Culmann criticises the mode of constructing rather than the theories of these barriers, but he does not appear to attribute to them other effect than to determine a deposit in the same way as does every other kind of barrier.” M. Cézanne visited La Roise in 1869, and he says,—“ In point of fact, the bed of La Roise presents to a visitor the ordinary appearance of the bed of a torrent. The repaired barriers are surmounted by deposits, and the old state of things appears to be exactly reproduced at a higher level. “ According to M. Marechal, Ingénieur des Ponts et Chaussées, the experi- ment tried on the Riou-Bourdoux has not been more successful ; the barrier hag perished through defective or vicious construction.” M. Cézanne states, in concluding, that notwithstanding failures, which have followed a practical application of it, which have been made, in some of which the failure was attributable to unsatisfactory workmanship, engineers who have to do with torrents, but who have not had much personal experience in connection with torrential phenomena, will read with much profit the memoir by M. Gras; they will find a great many facts carefully noted, and will learn how to make observations themselves. And others who have written upon the subject go, I may mention, far beyond this in their commendations of the measure proposed by M. Gras. In regard to triage, selection or successive deposit of materials of different H 82 LITERATURE ON TORRENTS. bulk or gravity, a subject underlying the proposal of M. Gras, M. Cézanne writes,—“ The triage of the matters borne along is very strongly marked in torrents which tend to extinction, or only, if the case be so, to take a régime of greater constancy. It happens even that the lesser stones, &c., being all borne along, there remain only the larger ; the bed is then furnished with a self-created rockery, which energetically resists erosion, and as a necessary consequence the torrent cannot deepen the channel in which it flows. It is then necessary to give some assistance to the torrent, and the larger blocks are removed and ranged along the bank. The water re-collected between these rude embankments digs away anew. This system is much used in Switzerland. The course to be followed is this : replant with woods these parts of the basin in which this can be done ; and when the torrent shows a tendency to cut a bed in the dejection, facilitate the process by removing the self-formed rockwork of blocks denuded by the triage.” In 1865 was published IJemoire sur les barrages de retenue des graviers dans les gorges des Torrents, by M. Philippi Breton, Ingenteur des ponts et Chaussées, Of this M. Cézanne says,— This treatise may be justly charac- terized a treatise on torrential geometry; the author demonstrates in it, with beautiful clearness and distinctness, the principal theories which relate to the transport of gravel,—to the profile or outline of the bed of deposit,— to the different kinds of cones thus formed, the troncature or section of which, and the reproduction of which, are explained by beautiful sketches taken from nature.” Of the design of the work, M. Breton writes,—“ Different questions connected with the establishment of barrages, or barriers, for the retention of gravel, have been raised and discussed. But, notwithstanding all that has been done, it appears to me that ideas in regard to what results are to be expected from these barrages are still vague, varied, and undetermined; there is still a great want of decision in regard to selection of location, to the number of barrages to be employed, to the best or most suitable means of constructing them, and to the duration of their efficiency. After having reflected long on these subjects, I have come to be of opinion that, to preserve a plain from invasion by a torrent which debouches on it, it is necessary to establish, in the first place, a single barrage, situated at the outlet of the gorge, or very near to this ; then a second barrage at some métres [or yards], and not more, above the first, when that one shall cease to be efficacious ; then a third at some métres above the second, when this in its turn shall have completed the service it can render; and so on. Such is the subject of this memoir.” “From this it appears,” says M. Cézanne, “ that the proposal of M. Breton is the very opposite of that of M. Scipion Gras, submitted eight years Ago 5 he speaks not of barriers but slightly raised above the level of the bed, or of silts stretching across expansions in that bed, but of solid massive walls, carried up as high as possible by successive stages into the throat of a gorge, and constructed, not of blocks bound to one another by chains, but of hydraulic masonry of the strongest that can be obtained. “ Barrages in which wood is employed to meet the want of cohesion in gravel, last (says he) but for a short time,—for the wood, buried half of its bulk in the gravel, often dry and often wet, will quickly rot, as quickly as do the Cabrettes, and more quickly than do the coffers known under the name of arks (arches) in the mountains of Dauphiny and Provence. Barrages MEMOIRE BY PHILIPPI BRETON. 83 constructed entirely of rockwork, and those constructed of dry stones, never cost much less, and they sometimes cost more, than those built with Roman cement, and these have a great advantage over the others in their greater cohesion. Ag soon as a breach occurs at any height in a barrage of rocks or dry stones, the violent current, passing through the breach, begins at once to enlarge it, and it soon effects a great destruction. In the hydraulic masonry any opening can only enlarge itself slowly, and the flood will have exhausted itself before the destruction has become serious. “‘Tn saying what I have done I am only extending to barriers retaining gravel the practical rule adopted in the department of Isére for longitudinal dykes. M. Picol, and the engineers under his orders, have often remarked that a dry-stone dyke is rent from the bottom to the top when a small breach has been made in the foundation. Wishing to make these observa- tions complete by comparison, they made the experiment of building with stones set in good hydraulic mortar. The experiment was not long in revealing—first, that the dykes so constructed did not cost much more than did those built of dry stones, as they could build with smaller material, and they did not require to give the same thickness to the wall; and then, what is of primary importance, that a wall built with good mortar can sustain a considerable destruction at its base without being instantly rent to the top, for the part above sustains itself in the condition of an arch or vault ; and thus time is afforded for assistance.” After having discussed in detail the different questions which are connected with barrages, M. Breton thus meets an objection which is often brought up:—‘“I have frequently heard educated and intelligent men object against the system of retaining gravel by barrages the danger of a rupture in the works. When these works shall have amassed a great mass of gravel behind them, if a rupture should occur, that entire mass, so retained above its level, would, it is said, suddenly begin to move, and would produce a frightful catastrophe below. And as a proof in support of this fear they adduce the effects attributed to the sudden emptying of the Lake St Laurent, which, escaping from the plain of the Oisans, laid waste the valleys of the Romanche, and of the Drac, as far as to Grenoble. They might adduce, in like manner, the lamentable disasters produced in a single night by the rupture of the reservoir at Sheffield! But they forget that in these two cases, ag in all others which may be cited in which the rupture of a reservoir has caused a sudden catastrophe at a lower level, the state- ment refers}to a reservoir of water, and not to a reservoir of sand, and earth, and gravel. “Tt is thus that I have no dread of this objection, if the work be judged of only by builders accustomed to see the movements of water, and of sand and gravel, and know the difference between them; never will an engineer bring himself to believe that gravel will flow as does water.” Numerous cases illustrative of the effects of the rupture of a barrage are then given. But M. Breton, while writing thus, is not unmindful of the importance of the bovsement or gazonnement of the basin drained by the torrent. He admits distinctly that it is vegetation which has the power to extinguish torrents ; he only proposes barrages as a temporary expedient against torrents which cannot be prevented, as are sometimes those connec- ted with glaciers, or as temporary appliances where, through the strength of prejudice or legal difficulties, the forest treatment must be for a consider: able time postponed. : 84 LITERATURE ON TORRENTS. In the same year, 1865, there was published in Lausanne, a Rapport au Conseil Fédéral sur les Torrents des Alpes Suisses, inspectés en 1858, 1859, 1860, and 1863, par M. le Professeur Culmann. Of this work M. Cézanne writes,—‘ Switzerland is a land