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1965

JAN 1 2 19(56

lUL 27 1956

DEC 2 0 BE 7

FORESTS AND MOISTURE;

EFFECTS OF FORESTS

HUMIDITY OF CLIMATE.

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, Fellow of the
Royal Geographical Society, Fellow of the Linnean Society, and
Honorary Vice-President of the African Institute of Paris, etc.

EDINBURGH:

OLIVER AND BOYD, TWEEDDALE COURT.

liONDON: SIMPKIN, MARSHALL AND CO.

187 7,

Kirkcaldy : John Crawford, Printer.

[All rights of Translation and Reproduction are reserved.']

CONTENTS AND ARGUMENT,

FAOE.

Index to Authorities Cited, - - - - xi

Preface, - - - - - - - xiii

States circumstances in which the voliune is published.

Introduction, . . . _ . i

States subjects to be discussed as being more particularly the effect of
forests on the humidity of the climate, including the rainfall ; but
treating this only as accessary to other effects, and these such as
may be produced by every blade of herbage according to its
measure.

PART I. — Phenomena op Vegetation on which the Meteor-
ological Effects of Forests affecting the Humidity
OF Climate depend, - - - - - 3

Chapter I. — Primary Phenomena of Vegetation, - - 3

Primary phenomena of vegetation are expounded as seen in the Red
Snow, the Yeast plant, Confervje, and Algse (p. 3), and thus is
illustrated the absorption of moisture by endosmose (p. 5), which
process is more fully detailed (p. 6). The liquid absorbel is traced
from the rootlets to the leaves (p. 10;; the rise of the sap is ex-
plained in accordance with the supposition of its being attributable
to endosmosic action (p. 12). The differeace between this and
capillary attraction is explained (p. 13), and the difference between
this and what is called vis a tergo (p. 15). The structure of the
leaf is described (p. 17), and the process of the evaporation of the
moiBtnre by the stomates of the leaves is illustrated (p. 19).

Chapter II. — On the Quantity of Moisture Evaporated through

the Stomates of the Leaves, - - - - 21

Facts illustrative of the quantity of moisture evaporated through the
stomates of leaves are cited from Marsh and others, embracing
observations on the Oik by Marshal Vaillant (p. 21), and on the
maple and the birch in Am?rici (p. 22).

Chapter III. — Disputed and Secondary Phenomena of Vege-
tation, - - - - - - 25

Section I. — On the Absorption of Moisture by Leaves, - 25

It is alleged that there is a lack of evidence of moisture being absorbed
by leaves in great quantity (p. 25).

Section II. — On the Production of Water by Plants, - - 26

A reference is made to quantities of water found in the KaflSr iron-
wood (p. 26), the pitcher plant and the teazle (p. 27), to water
secreted by ants (p. 28) and by the cuckoo-spit (p. 29) ; and it is
intimated that it is not unreasonable to suppose that water may be
secreted by vegetables (p. 31).

Section III. — On the Dropping of Water from the Leaves of

certain Trees, - - - - - -31

Eeference is made to observations on a cehbrated laurel in Fervo
(p. 31), and it is su^gest>-d that the dropping of water fiora its
leaves may be attributable to a c ipiims deposit of dew (p. 32), and
this is again relerred to in explanation of similar phenomena ob-
served in Madeira (p. 35) and in Europe (p. 37).

PART II. — Effects op Forests on the Humidity of the

Climate, - - - - - - 38

Chapter I. — Immediate Effects of Forests on the Humidity of

the Atmosphere, - - - - - 38

Keference is made to controverted views on this subject, and these are
discussed (p. 38).

Section I. — On the Humidity of Atmosphere in the vicinity of
Trees, indicated by the dampness of houses overshadowed
by Trees, or situated in close proximity to a Wood, - 39

This is attributed to the moisture evaporated throujjh the stomatea of
the leaves being absorbed or retained by the walls (p. 39).
Section II. — On Clouds occasionally seen surmounting Woods

while the Atmosphere around is comparatively clear, - 40

There is discussed a statement by Marsh in favour of the popular
▼iew that mountains attract clouds (p. 46) ; and phenomena seen

OONTSNTS, Vtt

on Table Mountain, at the Cape of Good Hope, are adduced to
show that these, like the alleged attraction of clouds by forests, are
attributable to a reduction in the temperature of the air (p. 48).

Chapter II — Effects of Forests on the Humidity of the Ground, 51

Section I. — O71 the Wetness of Roads where these are over-
shadowed hy Trees, - - - - - 51
While the profuse evaporation from the trees through the stomates
of the leaves is net overlooked, the wetness of roads is traced to the
effect of the shadow occasioned by the trees preventing evaporation
from the overshadowed portion of the road (p. 51); in illustration
of which effect of shade are adduced experiments and observations
made at the Cape of Good Hope (p. 52), and observations on the
effdct of shade on ponds in England (p, 55).

Section II. — On the Desiccation of Ground by Drying Winds

being prevented by the Shelter afforded by clumps of Trees, 55
Illustrations are given of the effect of shelter in arresting evapora-
tion, and of the extent to which even bush may aci as a wind-
brake (p. 56).

Section III. — On the General Phenomena of Evaporation from

Forests, - - - - - - 57

There are given indications of evaporation being retarded by forests
(p. 59), observations on the quantity of rain arrested by leaves
made by Marshall Vaillant (p. 61) and by M. Mathieu (p. 62),
observations by the latter on the different quantities of water
evaporated in woods and in adjacent open land (p. 63), and notices

' of corresponding observations made by Risler(p. 61), with the con-
clusion from the whole that under the same measure of rainfall the
soil of the forest retains notably more water than does uncovered
ground (p. 65).

Section IV. — On the Moisture being attracted from the Atmos-
phere, or otherwise retained in the Ground by Vegetable
Moidd, - - - - - - 65

It is stated how it may be seen that there is a greater quantity of
moisture in the soil of a forest than in the soil of open country
(p. 65) ; illustrations are given of the process whereby such mois-
ture is absorbed (p. 65); the difference between this and the
deposit of dew is pointed out (p. 66) ; the property is stated to be
possessed in a high degree by clay and by vegetable mould (p. 67);
the latter is shown to be a product of forests, and a mode of deter-
mining the quantity of it in the soil is described (p. 70), and the
humus is shown to be liable to decomposition when exposed to the
rays of sun, unshaded by herbage and trees (p. 71).

fiii CONTENTS.

Chapter III. — Effects of Forests on Marshes, - - 73

Section I. — On the Brying-up of Marshes on the Growth of

Trees, - - - - - - 73

It is stated that what is evaporated through the stomates of the
leaves is derived from the ground (p. 73). and Ihit the quantity
often exceeds many times that of the rainfall (p. 74); that to a great
extent what the atmosphere thus gains the earh loses (p 79); and
an illustration of the effect in drying up wet ground is given (p. 80).

Section II. — On the occcasional appearance of 3farshes on the

destruction of Forests, - - - - - 81

Cases of the appearance of marshes on the destruction of forests are
cited, which are attributed to the interruption of the withdrawal
of excess of moisture from the soil by the trees (p. 81).

Section III. — On the occasional Destruction of Forests by the

Creation of Marshes, - - - - - 83

The destruction of forests by marshes is attributed to the damming- up
of water outle's at a lower level (p. H3), and illustrative cases are
given from Russia (p. 83), Canada (p. 85), and the United States
of America (p. 88).

Section IV. — On the Desiccating Effects produced on Marshes

hy Forests in prolonged periods, - - - 90

The gradual conversion of marshes into habitable and arable land is
discussed (p. 90), and Ireland and Denmark are referred to in
illustration (p. 91).

Chapter IV. — On the Effects of Forests on the Moisture of a

wide expanse of Country, - - - - 93

Section I. — Cases in which the extensive destruction of Forests
does not appear to have perceptibly affected the quantity of
the Rainfall over a wide expanse of Country, - - 94

The difference between moisture and rainfall is pointed out (p. 94) ;
and illustrations of little eff ct having been produced on the quantity
of rain falling over a wide expanse of country having been produced
by an extensive destruction of forests are given from France (p. 95),
and from the United States of North America (p. 98).

Section II. — Cases in which the extensive destruction of Forests
appears to have been followed by a marked desiccation of
Land and aridity of Climate, - - - 99

It is stated that the extensive destruction of grass and herbage and
trees in South Africa has been followed by drought (p 104); and
there are cited statements in regard to corresponding observations

CONTENTS, IX

elsewhere by Marsh (p. 106); by Hooker (p. 108); by Schleidea
and Fries (p. 108); Fraas (p. 109); Becqaerel (p. 110); Laurent,
&c. (p. Ill); Humboldt (p. 112); Boussingault (p. 113) ; and
Hough (p. lis;.

Section III, — Cases in which the Destruction of Trees have been
followed by desiccation ; and the planting of Trees has been
followed by the restoration of humidity, - - 117

St. Helena fp. 117) and the Mauritius (p. 124) are adduced as cases
in which the destruction of trees has been followed by desiccation ;
and the replanting of trees with restoration of humidity. The
Island of Ascension is brought forward as a case, in which the
•absence of trees was accompanied by aridity, and the planting of
trees was followed by humidity (p. 128) ; the measures adopted are
detailed (p. 134) ; and the successful results are reported (p. 141).

Section IV. — Cases illustrative of Effects of Forests on

Humidity corresponding to such as have been adduced, - 144
Accounts are given of climatal changes on the Island of Madeira
(p. 144) ; and reference is made to alleged changes in Alexandria
and in Egypt fp. 146^; South Africa Cp. 148); South America, &c.
(p. 149).

Chapter V. — Local Effects of Forests o7i the Rainfall and on

Rivers, - - - - - - 150

Section I. — On the production of Rain, - . . 151

The production of rain is traced to the deposit of moisture in excess
of what can be retained at a reduced temperature by air by which
it had been absorbed ; and in view of this there is detailed the rise
of the Trade Winds (p. 151), the course of currents of air from
the polar to the equatorial regions, and their return thither deposit-
ing moisture absorbed while proceeding toward the equator (p. 152).
Reference is made to the quantity which must have been so absorbed
(p. 153). The production of clouds by eddies and whirlwinds is
described (p. 156) ; and the production of rain as detailed by Sir
John Herschel (p. 158).

Section II. — The Effects of Forests on the quantity of the Local

Rainfall, - - - - - - 159

There are brought forward the views of Boussingault and Becquerjl
that forests increase the local rainfall (p, 159), Observations by
Mr Draper are again brought forward, but with them an illustration
of the effect of forests by Coultas (p. 160) ; and statements of the
views of Marsh and the observations of Mat hieu in accordance with
the views of Boussingault (p. 161); with remarks on the same by
M. C6zanne (p. 162).

X CONTENTS.

Sectiox hi. — Effects of Forests and of the Destruction of

Forests on Rivers and Streams, - - - 165

Cases are cited from America North aad South i^p. 166), I'roui France
(p. 167;, from Germanyand from the Cape of Good Hope (p. 172) ;
illustrative of the flow of streams and rivers varying with the exist-
ence and destruction of forests. A resume is given of a treatise by
Herr Wex on the diminution of water in springs and rivers, with
augmentation of floods (p. 175) ; with reports on the sarne by the
Academy of Science of Vienna (p. 199), and by the Academy of
Science of St. Petersburg (p. 203) ; and a resume of observations
reported by Dr Ernst Ebermayer (p. 204).

Section IV. — Immediate Effects of Trees in Arresting the Flow

and Escape of Rainfall, - - - - 212

There are cited objections to the views of M. Becquerel in regard to
the effects of trees advanced by Marshal Vaillant (p. 212); but
with these, observations reported by M. Coute-Grand Champs, and
M. d'Arboise de Jubainiville (p. 214), by Mr Marsh and by M. Jules
Clave (p. 216), showing that trees have the effect of arresting the
flow and escape of the rainfall ; observations by Mr Marschand on
the increased hydroscopicity, capillarity, and permeability of soil
occasioned by the growth of trees (p. 2 17); and additional
illustrations of the same supplied by C6zanne (p. 221), by
d'Hericourt, and by Marsh (p. 223).

Section V. — Secondary Effects of Trees in Arresting t\e Flow
and Escape of the Rainfall, and thus Equalising to some
extent the Flotv of Rivers, . . _ . 225

The secondary effects of trees in arresting the flow and escape of the
rainfall, and thus equalising to some extent the flow of rivers, are
illustrated by reference to the effect of floo>ls in washing away
earth, and sometimes covering fertile land with infertile earth, in
connection with which are cited statements by Marsh in regard to
these effects (p. 226) ; and statements by Surell in regard to the
prevention of them by the growth of trees (p. 237) ; statements by
Cezanne in regard to natural arrest of torrents by forests (p. 242) ;
and by Costa de Bastelica on the effect of trees in increasing the
humidity of the soil and consequent drainage of water to subter-
ranean reservoirs (p. 244) ; of Marchand on the occasion of storms
in the Alps (p. 249) ; with a historical narration of the application
of reboisem.ent to arrest and prevent the effects of such storms
(p. 251).

Chapter VI. — On, the correspondence between the distribution of

the Rainfall and of Forests, - ~ . . 255

There is stated the course to be followed in this discussion (p. 255).

OONTEKTS. Si

SectiOiST I. — On the Measure of Correspondence between the

Distribution of the Rainfall and that of Forests, - 256

This is illustrated from statements by Dr Brandis in regard to India
(p. 256), by Mr Maclaren in regard to America (p. 259), by a com-
parison of report on the rainfall in North America, issued by the
Smithsonian Institution (p. 262), with the account of the forests
of North America given by M. Marny (p. 261); and a statement
in regard to the destruction of forests in South Africa (p. 269).

Section II. — On the Distribution of the Rainfall dependent on
Geographical Position, being determined by the Contour of
a Country, - - - - - - 271

An illustration of the distribution of the rainfall being affected by the
altitude of a country is given in the effects of a wind- wave which
passed over Europe in September 1866 (p. 272) ; with an illustra-
tion of the same operation in the production of a " mackerel sky" ;
and of the Table Cloth on Table Mountain (p. 273). Which are
followed by an exposition by Cezanne of his doctrine that it is
determined in a great measure by the rapidity wit;h which the
atmospheric current rises (p. 271) ; and illustrations of this being
the Case supplied by Kaulin (p. 280).

Section III. — On the Distribution of Forests Affected by the

Distribution of the Rainfall, - . - . 283

There is cited a statement by Marsh relative to a tendercy manifested
by ligneous vegetables to secure the universal occupancy of land
(p. 283). The operation of laws regulating the dispersion of
vegetables is illustrated (p. 286) ; and the operation of those on the
dispersion of trees is seen to depend in part upon the rainfall
(p. 289).

Section IV. — On the Local Effects of Forests on the Distribu-
tion of the Rainfall ivithin the Forest District, - - 293
The general effect of forests is shown to be to retard the flow of the
rain-water precipitated (293), and so in prehistoric times to have
converted torrents into peaceful streams (29i), while the same effect
is shown to be produced by them still (p. 295). There are cited
observations adduced to prove that appaiently they influence some-
what the quantity of the rainfall and the local distribut'on of it over
the year (p. 299) ; and the reconciliation of conflicting observations
and opinions (p. 302) is shown to be possible (p. 303).

Conclusion, ...--. 307

INDEX TO AUTHORITIES CITED.

Academy of Science of St. Petersburg, 203. Academy of Science

of Vienna, 199, 299.
Baines, 69. Balfour, 4. Barnard, 129. Barrington, 128. Becquerel, 110, 212.

Belgrand, 29i. Bell, 137. Berghaus, 176, 180, l9i. Blanqui, 120, 148.

Bloget, 301. Blore, 52. Boussingault, ll3, 148, 159. Biandis, 256.

Breton, 248. Brown, 142. Bryand, 150. Burnet, 129.
Cantegril, 174. Cezanne, 21, 59, 65, 68, 94, 147, 157, 162, 221, 242, 274,

293, 303, 305. Chapman, 26. Chouseul-Graffier, 213. Clav6, 216,

Chavery, 215. Conte-Grandchamps, 214. Costa de Bastelica, 244, 251.

Coile, 96. Coultas, 160.
D'Arboise de Jubainville, 214. Dallinger, 18. D'Hericourt, 223,

Draper, 100, 111, 160. Drysdale, 18. DupoDchel, 232. Dutrochet, 6.
Ebermayer, 204. Emerson, 23. Emsraan, 117. Espy, 304.
Faber, 236. Fraas, 109. Fries, 108. Frisi, 231.
Gosse, 25. Graham, 35, 145. Gras, 248. Gray, 5, 9, 59. Grehanau, 177, 184.

Guglielmini, 23 1.
Hagen, 177, 178, 183. Hales, 15. Hayes, 155. Henry, 98, 115, 262. Her-

Echel, 32, 34, 49, 158, 282, 303. Home, 56, 145. Marker, 108, 112, 128.

Hough, 100, 148. Humboldt, 34. Hummel, 169. Huxley, 18.
Irving, 154. Jamieson, 300, Janisch, 118. Job, 10. Johnstone, 37, 55.

Johnstrus, 225.
Kieser, 4.
Labuissiere, 295. Laurent, 111. Lemoine, 221. Lenneps, 32. Leslie,

41, 43. Livingstone, 28. Lombardini, 233.
Maas, 177, 179. Max Graham, 113. Maclaren, 159. Macvicar, 71. Marschand,

167, 217, 249. Mardigny, 232. Marny, 264. Marsh, 21, 22, 45, 46, 57,

64, 74, 88, 90, 106, 115, 125, 144, 148, 161, 167, 171, 216, 223, 226, 283.

Mathieu, 62, 64, 161. Maury, 156. Meguscher, 33. Meldrum, 134.

Mitchell, 43. Moffat, 104, 173. Mohl, 19.
Orlebar, 55.

Perrot, 192. Pfaff, 2l, 25. Piper, 169. Pkyfair, 124.
Renou, 302. Rogers, 126. Raulin, 95, 97, 279.
St. John, 127. Saussure, 34. Scbeubler, 92. Schleiden, 21, 25. Scoresby,

163. Shott, 100. Siemni, 169. Steinmitz, 152. Surell, 174, 230, 237.

Symons, 300.
Tennant, 30. Thf^mas, 164. Thomson, 272. Thornton, 124. Thurmann, 67.
Vaillant, 21, 61, 75, 212. Valles, 252. Van Eeenan, 172. Vampell, 90, 291.
Wells, 32. Wex, 175. Williams, 23. Wiseman, 204. Wisner, 175.

PREFACE.

This volume is one of a series. In the first of the series — a
volume published last year, 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," — it is stated that the
desiccation of the country is attributable, primarily and mainly to the
upheaval of the land and the consequent rapid draining oflf of the
water with which it was covered and of the subsequent rainfall;
and secondarily, to rapid evaporation occasioned by the temperature
and latterly promoted by the destruction of forests and herbage
and grass. There are adduced facts and testimony indicative of
this having been the case ; and in view of these the appropriate
remedies for the prevailing aridity are stated to be — 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 veldt,
— the conservation and extension of existing forests, — and the
adoption of measures similar to the reboisement and gazonnement
carried out in France, with a view to prevent the formation of
torrents and destruction of property occasioned by them.

There is now in the press, and shortly will be published, a
continuation of that volume on the " Hydrology of South Africa,''
supplying illustrations of the practicability of applying the first of
these remedies being a report on the water supply of South Africa :
its sources, its quantity, the difficulties (physical and other) in the
way of works of extensive irrigation being carried out at the Cape,
and the means of accomplishing these which are at command, with
notices of what has been done in connection with the storage of
water and irrigation in other lands.

This volume, on the efifects of forests on the humidity of the
atmosphere and of the ground, follows in the series, supplying
illustrations of the reasonableness of the suggestion made in regard
to the conservation and extension of forests, as a subordinate
means of arresting and counteracting the desiccation and aridity
of the country.

And early in the present year was published a volume entitled
" Eeboisement in France : or, Kecords of the replanting of the
Alps, the C^vennes, and the Pyrenees with trees, herbage, and
bush, with a view to arresting and preventing the destructive
consequence and effects of torrents."

Should encouragement offer, the publication of this volume will
be followed by the publication of a volume on the effects of
forests on the temperature of a country, and the correlation of
humidity and temperature in meteorological phenomena ; a volume
on the chemistry of vegetation, and the effects thereby produced
on the salubrity of a climate ; and a compilation of official docu-
ments, showing what arguments for the conservation and exten-
sion of forests have been submitted to the consideration of
legislative and S(;if>ntific bodies in different countries, in view of
the meteorological effects of forests, — and what measures have been
adopted in view of these to secure more extensively for the benefit
of man the meteorological benefits which may be thus produced.

Haddington, December 1876.

EFFECTS OF FORESTS

ON THE

HUMIDITY OF THE CLIMATE.

INTRODUCTION.

The following treatise ou Meteorological Eflfects of Forests relates
mainly to the effects of these on the humidity of the atmosphere and
of the soil. Besides these there are effects produced by forests on the
temperature and the salubrity of a country, and all of these are cor-
related— each of them affecting the others, and the others, each.

It is a matter of common observation that houses in the .close
proximity of trees are often damp ; it is also frequently observed that
both in summer and winter the temperature in a wood is different
from what it is in the open country ; and it is becoming generally
known that vegetation so affects the constitution of the atmosphere
as to keep the air fit for the support of man and beast. Phenomena
connected with each of these effects, and different phases of these,
will incidentally come under our notice ; and their correlation may be
attended to ; but the discussion of these does not come within the
scope of this treatise.

No eflPects are attributed by me to forests which are not produced,
or might not be produced, by any and every blade of herbage or of
grass according to its measure. The difference is considered to be only
a question of degree. As the hue of a single hair, or a thread of spun
glass, may be imperceptible to many observers to whom the hue of a
mass of the same hair or glass may be apparent at once, so the
meteorological eflfect of a tiny leaf or a tiny moss, scarcely percep-
tible by a hurried glance, or those of a single tree, may be inappre-
ciable because infinitesimally small, but the effects produced by a
forest with its countless trees, boughs, and leaves be most manifest ;
and then, with these eflfects known, we may with advantage proceed

D. H. HILL LIBRARY

2 INTRODUCTION.

to the closer study of any one of them, or of phenomena connected
with them in such of the less complicated vegetable structures as
supply facilities for the study of these phenomena free from compli-
cations which are met with in such masses of vegetation as are met
with in forests ; and by reasoning from the lesser to the greater, as
well as from the greater to the less, we may attain to what are at
once clearer and more compi'ehensive views of the truth on the
subject. This'is what I propose to do in the sequel.

To prevent misapprehension I may call attention to the circum-
stance that in treating of humidity it is not the rainfall alone of which
I speak. I attribute not a little of the prevalent popular opinions in
regard to the effects of forests, and controversies in regard to these to
the difference between these being overlooked.

PART I.

Phenomena op Vegetation on which Meteorological Effects
OF Forests Depend.

Chap. I. — Primary Phenomena of Vegetation.

The study of the phenomena of vegetation, on which meteorological
effects of forests depend, may advantageously be begun by the con-
sideration of what takes place in some of the more simple forms of
vegetables.

The simplest form of vegetable appears to be what is called Red
Snow. In Alpine and Arctic regions, there are occasionally seen on
the rock or on the snow patches of red-coloured matter, not unlike
dust. When this matter is examined microscopically it is found that
each particle of the dust-like substance is a small cell, or bladder-like
body ; it is not a crystal ; it does not appear to be an animal ; it
seems to be a plant — and a plant of simpler structure it would be
difficult to conceive. It is known to botanists as the Protococcus
Nivalis.

A plant similar to this, but somewhat more complex in structure
— if the term complex can be employed with propriety in speaking
of a structure so very simple — is seen in the Yeast Plant.

With a stick or a spoon there may be drawn from yeast in active
fermentation thread-like bodies which, when examined microscopi-
cally, appear like a string of beads, each bead being a cell, not unlike
the Red Snow in structure, but colourless. This is the Yeast Plant,
and if the thread be broken each cell may be developed into a thread-
like plant similar to that from which it has been dissevered.

In Confervce, and in many confervoid plants found in streams and
fresh water pools, we find a similar structure, but this is enclosed in
an investing skin, and the cells are drawn out from a globular into a
more or less elongated cylindrical form. And in the lai-ger Algce, or
sea weeds — some of which there are which are 1000 feet in length —
when they are examined microscopically we find, and find only, a
mass of such cells less regularly arranged, enclosed in an investing
skin of similar cellular structure.

4 CELLULAR GROWTH.

The growth of all such bodies — as it is of many others, but it is of
these I speak at present — is effected by the multiplication of the cells
of which they are composed. The process of cell growth and cell
production has been studied in numerous structures, both vegetable
and animal, with similar results ; and it may be described in general
terms thus : — In many cells, when examined microscopically, there
may be seen at one place a thickening of the cell wall ; in some may
be seen, in the cell contents, floating bodies, two, four, or more in
number, from which there is being developed a fine transparent
membrane, with an appearance like that presented by the glass on a
watch ; this gradually expands and is distended with liquid, until, in
process of time, the mother cell is ruptured by their distension, and
they continue to expand as independent cells, giving birth to others,
and in like manner giving place to these in their turn.

It is not necessary to my present purpose that I should discuss the
question of how this process is originated and maintained. It is with
the process and what follows from it with which I have to do. To
prevent misapprehension, I may state that I do not know of the process
having been in any case observed continuously from its commence-
ment to its completion ; but different cells have been seen and studied
In all the stages of growth and reproduction to which I have referred.

The increase of bulk in each cell may be too minute and too slow to
be noted, but with the process going on simultaneously in a long line
of cells the effect may be perceived. I have seen the extremity of a
conferva, held fast at the other end, advance across the field of vision
in a microscope with which I was examining it. Nor will this be
astounding if it be considered with what rapidity the process of cell
production, growth, and reproduction must sometimes go on. Large
tracts of snow in Arctic regions, and in Alpine districts, are some-
times quite suddenly reddened by the production of the Red Snow
plant, to which reference has been made, the consequence of the
development of innumerable cells. One form of fungus, the Phallus
impudiens, has been observed to shoot up three inches in the space
of twenty-five minutes. Another, Bovista Gigantea, the giant puffball,
" has grown," says Balfour, "in a single night in damp weather from
the size of a mere point to that of an enormous gourd. From an
approximate calculation it is found that in this plant not less than
20,000 new cells are formed every minute. Kieser estimated that
the tissue of some fungi augmented at the rate of 60,000 cells
per minute."

In South Africa I have frequently observed a marked difference in

ABSORPTION. O

the altitude of the flowering stem of the American Aloe, Agave
Americana, as I returned to my home in the evening from what it had
been in the morning as I passed on my way to Capetown. Dr Asa
Gray, wi'iting on the cell increase in this gigantic peduncle, says, —
" After waiting many years, or even for a century, to gather strength
and materials for the effort. Century Plants which grow in our con-
servatories send up a flowering stalk which grows, day after day, at
the rate of a foot in twenty-four hours, and becomes about six inches
in diameter. This, supposing the cells to average l-300th of an inch
in diameter, requires the formation of over twenty thoicsand millions
of cells in a day ! "

It is by such cell production, development, and multiplication
that the growth of all plants, from the Snow Plant to the monarch of
the wood, is effected ; nor is it without consideration that I make use
of the term multiplication in speaking of the increase of their number,
for it is the case that it is by such metrical progression that the
increase is effected. Not only may each cell be studied as in itself a
complete oi'ganism, an integer, and consequently an integral part of
the more comprehensive structure into which it enters — as a man is
in himself complete, an integei', and, consequently, an integral part of
the nation to which he belongs, and as such may be made the subject
of study apart from the other men of whom, along with him, the
nation is composed, — but, in the Red Snow, we have a single cell
constituting a complete plant ; and in this we may study more
conveniently some of the phenomena of vegetation on which some of
the alleged meteorological effects of forests depend as consequences.

The absorption of moisture appears to be an invariable concomitant
of cell growth and, consequently, of cell development and cell
increase. We may afterwards enquire what function the moisture
fulfils in the vegetable economy, at present it is only the fact and the
mode of its accomplishment which are brought under consideration.

A cell is too minute for ocular demonstration of the mode of
absorption of moisture through the cell wall to be given by it.
The cells vary in different plants, from about the thirtieth to the
thousandth of an inch in diameter ; an ordinary size is from 1-3 00th
to l-500th of an inch, so that there are generally from 27 to 125
millions of cells in the compass of a cubic inch of vegetable cellular
structure. In cells so minute occular demonstration of the modus
operandi is not to be expected. But they have been spoken of as

0 ENDOSMOSE

bladder-like bodies ; and with a bladder may be shown on a large scale
what is done by them on a small.

If a bladder be partially filled with water holding salt or sugar in
solution, have the orifice closed tight, and be put into a basin of
water, it will be found after a time that the bladder will become filled
and distended ; water has been absorbed through the tissue. While
it is thus with the bladder, if the remaining water in the basin be
examined it may be found to have acquired the peculiar taste of the
salt or the sugar of which a solution was introduced into the bladder
before its immersion ; or if the taste be not perceptible, an appli-
cation of appropriate chemical tests will show that there is such salt
or sugar there in solution. Apparently there must have been a
transference of water from the outside into the inside of the bladder,
and a transference of a lesser portion of the solution of salt or sugar
from within to the water without in the basin ; apparently this can
only have taken place through the tissue of the bladder ; and all
that is known of the process goes to prove that it is not only so to
appearance but that it is so in fact. To these two distinct operations
the designations Endosmose and Exosmose have been given by
Dutrochet, a French physiologist ; and these designations have come
into general use in treatises on the subject in our own and other
languages, Endosmose being applied to the passage of pure water, or
of weaker solution, or a solution of other matters, from without, and
exosmose to the passage of the water with matter in solution from
within.

Reasoning from a widely extended analogy, it is thus that the
moisture is imbibed, absorbed, or, to speak more guardedly, trans-
ferred from without into the interior of the cell.

In consideration of this process being the initiative of phenomena
of vegetation on which the alleged meteorological efi'ects of forests
depend, it may be well to ascertain, as satisfactorily as we can, how
it is that what takes place is effected, that we may carry with us a
definite conception of this radical operation in our subsequent con-
sideration of subsequent operations to which attention must be given.

Without entering on the question how matter is held together, I
may call attention to three manifestations of the attractive force :
that of cohesion, whereby particles of the same substance are held
together, as in a piece of wood, a drop of quicksilver, or a drop of
water; adhesion, whereby particles of one substance adhere to
another substance, as water, treacle, or tar adheres to the finger

AND EXOSMOSE. 7

dipped into it, while quicksilver does not ; and chemical afl&nity,
whereby particles of one substance attract and enter into combina-
tion with particles of another substance with which they may be
combined, as in a solution of soda-water powders the tartaric acid
attracts the soda from the carbonate of soda and combines with it,
leaving the carbonic acid with which it was combined disengaged and
free to escape as it does in the effervescence which it occasions.

A clear conception of the differences thus indicated will make the
process of endosmose and exosmose more intelligible. In the illustra-
tions of adhesion which I have given, the attraction of adhesion
between the finger and the quicksilver was of less force than the
attraction of cohesion by which the particles of matter of which the
finger is composed, and than the attraction of cohesion by which the
particles of quicksilver are held together, and the finger could be
withdrawn unbroken leaving the quicksilver entire. But in the
other cases mentioned the attraction of adhesion, though less in force
than the cohesion betwixt the particles of matter of which the finger
is composed, was greater than that by which the particles composing
the water, the treacle, or the tar were held together, and this giving
way a portion adhered to the finger.

In the endosmose taking place in the case adduced for illustration
the adhesion to the bladder of the water in the basin must have been
greater in force than the attraction of cohesion by which the particles
of water were held together, and the chemical affinity of the saline
solution within the bladder for the water greater in force than the
attraction of adhesion by which it was held by the bladder. From
the moistened tissue of the bladder, water by which it was moistened
was attracted by and combined with the saline solution ; this was
replaced by more from the basin, which in like manner was with-
drawn, and the process went on continuously, producing the pheno-
menon of endosmose.

The process of exosmose was similarly produced : the force of
adhesion between the saline solution and the inside of the bladder
was greater than the force of cohesion by which the particles of that
solution were held together ; but the chemical affinity of the water
in which the bladder was immersed for that saline solution was still
greater in force than that adhesion, and thus a portion of the saline
solution was withdrawn and combined with the water in the basin.

This is not given as a full explanation of all the phenomena of
endosmose and exosmose, but as an explanation of the more striking
phenomena produced, which is all that is required for the object in

8 RATIONALE OP

view. I may add that the explanation given does not render
necessary the supposition of two distinct cun-ents flowing in opposite
directions and crossing each other, one flowing in unbroken continuity
from without inwards, and the other flowing in unbroken continuity
from within outwards, either in the same or in different channels.
More probable is it that the transference is going on continuously,
simultaneously in both directions — a process which may perhaps be
made more intelligible by an explanation of what takes place in the
decomposition of water by galvanic influence. If a plate of zinc and
a plate of copper connected by a wire be kept apart and introduced
so into a vessel of water, the water will be decomposed, one of its
elements, oxygen, will be disengaged in connection with one of these
plates, and hydrogen, the other constituent element, will be dis-
engaged at the other ; but there is no appearance of decomposition
taking place at any one or more points, and of the elements flowing
thence to their respective issues, — and what is actually seen, may be
explained by supposing that in immediate contact with one plate, or
with each, a particle of water is decomposed by the liberation of one
of the constituents which escapes, and the other is transferred from
particle to particle, only becoming visible when it escapes in contact
with the other plate.

The process may be illustrated mechanically by means of a six-
inch parallel rule, thus : let the one scale represent oxygen and the
other hydrogen ; let perpendicular lines divide them into six equal
spaces, which conjointly may represent particles of water composed
of oxygen and hydrogen ; let these be numbered, the first couple
each marked 1, the second couple 2, and so on ; let the two scales of
the ruler next be drawn in opposite dii-ections, and if the spaces
marked on them be equal to the distance which each projects beyond
the other, you will have again spaces appropriately representing
particles of water ; but you will have oxygen No. 1 above hydrogen
No. 2, oxygen No. 2 above hydrogen No. 3, and so on ; hydrogen No. 1
and oxygen No. 6 representing what seems to take place in the
decomposition of water by that simple galvanic apparatus.