privileged indeed ; the philosopher, the artist, the humble foot-soldier—in a word, every one, whatever may be the tendency of his mind, finds there numerous subjects of study. By hundreds of thousands, tourists, from both worlds, annually visit this classic land of noble landscapes, of natural science, and of freedom.” He mentions in a foot note, that he was informed, by the monks of the great Saint Bernard, that they lodge upon an average 40,000 visitors annually, and sometimes 800 in a single day at the height of the season. And he goes on to say,— “Looked at from the point of view of our study, Switzerland is seen to be a protuberance, like a boss on a shield, which rises above the lofty plateaux of Europe; it isa reservoir, whence water is distributed; it is also a laboratory, whence issue many thousand torrents—working away, in combination with the glaciers, to level down the rough and rugged back of our planet. All of these waters, flowing from the eternal snows, precipitate themselves in cascades to the depths of the valleys below ; they keep on, ever sowing anew with their alluvial deposits the basins of a hundred score of lakes ; thence, partially clarified, they escape towards the four points of the compass to throw themselves into four seas, after having watered Germany by the Danube and the Rhine, France by the Rhine, and Italy by the Po and the Adige. “The engineers of this country, brought up within the sound of the torrents, and accustomed from infancy to the thousand caprices of the moun- tain streams, quickly acquire a special experience in thismatter. They are little given to generalizations, to systematic theories, to geometrical definitions; they give themselves more to the study of particulars, and seek out for each case a special solution adapted to the local circumstances. And such is the character of the work of M. Culmann. “Tn 1856, the rainfall which devastated France did not spare Switzerland ; the Federal Council bestirred itself and commissioned M. Culmann, one of the most distinguished students of hydraulics, to go through the whole of the cantons, and to report, in regard to each torrent, on the evil and the remedy. And at the same time, to meet the public demand, which attributed justly to the destruction of forests the ravages of the torrents, a commission was organized and appointed to report at the same time in regard to the forests. The two reports have been published in German and in French. They agree on the conservation effected by forests. That of M. Culmann relates more especially to those water-courses connected with which the mechanical appliance of the engineer is required to come to the aid of reboisement. “The report of M. Culmann passes in review many hundreds of torrents ; it is a repertory of isolated facts, well observed, calmly stated, with simple demonstrative sketches.” . . . With regard to boisement and gazonnement, he says,—“ In Switzerland, as elsewhere, the evils produced by torrents is not a necessary evil; it takes birth often from the waste and recklessness of the inhabitants. The principal remedy, and the only one which is decisive and definite, is the boisement or gazonnement, which stifles the evil at its source, principits obsta. The cantons which have given attention to their forests have been least attacked ; those which have devastated them—in particular the Italian cantons—are threatened, as are the HighAlps of France, with complete RAPPORT OF M. OULMANN. 85 ruin.” And he gives a great many examples of cases in which, in conse- quence of the grubbing up of a wooded place, a torrent, which till then had been inoffensive, became all at once dangerous. M. Culmann attaches greater importance to the initiative being taken by the people, than to interventions by the Government ; and he cites facts in support of his opinion. But he attaches, I may say, primary importance to securing connected action by all interested ; of the advantages of which, and the disadvantages arising out of the want of it, he gives facts in illustration. Proceeding to the consideration of mechanical works of engineering, he recommends—(1) The clearing of the water-courses of all large blocks resting there, in which he is supported by M. Cézanne ; (2) The erection, when and where it may be expedient, of barrages and dykes or embankments. “In regard to such works, the theory of M. Culmann,” says M. Cézanne, “may be stated thus :—Barrages are but a temporary expedient to be employed while awaiting reboisement ; it is necessary to construct them in a series, commencing from below ; when the first barrier is filled to the level with gravel, then should be constructed a second behind it, and so on continuously.” Barrages are the preferable structures to erect against torrents, dykes or embankments against rivers. With these, as with barrages, it is necessary to proceed from below upwards. Barrages constructed of faciues or of wood, &c., when but a temporary effect is to be produced, are often preferable to those of stones or of masonry, because they accommodate themselves to movements in the bed. Structures of facines form a moveable enclosure, on which vegetation easily establishes itself ; barrages, constructed with hurdles, are very useful in ravines, and even on sinking slopes; but in general stone-works are preferable to those constructed of wood; these, however, are very serviceable in cantons in which the population employ them. ‘All the barrages in torrents con- structed hitherto in Switzerland,” says he, “have proved beneficial ; all the people who have made use of them have showed themselves satisfied with them.” Epis, or stakes, avail nothing against torrents, or against mountain rivers ; they are available only against peaceful rivers, bearing along but little solid matter suspended in their waters, and this composed only of sand and small gravel, and not of blocks, which are able to attack the bank and change the direction of the liquid stream. “The stockade of these,” M. Culmann says, “ should form a continuous line ; for if some do not reach to this, and others go beyond it, the current, thrown from one bank to the other, may do greater damage than if there had been no works of enclosure. The epis, or stakes, should be sufficiently close to the bank to prevent any loop or expansion of water being formed between them ; and the’ less the banks the closer should they be. In mountain banks the space is so limited that continuous dykes are less costly. “Tn Bavaria, for example, the lower Danube is too small to allow of the system of stockade being applied ; they are under the necessity of adding a more or less extended wing to the back of each spike—that is to say, to construct immediately a portion of the future bank. They have also aban- doned the system of spikes along the Rhine, where they were greatly attached to it, and where they now construct continuous embankments of facines. Stakes can no longer be employed along the Lech ; and since the alteration of the course of the Linth, they have become satisfied that parallel 86 LITERATURE ON TORRENTS, dykes are much better suited for the enclosure of this small water-course. And on all the lower channel of the Linth, they have little by little replaced with these the stakes wherever these were not absolutely necessary.” M. Culmann then reports in detail in regard to the location and construction of bridges; and on the phenomena and effects of glaciers, torrents, avalanches, and landslips. The former subject is of local importance ; and the information communi- cated may be utilized, to some extent, by any employed in making surveys for roads and bridges ; but in every case local circumstances have such an effect in determining operations that it is deemed unnecessary to cite the views advanced. With regard to glaciers, torrents, avalanches, and land- slips, the case may seem to be similar. But avalanches, at least, are not confined to Alpine regions; and though woods may prevent the formation of a landslip, they cannot arrest its progress when once in motion. There is not a little in the graphic details of engineering operations given by M. Culmann in this chapter of his work which commands attention and illustrates the importance of the work. “Torrents issuing from glaciers,” says M. Cézanne, “are numerous in Switzerland ; they are subject to formidable débdcles, or outbursts of water, when the glacier in its movements of going and coming, after having dammed up some secondary valley, gives free passage all at once to its waters. To prevent such evils is for the engineer a formidable undertaking, and a difficult problem. How contend against a glacier? What physical force can he bring against the mass which is being unceasingly renewed by the ever recurring winters, and which, making use of the hardest rocks, trans- porting blocks of stupendous size by a movement almost imperceptible, would annihilate the most irresistible work of man? Here are two cases reported in which a simple idea sufficed to vanquish the inert Colossus : “The glacier d’Aletsh, an affluent of the Rhine (Valais), dammed up a small lateral valley, situated behind the Eggishchorn, and created thus the lake of Meerjelen. ‘ This lake,’ says M. Agassiz, in his Btudes sur les Glaciers, ‘was formerly more extensive than it is now; and when it happened that the melting of the snow and ice became excessive, it would often happen that the whole of this body of water would with violence eat away an outlet under the glacier, and occasion the greatest destructive ravages in the bottom of the valley. To obviate this they dug, in the direction of the glacier of Viesch, an artificial channel to this lake, which could no longer rise above the level of its orifice. The ice did not rest immediately on the water ; there was, on the contrary, between the bottom of the glacier and the surface of the water a space of some centimetres, perhaps an inch or two, occasioned by the temperature of the lake being always during summer higher than that of the glacier. By means of this space, enormous blocks of ice often detach themselves and float on the surface of the lake, imitating exactly the floating icebergs of northern regions.’ “But the most characteristic example is that furnished by the glacier of Gittroz—the assault made against which is somewhat dramatic, and exceedingly interesting : “At the bottom of the valley of Bagnes, one of the branches of the Drause, at sixteen kilométres, or about twelve miles from Chables, there rises vertically a high wall of rocks, surmounted by the glacier of Giétroz. The moving mass protrudes itself, projects beyond the support, and falls at the 4 GUIDE JOANNE. 87 foot of the precipice ; the broken fragments congeal anew and form a cone- shaped glacier, which pushes before it its moraine. What ensues must be | given in the narrative of Guide Joanne:—‘In those years in which avalanches are very frequent the heat of summer does not suffice to melt a quantity of ice equal to what the mountains cast down. The enormous block which then forms a bridge on the Drause becomes always larger and larger, and as the arch of this bridge, dug in summer by the torrent, closes up in winter, it happened in 1597, and in our own times, in 1818, that the early months of spring sufficed not for the Drause to open for itself a passage, and a lake was formed behind the ice. “ «When this became known (wrote M. Simond, some months after the event), alarm spread at once, not only throughout the whole valley but in Le Valais, and on so far as Italy. Travellers feared to take the route of the Simplon; it was felt that when this dyke should come to break up there would be there a sudden débacle which would sweep over the country to a great distance. The preceding winter had been severe; the ice had even then cast a dam across the valley, but without stopping the water, which had eaten out a passage for itself; but a second severe winter had produced such a fall of ice that the obstacle had become insurmountable and impervious. “¢The Government sent an engineer (M. Venetz) ; he found that the dyke was 110 toises (nearly 700 feet) in length from the one mountain to the other, 66 toises (or about 400 feet) in height, and 500 (or 3000 feet) in thickness at its base. The lake was 1200 toises (or upwards of 7000 feet) in length, and had already risen to half the height of the dyke, that is to say, was from 30 to 40 toises (from 180 to 240 feet) indepth. The engineer determined to cut a gallery or tunnel through the thickness of the ice, beginning 54 feet above the actual level of the lake, to give time to complete the work before that height should be reached by the accumulating waters, which were rising at the rate of from 1 to 5 feet per day, according to the temperature ; and he began the work on the 11th of May at both ends of the tunnel. Fifty men in relays, relieving one another alternately, wrought there night and day at the peril of their lives,—one and another of the avalanches which were falling every moment threatening to bury them alive in the tunnel; many were wounded by lumps of ice, or had their feet frozen, and the ice was so hard that it frequently broke the pick-axes used. In despite of all these difficulties the work advanced rapidly. On the 27th of May a great piece of the dyke broke off from the bottom with a fearful crash ; it was believed that the whole was about to break up, or to rise in a mass, and the workmen fled; but soon they courageously resumed their work. Similar accidents occurred repeatedly ; some of the floating masses, calculating from the distance at which they stood above water, must have had a thickness of 70 feet submerged. On the 4th June the tunnel, 608 feet long, was cut from end to end; but as it had an elevation of 20 feet or more in the centre it was necessary to level it. The weather had been cold, and the lake had not yet risen to the level of the mouth of the tunnel, so they continued to lower this till the 13th, the day on which the flow commenced, at ten o’clock at night. The lake still rose for some hours ; but next day at five o’clock in the afternoon it had sunk 1 foot; on the morning of the 15th, 10 feet ; on the morning of the 16th, 30 feet ; at two o’clock that day the length of the lake had shrunk 325 toises (nearly 2000 feet), for the tunnel, being continually eaten away, lowered itself as quickly 88 LITERATURE ON TORRENTS. as the lake. The Drause flowed, filled from bank to bank, but without overflowing, and a few days more would have sufficed to empty the immense reservoir, «¢ But detonations in the interior of the dyke announced that glacions, blocks and pillars of ice, were detaching themselves from the mass, through their low specific gravity, and were thus diminishing the thickness of the dyke on the side towards the lake, while the current out of the tunnel was eating away this dyke on the outer side, and was threatening a sudden rupture ; the danger increasing, the engineer despatched from time to time expresses to warn the inhabitants to keep themselves on the out-look. The water began to make way under the ice, sweeping along the stones and earth at its base under the tunnel; the crisis appeared inevitable and close at hand. At half-past four o’clock in the afternoon a tremendous crash announced the rupture of the ice-work ; the water of the lake shot along with fury indescribable ; it formed a torrent 100 feet in height, which traversed the first 6 leagues, or 18 miles, in forty minutes, although kept back in many places by narrow gorges through which it had to pass, carrying off in its course 130 chalets or cottages, a whole forest, and an immense quantity of earth and of stones. Debouching over against Chables, the chief place of the valley, the water was seen pushing before it a moving mountain of all kinds of debris of 300 feet in height, from which was rising a thick black cloud like the smoke of a conflagration. An English traveller, Mr P., of Lausanne, accompanied by a young artist, and a guide, was returning from seeing the works, and going towards Chables ; happen- ing by chance to turn round, he saw advancing with fearful rapidity the moving column, the distant roar of which he had not heard through the noise made by the Drause. He hastily warned his two companions and three other travellers who had joined them ; all leapt from their mules, scrambled up the mountain, and got safely beyond the sweep of the deluge, which filled in an instant the whole gorge beneath them. But Mr P. was nowhere to be seen; for some hours they believed him to be lost; but then they learned that his mule, shying at an overturned tree which she saw on the road, wheeling round, saw all at once an object far more dreadful close upon her, and, darting off towards the mountain, had carried him far away from the scene of danger. “From Chables the débicle arrived at Martigny—4 leagues, or 12 miles, distant—in 50 minutes, carrying off, as it advanced, 35 houses, 8 mills, 95 barns, but only 9 people, and no cattle, the inhabitants having all been warned to be on guard. The village of Bovernier was saved by a jutting rock turning off the flow of the torrent ; and the people saw it pass like a shot by the side of the village without touching it, although much higher than their heads. The rocks and stones were dropped before it arrived at Martigny, blasting with sterility extensive meadows and fertile fields. “ mB | mR wm B® re aN oO we N oO ri N 3 = N oO PLANTS SENT OFF, 3 - Black Pine of - 3 Scotch Fir. Aasieie. Norway Fir. Observations. ° m2 m ° nm mR . m Rm « Dm ¢ 28/242 /2 83/8 8 3 p> bm B > BB BBR] RR OB a N CO a AN oO ce NN inn} me WN oD The date of des- patch and destina- tion are marked in this column. “This register will be kept by the official in charge of the nursery under the inspection of the chief of the district, “ At the end of every month the work will be repeated by making an entry in each column of the plants then fit to be disposed of, and of those despatched. “ An extract of this register is to be sent to the Administration at the periods to be hereafter specified. * 196 LEGISLATION ON TORRENTS. “ Eleventh Question. ; “ Sécheries.