As in the decomposition of water by galvanism thus illusti'ated,
the escape of the hydrogen of water in contact with one plate, and
that of the oxygen of water in contact with the other plate, seem to
result from a transference of hydrogen from particle to particle, and
simultaneously with this a transference in the opposite direction of
oxygen from particle to particle, through the whole line of particles
of water intervening between the two plates, — so in the exosmosic

ENDOSMOSE. 9

and endosmosic action may the tranference be going on from particle
to particle, through the whole tissue of the bladder, without the
formation of any distinct currents of the two fluids as they exist.

It may be mentioned that the eflfect would be similar if the pure
water were put into the bladder, and the solution of salt or sugar
into the basin in which the bladder is immersed ; but in this case, in
accordance with what has been stated, the exosmose would be in
excess of the endosmose, more water would be withdrawn than would
be replaced. The difference in the quantity passed by endosmose
and exosmose may in both cases be attributed to the difference
between the force of the chemical affinity of the saline solution, or
the salt in it, for water, and the force of the attraction of adhesion, by
which the water is kept attached to the bladder, being greater than
the difterence between the force of the chemical affinity of the piu'e
water for the saline solution, and the attraction of adhesion by which
that solution is attached to the bladder.

If the chemical affinity of the saline solution for water be equivalent
to 8, and the attraction of adhesion of this solution to the bladder be
equivalent to 6, the difference between these is 2. If the adhesion of
water to the bladder be equivalent to 1, and the chemical affinity of
the pure water for the salt in the solution be equivalent to 1, the
difference between these is 1 ; and the endosmose would be to the
exosmose as 2 is to 1.

Dr Asa Gray, Professor of Natural History in Harvard University,
Cambridge, Massachusets, in writing of endosmose and exosmose with
a solution of sugar as the subject of experiment remarks, in
accordance with what I have stated, — " At the same time, the water
in the vessel will become slightly sweet j showing that a small
quantity of syrup has passed through the pores of the membrane into
the water without, while a much larger portion of water has entered.
The water will continue to enter, and a small portion of syrup to
leave it, until the solution is reduced to the same strength as the
liquid without. If a solution of gum salt, or any other substance, be
employed instead of sugar the same result will take place. If the
same solution be employed both in the vessel and in the [bladder]
no transference or change will be observed. But if either be stronger
than the other a circulation will be established, and the stronger
solution will increase in quantity until the two obtain the same
density. If two different solutions be employed, as, for instance,

10

MOISTURE ABSORBED IN

sugar or gum within [the bladder] and potash or soda without, a
circulation will in like manner take place, the preponderance being
totvards the denser fluid, and in a degree proportionate to the
diff"erence in density. Instead of animal membranes, any vegetable
matter with fine pores, such as a thin piece of wood, or even a
porous mineral substance may be substituted with the same result."

All this is in accordance with observations made by Mateucci, an
Italian physiologist, who gave very careful consideration and study
to the phenomena as produced by experiments with various
substances, transferred by endosmose and exosmose through various
media, embracing the analogues, or homologues of almost every action
of the kind observed in animal physiology ; and many, if not all
similar actions observed in vegetable physiology may be accounted for
as being thus produced. Thus, apparently, is the moisture absorbed
by uni-cellular plants like the Red Snow, and by the cells of which
such plants as the Yeast Plant, the Confervse, and the sea-weeds are
composed, and by the cells entering into the structure of such plants
as grass, and herbs, and bushes, and trees.

With the knowledge thus attained, attention may be given to the
absorption of water as a concomitant of vegetation.

" There is hope of a tree if it be cut down that it will sprout again
and that the tender branch thereof will not cease. Though the root
thei-eof wax old in the earth, and the stock thereof die in the ground ;
yet through the scent of water it will bud and bring forth boughs like
a plant." Thus wrote the author of the Book of Job more than three
thousand years ago — more than fifteen hundred years before the
coming of Christ ! On the other hand, drought is, I shall not say
destructive, but, interruptive to vegetation.

We need not yet enquire into the function of the moisture in the
cell development, we have only to do at present with the two facts
adverted to, that the scent of water promotes and revives vegetation,
while drought interrupts it.

In the case of the most of the lower forms of vegetation which have
been cited, the absorption is supposed to take place over all parts of
their surface, and in the case of all of these, excepting the Red Snow,
they are found growing surrounded with moisture ; and thus the
growth of the gigantic sea-weeds is continued by the absorption of
moisture by the myriads of cells of which exclusively their covering
is composed.

But forests consist of trees and not of sea-weeds. And trees are

THE PROCESS OF VEGETATION. 11

not algee and confervse, but gigantic plants growing on dry land —
land hard and dry as the mountain brow. And to another phase of
vegetation promoted by the absorption of moisture attention may
now be given.

As with algse so with grasses and herbs, and shrubs and trees, their
whole structure is built up of cells, some of which may have been
elongated into vessels, or otherwise metamorphosed; and the dry
dead cell walls of these constitute the pith and the woody fibre of
which trees seem chiefly composed. Of some of the vessels through
which the milk sap flows it may be that they have been formed
otherwise ; but the principal difference between the gigantic tree
and the gigantic sea-weed in the source of growth is only this, that
while the latter absorbs nutriment over the whole of its surface the
former does it mainly by the roots, and almost exclusively by the
cells at the extremities of the rootlets, where are masses of them,
which have, in reference to this function, received the designation
spongioles, or little sponges, resembhng these as they do, not in their
structure, indeed, but in their power of absorption. They are often
represented in cuts as rounded elongated expansions, but they are
not always to be so seen by the enquiring learner; examined micro-
scopically, they appear as numerous unprotected living cells at the
extremities of the rootlets, of which those furthest from the root to
which they belong continue to increase and multiply with rapidity in
appropriate soil, while those behind, and nearer to the stem, seem to
have lost in a great measure this power of reproduction.

It may seem that the absorbing surface bears but a very small pro-
portion to the entire bulk of the plant, and I am not concerned to
dispute the correctness of the conclusion that proportionally it is
small, but what is proportionally small may be absolutely great.
Count the rootlets of an onion, or of a leek, or of a stalk of wheat,
and estimate if you cannot measure the superficial extent of the
spongioles ; calculate if you cannot count, and estimate if you cannot
even calculate, the hair-like fibrillaj of the roots and ramified rootlets
of a shrub or a tree, and by reasoning try to form some idea of the
vastness of the superficies of the spongioles there, and you may find
that it is not to be despised. Bear in mind that much of the mass of
a growing tree is fixed and stable, — that a small streamlet may have
filled and may keep filled an extensive lake, provided only the out-
flow do not exceed the supply, — that a very small orifice or mouth,
and that used only occasionally for the purpose, may suffice and does
suffice for the feeding of a man or other animal, — and any prejudice

12 RISE OF SAP

hindering the ready acceptance of the doctrine, that the absorption of
moisture by the spongioles of a tree is the homologue of the absorp-
tion of moisture by the whole surface of the confervse of the streamlet
and of the algse of the sea, will be removed.

I have oftener than once made use of the term absorption, but
as may have been seen, from the explanation of esosmose and endos-
mose which has been given, it is scarcely applicable with propriety to
such a process ; but with this caveat I may be allowed to make use
of it in lack of some term less exceptionable. It is solely in reference
to that process that I here employ it.

The water thus absorbed by the several cells composing the
spongioles of the root is by a similar process absorbed from them by
cells behind them ; and by continuous repetition of it by those beyond
the moisture absorbed from the soil is passed on and on, from the
extremities of the rootlets to the extremities of the smallest twigs,
and to the furthest and the loftiest extremities of the branches of the
trunk. There, through the leaves, a part, and that a large portion
of it, is given off into the atmosphere, while a part, comparatively a
small portion, is returned by the same duplex process of exosmose and
endosmose by the same cells, and others, their progeny, towards the
root. By the way is deposited, by exosmose, nutriment for the tree,
the leaf, the flower, and the fruit; and the residuum is in part deposited
by the same process in the leaves, the bark, or the root, and passed
off into the soil by the exosmosic action of the cells composing the
spongioles of the root.

It may now be seen how vegetation may have some effect in
increasing the humidity of the atmosphere ; but, as a 'preliminary to
the consideration of this, some further attention may be given to the
phenomenon of the rising of the sap.

The rise of the sap in trees is to many a phenomenon or fact for
which they cannot account satisfactorily to themselves ; or, if this
they can do, or think they can, they cannot do so in such a way as to
cover all the phenomena to the satisfaction of others. The pressure
of the atmosphere will not account for what is seen. Capillary
attraction has been thought of, but this does not account for a down-
ward flow of the sap, which is a part of the phenomenon, and it is a
downward as well as an upward flow which has to be accounted for.
Experiments have been made with a view to account for the upward
flow, the results of which, and perhaps some others, could be

BY ENDOSMOSE. 13

accounted for by what was called a vis a tergo, a power or pressure
from behind ; but this, like the older aphorism that Nature abhors
a vacuum, will not stand examination ; and the elasticity and tension
of the wood accounts for all that was seen in the experiment which
suggested the phrase vis a tergo, or pressure from behind, though not
for all the phenomena connected with the rising of the sap. But in
endosmose there may be found a satisfactory mode of accounting for
all that is known to take place in connection with the flow of the sap.

I do not know a more simple illustration of exosmose and endosmose
than that which I have given, but to illustrate more fully the pheno-
mena, with a view to the explanation of the rising of the sap, I may
give the following : Let a piece of bladder be stretched over the
mouth of a funnel and tightly fastened there, and let a tube, if one
of glass so much the better, be attached to the orifice of the funnel ;
let this funnel, half-filled with a solution of salt, be immersed in water
with the tube projecting upwards. The water in the vessel will
become slightly saline through the escape, by exosmose through the
organic tissue, of a small portion of the solution of salt, but this will
be replaced by a much greater quantity of water entering by endos-
mose, and so increasing the quantity of water within the funnel
and tube, that this will be seen to rise in the tube, until — through
the dilution of this, and the loss, by exosmose, of a portion of the
substance held in solution — an equilibrium be established between
the strength of the solution on the one side and on the other of the
separating membrane. But should the tube be insufficient to contain
such a quantity as this would render necessary, the surface of the
solution will rise till the solution overflows, and it will continue to
flow until the equilibrium spoken of be established.

This experiment, with its results, makes manifest the difference
between endosmose and capillary attraction, depending, as they do, on
different actions; and it seems to indicate that the process of endosmose
may supply a satisfactory explanation of the rise of the sap in lofty
trees, though capillary attraction fails to do so.

The phrase capillary attraction is employed to account for the rise
of liquids to a considerable height in tubes of small diameter, and
through interstices of similar size in solid bodies. If several tubes
of different diameters of bore have their lower extremities immersed
in water and be held erect, the water will rise in them to different
heights and be sustained so elevated. The smaller the bore is the
greater will be the height to which the water will rise and at which
it will be sustained, hence the derivation of a name from capilla, a

14 CAPILLARY ATTRACTION.

hair. In such phenomena the attraction of adhesion may be inferior
in force to the attraction of cohesion, or equivalent thereto, but it ia
so great as to overcome the attraction of gravitation and to elevate
the contained column of water above the level of the mass to which
the attraction of gravitation would lower it but for the conteracting
influence thus exercised upon it. The quantity of water thus raised
is proportional to the area of the surface of adhesion, and to this the
attraction is confined ; and thus it comes to pass that capillary
attraction cannot raise water till it overflow, as it does in the experi-
ment on endosmosic action which has been spoken of, and for which
the different action by which endosmose is effected enables us to
account. That action has already been explained.

If a worsted thread six inches long have two inches at the one end
immersed in water filling a basin to within half an inch of the top,
and the other end be allowed to hang down outside the vessel, the
water may rise in it and after a time begin to drop from the pendant
extremity, which it will do more readily if it be thoroughly
moistened immediately before ; and this may seem at variance with
what I have just said. If, however, we distingnish things which
differ, we may see that it is not so. The water may be raised in the
capillary interstices of the worsted thread in opposition to the attrac-
tion of gravitation to the level of the basin, and it may be onward
beyond it ; it may have been attracted a little v?ay on its descent out-
side by the same force, but here there came into operation along with
this the attractive force of gravitation; as the water was drawn
onwards and downwards by capillary attraction, the co-operating force
of gravitation would be inci-eased ; and at length the worsted thread
without ceasing to act by capillary attraction would become a verit-
able syphon, in which the gravity of the water in the longer limb,
and the pressure of the atmosphere on the surface of the water in
the basin would occasion a continuous flow.

I have not said all that might be said in regard to this ; but I have
said enough to show that this is diff'erent from the overflow at its
upper extremity of a tube filled by endosmose from below, and, con-
versely that this is diff'erent from that, leaving it free to indicate that
endosmosic action may, as has been said, supply an explanation of
the rise of sap in lofty ti'ees, though capillary attraction fails to do so.

I have referred to an opinion that the rise of the sap may be
attributable to a vis a tergo, and some of my readers may think that
in endosmose he has found this vis a tergo, or, at least, a vis a tergo
which will explain all ; and to this I would next attend.

VIS A. TERGO. 15

The indication of tlie existence of what is called a vis a tergo, and
the illustration of its power usually given, is one supplied by an experi-
ment devised by Hales to measure, as he thought, the force with
which sap ascends in a stem. A tube, bent so as to ascend, descend,
and ascend again, had a quantity of mercury introduced into the
curvature between the descending and re-ascending portion, and was
attached firmly to a stem, the top of which had been cut off. It was
fastened on the stem by means of a copper cap which was secured by
a lute, and this was covered with a piece of bladder firmly bound
above and below the upper and the lower extremities of the cap ; the
level of the mercury at the commencement of the experiment was
noted, and as the sap rose in the stem, and through the stem into
the ascending limb of the tube, which it did, the pressure caused the
mercury to sink in the descending limb and rise in the ascending
one ; and thus could the pressui*e occasioned by the ascending sap
be measured.

Brucke, experimenting with such an apparatus, found that in a
vine the spring sap, having a specific gravity of TOOOS, raised a
column of mercury to the height of 4| inches, and therefore must
have created a pressure equal to that of a column of water 195 inches
high. In another experiment, sap of specific gravity 1-0009 raised
mercury to the height of 17| inches.

The force of the pressure in one experiment which was tried was
found to be equal to 38 inches of mercury, which Hales states is
nearly five times greater than the force of the blood in the crural
artery of a horse, and seven times greater than the force of the blood
in the same artery of a dog.

These statements I accept unhesitatingly. I know not what
precautions were adopted against error, and I cannot divest my mind
of the impression that the force of the pressure may have been due in
some measure to the elasticity of the stem released of the pressure of
the portion of the tree cut off. Knowing of no vis a tergo but that of
endosmose, I accept the facts as an approximate measurement of that
action, and an indication of the rapidity with which it is carried on ;
but I do so only provisionally. The impression to which I have
referred remains. I have oftener than once cut down a banana plant
in vigorous growth, and in a few minutes seen the inner portion half
an inch or more above and beyond tlie entire integument, which may
have been occasioned by rapid growth ; but in the one case as in the
other, in the absence of certain knowledge, I cannot divest myself of
the impression that the phenomena may have been to some extent

16 EVAPORATION FROM LEAVES.

the result of the elasticity of the stem released of the pressure of the
portion cut off; and I claim only to have shown, as yet, how water is
taken up by trees from the soil, and that endosmose may supply an
explanation of the rising of the sap to the highest twigs, and to
the extreme ramifications of the most distended boughs.

Exosmose and endosmose are found to take place freely through
two tissues, the surfaces of which are contiguous to each other, the
double tissue acting much as a homogeneous tissue, thicker than
either of them would do ; and in the knowledge of this — the know-
ledge of the fact that sap does rise from the rootlet to the stem, the
knowledge that capillary attraction cannot explain all the phenomena
of the case, the knowledge of the fact that no other vis a tergo has
been discovered, and the fact that by endosmose and exosmose all
the phenomena of the case are explicable, — it seems not unreasonable
to conclude that thus it is that the rise of the sap may be effected.

At this stage of our consideration of these phenomena the determi-
nation of this is of importance, mainly, in satisfying us that we have
not lost sight of the moisture in tracing, or endeavouring to trace, its
course from the rootlets to the leaves. It will subsequently again
demand our attention. It is the absorption of moisture from the soil
and the emission of a large portion of this into the atmosphere with
which we have chiefly to do in studying the meteorological effects of
forests on the humidity of a climate. It is by the spongioles that it
is absorbed, and by the leaves that it is emitted. The transmission
of that moisture from the spongioles to the root is, in so far as our
present study is concerned, not unimportant, but its importance is
only secondary in view of the absorption and emission ; and to the
means whereby this passage of moisture from plants by their leaves
is effected would I next direct attention.

The passage of moisture from plants by their leaves is effected
by means of what may be described, in mechanical phrase, as a
beautifully simple selfregulating ventilating-evaporating apparatus.
The operation of this I would illustrate thus : In the oxalis as in the
clover we have a leaf composed of three leaflets. In an oxalis
brought from Guatemala the whole leaf is almost transparent, and it
is said that six sets of vessels can be distinctly traced — three pairs,
one pair proceeding from each leaflet; and it is conjectured that in
other plants a similar arrangement exists ; but in most plants it is
difficult to separate and distinguish the different sets of vessels.
These vessels, with less or more of cellular matter, constitute the

STRUCTURE OP STOMATBS. 17

mid-rib and leaf-stalk, and go to form the twig, branch and stem, or
triink and root.