—The Administration having ascertained that seeds prepared in the Government drying booths are superior in quality to seeds obtained by purchase, it is desirable to consider whether it be not desirable to erect additional drying-booths (sécheries), or seed depdts. “ Opinions, ke., of the Agents. “The agents at the conference at Clermont have observed that the seeds furnished by the Goverment sécheries, or drying-booths, of Murat (Cantal), or gathered in the country, are incomparably superior to the seed purchased. This sécheric furnishes only 4000 kilogrammes of seeds yearly, which is a quantity much below the requirements of the departments of La Lozére, of Puy-de-Déme, of Cantal, of the Haute-Loire, and of the Loire ; the quantity required annually being estimated at 10,000 kilogrammes, it is desirable to establish a new sécheric. This the conference proposes should be located at Puy. Subsequently another might be constructed at Marvejols. “A member of the conference at Clermont showed that the Corsican pine might be advantageously employed in reboisement,—that the price of the seed of this species is from 7 to 12 francs per kilogramme,—and that, without doubt, it would be possible to establish in Corsica one or two séoheries, by which the seed of the Corsican pine would be furnished at the cost of 4 francs at most. “ The agents at the conference at Foix state that the sécherve of La Lagonne is capable of furnishing annually 4000 kilogrammes of seeds. They think that it would be desirable to establish in the inspection district of Simoux, within reach of the nurseries, a sécherte for fir-tree seeds. “ At Carpentras the agents expressed in general terms the opinion that there would be great advantage in erecting sécherzes, or seed depdéts, where- ever the existence of extensive masses of forest admit of this being done. “ Remark of the Administration. “Notes have been taken of the different opinions expressed by the agents on the question of establishing new Government sécheries. “ Twelfth Question. “ Examine, and say whether it would not be desirable to gather seeds in the Government forests under the charge of the local officials, and to have them put into places of deposit, from which at a fit time they might be sent off to the places to be reforested. “This measure promises to the agents of the three conferences to be productive of advantageous results. The agents of the conference at Car- pentras express the wish that the gathering should also be made in the communal forests. ‘VV, MEASURES FOR SECURING ORDER. “Thirteenth Question. “ Discuss the measures taken to insure the thorough execution of the works, and to justify the use made of the credit accounts opened by the Gavernment. “ Opinions, dc., of the Agents. “ At Clermont, the conference expressed the opinion that the first condi- tion of the success of the works of veboisement is, that the direction and over- sight of these works should be entrusted exclusively to the agents, and that RESUME OF CONFERENCES IN 1862. 197 it is necessary that a guard should be constantly stationed at the wood-yard of the works. This obligation necessarily causing heavy expenses to the officials, it is desirable to extend the arrangements of circular No. 708 to each official compelled to sleep away from home. “ Remarks, &c., of the Administration. : “The Administration is of opinion that the works being executed under the direction of agents gives the only security for success. It does not seem possible always to exact the presence of an official on the spot. This ought, however, to be secured whenever it is possible. The Government has the intention to remunerate in a suitable degree the officials who accomplish onerous duties, and who render important service. In this respect no absolute rule can be fixed, the rewards must vary with circumstances. “ Special propositions on this head may be sent in; and, in order to + prevent these coming at all times of the year, (which occasions serious loss of time to the Administration) it is desirable, hencefor- ward, to collect them into two despatches, added to’the forms ordered, Nos. 16 and 17 (Circular 806). “Tn justification of the credits opened, the agents stated that in the delay of a month, which occurred in the settlement of accounts, the agents have produced tables with margins of the accounts of the day’s work of the labourers, as a return for the sums put to their account ; for the supplies, they have presented receipted bills, all according to the rules of debit and credit. “The conference at Clermont submitted to the Administration the following question : When the aid granted, according to the estimate of the works, exceeds that estimate, should the extra sum be granted to the appli- cant, and if the expense is less than the allotted aid, should a credit for that extra sum be demanded ? “ Rupiy, &c.—The estimate of the expenses of the works can only be an approximate one. Consequently, when the aid is greater than the actual expense, the course to be pursued is to extend the works over a space proportionate to the excess ; or, if that extension is imprac- ticable, to leave unemployed the said excess in money, which will thus be disposable for other works. If the aid granted be less than the expense would be, the works should be reduced by an extent corresponding to the difference of means. “The agents at the conference at Foix proposed that the good or bad execution of the works should be established by a minute declarative of the facts, and to extend the application of this measure to the sanctioned rebdoisements of communal lands, when undertaken by individuals with the grant in aid. “ Remarks, de. : “Nothing would be gained by the establishment of the good execution of the works by such a minute ; and in regard to the bad execution of the work, it is already prescribed by the regulation to supply grounds for exacting repayment, in whole or in part, of the grant made. “The agents at the conference at Carpentras, in giving account of the means employed to insure the good execution of the works, and the pay- ment of expenses, stated, in regard to delivery of orders, that where this is done it is by small coupons, which has facilitated payment and rectification 198 LEGISLATION ON TORRENTS. of accounts, and has rendered unnecessary the making of advances, and repayments of these, which it is always desirable to avoid in accounts. “ Remark. “To this there is nothing to object, but the fear that it may lead to too great complication of accounts. “ Fourteenth Question. “The allotting of aid having, up to this time, been made as fast as the production of the demands, the Administration have been obliged to leave to each conservator the care of procuring by purchase the seed required, and the necessary plants. It would seem to be more simple, more convenient, more regular, and doubtless more economical, that the Government should centralize the orders for, and the despatch of, these seeds and plants ; Discuss the means of effecting this centralization, if it does not appear to the agents better to leave the ordering of seeds and plants to be done directly, as heretofore, by the agents. “ Opinions, dc., of the Agents. “The agents of the conference at Clermont considered that the centraliza- tion would be very useful, and proposed, for this purpose, the mode of organization which seemed to them most convenient. “The agents of the conference at Foix expressed the same opinion, and presented their proposals. “ At Carpentras the conference expressed the opinion, that, whenever the articles required can only be obtained by purchase, the centralization of the orders for these supplies will be more simple, more convenient, and more regular, but not always more economical: (1) because the seeds purchased are generally inferior in quality to those bought on the spot by the agents themselves ; (2) because the expenses of carriage are great in the one case and nothing in the other. The centralization of orders does not then appear in all cases to offer the advantages to be desired, and ought to be restricted in the one case to species rare in France, such as cedars, Austrian pines, Corsican pines, and in the other, to supplies of seed which cannot be had in the locality. “ Remarks, &e., of the Administration. “The ordering of seeds from merchants at a favourable time for the procuring of the supply, and the ordering of these in large quantities are favourable conditions for obtaining them on the most favourable terms possible. But notwithstanding this, the Administration does not intend to prevent in any way the agents from taking advantage of local supplies. To this end, at the periods for the despatch, of the collective demands for aid, the agents will add to these demands the following information : (1) the quantity of seeds or plants of each kind necessary to meet the said demands, which can be delivered at their destination by the direct care of the conservator through the local resources ; and let the destination of these seeds be stated ; (2) Quantity of seeds or plants presumed to be necessary for the reboisements obligatotres during the season following the despatch of the information. In this let the quantity and species of plants and seeds to be sent by the Government be indicated, also the place of destination and time at which they are required ; (3) Extract from the register of the nursery. Let each conservator state the number of plants required by him and their destinations ; (4) Situation of RESUME OF CONFERENCES IN 1862. 