When the leaf itself is broken across, or cut, it may appear to be as
homogeneous as a sheet of paper of the same thickness, with scarcely
space sufficient for any more complicated structures; but when
examined with a microscope of considerable power it is seen to be
composed of a great number of cells piled loosely together, six or
eight or even more it may be in depth, with large spaces
intervening, and framed by a layer of similar cells, compactly
arranged like a brick floor, forming the back of the leaf,
and a double or triple layer of cells, similarly compactly arranged
like brick-work, two bricks or three bricks thick, forming the face of
the leaf. These are compact enough, but those constituting the
body of the leaf, filled with sap, are so loosely grouped, apparently
without any very determined or strongly marked arrangement, that
they only touch each other on parts of their surface, and the air may
play freely almost entirely round each and through amongst them
all. A simpler arrangement for thorough ventilation perhaps man
could scarcely imagine.

In the back of the leaf are numerous stomates, or mouths. The
structure of these differs in different plants, but what may be con-
sidered the typical structure is two elongated cells, resembling a
microscopic black pudding or thick sausage, so built into the struc-
ture of the skin of the leaf that this will not admit of their being
further elongated ; each of these is, along one side, attached to that
skin, but on the sides along which they are in contact they are free.
When moisture is in excess they become distended, but the structure
of the skin of the leaves is such that they cannot be elongated, and
they bulge away from each other, leaving a wide opening between
them through which the vapour with which the air surrounding the
cells in the interior of the leaf is charged finds an open exit. When
the pressure is relieved they, having lost some of the moisture or water
with which they were filled and distended, collapse to such an extent
as to diminish the opening ; and in this way, exactly to the degree
required, they vary and regulate that aperture — varying it, it may be,
I shall not say twenty times in the day, but, if necessary, twenty
times in the minute ; and if drought become such as to render it
desirable that every drop of moisture in the plant should be preserved,
under the influence of that drought they become flaccid and com-
pletely close the aperture.

Such is the arrangement, in these galleries of the laboratoj-ies of the

18 SIZE OF CELLS.

tree, for carrying off by evaporation all naoisture which may escape from
the cells, which may ooze out, or may be passed by exosmosic action j
and a little further consideration may lead to the conclusion that the
arrangement has been made, not to get rid of accidental leakage, but of
all moisture in excess of what is actually required after the sap has been
so elaborated as to fit it to minister to the nutriment of the tree. Be
this as it may, it is not unreasonable, but the reverse, to suppose that,
however compact the tissue or structure of the cell wall may be, there
may be, or that there must be, interstices between the molecules of
which it is composed. A drop of water falling upon a heap of fine
dust, or of powdered rosin, immediately draws around it a water-
proof covering of the material amongst which it has fallen, which,
though waterproof, is not airproof, and the enclosed waters may be
evaporated through the interstices of the investing covering. So may
it be with these, though on a scale infiuitesimally reduced.

Professor Huxley, in a paper " On the Border Territory between
the Animal and Vegetable Kingdoms," which appeared in Macmillan's
Magazine for February 1876, citing some remarkable observations on
certain monads by Messrs Dalliuger and Drysdale, which were
embodied in two papers in the Monthly Microscopical Journal for
1873, speaking of certain granules, living embryos, remarks, — "The
authors whom I quote say that they cannot express the excessive
minuteness of the granules in question, and they estimate their
diameter at less than l-200^000th of an inch. Under the highest
powers of the microscope at present applicable such specks are hardly
discernible. Nevertheless, particles of this size are massive when
compared to physical molecules ; whence there is no reason to doubt
that each, small as it is, may have a molecular structure sufficiently
complex to give rise to the phenomena of life." Compared with such
embryos, cells such as those of which the substance of a leaf is com-
pose are giants. In a cubic inch of a leaf of the carnation there are
said to be upwards of three millions of cells ; in some of the cucumber
tribe, and in the pith of aquatic plants, what are reckoned larger cells
are found — they are from l-50th to l-30th of an inch in diameter ;
but cells are frequently seen only l-300th, l-500th, and 1-lOOOth
of an inch in diameter. It would be difiitiult for many to conceive of
the size of a cell 1-lOOOth of an inch in diameter ; but these granules,
were not the two hundredth part of that in diameter, and one of
these smallest cells, could contain sis millions of the granules in
question !

To one conversant with structures so aiinute there is nothing

NUMBER OP STOMATES. 19

astonishing in the supposition that molecules of moisture should pass
through interstices between the molecules of which the cell walls are
constructed ; and, with what is known of endosmosic and exosmosic
action, it seems to be not unreasonable to suppose that any moisture
passing through the cell wall from within outwards might, by the
increased density following the evaporation of a portion of it, deter-
mine a current to follow it which would flow continuously. To the
consideration of what function of the leaf is thus subserved we shall
afterwards return : it is with the arrangement for the passage into
the atmosphere of moisture taken up by the spongioles with which
alone we are at present concerned.

Of the extent of the provision made for this evaporation some idea
may be formed from a consideration of the number of the stomata or
sto mates to be found in the leaves of plants, often symmetrically
disposed. The number varies in different plants, for which variation
a reason may be found in the different conditions of growth to which
they are subjected in their several natural habitats. In the back of
the leaf of the apple tree there are about twenty-four thousand
stomates to the square inch. In the leaf of the lilac there are
a hundred and sixty thousand of them to the square inch.
Sixty thousand have been reckoned in a square inch of the under
surface of the white lily and three thousand in a square inch of
the upper surface. In the leaves of the cherry-laurel there are
none on the upper surface of the leaf, but ninety thousand have
been counted on the lower surface of the leaf. In the true lilies
they are so large that they may be seen with the aid of a
simple lens of an inch focus. In the water lilies, and other
plants having leaves which float upon water, all the stomates
are on the upper surface, where alone evaporation can take place.
Leaves of plants which grow entirely under water, where there can be
no evaporation, have none.

The mechanism of the opening and shutting of stomates has been
carefully investigated by Mohl, a distinguished German botanist, the
results are given in the Botanische Zeitung for 1866, p. 697 ; and it
appears that, while the general action is such as I have described,
other processes co-operate to ensure the result. It is partly controlled
by the effects of light, though depending mainly upon endosmose.
Mohl has shown that while the cells of the stomate themselves act so
as to open the stomate in moist weather and close it in dry, the

20 PHENOMENA OP VEGETATION.

adjacent cells of the epidermis, or skin enveloping the leaf, in swelling
when moist, tend to close the stomate, and their contraction when dry
to open it ; so that the actual state of the stomate at any one time is
the resultant of nicely adjusted opposing forces, and thus is secured
a self-regulation of the apparatus far more efficient than could be
secured in any laboratory of man, though an attendant were stationed,
hydrometer in hand, ready to close partially or entirely, or to reverse
such action in the ventilators of the evaporating chambers exactly in
regard to time and extent as the ever-varying state of the process of
evaporation in the chamber and state of the atmosphere might render
desirable.

But furthei-, it is possible that in some cases, under peculiar
conditions or circumstances, it might happen that more moisture
might be evaporated than was conducive to the vigorous vitality of
the plant — in other words, the process of evaporation might go too
far — and we find that provision against this exists in many leaves,
in the existence of hairs which by endusmosic action can imbibe
additional moisture.

These hairs are always more numerous on the back of the leaf than
on the face, which in some plants is entirely devoid of them, though
the back be densely covered with them ; and they may be found in
8ome plants to be always at the junction of veins in the back of the
leaf, as if designed only to act when it should become manifest that
sui'plus water which might happen to be retained in one of these
would not suffice to counteract a deficiency in the other.

Such is the beautifully-simple self-regulating ventilatiug-evaporating
apparatus in the leaf of a plant.

In the absorption of moisture by the spongioles of the rootlets, the
ascent of the sap, and the evaporation of excess of moisture after the
elaboration of the milk sap, we see some of the principal phenomena
of vegetation on which meteorological effects of forests depend.

CHAPTEU II.

On the Quantity of Moisture Evaporated through the Stomates
OP Leaves.

On results obtained by observation and calculation in regard to the
quantity of moisture evaporated through the stomates of leaves a
considerable difference of opinion exists.

Eemarking on the results arrived at by observations of Schleiden,
Pfaff, and others, Marsh says, — " Allowing two hundred days for the
period of forest vital action, the wood must, according to Schleiden's
position, exhale a quantity of moisture equal to an inch and one-fifth
of precipitation per day ; and it is hardly conceivable that so large a
volume of aqueous vapour, in addition to the supply from other
sources, could be diffused through the ambient atmosphere without
manifesting its presence by ordinary hygrometrical tests much more
energetically than it has been proved to do ; and in fact the observa-
tions recorded by Ebermeyer show that though the relative humidity
of the atmosphere is considerably greater in the cooler atmosphere of
the wood, its absolute humidity does not sensibly differ from that of
the air in open ground. The daily discharge of a quantity of aqueous
vapour corresponding to a rainfall of one inch and a fifth into the cool
air of the forest would produce a perpetual shower, or at least a drizzle,
unless, indeed, we suppose a rapidity of absorption and condensation
by the ground, and of transmission through the soil to the rootlets
and through them and the vessels of the tree to the leaves, greater
than have beea shown by direct observation."

Cezanne, also, writing in regard to the action of vegetables as
"veritable alembics, which distil into the air a certain quantity of
water which their roots have drawn up from the soil," says, —
" The Marshal Vaillaut put a branch of an oak like a bouquet into
a vase full of water ; he measured the water lost through its leaves
and he considered himself enabled to conclude that the tree from which
this branch had been detached would be emitting into the atmosphere
in twenty-four hours upwards of two thousand kilogrammes of water.*

* " Revue des Eaux et Forets," July 1865 and June 1867.

22 PHENOMENA OF VEGETATION.

But this experiment has not satisfied all others. First of all, the
branch thus treated died in three days ; and then, even if it had lived
longer, it might have been said that the vegetable cut off from the
nourishing sap may have been able to absorb more than its usual
ration of clear water. It was in the situation of an animal deprived
of substantial aliment, which availed itself of pots of weak bouillon,
and yet died of hunger. And, moreover, the experiment has been
repeated not with a branch but with a young tree deprived of its
roots, and the evaporation proved to be very insignificant."

But whatever may be said of such experiments, and of calculations
founded on them, we have other means of testing the quantities of
water passing through trees in the process of their growth ; and we
find they must be far from inconsiderable. I have cited one state-
ment by Marsh, with this I cite also the following : —

"The amount of sap which can be withdrawn from living trees
furnishes, not, indeed, a measure of the quantity of water sucked up
by the roots from the ground — for we cannot extract from a ti-ee its
whole moisture — but it supplies numerical data which may aid the
imagination to form a genei-al notion of the powerful action of the
forest as an absorbent of humidity from the earth.

" The only forest tree, known to Europe and North America, the
sap of which is largely enough applied to economical uses to have
made the amount of its flow a matter of practical importance and
popular observation, is the sugar maple, -4cer saccharinum of Anglo-
American Provinces and States. In the course of a single * sugar
season,' which lasts ordinarily from twenty-five to thirty days, a sugar
maple, two feet in diameter, will yield not less than twenty gallons of
sap, and sometimes much more. This, however, is but a trifling
proportion of the water abstracted from the earth by the roots during
this season ; for all the fluid runs from two or three incisions or
augur holes, so narrow as to intercept the current of circulation of
comparatively few of the sap vessels, and, besides, experience shows
that large as is the quantity withdrawn from the circulation, it is
relatively too small to afi'ect very sensibly the growth of the tree.
The number of large maple trees on an acre is frequently not less than
fifty, and, of course, the quantity of moisture abstracted from the soil
is measured by thousands of gallons to the acre. The sugar orchards,
as they are called, contain also many young maples too small for
tapping, and numerous other trees — two of which, at least, the Black
Birch, Betula lenta, and Yellow Birch, Betula exeelsa, both very
common in the same climate and far more abundant in sap than the

EVAPORATION. 55^

maple — are scattered among the sugar trees ; for the North American
native forests are remarkable for the mixture of their crops.

" The sap of the maple and of other trees with deciduous leaves,
which grow in the same climate, flows more freely in the early spring,
and especially in clear weather, when the nights are frosty and the
days warm ; for it is then that the melting snows supply the earth
with moisture in the justest proportion, and that the absorbent
power of the roots is stimulated to its highest activity."

In foot notes he adds : — " Emersou (iu his Trees of Massachicssets,
p. 493), mentions a maple, six feet in diameter, as having yielded a
barrel, or 31| gallons of sap in 24 hours, and another, the dimensions
of which are not stated, as having yielded one hundred and seventy-
five gallons in the course of the season. Tbe Cultivator, an American
Agricultural Journal, for June 1842, states that twenty gallons of sap
were drained in eighteen hours from a single maple, two and a-half
feet in diameter, in the town of Warner, New Hampshire ; and the
truth of this account has been verified by personal enquiry made on
my behalf. This tree was of the original forest growth, and had been
left standing when the ground around it was cleared. It was tapped
only every other year, and then with six or eight incisions. Dr
Williams (History of Vermont, p. 91), says, — * A man much employed
in making maple sugar, found that, for twenty-one days together, a
maple tree discharged 7|^ gallons per day.'

" An intelligent correspondent, of much experience in the manufac-
ture of maple sugar, writes me that a second growth maple, of about
two feet in diameter, standing in open ground, tapped with four
incisions, has for several seasons generally run eight gallons per day
in fair weather. He speaks of a very large tree from which sixty
gallons were drawn in the course of a season, and of another, some-
what more than three feet through, which made 42R) of wet sugar,
and must have yielded not less than 150 gallons.

" The same correspondent informs me that a Black Birch, tapped
about noon with two incisions, was found the next morning to have
yielded sixteen gallons. Dr Williams (History of Vermont, I. p. 91)
says, — * A large birch, tapped in the spring, ran at the rate of five
gallons an hour when first tapped. Eight or nine days after, it was
found to run at the rate of about two and a-half gallons an hour, and
at the end of fifteen days the discharge continued iu nearly the same
quantity. The sap continued to flow for four or five weeks, and it
was the opinion of the observers that it must have yielded as much
as sixty barrels [1890 gallons]."

24 PHENOMENA OP VEGETATION.

These observations may give some idea of the quantity of moistnre
taken up by the rootlets of trees.

Such is a report of facts ascertained in regard to the maple. It
does not follow that an equal quantity of moisture is raised by every
kind of tree ; but it may be said a corresponding quantity is, by every
one, or a quantity which may be spoken of as something like an
approximation to this. And though the ftict has not, so far as I
know, been tested by exact observation, it is probable that the greater
portion of the moisture thus raised from the ground by plants,
whether arborescent or herbaceous, is by many of them passed into the
attrosphere by the stomates of the leaves— succulent plants with few
Btomates being the exception — and that a portion, and it may be a
large portion, of the remainder passes into the soil by the process of
exosmose by which the circulation of sap in the plant is effected,
but returns to the soil only to be again taken up by the rootlets of
the same, or of some other plant, when it has been relieved of some
of the residuary matter with which it returned charged, and has taken
up a return load of nutriment ; but the probability that the quantity
thus returned to the soil bears but a small proportion to the quantity
passed into the atmosphere may be demonstrated by an observation
of the process referred to.

To some one charged with the watering of flowers, and who finds
the charge a burden, it may have occurred that he seemed to have
to supply far more water than could be employed in the structure of
the plant, that some, such as the balsam, seemed to require a fresh
supply morning, noon and night to keep them growing, and that to
planted cuttings and transplanted plants he could scarcely give too
copious a supply, and unless he had trimmed them by removing some
of the leaves scarcely would what he gave have sufficed : now perhaps
it may be understood why all this was necessaiy, and how the diminu-
tion of the foliage helped the growth of the plant when the supply
of moisture might otherwise have been inadequate to its maintenance
in life.

CHAPTER III.

Disputed and Secondary Phenomena op Vegetation.

Besides the phenomena of vegetation which have been detailed
there are other alleged phenomena, the import of which is more open
to question : amongst these may be reckoned the absorption of mois-
ture by the leaves of plants, the production of water by the plants
themselves, and the dropping of water from the leaves of certain
trees.

Sect. I. — On the Absorption of Moisture by the Leaves of Plants.

It is a prevalent opinion that moisture is absorbed by plants by
their leaves. I scarcely open a popular treatise on the subject in
which I do not meet with it ; but I have met with no evidence that
this is a normal action of leaves, excepting to a very limited and
easily defined extent. Abnormal action of leaves absorbing moisture
would prove as little as the abnormal absorption of moisture and
nutriment into the human frame by enemas and baths; and the absorp-
tion of moisture by gigantic algae over the whole surface of their stalks
and their fronds proves as little. But this cannot be said of experi-
ments which have been made on the growth of epiphytes and of
mundane plants, which have grown and flourished when freed of all
soil; or of trees growing naturally and at the same time luxuriantly
on narrow ridges, on steep declivities, on partially decayed stumps
many feet above the ground, on walls of high buildings, and on rocks,
in situations where the earth within reach of their roots could not
possibly, it is alleged, contain the tenth part of the water which,
according to Schleiden and Pfaff, they evaporate in a day. There
are, too, forests of great extent on high bluffs and well-drained table-
lands where, it is said, " there can exist neither in the subsoil nor in
infiltration from neighbouring regions an adequate source of supply
for such consumption,"

These are facts established beyond all question; but in regard to
what seems to.be the natural conclusion, that in such cases the mois-

26 PHENOMENA OF VEGETATION.

ture must have beeu absorbed by the leaves, I may remark that this
appears to me to be a non-sequitur ; aod the burden of proof rests on
those by whom it is advanced.

In regard to the general opinion that moisture is absorbed by the
leaves of trees I may state that I believe this to be the case where
leaves are covered more or less densly with hairs, which are highly
hygroscopic, and which appear to be organs well fitted for the accom-
plishment of such a function, and are often placed as if such were
their function in given conditions ; and furthex', that to some extent
moisture may have been absorbed by endosmose where a deposit of
what may be called a secretion on the surface of the leaf gives some-
thing like an indication of this having occurred, but that the effect of
this must be small.

I have no testimony to the alleged absorption of moisture to an
appreciable extent by leaves having been observed ; and on the other
hand I have testimony on which I can rely that in South Africa there
are fig trees growing on rocks, over which the roots spread like
solidified molten lava or rosin, dipping down into every crevice and
spreading onward to the earth beyond ; and in the absence of evidence
of extensive absorption by leaves I consider it more probable that the
moisture is absorbed by such roots than by the leaves of the tree,
and the conclusion justified in such cases suggests the conclusion that
so may it be in others.

Sect. II. — On the Frodicdion of Water by Plants,

Amongst trees brought under my consideration in Africa by the
late Mr James Chapman — a man of cai'eful observation who travelled
extensively throughout the whole region from Walfish Bay to the
Victoria Falls of the Zambesi and thither from Natal, traversing in
various directions the country intermediate between the region thus
indicated and Table Bay at the Cape of Good Hope — was the Kusch6,
a large tree with a smooth dark grey-coloured bark and dark-coloured
oblong leaves, in the heart of the trunk of many of which is found a
large reservoir of water. From the description given to me, the tree
appeared to be the Millettia Caffra, known elsewhere in South Africa
as the Oomzambeete, or Kaffir Iron wood.

Mr Chapman first saw this tree when he and his companions were
suffering from thirst. Observing one of his native servants placing
forked boughs against a tree and preparing to climb, he asked what
he was going to do. " Look for water," was the reply. The man

APPARENT PRODUCTION OF WATER. 27

having mounted, cried " Here it is." The hard -wood had decayed,
leaving a very deep hole, which was almost closed at the top,
apparently by the spreading arch of subsequently formed bark. One
of the companions of the man cutting then a twig or shoot from the
root, cut through the bark of this at two places two feet or thirty
inches apart, treated this as boys in Europe treat branches of alder,
of which they wish to make whistles, beating and pressing it ; and
drawing out the wood, like drawing a sword fi'om its sheath, he
handed up the bark to the man aloft, who, using this as a suction-
pipe, soon quenched his thirst, and made way for the others iu
succession to do the same.

Frequently did Mr Chapman while travelling avail himself of the
supply of water thus retained.

Between the Victoria Falls of the Zambesi and Daka these trees
are found in clusters, sometimes 10 feet in circumference, and of
a much greater height than the other trees of the forest-country
around. They generally grow in clumps, in the higher portions of
the country.

Similar supplies of water are found in the Pitcher Plant, and several
other herbaceous plants of somewhat similar structure ; and in the
Teazel, the Dipsacus fullonum, a quantity of water is often found in
the cup-like receptacle formed by the opposite leaves embracing
the stem.

In more than one of these cases the water may possibly be only
rain-water collected and retained, and in the other cases it may be
elaborated sap, the water of which was derived from the soil ; but
even were such cases thus disposed of, the question has been raised
and awaits' an answer — May not water be a secretion of plants
themselves ?

I have intimated or stated explicitly what are my views in regard
to the source of the great bulk of the moisture passed into the atmos-
phere by the stomates in the leaves of vegetable production ; but I
know of nothing incompatible with the supposition of a portion being
added from the combination of oxygen and hydrogen, meetino- in a
nascent condition in the process of chemical changes accompanying
vegetation.

Water is a product of the combustion of wood, and of coal, of oil
of tallow, and of gas ; it is a product of respiration in man and many
other animals, and may be obtained deposited by their breath ; and
there are lower forms of animals by which it is produced, and that

28 PHENOMENA OP VEGETATION.

in proportion to their size, much more abundantly. The question,
Whence is this obtained 1 has been raised oftener than once.

Dr Livingstone, in describing a severe and long-continued drough:|
at Kolobeng (the mission station occupied by him before he entered
on his journeyings in the interior), a drought during which " needles
lying out of doors for months did not rust, and a mixture of sulphuric
acid and water, used in a galvanic battery, parted with all its water to
the air instead of imbibing more from it, as it would have done in
England," says, — " The leaves of indigenous trees were all drooping,
soft and shrivelled, though not dead; and those of the Mimosse were
closed at mid-day, the same as they are at night. In the midst of
this dreary drought, it was wonderful to see those tiny creatures the
ants running about with their accustomed vivacity. I put the bulb
of a thermometer 3 inches under the soil in the sun at mid-day, and
found the mercury to stand at 132'^ and 134°; and if certain kinds
of beetles were placed on the surface they ran about a few seconds
and then expired ; but this boiling heat only augmented the activity
of the long-legged black ants." And having raised the question,
"Where do these ants get their moisture?" he proceeds, — "Our house
was built on a hard ferruginous conglomerate, in order to be out of
the way of the white ant, but they came in despite the precaution ;
and not only were they, in this sultry weather, able individually to
moisten soil to the consistency of matter for the formation of galleries,
which in their way of working is done by night (so that they are
screened from the observation of birds by day in passing and repassing
towards any vegetable matter they may wish to devour), but when
their inner chambers were laid open these were also surprisingly
humid ; yet there was no dew, and the house being placed on a rock
they could have no subterranean passage to the bed of the river,
which ran about 300 yards below the brow of the hill. Can it be
that they have the power of combining the oxygen and hydrogen of
their vegetable food by vital force so as to form water f

A still more remarkable case is mentioned by Dr Livingstone.
Writing from Golungo Alto Angola, on the west coast, lat. 91° S., he
says, — " Before leaving I had an opportunity of observing a curious
insect which inhabits trees of the fig family (Ficusj, upwards of
twenty species of which are found here. Seven or eight of them
cluster round a spot on one of the smaller branches and there keep
up a constant distillation of a clear fluid, which, dropping to the
ground, forms a little puddle below. If a vessel is placed under
them in the evening it contains three or four pints of fluid in the

APPARENT PRODUCTION OP WATER, 29

morning. . . To the question, Whence is this fluid derived ? the
people reply that the insects suck it out of the tree, and our ovm
naturalists give the same answer. I have never seen an orifice, and
it is scarcely possible that the tree can yield so much. A similar, but
much smaller homopterist insect, of the family Cercojndce, is known
in England as the frog-hopper (Aphrophora spmnaria) when full-
grown and furnished with wings ; but while yet in the pupa state it
is called ' Cuckoo-spit,' from the mass of froth in which it envelopes
itself. The circulation of sap in our climate, especially in the
GraminacesB, is not quick enough to yield much moisture. The
African species is five or six times the size of the English. In the
case of branches of the fig-tree, the point the insects congregate on
is soon marked by a number of incipient roots, such as are thown out
when a cutting is inserted in the ground for the purpose of starting
another tree. I believe that both the English and African insects
belong to the same family and differ only in size, and that the chief
part of the moisture is derived from the atmosphere. I leave it for
naturalists to explain how those little creatures distil, both by night
and day, as much water as they please, and are more independent
than Her Majesty's steam- ships, with their apparatus for condensing
steam, for without coal their abundant supplies of sea water are of no
avail. I tried the following experiment : — Finding a colony of these
insects busily distilling on a branch of the Ricimis communis, or
castor-oil plant, I denuded about 20 inches of the bark, on the tree
side of the insects, and scraped away the inner bark so as to destroy
all the ascending vessels. I also cut a hole in the side of the branch,
reaching to the middle, and then cut out the pith and internal
vessels. The distillation was then going on at the rate of one drop
each 67 seconds, or about 2 ounces 5| drams in 24 hours. Next morning
the distillation, so far from being affected by the attempt to stop the
supplies, supposing they had come up through the branch from the
tree, was increased to a drop every 5 seconds, or 12 drops per minute,
making one pint (16 ounces) in every 24 hours. I then cut the
branch so much that during the day it broke ; but they still went on
at the rate of a drop every five seconds, while another colony on a
branch of the same tree gave a drop every 17 seconds only, or at the
rate of about 10 ounces 44 drams in 24 hours.

" I finally cut off the branch ; but this was too much for their
patience, for they immediately decamped, as insects will do from
either a dead branch or a dead animal, which Indian hunters soon
know when they sit down on a recently killed bear. The presence

30 PHBXOMEN& OP VEGETATION,

of greater moisture in the air increased the power of these distillers ;
the period of greatest activity was in the morning, when the air and
everything else was charged with dew.

" Having but one day left for experiment I found again that
another colony on a branch denuded in the same way yielded a drop
every two seconds, or 4 pints 10 ounces every 24 hours, while a
colony on a branch untouched yielded a drop every 11 seconds, or
16 ounces 2~^ drams in 24 hours. I regretted somewhat the
want of time to institute another experiment, namely, to cut a branch
and place it in water, so as to keep it in life, and then observe if there
were any diminution of the quantity of water in the vessel. This alone
was wanting to make it certain that they draw water from the atmos-
phere. I imagine that they have some power of which we are not
aware besides that nervous influence which causes constant motion to
our own involuntary muscles, the power of life-long action witliout
fatigue. The reader will remember, in connection with this insect,
the case of the ants already mentioned."

The same question is taken up by Sir J. E, Tennant, in writing of
what he had observed at Ceylon.

" Entomologists," says he, " have raised the intei-esting question.
Where do the termites, or so called white ants — though of another
genus than the common ant — where do they derive the large sup-
plies of moisture with which they not only temper the clay for the
construction of their long-covered ways above ground, but for
keeping their passages uniformly damp and cool below the surface ?
Yet their habits in this particular are unvarying — in the seasons of
drought as well as after rain, in the dryest and least promising
positions, in situations inaccessible to drainage from above, and cut
off by rocks and impervious strata from the springs below. Dr
Livingstone, struck with this phenomena in Southern Africa, asks —
Can the white ants possess the power of combining the oxygen and
hydrogen of their vegetable food so as to form water] And he
describes at Angola an insect resembling the Aphrophora spumaria,
seven or eight individuals of which distil several pints of water every
night. It is highly probable that the termites are endowed with
some such fiiculty. Nor is it more remarkable that an insect should
combine the gases of its food to produce water, than that a fish
should decompose water to provide itself with gas. Fourcroix found
the contents of the air-bladder in a carp to be ^)?«re nitrogen ; and
the aquatic larvse of the dragon-fly extracts air for its respiration,
from the water in which it is submerged. A similar mystery per-

DROPPING f ROM LEAVES. 31

yades the enquiry — ^Whence plants, under peculiar circumstances,
derive the water essential to vegetation V

The constituents of water are oxygen and hydrogen ; the con")
*stituent8 of ammonia are hydrogen and nitrogen ; the constituents of
carbonic acid are carbon and oxygen ; and the principal constituent
of atmospheric air are nitrogen and oxygen ; with these is combined
or intermixed carbonic acid ; carbonic acid and ammonia are likely to
be absorbed largely by water, and so carried into the plant ; carbon is
fixed, being the principal constituent of wood, and thus oxygen is set
free; a smaller quantity of nitrogen is fixed, but enough to indicate a
decomposition of ammonia to have taken place ; and it is not un-
reasonable to suppose that all the ammonia taken up by the plant
may have been decomposed, the nitrogen combining with oxygen, set
free by the decomposition of the carbonic acid yielding material for
the woody structure, and appearing as atmospheric air, and the
hydrogen combining with oxygen and forming water.

With legard to the second statement by Dr Livingstone, I would
require to be in possession of much more information than I am
to enable me to form an opinion on the subject ; but I may state
that I find nothing in the narrative incompatible with the supposition
of the moisture in this case having been obtained from the tree ; and
I avail myself of the interest which such a narrative may have
excited to direct attention to the similar copious supplies of moisture
flowing from leaves and from incisions in the trunks of trees.

Sect. III. — On the Dropping of Water from the Leaves of certain Trees.

Qi the dropping of water from trees there are numerous instances ;
but while in some of the more remarkable cases the popular opinion
is in favour of the supposition that this was one of the primary
phenomena of their growth, the consideration of the conditions under
which it occurs leads to the conclusion that it is one of the secondary
effects of vegetation.

I have spoken of some of the more remarkable cases. In an old
work, entitled Historia de la Conqicista de las siete islas de Gran
Canaria de Juan de Abreu Gal indi, published in 1832, at page 47,
mention is made of a celebrated laurel, in Ferro, which is said to
have furnished drinkable water to the inhabitants of the island.
According to the statement, every morning the sea breeze drove a
cloud towards the wonderful tree, which attracted it to its huge top,

32 PHENOMENA OF VEGETATION.

and the water flowing from its foliage uninterruptedly, drop by drop,
was collected in cisterns.

I have met with a similar account of a tree to the east of Tocat in
Asia-Minor, visited by the Rev. Mr Van Lennep, and described by
him. Mr Lennep is said to be well-known as a competent observer, '

In the case mentioned first there is the explicit statement that
" Every morning the sea breeze drove a cloud towards the wonderful
tree." And there is nothing in any of the statements I have seen
relative to these phenomena inconsistent with the supposition that
they may have been produced by the deposition of moisture on the
surface of the leaves, irrespective of the source whence the moisture
was obtained.

Dr Wells, in an essay on Dew, — a little work which, according to
Sir John Herschel, deserves to be considered as a model of experi-
mental enquiry, — was the iirst to place in a clear light the nature of
the process of dew formation. According to his views, as epitomised
by Sir John Herschel, " The chief facts to be accounted for are these :

1. Dew (as distinguished from small rain or moisture produced by
visible fog) is never deposited except on a surface colder than the aii".

2. It is never deposited in cloudy weather ; and so strict is its con-
nection with a clear sky that its deposition is immediately suspended
whenever any considerable cloud passes the zenith of the place of
observation. 3. It is never copiously deposited in a place screened
or sheltered from a clear vieio of the sky, even if the screen be of very
thin material, such as muslin or paper suspended over it. 4. It is
most copiously deposited on all such leaves as are good radiants and
had conductors of heat, such as grass, paper, glass, wood, &c., but
little or not at all on had radiants, such as polished metals, which are
also good conductors. And lastly, it is never deposited if there is
much wind. All these circumstances, as Dr Wells has shown, point
to the escape of heat from the bodies exposed by radiatio7i out into
space, or into the upper and colder regions of the air, faster than it
can be restored by counter-radiation, or by conduction, from contact
with the warm air — or with solid substances — the wind acting in this
respect with great efficiency by continually removing the air in con-
tact. Hoar frost differs only from dew by being frozen in the
moment of deposition, and therefore accreting in crystalline spiculse."

It may have been observed that tufts of grass and other herbage
are often covered with dew-drops in the early morning, or with hoar
frost if it be winter, though the ground be not so ; and it may have
been observed that heavy drops of water fall from a tree in a fog

DROPPING FROM LEAVES, 33

though not a drop of rain may be seen to fall beyond it. The
phenomena may be similai'.

The temperature of the humau body, as ascertained by a thermo-
meter with its bulb placed in the shoulder-pit or under the tongue,
is within a very limited range — when the man is in a state of health^
the same in the Arctic regions and in the tropics, and the degree
known as blood-heat is as stable as is the boiling point of water.
Scarcely less stable is the fi'eezing point of water or the freezing
point of mercury. It is something similar with trees. According to
experiments made by Meguscher, in Lombardy, and results of these
recorded in Memoria sicr Boschi della Lomhardia, and cited by Marsh,
trees maintain at all seasons a constant mean temperature of 54° Fahr.

Observations which have been recorded by others have made it
appear questionable whether a tree does resist the cooling process
induced by external cold, but I know not of any question having been
raised in regard to its counteracting the effects of external heat of
a higher temperature than its own. This seems to be generally
admitted. In the animal this resistance is effected by evaporation;
in the vegetable it is probable it is effected by the same means, or by
evaporation and radiation combined. The subject will again come
under consideration, when it may be discussed at greater length.

I have called attention to the dew and hoar-frost being seen on
the grass and herbage at early morn. In hygrometry mention is
frequently made of the dew-point : this is the temperature at which
the air is exactly saturated with the quantity of moisture it contains,
any fall from which would occasion a deposit of all that was in excess
of what exactly saturates the air at the lower temperature. In
accordance with observation, and with reasoning on the subject, the
dew-point is frequently the same as the lowest temperature of the
night j and the lower temperature of the grass and herbage, con-
sequent on radiation from their surface, occasions a deposit of dew-
drops in the same way as a glass of cold water, by lowering the
temperature of the air adjacent to it, is in like manner bedewed.