199 the sécheries. And let each conservator report the quantity of seeds required by him, and their destinations. “By help of this information the Administration will be able to give to the trade the necessary orders, and to provide for the direct trans- mission to their destination of the seeds and plants which cannot be obtained in the locality. “ Various Questions DiscussED BY THE AGENTS IN ADDITION TO THOSE SUBMITTED BY THE ADMINISTRATION, “The questions discussed by the agents, in addition to the programme, do not appear to present in general other than purely local interest, and consequently it would be useless to reproduce the whole of them in the present summary. There are, however, some of those questions, which, on account of their wider interest, will be mentioned here. “ Opinions, &c., of the Agents. “The agents of the conference at Carpentrashave remarked, that the method of reboisement by strips and by clumps seems a desirable one to practise in cer- tain regions, especially in the departments of the L’Izére and the Hautes-Alps. Clumps of larch would suit well for the high mountain pasture lands. “ Remarks, &c., of the Administration. “This method of reboisement would only be efficacious in so far ag it was practised concurrently with the works for improving pasture, and it is necessary to have it kept in mind, that the law for the reboisement of mountains limits its action to works of reboisement properly so called. Besides this, reboisement by clumps would have the effect of extending the defences to embrace very vast areas during the whole period of the first growth of the new plants, and during the successive periods of reborsement. “The question of the mixture of different kinds of trees in the reboise- ment was under discussion at the conference at Carpentras, but the discus- sion elicited nothing new. “ Remarks, dc. “ There has not been obtained as yet a sufficiency of results to decide this question. “At Foix, an agent said he had tried the effect of sulphur upon seed- beds of laburnum, of ailanthus, and of pines of Aleppo. It brought only to the laburnum a sensible augmentation in vigour of vegetation. The sulphur was only applied at the period of the August sap. The attention of the conference was called to the operation, which might be made the subject of interesting experiments. “ Remarks, é&c. “ The operation of applying sulphur, which is pretty expensive, seems here to have had no other effect than to increase the power of vege- tation in the plants of the seed-beds. It does not appear certain that important advantages result from its use. It will not be with- out use, nevertheless, to make experiments in this direction when a good opportunity may present itself. “A proprietor of the department of L’Arié¢ge had proposed to the Administration to grant to him land for the establishment of a central place for trials, experiments, and observations, in forest, pastoral, and hydrological matters, in relation to the reboisement of mountains, 200 LEGISLATION ON TORRENTS. “The agents deemed that such a field of experiments, however useful for the district in which it might be placed, would not be capable of furnishing certain information for other regions, and that, in this point of view, the proposed establishment does not present the promise of adequate general interest. “ Remarks, ke. “The Administration shares the opinion of the agents at the conference at Foix. “ Desrres EXPRESSED BY THE AGENTS ASSEMBLED IN CONFERENCE. “The Agents at the conference at Foix expressed the wish that the Administration of Forests should be charged with the mise en valeur, or improvement, and the reborsement of the communal lands situated on the- mountains. “The execution of the law on the mise en valeur of the communal uncul- tivated lands lies with the prefects, There is nothing to prevent the execution of such works of this character, as have for their object reboisement, taking place under the care of the forest agents. It is thus that the law in question is applied in the department of the Vosges. The conservators will consider whether they ought not in this matter to advise with the depart- mental administrations. “The agents at the conference at Carpentras have expressed the following wishes : (1) That in future the programme of the conference should be sent to each agent at least a month in advance ; (2) That the members appointed should bring with them samples, models of instruments, &c. ; (3) That they should put down beforehand in writing, as far as possible, their answers to the questions on the programme, and their observations. “ (Signed) H. Vicarre, Director-General of the Forest Administration. “ Paris, January 10, 1862.” The following is an Abstract of Report of operations in 1862 :— In 1861 the expense of the reboisement of the mountains was settled as follows :— Subventions for reboisements facultatifs, or sanctioned opera- tions, granted to communes and private individuals for labour upon Crown lands, for nurseries, for sécheries (or places for collecting and drying seeds), for keeping up the works, and for various kinds of labour, Frances, 548,855,30 Support of agents and overseers, ‘F 46,718.94 Indemnities to agents, overseers, and assistants, is 42,439.40 Francs, 638,013,64 A. Reboisements Facultatifs. In 1862 the demands for subventions have been as follows :— By communes and public establishments, 730 \ 1498 By private people, 698 = Of which only 40 have been rejected, as not falling withinthe scope of the law. These demands came from 39 departments in all. The areas reforested were, for what had been done by 742 communes and public establishments, 5,774 58a ; by 394 private individuals, 1,714m 15a—total, 7,488u 73a 00. It was in the departments of Puy-de-Déme and of Vancluse that there was the largest extent of communal reboisements. ABSTRACT REPORT 1862. 201 Subventions in money and in kind, amounting to 280,000 francs, representing about two-thirds of the total expense of the works, The reboisement of private property has been most extensively carried out in the departments of the Gard and the Dréme, where the subventions amounted to 70,000 francs, representing about 40 per cent, of the total expense of the works. The discovery, it is stated, is being made, that rebotsement is an opera- tion much more fruitful in immediate advantages than had been generally believed. : The report cites two examples of these advantages : A commune possessed a district of 64 hectares covered with heath, which had not been sold, though in 1844 offered for sale at 7000 francs, At this time a sowing of pin sylvestre was undertaken, at the expense of the municipal chest ; there was little additional expense ; and now this district is valued at more than 70,000 francs, Another commune possesses a wood of 47 hectares in extent, planted with pins sylvestres about 15 or 16 years old. Lately a thinning was effected, which produced 16,000 francs. These well-known facts have not a little contributed to the favour with which the works of rebotsement are regarded in the departments in which they had been carried out. Joint stock companies, or associations of capital, are now very advan- tageously employed for the exploctation of different branches of industry. The acquisition of mountain districts on generally very moderate terms, and their replenishment with wood by the help of large subventions, seems to form the basis of a speculation which is both productive and exempt from risk of loss. The restocking of the mountain Crown lands had extended, in 1862, over 1866uH. 03 ares, at an expense of 146,747 fr. 51 ct. B. Reboisements Obligatoires, or Enjoined Reboisements. In all cases in which public safety demands the creation of such hinder- ances as reboisement can offer to the irregular action of rivers or floods, or to the crumbling of the ground, and where the safety of the inhabitants, the condition of the roads, and the culture of the lower declivities, are most threatened by torrents and avalanches, the law has commanded the formation of woods; the extent of these is in proportion to the hydraulic effects they are designed to produce. The Administration has carefully considered the condition of the dis- tricts where veboisement seemed to be most urgently required. These careful inquiries in 1861 and 1862 extended over 21 departments, and gave rise to the origination of 269 enterprises, comprehending 136,756 hectares. 