According to the observations of Meguscher, whenever the temper,
ature of the air is above 67° degrees Fahr., the temperature of the
tree will be, to the extent of the excess, lower. If the temperature of
the atmosphere be 90°, and the dew-point 75°, there will be a copious
deposit of dew ; and if the lower temperature be the consequence of
radiation the deposit may be expected to take place over the whole of
the upper sui-face of the leaves, these in the aggregate, according to

0

34 PHENOMENA OF VEGETATION.

the statement of Humboldt, measuring several thousand times the
area of the ground they cover. And there should be as little to
startle one in finding dew-drops falling from a tree while the sky
is cloudless and serene, as in finding melted hoar-frost dropping
when the sun has arisen upon the tree in winter.

But in the case of the laurel at Ferro it is expressly stated, " every
morning the sea breeze drove a cloud towards the wonderful tree,
which attracted it to its huge top." Such were the phenomena, and
the explanation which suggests itself is more simple. In regard to
fog or mist — and a cloud is only a form of this — Sir John Herscheh
in the treatise from which I have already quoted, says, — " The form
in which the moisture so precipitated first appears will necessarily be
that of very minutely-divided particles, which, however, having the
refractive power of water, reflect and refract light as such, and appear
therefore as a mist, fog, or cloud of greater or less density and opacity,
according to the amount precipitated in a given volume. It is a
favourite dogma with many meteorologists that the particles so pre-
cipitated assume the form, not of drops, but of hollow spheres or
bubbles. De Saussure states that he has seen such, floating before his
eyes in clouds and fogs on the Alps, and the dusty appearance of the
vapour floating over a cup of cofi'ee in the sunshine is adduced in
illustration. The strongest argument adduced in their favour, however
(for there is great room for optical illusion in such matters), is that
adduced by Kratzenstein, that the sun striking on a cloud or fog
produced no rainbow, which it ought to do were the water collected in
spherical drops. This argument does not admit of a ready answer ;
but the difficulty, on the other hand, of conceiving any possible mode
in which such bubbles can be formed disposes us to believe that the
extreme minuteness of the globules may be found to afford one, their
diameter being of an order comparable with the breadth of the
luminiferous undulation."

Thus wrote Herschel in the article in the Encyclopaedia. To the
second edition of the article, published as a volume in 1861, he added
in one foot-note that he had never himself seen such a phenomenon as
was spoken of by Saussure, and that he had questioned Alpine excursion-
ists of far more extensive experience than his own, with a like negative
reply. And in a second foot-note he says, — " On the Newtonian
doctrine of fits of easy transmission and reflection, or (which comes to
the same thing) on the hypothesis of light consisting in rotating cor-
puscles with attractive and repulsive poles, there would be no difficulty
of the kind [mentioned in the text]. A globule, or a particle of water

DROPPING FROM LEAVES. 35

of any other form, whose greatest linear diameter did not exceed the
thickness of that central spot in a soap bubble which reflects no light,
would be equally non-reflective, and therefore incapable of forming a
rainbow. In the undulating theoiy, however, it is the parallelism of
the surfaces of the film of which that central spot consists which
renders it non-reflective. I suspect, however, that in the case con-
templated in the text that theory, carefully re-examined, would render
a somewhat difi'erent account of the singular abruptness of transition
from the most brilliant reflexion to an almost absolute extinction of
the reflected ray, and of the uniformity over large areas of a thin film
of the still remaining fraction of the incident light which it does
reflect, than that usually given."

Of the undulatory theory of light I shall have occasion, in a sub-
sequent part, to treat at some length.

Whatever may be the form of the cloud particles, be they drops or
bubbles, they are in the cloud or mist so far apart — and are kept
apart by conflicting attractions, exercised by all upon each and by
each upon all — that it is long before multitudes coalesce to form rain-
drops, and a slight rise of temperature may lead to their being again
absorbed by the air without their falling to the ground; but the
particles deposited on the leaves, brought into closer proximity, and in
many cases contact, rush into each other like drops of quick-silver,
and the attraction towards the earth becoming greater than the
attraction of adhesion they fall from the leaf to the ground. And
thus may the dropping reported have been occasioned.

In passing through a fog the moisture collects like dew-drops on the
hair, the whiskers, the eye-brows, and even on the eye-lashes, and on
every projecting filament of wool in the clothes ; and so is it also
with the cloud or mist surrounding a tree, or borne through the
interstices of its twigs by the wind, the minute drops collect upon
its leaves. And I presume the fact has only to be mentioned to
recall to some of my readers that in a mist they have seen heavy
drops falling from foliage while there was no rain.

I find some pertinent observations on this point in a work entitled
"The Climate and Resources of Madeira," by Dr Graham, a work-
which I shall afterwards again have occasion to quote. The author
remarks, — "The power of trees upon mist is very great. Where
there are no trees, the cloud drives along, depositing little or no
moisture. But trees largely intercept mist ; and the small component
vesicles of water coalesce upon the leaves and branches, and fall in
drops of water upon the earth. The mists form, whether there be

36 PHENOMENA OF VEGETATION.

trees or not ; but the water is strained out and saved by the forest
foliage." He says, " I have watched with much interest for the com-
mencement of dripping, in reference to the pre-eminence of certain
kinds of foliage in powers of condensation. The pine trees invariably
begin first, the rough brush-like clusters of leaves being well adapted
to intercept the smallest particles of moisture. The yield of water
from this source is very great. The laurels extract water plentifully
from mists which are more sensibly damp."

Dr Graham further states that, — " In one of the Canary Islands,
the people show the place where, at the head of a deep valley, stood
a fine solitary til tree, which daily used to strain a large quantity of
water from the humid mist, conveyed inland by the sea breeze.
The tree is mentioned by Cordeyro and subsequent writers. But
both the spring of water and the tree are now gone ; and the mists,
though they still remain, pass over unstrained of their moisture."

The difference noted by Dr Graham in the effect of different kinds
of trees may be attributed in some cases — in others if not in those
mentioned by him — in some measure. First, to differences in the
number of stomates through which the evaporation from the leaves
of the tree itself is effected. These vary in different plants from a few
to 160,000 or more in the square inch of surface. The number in
the leaves of the cherry-laurel is 90,000 in every square inch on the
back of the leaf. In such state of atmosphere as is specified by
Dr Graham, every stomate would probably be distended, an atmos-
phere of dense moisture would surround the tree and this precipitated
by a fall of temperature might in part create the supply.

The difference may be attributable, in some measure, Secondly, to
diff'erences in the extent of the radiating surface, supplied by the
leaves, whereby the temperature might be effected. This is much
greater in the foliage of a pine tree than in the herbage of a laurel.

And the difference between the eff"ect produced by the laurel and
other trees may be attributable, in some measure, to diff'erence in
the attraction of adhesion between water and the leaf. From the
glossy surface of the laurel leaf the moisture deposited might run off"
quickly, while to the leaves of other trees it might cleave, as if loathe
to shake itself free, and adhere till again evaporated, or till it fell in
drops undistinguishable from the rain, when this began to drizzle.

In all such cases as have been mentioned, whether fog be visible
or it be otherwise, the precipitation and consequent dripping is
attributable to the temperature of the atmosphere surrounding the
tree being below the dew-point, and the moisture contained in it

DEOPPING FROM LEAVES. 37

there being in excess of what saturates it, in accordance with the
elements by which that dew-point is determined. These are ascer-
tained by observation of the difference of temperature indicated by a
wet and a dry bulbed thermometer, of the barometric pressure, and
of the elastic force of the vapour at the temperatures, and under
such pressure. The elements are numerous, but the formula of
calculation simple, and copious tables for facilitating this have been
published.

In regard to the eflfects of different trees, I find it stated by a
writer on the subject, in " The Farmers' Magazine," Mr Cuthbert W.
Johnstone, that " the dew under some large oak trees, by the side
of his bowling green, at Croydon, is always considerable of an
evening ; but that under a witch-elm growing by Iheir side the dew ia
almost always absent." In Europe, generally, it has been found that
the most copious humidity or moisture has been produced by the
elm, and, in decreasing order, by the poplar and horse-chestnut, while
the least effect is produced by firs.

PART II.

Effects op Forests on the Humidity of the Climate.

Chap. I. — Immediate Effects of Forests on the Humidity
of the Atmosphere.

There is a wide-spread opinion that forests attract clouds and rain,
and a similar effect is attributed to mountains. The facts which have
been adduced may enable us satisfactorily to account for the pheno-
mena upon which the former opinion is founded ; and with the
explanation thus supplied we may be enabled also satisfactorily to
account for the latter. The phenomena referred to may be stated
generally to be these : forests and mountains are frequently seen
surmounted by clouds, stationary or passing over them, when few or
none are seen elsewhere in the heavens ; and, though it may be an
unwai'rantable conclusion that they have been attracted thither, it
does not excite surprise that this conclusion has been drawn from the
phenomena observed. In the case of forests we know, however, of
no kind of attraction exercised by them which could produce this
effect ; the effect can be accounted for satisfactorily in accordance
with the phenomena of vegetation which have been under consider-
ation ; and in these circumstances it is reasonable to conclude that
these supply the correct rationale of what is seen. Of this a simple
exposition can be given, and one not less simple can be given of the
similar phenomena in the case of the mountains ; and the exposition
of the former supplies at the same time the means of accounting for
the proverbial dampness of houses overshadowed by trees, or situated
in close proximity to woods.

The meteorological effects of trees and forests may be apparently
paradoxical, and accounts of them conflicting and contradictoiy ; but
if instead of acting on the principle of cutting the knot we act on
the principle of unloosing it we may find that all facts observed and
reported are consistent with each other, and that many of them can
be accounted for satisfactorily in accordance with what is known of
operations patent to all. If, instead of attempting the reconciliation

DAMPNESS NEAR WOODS. 39

«f conflicting theories, we study the facts separately and apart^
we may find that, when all is done, there are no conflicting views to
reconcile ; and this I shall endeavour to do, stopping at any point
when lack of information renders further advance hazardous.

Shot. I. — On the H^imidity of the Atmosphere in the Vicinity of Trees,

indicated by the Dampness of Houses overshadotved by Trees,

or situated in close proximity to a Wood.

It is matter of common observation that houses closely surrounded
with trees are damp. Oftener than once have I heard a sufierer from
rheumatism told. You must get your husband to cut down that tree
overshadowing the house, or you will never be well.

There may be nothing injurious in damp itself, but in evaporation
damp induces cold, and cold may be injurious to the human frame ;
damp, moreover, is conducive to the decomposition of dead organic
matter; the products of vegetable decay or decomposition tend to
produce ague, intermittent fever, rheumatism, neuralgia, and tooth-
ache ; and in the absence of appliances for determining the hygro-
metric condition of the atmosphere, the frequent occurrence of such
maladies may be considered indicative of the existence of the moisture
to which reference is made.

With the information which has been produced, one need not be
surprised at the dampness of houses so situated. With evaporation
going on continuously, from stomates so numerous in every one of
such a multiplicity of leaves, the quantity of moisture in the air must
be much greater than it is in an open space ; and though the
temperature may be such as to keep it suspended in solution, an
affinity for moisture in the material of which the house is built will
attract it thence and keep the walls, and the apartment within, damp,
or at least less dry than otherwise they would have been.

The quantity of moisture which clay, bricks, and granite, and other
forms of stone can retain in their structure, while to touch and to si»ht
they appear to be dry, has been ascertained, and it has been found to
be great ; and some of them not only retain moisture, but |absorb
moisture from the atmosphere. I know a noble mansion uninhabit-
able in consequence of the dampness produced by this property of the
stone of which it is built. I have known a wall to be kept constantly
damp through the attraction of moisture from the atmosphere by the
sand employed in the manufacture of the mortar; and I do not
recollect of ever seeing a house, built of unburnt brick, perfectly dry,

40 EFFECTS OF FORESTS ON HUMIDITY.

— and I hare seen hundreds,— the clay having this property in a pre-
eminent degree.

The walls of houses built of such materials, standing in an atmoS'
phere kept humid by over-shadowing trees, or trees growing in close
proximity, or even in a proximity not very close, absorb moisture
■with which the atmosphei'e is charged. The moistui'e transmitted or
permeating it to the inner surface may be evaporated by the heat of
the apartment within, but only to be followed by more and more,
keeping the interior of the house constantly humid. Many have
sufifered for years in consequence of taking up their abode in a newly
built house not thoroughly dried. In the case of such a house as I
have referred to, it is never thoroughly dried, the drying process will
go on continuously, or be continuously renewed, for a hundred years
and more, if the house stand as long.

Not a little of the dampness may be attributed to the shade and
the shelter of the trees, and the consequent want of ventilation ; all
which will afterwards come under consideration. "What is brought
under consideration at present is the humidity of atmosphere
consequent on the copious evaporation of moisture by the leaves
of trees. Keference has been made to the hydroscopicity of the
walls of houses simply to show that the damp is not produced, but
only transmitted by them; and it must be apparent that, in
like manner, the damp experienced in connection with want of
ventilation with shade and shelter, is damp not produced but
only retained by them. The dampness of houses overshadowed by
trees, or situated in close proximity to a wood, is indicative of
humidity of atmosphere ; and this humidity of atmosphere is
occasioned, in part at least, by the copious evaporation proceeding
from the leaves of the trees.

Sect. II. — On Clotich occasionally seen sii^rmounting Woods, while
the Atmosphere around is cormparatively Clear.

The clouds occasionally seen over woods, while the atmosphere
around is comparatively clear, are consequent on the condensation of
the humidity occasioned by the evapoi'ation from the leaves.

There is always moisture existing in the atmosphere ; it is reckoned
one of its constant constituents, but it vai-ies in quantity. The quantity
is minute compared with that of the oxygen and nitrogen of the air ;
but it is never absent. There it is, on the highest mountain and in

CLOUDS SURMOUNTING POBESTS. 41

the deepest mine ; on the ocean's surface and on the dry land a
thousand miles away.

But, as has been mentioned, while moisture may be found in the
atmosphere everywhere, it is not always present in the same quantity
in the same space. In almost any circumstances, but more especially
where there is an unlimited supply of moisture, the quantity varies
with the temperature, and varies with the temperature to a very
great degree. According to Sir John Leslie, it doubles with every
rise of twenty-seven degrees of temperature; and, according to
subsequent observers, it varies to a still greater extent, the doubling
taking place at different intervals, which increase slowly with the
temperature — the mean being 23° 4' — from the freezing point to 100°
Fahrenheit.

According to Leslie's calculation, the air at a temperature of 59° or
60° will hold twice as much as at 32°, or the freezing point ; and at
86° it will hold twice as much again. And, according to later
observers, at 121° it will hold twice as much again, or sixteen times
as much as at 32°, eight times as much as at 53°, or four times as
much as at 75".

It is customary to speak of this as the solvent power of the atmos-
phere, as if the moisture were dissolved in the air as sugar may be
dissolved in water ; but it is more in accordance with fact to consider
that as water requires a certain amount of heat to keep it from
passing into a state of ice, so it requires a certain amount of heat to
keep it in a state of vapour and prevent it from passing into a state
of water.

In accordance with this, it happens that if air of a higher temper-
ature, having as much moisture in it as can be sustained in a state of
vapour, be cooled down some degrees, a quantity of moisture, which
can no longer be maintained in a state of vapour, will assume the
form of water in minute drops, and appear as fog, or cloud, or mist ;
but let the temperature be again raised to the same elevation as
before, and this water will again assume the state of vapour, and the
air become transparent, the fog or cloud having melted away. In
illustration of this fact, I may i-efer to what is seen in the laying of
the cloth on Table Mountain when the south-east wind blows. The
temperature on the top of Table Mountain is lower than that of the
wind blowing over its summit, and the mountain cooling down the
air, a quantity of the vapour intermixed with it is deposited in the
form of a cloud which is blown over the face of the mountain, and
falls, threatening to bury the city below ; but before it can reach

42 EFFECTS OP FORESTS ON HUMIDITY.

Cape Town it must pass through an intermediate stratum of air of a
higher temperature than that to which it has been reduced. By this
it has its temperature again raised, and the cloud evaporates and
disappears, followed by continuous masses of cloud, which on reaching
the same level vanish into thin air, leaving no trace behind.

The quantity of moisture passing into the atmosphere from the
leaves of a forest in active vegetation must be considerable. Cal-
culate the number of stomata, or stomates, on a leaf, multiply this
by the number of leaves on a branch, the product by the number of
such branches on a tree, and the product of this by the total number
of trees in the clump, or the total number of trees in the forest, and
the final product will indicate the provision made for evaporation
from the forest. There are similar stomates on every verdant plant
on the dry land ; but the evaporating surface supplied by the leaves,
rising tier above tier, far exceeds in extent that supplied by the
herbage and the grass growing elsewhere ; and in many places these
may be found growing as luxuriantly on the soil of the forest as in
the fields beyond, or perhaps more so, and adding their quota of
evaporation to the evaporation from the trees.

Of the moisture thus raised by the tree, and no longer required
when the sap has been elaborated in the leaf, the air will only take
up what quantity it can, at the temperature at that time and place,
dissolve and hold in solution ; and cases have been cited in which the
excess is so great that the leaves seem to act as alembics, distilling
water which falls in great drops to the ground.

Where this does not take place, what the air dissolves it will hold
in solution so long as the temperature is maintained at the same or a
higher point ; but if the temperature fall below the point at which it
can do this, what it cannot sustain as invisible vapour will be
deposited or suspended in the form of mist, or cloud ; and such a
reduction, may follow the setting of the sun, or even the decline of it
in the afternoon and towards nightfall ; or if there come over the
trees a wind in any degree colder than the air in which they are
enveloped, the air is thereby cooled down, and a quantity of the
moisture which it held in solution may be deposited in the form of
fog, or of dew, or of rain.

But this is not all ; we shall afterwards have occasion to consider
more fully the effect of vegetation on temperature, but here it may
be remarked that it will generally be found that the temperature,
both of the earth and of the atmosphere, is lower amidst abundant

CLOUDS SUEMOUNTING FORESTS. 43

vegetation than in a barren, sterile, stony district, probably by heat
being absorbed and retained in a latent form by the process of
vegetation in the one case, while in the other it is reflected
unchanged. In consequence of this, if a wind in any degree hotter
blow over the district covered with trees, this wind is cooled down ;
its power of holding water in a state of vapour is thereby diminished,
in a geometrical ratio, with every fall of temperature, and a large
deposit of moisture may follow in the form of dew, of mist, or of rain.

The deposit may be much greater than may seem to be pro-
portionate to the fall of temperature, but a reference to the
observation of Sir John Leslie, and others, that a fall of temperature
from 121* to 86®, which is not impossible in a semi-tropical country,
occasions a deposit of half of the whole of the moisture held in
solution, which is sixteen times as much as could be held in solution
by air at 32°, eight times as much as could be held at 53°, and four
times as much as could be held at 70°.

In illustration of what deposit of moisture might take place on
such a fall of temperature if the air were nearly saturated, and the
quantity of air so saturated great, I may quote the following descrip=
tive account of one of those storms which frequently relieve the heat
of Bengal, given by Mrs Murray Mitchell, in a volume, entitled
" Indian Sketches of Life and Travel," lately published. The
oppressiveness of the heat is described as such that one's hands
" have a boiled feeling, like a washerwoman's who has been all day
manipulating in the tub." Outside, the sun floods everything with
one white blaze. " Nature is perfectly still, as if awed ; the leaves
hang limp and parched ; the grass crumples up and disappears ; the
poor birds hide themselves away in any corner where there is a bit of
shade ; there is not even a fly abroad ; all life seems frightened into
quiescence, and mankind — at least the native portion — is asleep." At
such a moment the storm suddenly descends. It is thus described : —

" Last week we arranged a nice little garden entertainment for our
native friends, and invited some people to meet them. The green
was set with numbers of small tables, covered with cakes, and tea,
and ices, and flowers. Seats of all sorts and bits of carpet were put
down everywhere. Some of our friends had come, and our garden-
party promised to be both pretty and pleasant, when, lo ! Mr Don
said quietly, ' Look there ! ' and truly enough a cloud like a man's
hand had risen in the west, and we knew what would follow. Con-
sternation seized us; we all jumped to our feet; each one snatched
up something — chair, table, cups, fruit, everything — and rushed pell-

44 EFFECTS OF FORESTS ON HUMIDITY.

mell into the house. Not a moment too soon. The heavens grew
black as ink ; the birds flew in terror to some cover, filling the air
with their screams ; the wind swept past with a low portentous sigh :
and we had hardly our goods and ourselves uuder shelter, and the
doors and windows secured, when the storm was upon us, and raging
in mad tumult without.

" The air becomes thick with sand, and lurid, like the yellowest of
London fogs ; the wind rises into fury, and the dust is driven hither
and thither as by a whirlwind. The sun seems blotted out, and in
the appalling darkness you see the lightning play and dart, and zig-
zag from heaven to earth, without one moment's intermission. The
thunder comes, not in distinct explosions, and then a pause, but in
one continuous roll of terrific reverberating noise, while the rain
descends with an abandon quite in keeping with the other forces of
the storm. It generally comes in horizontal sheets of water instead
of drops, and is driven by the mighty wind as you have seen seaspray
driven from the wave-tops in showers of foam. A storm like this is
a magnificent spectacle, and its effects are delicious. In a wonder-
fully short time the conflict ceases — the thunder rolls away into the
distance, the wind is hushed, the sun shines out, and Nature, though
tearful, looks happy and refreshed. Everything Hterally rejoices on
every side ; the air feels cool and light, and for some days there is
pleasure in existence.

" Our little fete was spoiled ; but when the war without ceased, we
made up by doing what we could for the pleasure of our guests
within, and all is well that ends well."

I design not to convey the idea that the moisture thus precipitated
had been passed into the atmosphei-e by the foliage of a forest ; I
find no indication that a forest was there — it is the precipitation
occasioned by the reduction of temperature alone which I seek to
illustrate.

Previous to such a downpour of rain the heavens were perfectly
clear, without a cloud to be seen ; yet there, it may be, the whole of
that moisture was suspended, dissolved in the air. The rain-cloud
may have appeared to proceed from beyond the horizon, and to come
thence, advancing onwards with resistless force, borne forwards by
the gust of wind, more like a tornado than aught else ; but there are
reasons, and these satisfactory ones, to warrant the conclusion that
the cloud had not been blown thither by the blast, but had been
formed at the various points of its advance, by the wind suddenly
cooling down the air below a temperature at which it could hold the

CLOUDS SURMOUNTING FORESTS. 45

moisture in solution : very mucli as is the case with the sand and
dust filling the air immediately before the falling of the rain ; what-
ever proportion of these may have been brought'from a distance
more or less remote, most of it may have been seen raised from the
ground on the spot as the mighty rushing wind passed on in its
course ; and the little lapse of time between the appearance of this
precursor and the precipitation of the rain was only such as was
required, or at least such as was occupied, in the aggregation of the
rain particles into the larger drops which fell, and the precipitation
of these by gravitation and by the blast, aided, it may be, by the
co-operation of electric force, the process being essentially the same
whether the blast have come on like an onward moving cold wave,
or have advanced as an advancing whirlwind which raised the air
through which it passed to an elevation at which, it may be in
consequence of sudden expansion, the temperature was too low to
retain all the moisture in solution.

With the copious evapoi-ation going on fx-om the leaves of a forest
there is nothing, in view of such a rainfall, surprising in any change
of wind producing a cloud or mist above a forest, where formerly
the air had been perfectly transparent ; and everything known in
regard to such phenomena makes it probable that in general, if not
invariably, the cloud is produced there, and not attracted thither by
the forest.

In connection with this, there is an observation, made by Mr Marsh,
which demands attention : — " There is one fact," says he, " which I
have nowhere seen noticed, but which seems to me to have one
important bearing on the question, Whether forests tend to maintain
an equilibrium between the various causes of hygroscopic action, and,
consequently, to keep the air within their precincts to an approxi-
mately constant condition, so far as this meteorological element is
concerned. I refer to the absence of fog or visible vapour in thick
woods in full leaf, even when the air of the neighbouring open ground
is so heavily charged with condensed vapour as completely to obscure
the sun. The temperature of the atmosphere of the forest is not
subject to so sudden variations as that of cleared ground, but, at the
same time, it is far from constant, and so large a supply of vapour as
is poured out by the foliage of the trees could not fail to be condensed
into fog by the same causes as in the case of the adjacent meadows,
which are often covered with a dense mist while the forest air
remains clear, were there not some potent counteracting influence

46 EFFECTS OF FORESTS ON HUMIDITY.

always in action. This influence, I believe, is to be found in the
equalization of the temperature of the forest, and partly in the
balance of the humidity exhaled by the trees, and that absorbed and
condensed invisibly by the earth."

I accept the statement with all confidence in the correctness of the
observation by Mr Marsh. The fact was previously unknown to me.

By the faU of leaves and their decay, and in other ways, the soil
in which trees grow becomes rich with humus, by which means its
power of attracting moisture from the earth is increased. In a forest
the temperature is more equable than in the open country ; to both
of these facts Mr Marsh refers, and I may add, what is also held by
him, that there is heat evolved as well as heat absorbed in vegetation,
a point which will afterwards be discussed more fully. In virtue
of this and of the shelter of a forest, it may in certain conditions
continue for a time, more or less protracted, protected from a change
of temperature, producing a fog in the open country around.

Without ampler information, or personal observation of the fact
with opportunity of noting the circumstances, I am not in a position
to say more.

Sect. III. — On Clouds occasionally seen surmounting Mountains while
the Atmosphere is otherwise Clear.

With regard to the phenomena of clouds apparently attracted by
mountains, Mr Marsh, in his treatise " On the Earth as Modified by
Human Action," writes, — " In discussing the influence of mountains
on precipitation, meteorologists have generally treated the popular
belief that mountains attract to them clouds floating within a certain
distance from them as an ignorant prejudice, and they ascribe the
appearance of clouds about high peaks solely to the condensation of
the humidity of the air, carried by atmospheric currents up the slopes
of the mountains to a colder temperature ; but if mountains do not
draw clouds and invisible vapour to them, they are an exception to
the universal law of attraction. The attraction of the small Mount
Shehallien was found suflBcient to deflect from the perpendicular, by
a measiu-able quantity, a plummet weighing but a few ounces. Why,
then, should not greater masses attract thence volumes of vapour
weighing many tons, and floating freely in the atmosphere within
moderate distances of the mountains 1"

As stated thus, the popular belief assumes a form in which it can
be dealt with more satisfactorily than in the vaguer form in which it

CLOUDS SURMOUNTING MOUNTAINS. 47

is generally met with. The answer I would give to the question is,
However plausible the supposition may be, I desiderate evidence that
gravitation can occasion a deposit of moisture suspended in a state
of solution in the atmosphere, operating on it otherwise than it
does upon the other constituents of the air; and the phenomena
seen can be accounted for satisfactorily otherwise.

All that was done by Mount Shehallien was to cause a deflection of
the plummet ; the preponderating attraction was towards the earth's
centre. The phenomenon under consideration is not a deflection
from the perpendicular, but the appearance of clouds on the moun-
tains alone.

We cannot get rid of the idea that the earth by gravitation exerts
an attractive force upon clouds, but they do not fall precipitately upon
the earth. Solid matter, so comminuted as to appear as dust, floats in
the atmosphere for a length of time, rising even with aerial currents
in despite of gravitation ; so is it with the molecules of water in a
fog. With regard to invisible vapour, it appears to be subject to the
law of gaseous diflfusion, in which, though still held by gravitation
within the atmosphere, it is free within the limits of this to go any
whither. True, moisture can be withdrawn from the atmosphere, and
it is so withdrawn, but this is not attributable to gravitation ; it is
attributable to chemical affinity, whatever that may be, and it varies
with the composition of the soil and the chemical affinity of its con-
stituents for moisture.

In lack of evidence that the attraction of gravitation exercised by
the earth abstracts moisture dissolved in the atmosphere from the
air, I see no reason to conclude that by gravitation has moisture been
abstracted from the air on the mountain top when there the cloud is
formed.

While I desiderate evidence that gravitation can occasion a deposit
of moisture suspended in a state of solution in the atmosphere,
operating on it otherwise than it does upon the other constituents of
the air, and evidence that the gravitation occasioned by mountains
difiors in its nature from the more powerful gravitation exercised by
the earth, I see no evidence of their attracting clouds ; and all the
phenomena connected with the appearance of clouds surmounting
mountains may be accounted for in accordance with the way in which
the appearance of clouds surmounting forest has been accounted for,
that is by a fall of temperature below that at which the vapour there
suspended in the atmosphere could be sustained by it in solution.

It is in defence of that view that the subject comes under consider*

48 EFFECTS OF FORESTS ON HUMIDITY.

ation, and what has first to be established is the possible production
of clouds in a transparent sky. The case of a Bengal storm has been
cited ; but as evidence of the case in question it may be considered
insufficient, I therefore supplement it with more explicit testimony.

At the Cape of Good Hope, again and again, I have seen the
heavens gather blackness where shortly before the sky was cloudless,
the first manifestation of a change being the appearance of clouds
the size of a man's hand, not blown thither, but there appearing as if
formed there, and the progress and completion of the change resemb-
ling somewhat the dissolving view represented by a magic lantern. The
clouds were neither blown thither bodily nor attracted, but were formed
there, apparently by an intermixture of currents of air of diflferent
temperatures. And again, the whole cloudland structure — bold in
its outline as the smoke belching forth from the cannon's mouth at
the moment of discharge, and magnificent as a realization of Fancy's
dream of Ossa piled on Pyleon, and Pyleon-like mountains on Ossa
again — passed away like the deposition of vapour breathed upon the
polished steel, passed away as if it had never been, leaving not a
wreck behind. And the corresponding phenomenon I have seen when
according to the local phrase, the Devil lays his table-cloth on Table
Mountain. To this I have already had occasion to refer.

At these times the summit of the mountain is covered with a dense
mass of beautiful white fleecy cloud in constant flow over the precipice
and pouring down the almost vertical front of the mountain facing
Table Bay as if threatening to bury in an avalanche the capital of the
colony at its base ; but long ere it reaches the town, notwithstanding
the continuous flow, it stops ; to that line it flows on continuously,
but beyond it, not : there the cloud in unceasing flow terminates, the
spectator sees not why.

The beautiful and interesting phenomenon is occasioned by a south-
east wind, which, up to the Table Mountain range, was undimmed.
The wind was strong, but the sky blue and serene, though the wind
was loaded with vapour — vapour dissolved and invisible.

But passing over Table Mountain the elevation of this is such
that the decrease of temperature, consequent on expansion under
diminished pressure bringing this below the dew-point, the moisture
is deposited by the air in the form of cloud, which, as it reaches at
lower level to leeward, a locality with a higher temperature, the
moisture is again absorbed and the air loaded with it is again trans-
parent, as is all the air around, and as it was itself before passing
over Table Mouutwu in its course.

CLOUDS SURMOUNTING MOUNTAINS. 4^

From Claremont, or Wynberg, or the Flats, or any place to the
back of Table Mountain, it may be seen that the cloud is not blown
to the mountain, but there it first appears ; and if some few cloudlets,
formed over the crests of hilla belonging to the range situated to
windward, be seen sailing towards it, it is evident that they are
*' A sailing, a sailing with the wind," and not attracted only, for none
are seen floating towards the Table-Cloth in other direction than that
in which the wind blows.

Of this phenomenon Sir John Herschel writes, " That the mere self-
expansion of the ascending air is sufficient to cause precipitation of
vapour, when abundant, is rendered matter of ocular demonstration
in that very striking phenomenon so common at the Cape of Good
Hope, where the south or south-easterly wiud which sweeps over the
Southern Ocean, impinging on the long range of rocks which ter-
minate in the Table Mountain, is thrown up by them, makes a
clean sweep over the flat table-land which forms the summit of that
mountain (about 3850 feet high), and thence plunges down with the
violence of a cataract, clinging close to the mural precipices that
form a kind of background to Capetown, which it fills with dust and
uproar. A perfectly cloudless sky meanwhile prevails over the
town, the sea and the level country, but the mountain is covered with
a dense white cloud, reaching to no great height above its summit,
and quite level, which, though evidently swept along by the wind,
and hurried furiously over the edge of the precipice, dissolves and
completely disappears on a definite level, suggesting the idea (whence
it derives its name) of a * table-cloth.' Occasionally, when the wind
is very violent, a ripple is formed on the aerial current, which, by a
sort of rebound in the hollow of the amphitheatre in which Capetown
stands, is again thrown vip, just over the edge of the sea, vertically
over the jetty — where we have stood for hours watching a small
white cloud in the zenith, a few acres in extent, in violent internal
agitation (from the hurricanes of wind blowing through it), yet
immovable as if fixed by some spell, the material ever changing, the
form and aspect unvarying. The ' table-cloth ' is formed also at the
commeocement of a ' north-wester,' but its fringes then descend on
the opposite side of the mountain, which is no less precipitous."

I mean not to affirm that in every case the clouds capping
mountains and mountain ranges have been formed in the same way.
All that 1 affirm is that thus it is there in the circumstances stated,
and thus it may be elsewhere oftimes when clouds are seen covering a
mo untain brow, and that, whether these mountains be wooded or bare.

60 EFECTS OF FORESTS ON HUMIDITT.

When the mountains are covered with forests of deciduous trees,
the great quantity of moisture passed into the atmosphere by the
stomates of the leaves may render the air more readily indicative of
any fall oC temperature, but that is all.

The phenomenon in question comes under consideration here solely
because this and the phenomenon of clouds surinountiug woods are
generally referred to as indicative of an attractive power over clouds
beino- exercised by the one and by the other ; and it may be satis-
factory to some student of the meteorological eSfects of forests to see
that neither in the one case nor in the other is there any necessity to
call in the aid of some unknown, and consequently mysterious, power
of attraction to enable us to account for the phenomena observed.

CHAPTER II.

Effects of Forests on the Humidity of the Grouitd.

It may be considered a departure from the professed subject of thi»
treatise to speak here of the effects of forests on the humidity of tha
ground ; but the subjects are correlated. Practically it is humidity of
goil which is what is desired, and the coaservatioa of m )istLira iu tha
soil has a direct influence, in different ways, on the moisture iu tho
atmosphere, so important as to justify, if not to require, soma
attention, being given to it in treating of the meteorological effects of
forests.

The subjects coming under consideration here are the following :
The wetness of roads when overshadowed by trees ; the shelter afforded
by trees against drying winds ; and the attraction and retention of
moisture by vegetable mould ; and to this might be added the effect
of trees in arresting the flow and escape of the rainfall— but a better
opportunity for bringing these under consideration will afterwards
present itself.