89 undertakings, extending over an area of 59,833H. 28a. have been offi- cially inspected. The projects have encountered a good deal of opposition, “Tt is necessary clearly to define the character of this opposition,” says the Director General of Forests, ‘‘in order to exhibit the influence of the operation of reboisement upon the condition of the mountain population. “Tn most cases the herds of cattle do not belong to the poorer inhabit- ants. The flocks of sheep belong toa certain number of local owners, who make all they can out of the communal lands, or to people from a distance, whose immense flocks, known by the name of transhumant flocks, every year cover the mountains leased from the communal bodies, at usually a very moderate rent. Zz + 202 LEGISLATION ON TORRENTS. “The operation of reboisement, far from introducing new restrictions into the already straitened circumstances of the poor inhabitants, would, on the ncotrary, be a source of numerous advantages. Without mentioning one of these advantages which can only be realised in the more or less distant future, there can be pointed out as an immediate and direct result, the unusual comfort diffused over these poor districts by the money devoted to the execution of the works in the form of wages, purchase of seeds and plants, and other outlays of various kinds. “ There is reason to think that the mountaineers, with their characteristic mental quickness, have already come to appreciate the operation of reboise- ment, and that the opposition which has arisen in several cases is only an expression of personal and isolated interests. “It is, moreover, only through mistake that the pastoral population takes alarm at the undertakings of the Forest Administration, the greatest number have been in favour of this industry. Besides the immense tracts known by the name of pastoral mountains, which lie above the zone of forest vegeta- tion, and of which the destination indicated by the nature of things cannot be modified, the actual sheep runs are in many cases not only preserved but improved from the double point of view of the pastoral interest and the preservation of the turf.” Nearly all the commissioners charged with the direction of these inquiries have earnestly approved of the projected reboisement, and in all cases the special commissioners, the Councils of the Arrondissement, the General Councils, and the prefects have adopted these projects. Besides, the General Councils have voted subsidies in favour of the reboisements. These subsidies, 20,000 francs in 1860 rose to 40,000 francs in 1861, and to 71,000 in 1862. The gradual increase of these sums, more than their absolute importance, is an indication of the increasing movement of public opinion in favour of the operation. Reboisements obligatowrs, or enjoined reboisements, had extended in 1862 into three departments, and into seven périméters, or defined areas, of over 2061 hectares 87 ares, and has cost the State 69,576 francs 21 cents. ie the reboisements effected in 1862 amount in all to 11,416 hectares ares. C. Sécheries and Nurseries. The reborsement in 1862 has been effected, by means of sowings, upon 8344H. 264.—by means of planting, upon 3072H. 37a. For the sowings 95,403 kilogrammes of the seeds of different trees have been used. For the plantations there have been used 22,137,500 plants of different sorts of trees, besides those transplanted from the woods. The pin sylvestre, or Scotch fir, épicéa, or Norway fir, and the larch, have been most generally employed. Other trees have also been used—as the oak, the Austrian pine, the Mugho, the Aleppo pine, the cedar, the ailanthus, which are introduced gradually in proportion as new experiments are tried. The selection of trees has generally been directed by local indications. Four sécheries were formed in 1861; two others were established in 1862. These supply from 15,000 to 20,000 kilogrammes of seed, corres- ponding to the reboisement of 2000 hectares, Tne outlay in 1862 amounted to 38,515,24 francs. ABSTRACT REPORT 1863. 203 The Administration has, morover, in 1862, set agoing the collecting of seed in the Crown forests, and has collected considerable quantities at a very moderate expense. In 1861 there had been formed 473 nurseries, 330 hectares in extent, and capable of supplying about 60 millions of plants per annum. In 1862 there had been formed 359 new nurseries, covering 272 hectares 96 ares, capable of producing annually about 40 millions of plants. Many of these nurseries are of small extent, and are designed to supply plants for restocking the immediate vicinity. But in several cases central nurseries of considerable importance have been formed, situated in suitable districts, which had been bought or rented with a special view to the work in hand. These nurseries have been the object of the greatest care, they are 14 in number, and are spread over ten departments. It is calculated that 5000 hectares is the extent annually reforested by means of planting, and that 40 millions is the necessary supply of plants. At the market price this quantity of plants would cost 240,000 francs. In 1852 the expense for the formation of new nurseries, and the keeping up of the old ones, amounted to 153,772 franes. D. Administrative Measures, A new district under a forest conservator has been formed. Annual conferences, attended by those taking a part in mountain reboisement, have been instituted. The Director of the Government School of Forests has been appointed to visit the works of reboisement in the Pyrenees, the Alps, and the moun- tains of Central France. The object of this visitation is to encourage the efforts of those employed, to secure everywhere good methods of culture, and to report to Government upon the execution of the works and the result obtained. According to the preamble to the law of 28th July 1860, the expense of veboisement was estimated at 180 francs per hectare. In 1861 and 1862 160,055 hectares 63 ares had been reforested. The expense during these two years had been 1,738,000 francs, or 180 francs per hectare, without taking into consideration the part of the above mentioned expense incurred in the preparation for enjoined reboisements, the formation of sécheries, the purchase of Jand, and other expenses not directly belonging to the work of replanting, properly so-called. The expense per hectare reforested will be still further reduced through use being made of the extensive resources supplied by the nurseries and sécherdes, and of experience acquired by practice in the execution of the works. ABSTRACT OF REPORT FoR 1863 :— According to the detailed accounts of expenditure on the work in 1862, the expense has been as follows :— Subventions, - Frances, 350,000,00 Purchase of Property, 5 ee 231, 300 Execution and Superintendence of the Works, ss 761, "957, 31 ae Total Francs, 1,125,188,31 204 LEGISLATION ON TORRENTS. A. Reboisements Facultatifs, or Sanctioned Reboisements. Subventions have been granted to 450 communes, or public establish- ments, and to 983 private individuals. These reboisements are extended over communal lands, 7,073H. 24a. ; private property, 2,157. 05a. ; crown lands, 1,750n. 88a. ; total 10,981x. 17s. Outlay, at the Government expense, 595,000 francs, besides the expense of keeping up the sanctioned reboisements of former years, 81,800 francs. When requested by proprietors, the Forest Administration have carried on the work of reboisement under the superintendence of its agents and guards, and they will continue to keep them up and develope them, so far as possible, till success appears assured. The works have been spread over 40 departments. The report specially mentions an experiment of reboisement in the Crown forest of the Luberon, situated on the formation called neocomien, belonging to the lower portion of the chalk formations, where the bare places are covered by enormous heaps of rocks, burnt by the sun, and entirely destitute of vegetable mould. Such is the district of which the forest agents have not been afraid to attempt the reboisement. Nothing has been neglected to ensure the success of this bold enterprise. After several attempts at plantation, which proved either fruitless or else too costly, the agents fixed on the method of replenishment by sowing, principally with the seed of the pine of Aleppo. The small quantity of vegetable mould still remaining between the rocks was gathered together into narrow ridges, and prevented from falling down by layers of stones. Upon soil prepared in this manner the sowings were most successfully effected. In the month of September, after the trial of an exceptionally dry and hot summer, the young plants appeared quite flourishing. Toone who has seen the sowings of Luberon, (says the report) no reboisement will appear impossible, Among private individuals the taste for forest improvement seems to have a tendency to increase wonderfully. The number of private pro- prietors who had received subventions, which was 394 in 1862, ‘1 1863 amounted to 983, B. Reboisements Obligatoires, or Hnjoined Reboisements, On the 1st January 1864, the districts comprehended in the Government undertakings were to be found in 23 departments. Digests have been prepared of 264 enterprises, of which 77, embracing about 60,000 hectares, have been approved, with decrees declaring their public utility. The works of rebotsement then in course of execution in 26 circles ex- tended over a surface of 1,853n. 57a. The expense has been 154,850 francs, besides 13,100 francs for keeping up the works already effected. This outlay, however, is only a Government loan in terms of Articles 8 and 9 of the law of 28th July 1860. Tn cases where direct reboisement did not present a sufficient probability of success, because of the absence of vegetable mould, it has been preceded by the restoration of the soil, by means of planting or sowing herbs or bushes. The principal plants growing spontaneously on the mountains are juniper, barberry, V’argoussier, l’amélanchier, which are chiefly found in the rockiest places, white fescue grass, whose luxuriant tufts appear on the steepest parts of the ravines, ‘the sainfoin and lucerne, the long matted roots of which are well fitted to retain the soil upon the slopes. ABSTRACT REPORT 1863. 205 A considerable number of rustic barriers have been formed on the upper branches of the torrents. Instead of a large work of art constructed at the mouth of the ravine, which nearly always gives way, the system of defence consists in the formation of a number of dams across its ramifications throughout the upper portion of its course. The small furrows which form the highest branches of the torrents are dammed by simple faggots fastened with stakes. In the larger branches, and where the presence of rocks or any other circumstance appears to favour the construction, there are formed dams made of hurdles and boughs, or walls of stones placed one upon _. another strongly attached to the banks, or by rude carpenter work, the whole being completed by interweaving quantities of willow and osier wands into the banks, and into collections of earth which accumulate above the barricade. “The success of these simple and economical works is remarkable. The water, arrested everywhere in its descent, falls with much less violence and rapidity ; a great part of the materials which it bears along are stopped by the barricades, and no longer spread themselves over the villages and lands situated at the foot of the mountain; finally, the accumulation of these materials, joined to the quick growth of the willow wands, tends to efface the effects of the torrent between the successive barricades, and in some measure to lessen the torrent by stopping up the ramified furrows of which it was composed.” Total extent of rebovsements effected in 1863, was 12,8345, 74a, C. Preparatory Works. The question, which of the two methods of replenishment, sowing or planting, should be preferred, does not admit of absolute solution. “In planting, two principal dangers are to be dreaded : The swelling up or upheaval of the soil in spring, produced by the alternations of frost and thaw, the effect of which is to lay bare the roots, and even to throw out the plants,—and the drought in summer. These dangers may often be averted or escaped, by placing, when circumstances permit, at the root of the plant one or two stones, intended at the same time to hinder the swelling of the soil and to keep the surface of the ground cool. When the trees are planted amongst herbage, after a turf is cut, for the purpose of planting a young tree, it is cut in two and placed at the root, either in the position which it occupied before the operation, or turning the grass side towards the ground. « Autumn has been preferred for planting, spring for sowing ; but experi- ence has proved that sowings completed after the greatest heat of summer are the most successful; the young plant appears before the cold, then comes the snow to cover and protect it till the return of spring ; it then resumes its scarcely interrupted growth, and when summer arrives it is robust enough to resist the heat.” D. Nurseries. Since the beginning of the enterprise of the reboisement of the moun- tains, Government has felt the necessity of getting rid of the obligation to have recourse to purchase, because the outlay is great and the produc- tions are not always to be depended upon. The harvest of the fruit of this foresight is now beginning to be reaped. Two kinds of nurseries have been formed. (1) Small nurseries, scattered over the district where the reboise- 206 LEGISLATION ON TORRENTS. ments are of small extent ; (2) More important nurseries, intended to supply subventions of plants to communes and to private individuals, as well as the reboisements obligatoires of specified périmétres. The first-mentioned nurseries, containing less than 50 ares, are 355 in number, and cover in all 41 hectares 42 ares. The second, of greater extent, containing more than 50 ares, are 97 in number, and cover in all 144 hectares 72 ares. The expense of the nurseries, for establishment and keeping up, has been 163,000 francs. The following is an account of the expense and returns of two nurseries of the second class, those of Arpajon (Cantal) and of Bourg (Ain) :—The first, 7 hectares 43 ares in extent, has cost in all 51,252 fr. 60 ct. It has produced since its formation 4,365,310 resinous and broad-leaved plants, of the value of 42,712 fr. 60 ct., according to market value. The expense of keeping up will be from 10 to 12 thousand francs annually, and the return from 6 to 8 millions of plants, which, at an average price of ten francs per thousand, represent a value of from sixty to eighty thousand francs. The second nursery, 4 hectares in extent, has required an outlay of 29,107 fr. 53 ct., and it has supplied 2,050,000 plants, 20,000 francs in value. Its keeping up costs annually from 5 to 6 thousand francs, and it produces about two millions of plants, valued at 20,000 francs. E. Co-operation of the Departnents. The General Councils have approved of the greater part of the projects submitted to them, In 1863, 35 departments have granted sums amonuting to 98,000 francs. These subsidies have been in 180, 20,000 frances. ” 29 ” 161, 40,000 2»? ” ” ” 162, 71,000 ” ABSTRACT OF REPORT FoR 1864 :— In 1863 the expense of the reboisement of the mountains amounted to 1,316,652 fr. 15 ct., apportioned as follows :— Subventions to communes, to public establishments, and private proprietors, - Franes, 494,000.00 Purchase of land, - 5 23,879.13 Execution and superintendence of work, - 5 798,773.02 Total Francs, 1,316,652.15 In 1864 the expenses were, - i 1,401,822.48 A. Reboisements Facultatijs, or Sanctioned Reboisements. Tracts of land belonging to communes or public establishments.—458 com- munes or public establishments have received, in 1864, grants of seeds and plants, or of money, amounting to 352,210 francs 15 centimes, The tracts reboiséd with the help of these grants were, 6,164 hectares 32 ares in extent. According to results determined by forest officers, the sowings and plantings. succeeded in at least a proportion of from 60 to 80 per cent, Land belonging to private individwals—Government had in 1864 granted subventions to 739 private individuals for the reboisement of mountain terri- tory, covering an extent of 1,601 hectares, dispersed among 28 departments. ABSTRACT REPORT 1864. 207 Crown tands,—In the departments where the State possesses bare moun- tain territory, the Forest Administration has set the example of reboisement by sowing or planting every year areas more or less considerable. 1,834 hectares 70 ares of this kind of ground has been rewcoded in 1864. It is chiefly in the department of Ariége that the restockings of this kind have taken place during several years with remarkable success. Altogether the reborsements facultatyfs of evéry class, in 1864, covered 4,743 hectares 90 ares. B. Reboisements Obligatowres, or Enjoined Reboisements. At the end of 1864 the number of projected enjoined reboisements were 322, covering a total extent of 168,300 ares. Of this number, 84, covering 61,814 hectares, have been at the same time subjects of a decree declaring them to be of public utility, In the course of the same year, works have been executed in 65 péri- métres, These works have consisted of redoisements properly so called, the keeping up of reboisements effected in preceding years, sowings or planta- tions of herbs or bushes, construction of dams, lopping trees, and enclosures. These have cost 249,000 francs. The Government in 1864 hag only had recourse to expropriations in the cases of two tracts of ground, extending to 25 hectares, for which the price paid amounted to 9,476 francs 47 centimes. , It is with the utmost reluctance that Government makes use of the privilege accorded by the 2nd paragraph of Art. 7 of the law of 28th July 1860. Since the law has come into operation, there have only occurred some three cases in which it was needful in the public interest to proceed to ex- propriation. C. Conferences. Conferences held in cantons to determine what lands should be re- planted have continued to discharge this duty in a manner the most satisfactory. D. Résumé of Work executed in 1864. The total sum of reboisements effected in 1864 embraces an area of 12,193 hectares 32 ares. E. Kinds and quantities of Seeds and Plants used in 1864, and ways in which they have been apportioned. Of the 12,193 hectares 32 ares rewooded in 1864, 7632 hectares 44 ares have been sown with seed ; and 4559 hectares 88 ares have been planted. The principal kinds of trees thus used have been, as in years preceeding, le pin sylvestre, or Scotch fir; Pépicéa, or Norway fir; le pin maritime, or maritime pine ; Ze méléze, or larch ; le pin noir d’Autriche, or Austrian pine ; le pin laricio, or Corsican pine ; le pin & crochets, or Mugho pine ; le sapin, or silver fir; le chéne, or oak ; le chdtaigner, or chesnut ; le hétre, or beech ; le fréne, ov ash. It is with the greatest reserve that attempts have been made to introduce other kinds of tree, which are not indigenous, in such districts as have been rewooded. Of the 161,260 kilogrammes of seed used in 1864, 137,028 kilogrammes have been supplied by sécheries domamials. But the Administration has not found any great advantage in preparing their own seeds. 208 LEGISLATION ON TORRENTS. In regard to plants, of 55,740,000, 49,334,000 have been reared in nurseries belonging te the State; and the others, 6,408,000 have been obtained from nurseries belonging to private parties. The expenses of all kinds incurred in maintaining the State nurseries has amounted, in 1864, to 175,892 francs; and the value of the plants supplied from them in the course of the year, estimated at 6 francs per 1000, which is much below the average market price, amounts to about 300,000 frances. It is of some importance to add that, in regard to adapta- tion to their destination, the quality of the plants supplied from the State nurseries is in general much superior to that of the others; and, in the report it is added, there is reason to hope that the Administration will soon be in a position to dispense entirely with having recourse to purchase for the supply of plants. The principal nurseries of the Administration collectively cover an area of 257 hectares 34 ares, and can supply 93 millions of plants per annum. F. Co-operation of Departments. The amount of subventions voted by the departments in 1864 is nearly the same as in 1863, being 81,104 francs, as against 78,000. The following is a general résumé of what was effected in these first four years of the enterprise -— In these years there were replanted with woods 41,083 hectares 26 ares. Of these there were reboisements facultatifs, or sanctioned reboisements, on property belonging to private proprietors, 6056H 134 to communes, - 216655 84a to the domaine, 6853H 564 34575 53a Rebotsements obligatotres, or enjoined reboisements, 65078 73a 41083H 264 The accomplishment of the work cost the State, in 1861, 638,013 fr. 64 ct. ; in 1862, 1,125,188 fr. 21 ct.; in 1863, 1,316,652 fr. 15 ct.; in 1864, 1,401,822 fr. 48 ct.,—total 4,481,676 fr. 48 ct., being, on an average, 102 francs per hectare. Thus far all seems to have gone on satisfactorily. Every thing had been done to carry public opinion, and the sympathies of those who were more immediately affected by the operations, with the enterprise. But it becomes necessary at this point to advert to the results of this commendable endeavour, and the supplementary legislation which this necessitated. From the first the work had been prosecuted with vigour, and it had the support of many of the more intelligent inhabitants of the district ; but after a time, as may be seen from these reports, a reaction began to mani- fest itself, and this became at length developed into strong opposition on the part of many. “ As may always be expected,” says Cézanne, “ difficulties which had not been taken into account began to make themselves apparent when the work was commenced, The word reboisement frightened the pastoral communities ; there was promised to them herbage growing under the trees in about EXPOS DES MOTIFS OF LAW OF 8TH JuNE 1864, 209 twenty years; but in awaiting this how were they to support the flocks, which supplied their only income? ‘The operation,’ cried they, ‘is a ene injustice ; they are ruining the mountains in order to enrich the plains.’ “The Administration saw that there was some foundation for this com- plaint, and they resolved to do what was right in the case; but the law spoke only of reboisement—their powers, and the funds placed at their disposal, related only to this; and something must be done to meet the case. “It was thought at first that this might be effected by the law, Sur la mise en valeur des biens communaue, for the improvement of communal pro- perties. The greater part of the lands to be replanted being communal lands, it was thought practicable to unite the two objects, and combine the two funds for a common action, and a mixed commission was nominated by the three ministerial departments interested ; but it was found that the two laws which they sought to combine in joint action had two very different objects: the law on reboisement had for its object to secure the public safety, the other to promote the national wealth; the former acted on decrees with credits and subventions, the second by prefectoral resolutions granting simple advances ; by the first the Agents des Eaux et Forets were charged with the reconstitution of communal property, to carry out the second the officials of Les Ponts et Chaussées labour to convert communal into national or personal property.” The Mixed Commission soon reported its powerlessness, and the Govern- ment had to follow up the law in regard to reboisement with one relative to gazonnement, The following is a translation of the Zuposé des Motifs, which accompanied the draft of this law, addressed to the councillors of State charged to support it before the Corps Legislatef :— “‘ GENTLEMEN,—When the law of the 28th July 1860, on the reboise. ment of the mountains, was submitted to the consideration of the Corps Legislatif, the honourable reporter, in the name of your commission, expressed himself in these words :— “Tt may be well, then, to recognise the fact that the deboisement, or destruction of woods on our mountains, is not the only cause, or even the principal cause, of the disasters produced by the ravages of the waters, Along with this, as still more hurtful, must be classed as a disturbing cause degazonnement, or the destruction of herbage. ; “<«Tn like manner, reboisement alone is not enough to remedy these evils, It would be impossible to replant with trees all the bare mountains, on account of the great expense. It would also be useless, as keeping up the turf is a sufficient preservative, the benefit of which has been proved by experience. It would also be difficult, looking at it from the stand-point of the wealth of the country, as it would substitute comparatively profitless forests for the magnificent pasturage, the destruction of which would ruin the population of the mountains. “But it is not the less true that, in conjunction with gazonnement, reboisement will have a most happy effect. “«The present law will only produce all the good effects which may be expected when it shall be supplemented by gazonnement, 2A 210 LEGISLATION ON TORRENTS, “¢The experience and the investigations of engineers have shown that in certain cases it is indispensable to arrest a daily increasing evil, for only in this way can possibly be preserved certain districts unfitted for pasturage, and threatened with approaching destruction. Reboisement will create a great protection, preserving even the pasture lands, regulating the flow of the water, and preventing the formation of avalanches, and exercising certain specific effects during atmospheric perturbations. “¢The measure which is now proposed is truly a law for the public welfare, and has a right to all our sympathy ; but it will not produce all the good that may be expected, until it shall be supplemented by measures for the protection of the herbage, and by measures repressing the increasing evils of depasturing. “The commissioners appointed by you pray earnestly for these measures, regarding which they have no power to take the initiative.’ *¢ Goverment has not overlooked this view of matters in the preparation of the law of 1860. The Exposé des Motifs, or reasons assigned for this law, explained to the legislative body the various reasons which at that time led the Government to determine not to extend the action of the law to the restoration of herbage. One reads as follows, at page 17 :— ~ «¢We do not conceal, that, even looking at it from the point of view of hydraulic results, which is the stand-point of the law, the restoration of the herbage is fitted to give important help to reboisement. At the same time, it does not appear possible to extend go far the operation of the pro- posed measures, and that for several reasons. “¢ First, the financial resources which are at command are not adequate to meet the expense of the reboisement which it is desirable to encourage and execute, unless they be laid out with the greatest economy and wisdom ; no part, therefore, should be diverted to works of a different nature, or inferior utility. “