Sect. I. — On. ths Wetness of Roccls where these are Ooershadowsd

hy Trees,

We have had under consideration the dampness of houses over-
shadowed by trees, or situated in close proximity to woods. Not less
noticeable than this is the wetness of roads where these are over-
shadowed by trees. This may frequently be observed while elsewhere
the road is dry, and it may be supposed that in this we have only an
exaggerated effect of what occasions the dampness of such houses ;
but there is more in the phenomenon than this would imply.

While much of the rain which falls upon the earth, and much that
falls in the form of snow and hail, flows away to the sea — the tiniest
streamlet and the mightiest river or flood being alike the product
of such flow— and while a portion is absorbed by the earth, a great deal
is evaporated and absorbed by the air. The higher the temperature of

52 EFFECTS OF FOBESTS ON HUMroiTT.

the ground the more rapid is this evaporation. The effect may be
seen in the steaming of the streets after a short shower in summer :
there is then more evaporated from the hot stone than the super-
incumbent air can sustain in solution, and the surplus is temporarily
deposited in a visible form. And in the wetness of the I'oads under
the condition stated we see, in addition to effect of the trees iu
increasing the humidity of the atmosphere by evaporation through
the stomates of the leaves, the effect which they bear in checking or
preventing such evaporation from the ground.

The quantity of moisture held suspended in solution in air, or
which may be so held, increases with the temperature, and when the
sun's rays fall unimpeded upon the road this raises the temperature
of the earth and stones ; and these by contact and radiation raise the
temperature of the incumbent air, which in its turn takes up the
moisture with which they were co veered : the moisture being evaporated
in t!ie same way as is a drop of water falling on a hot stove, or as the
moisture on a wet handkerchief when this is held to the fire, but less
rapidly, as the temperature is not so high.

The same difference as is seen on the exposed and shaded part of
the road may be seen in the ground on the sunny and shaded sides of
a house, only less marked because the shade is less complete.

I have stated in another volume that, to test the correctness of
some statements, I had had occasion to make at the Cape of Good
Hope, on the effect on the destruction of herbage by fire on the
desiccation of the country, Mr W. Blore, M.L.A., Fellow of the
Meteorological Society of London, and Secretary of the South African
Meteorological Society, made some experiments with the following
result : — He sunk two cylindrical jars, of the same size, in the ground
to the depth of 4 inches, leaving them projecting an inch above the
surface, as a precaution against sand and other matters being blown
into them, and covering each with wire gauze to keep out fl.ies, &o.
The one was placed where it was partially protected, but not covered
by bush, the other was sunk in a newly cleared plot of ground,
measuring about 60 feet in diameter, surrounded by sugar bushes,
Protea melUfera Thhg, of a considerable height, and otherwise pro-
tected from the prevailing wind by a belt of pine trees, about 120
feet distant.

Into each of these jars was put 20 oz. of water on January 31st, at
10 A.M. On Feliruary 5th, at 5 p.m., the water remaining iu each
was carefully measured, and the evaporation was calculated, when

EXPERIMENTS ON EVAPORATION. 53

it was found that the evaporatioa from the jar sunk in the cleared
ground had been more than double the evaporation from that which
was partially protected, though not covered by the bush ; the
former being 1-854 in.; the latter -863 in.; giving an excess of
"991 in. The experiment was repeated with similar results.

In reporting these results Mf Blore remarked that had the experi-
ment been made in a more arid district, the evaporation would have
been greater ; and that had it been made in the open country, the
difference would have been marked. But, taking the results obtained
as the basis of calculation, he arrived, by the following process, at a
conclusion for which, probauly, few who have not given attention to
the subject are prepared.

The excess of evaporation from the more exposed jar above that
from the jar partially shaded, but not covered, beiug one inch, more
strictly speaking upwards of ^f^J of an inch of water, and more than
doable that of the latter. " An inch in six days," says he, " will give
for 102 days, the ordinary duration of the hot windy and dry season
in the district, 17 inches. This is equal to about three hundred and
eighty-four thousand (384,000) gallons per acre, and supposing 1,000
acres to be burned, blackened, and di-ied — what with sunlight, fire,
heat, and wind, the evaporation would be an excess of three
hundred and eighty.four millions of gallons of water above what
would have been evaporated if the bush or grass had been left
unbnrued."

In the prosecution of his researches, Mr Blore ascertained by
experiment that on Wynberg hill, while the deposit of dew on a
green surface amounted to 4-75, that on a white surface amounted
only to 2, showing that the deposit of dew upon a green surface is
more than double that upon a white ; and he further ascertained
that, while the difference of temperature in the water in the two jars
employed in the former experiment was only a few degrees, the
difference of temperature between black ground and ground shaded
by bush was about 25°, which would occasion a vastly greater
difference in the amount of evaporation than that which occurred in
his experiment.

In a letter on planting trees by water-courses, appended to Report
of Colonial Botanist for 1863, it is stated: — "In the course of
my tour I have found that in some places an opinion prevails
that trees growing by the side of a stream, steal away the water.
And in support of this opinion, my attention was directed to the

64 EFFECTS or F0BEKT8 ON HrMIDlTY.

fact that under trees or plants the moisture spreads for several
inches, eighteen or twenty it may be, over and through the banks
towards the tree, while at exposed places between the trees the
moisture spreads not above one or two inches from the surface
of the water. Bat this, so far from proving what was alleged,
may be adduced as evidence of the correctness of my view of tho
matter. The A\ater spreads from the stream by what is called
capillary attraction, and spreads in all probability quite as far in the
exposed as iu the covered spots, but where it is exposed it is con-
tinuoasly evaporated by the heat of the sun's rays, so that, excepting
during the night and early in the morning it never becomes visible in
the darkened hue of the soil, while uuder the shade of the trees it
has been protected from evaporatiou. There tho water which has
spread so far is retained with very little loss. But at the exposed
parts of the bank there is a constant drain throughout the day.
Water evaporates ; more rises to supply its place ; but this is carried
oflf in like manner, till the setting of the sun suspends for a time thia
wasteful process. So far from the tree stealing the water, it takes up
no more than it retains in the structure of its sap, wood, flowers,
fruit, and green leaves ; the heat is the thief, if thieving there be.
The tree has not stolen away the water which occasions the moisture
seen under its shade. The soil did that, and it did the same all
along the water-course ; and the tree, like the faithful dog, has
Watched over and protected that portiou from the heat of the direct
rays of the sun, by wliich it would otherwise have been conveyed away
and transported by the air to regions, it may be, far remote."

While I adhere to the statement thus made, I may add that in
the remark which called it forth there is — as there often is in popular
remarks — a mixture of truth and error ; it was neither absolutely
correct nor absolutely erroneous : the tree had actually withdrawn
moisture from the streamlet, for thence it was that the moisture re-
tained in its structure and the moisture evaporated by its leaves had
mainly been obtained ; but the blackness and dampness of the soil
between the streamlet and the ti ee to which it was that my attention
was called had not thus been produced, — that moisture had not been
occasioned by the vegetation of the tree but by the capillary attrac-
tion of the soil. The shade of the tree had prevented the direct rays
of the sun falling upon this as they did upon the ground around ;
thus an evaporation, such as had dried the ground beyond, bad been
prevented ; and in the same way is the desiccation of a road retarded
where it is overbbadowed by trees.

SHELTER TO PONDS. 55

In the Journal of the Royal Agricultural Society, N.S,, vol. ii.,
p. 110, there is a statement, by Mr R. Orlebar, of Williogborough, oq
the advantage of planting treps around ponds, in which he says, " It
is astonishing what effect a little shade has in checking evaporation.
A pond that is well shaded will hold water for weeks after one
of equal dimensions, but lacking shade, will become dry. The best
shade is that given by fir trees, or other evergreens, for they give it
all the year round. The yew, perhaps, would be even better for
shade than the fir, but for its poisonous qualities. After the fir, I
doubt whether there is, on the whole, any better plant for shade than
the hawthorn bush. Its leaves sprout early, and fall late ; and it
possesses, besides, the great advantage that it forms its own fence."
And the writer tenders the counsel, suitable for Europe and countries
in the northern hemisphere, "Always, if possible, have the rrouth
of your pond on the north side, and the shade on the south side."
A suggestion which commends itself. While the writer speaks only
of shade, it may be that the eflfect mentioned by him was to some
extent due to shelter afforded to the pond from wind.

I find it stated, in reference to the suggestion of Mr Orlebar, by a
writer. On the Dew of Heaven and the Influence of Forests, in the
Farmer's Magazine, Mr Cuthbert W. Johnstone, that in some parts of
England they are careful to have the oak planted around their ponds ;
and he mentions, as bearing upon this point, a fact to which I have
alreadj' referred, that the dew under some large oak trees by the side
of his bowling-green, at Croydon, is always considerable of an evening ;
but that under a witch-elm, growing by their side, the dew is almost
always absent. Observation will show whether this difference is attribu-
table to the difference in the shade afforded, or to a difference in the
quantity of moisture evaporated through the stomates of the leaves,
in accordance with what has previously been stated with regard to
the dropping from trees (ante p. 35),

Sect. II. — On the Desiccation of Ground hy Drying Winds being
Prevented hy the Shelter afforded hy CL%i.mps of Trees.

In the case of a tree by the side of a stream with the ground
between the stream and its trunk moist, while all beyond was dry, we
had an indication of the effect of a tree in preventing evaporation by
protecting the moist ground from the sun's rays, and it may be, in
part, by reflecting or confining vapour rising from the soil ; but not
less important is the influence exerted by a clump of trees in

56 EFFECTS OF FORESTS ON HUMIDITY,

preventing evaporation, by protecting moist ground from the
desiccating effect of wind.

We often hear of a drying wind ; and many may have remarked
that a clear wind does more to dry the roads in spring than does
even bright sunshine. Every clear wind is a drying wind ; it is
composed of air not surcharged with moisture ; up to the measure of
saturation eveiy particle of this air can take up and dissolve
additional moisture, and it will do so by simple contact therewith.
Were the air stagnant, evaporation might go on slowly, the air in
contact with the moisture taking up a portion of it and slowly
transferring this to the stratum above, to be in like manner trans-
ferred to the strata beyond ; but moved on, as every particle of the
air is, by and with, and in the wind, it imbibes a portion and passes
off loaded to let more follow to do the same ; and we see the effect
in the rapid drying of ground over which the wind has free course ;
while we see the effect of shelter in the continued humidity of the
ground wherever it is protected from the wind by a wall, a house, a
hedge, or a clump of trees.

To this effect of wind, and the modification of it produced by
shelter, reference is made in the before mentioned experiments and
observations made by Mr Blore.

It is stated by Mr Milne Home, chairman of the Council of the
Scottish Meteorological Society, in a paper containing suggestioais for
increasing the supply of spring-water at M;ilta, and improving the
climate of the island, to which I shall afterwards have occasion to
refer at greater length, " Halley found that, when water is kept in a
room, to which neither sun nor wind had access, the evaporation
amounted to 8 inches in a year ; but when exposed to sun and wind,
even in the cloudy atmosphere of Loudon, it amounted to 48 inches
yearly. More recent and accurate observations make the natural
evaporation from soil kept moist not quite so much. Howard of
London gives, as the mean of eight years' observations, 30 inches.
Dobson of Liverpool found, after four years' observations, a mean
annual loss by evaporation of 37 inches ; — the least evaporation
being in December, when the temperature was 44°, the greatest in
July, when the temperature was 70°. D.dton of Manchester found
that evaporation there was at the rate of 30 inches ;^the lowest
being 101 inches, in Djjember, the highest 40-9, in July.

" An instructive table was framed by Dalton, showing the number
of graius of water evaporated, from a given surface and during a

SHELTER TO WINDWARD.

17

given period, at different temperatures, and with different velocities
of wind. Tlie following extracts are made from this table : —

Temp. Fahr.

Light Wind.

Strong Wind.

50°

150

2 36

60°

2-10

3 33

75"

3 40

5 34

80"

4-0

6--^9

85"

4-68

746

The shelter from drying winds, and the consequent protection
against rapid desiccation of ground, afforded by a wood, extends far
beyond the shade of the trees ; and thus the prevention of evapora-
tion by the wind becomes, in most cases, of more importance than
the prevention of evaporation by sunshine.

Of the extent of such protection there are illustrations given by
Mr Marsh, in his treatise on the " Earth as Modified by Human
Action" (pp. 162-166). They are adduced by him in illustration of
the effects of forests on climatal temperature ; but tlje subjects are
correlated, and the statement by Mr Marsh will be afterwards given.

It is not only to leeward that the beneficial action of a forest
in giving direction to the wind is felt ; in some respects the calm it
secures to windward may be equal in importance to that which it
ensures beyond. Some years since a stage coach from the head of
Loch Long to Oban was usually driven by a coachman whose jests,
and jibes, and pleasantries, and humours, often kept the occupant of
the seat beside him, and the occupants of the seat immediately behind
in roars of laughter foi miles. It is said that on one cold windy day
he had as occupant of the box-seat a Scottish Judge, one of the
Lords of Session, who remarked in many places sheep crouchino- on
the windward side of whin bushes, and after a time, calling the atten-
tion of the coachman to the circumstance, he asked him why they did
so, " To keep them from the wind, my lord," was the respectful
reply. This oallei forth the unhappy remark. " If I were a sheep
I would lie down on the other side of the bush." When forth came
without a moment's warning the rejoinder, " Ah ! but, my lord, if you
were a sheep ye wud hae mair sense !" The sheep and the coachman
were right. The beautiful curve of a snow-wreath shows what was
the course taken by the wind in its formation and indicates the course
usually taken by it in surmounting a barrier : a long sweep on the

68 EFFECTS OF FORESTS OS HUMIDITY.

windward side, a comparatively precipitous fall to leeward. The
observatory erected by Sir Jolaii Hersohel with a view to securing
calm for the immense tube of his telescope was erected in relation to
prevalent winds to windward, not to leeward, of Table Mountain.
And a calm prevails at Herschel and Bishop's Court while the wind
is blowing strongly on the Fiats, and pouring over the front of
Table Mountain lilie an avalanche.

To some to whom the fact may be new, it may prove coiToborative
of what has been stated if I call attention to another fact, which has
been observed by others. In walking along the edge of a sea-clifF
facing the wind it has been found, when the breeze was slight or
moderate, that it was felt in full force up to the edge of the preci-
pice ; but when the breeze was strong, there was a breadth of perfect
calm along the edge of the clitf, while a little way inward the blast
was felt in all its fury, — the width of the calm being proportionate to
the force of the wiud^ the upward concave curve of the leeward current
passing into a convex curve carrying it over the head of the observer.

It is in connection with my advocacy of the conservation and
extension of forests at the Cape of Good Hope as a remedial measure
against the rfl-idity — and progressing aridity — of the soil and climate,
that I have brought this subject under consideration. I am quite
aware that an argument in favour of the cutting down of forests,
woods, and trees, as well as an argument for the conservation and
extension of them by plantation, may be founded on the fact to
which I am calling attention. It is the case that there are places
in which the one operation may be as advisable as the other may be
in others : there are countries, in which woods and moisture are both
in excess, the clearing away of forests to a certain extent is advocated
on the very ground that their effects are such as I am endeavouring
to show that they are. But this only goes to strengthen my
argument and establish the fact which I am endeavouring to ex-
pound, irrespective of the practical application of it which may be
made by myself or others : that fact is, that belts of wood, and
fences, and forests, in their several degrees, acting as windbrakes,
retard both to leeward and to windward the desiccation of ground by
the evaporation promoted by drying winds.

Sect. III. — On the General Phenomena of Evaporation from Forests.

It appears to be unquestionable that by the shade which they
occasion, and by the shelter against drying winds which they afford,

PREVALENCE OF EVAPORATION. B9

forests exercise a considerable influence in diminishing the evapora-
tion of moisture from the soil ; but, in connection with the con=
sideration of this, there should be taken into consideration the
general phenomena of evaporation from forests.

. M. Cezanne in his Suite to Etude sur les Torrents des Hantes Alpes,
by M. Surell, i-emarks that "evaporation is for modern physical science
a phenomenon comparatively simple and well understood. It is known,
for each degree of ten)perature, what is the tension and what is the
measure of saturation of tlie air. But looked at from a meteorological
point of view the phenomenon is one of the most obscure ; and the
limited number of observations which have been made cannot admit
of their being compared together.

" What, in a given place, is the depth of water which is carried off
in one hour by evaporation"? Tliis varies according as the evaporating
surface specified may be drenched or only damp, be stagnant or
running water, be in the sunshine or shade, according as it may be
summer or winter, according as the air may be saturated or not, or
be more or less saturated, and according as the air may be at the
time windy or calm.

" Two adjacent basins, placed in the same meteorological circum=
stances, evaporate unequal quantities of water if they be larger or
smaller, if their sides be more or less elevated, if they be sheltered
from the wind or not, etc.

" When it is said that the annual evaporation at Rome is 2*462
millimetres, at Marseilles 2-289, at Paris 0698, at London 0754, at
Toulouse 0-649, at Copenhagen 0209,* all that is meant to be said is
that in the circumstances in which the observers were placed they
have determined these results. But the mean annual evaporationg
furnished for each place are far from having the same scientific value
as the mean annual rainfalls, which present on the contrary a specific
character. It may always be aflSrmed with certainty that evaporation
goes on decreasing from the equator to the pole, where, however, it is
far from being nil, even in the greatest frost ;t that it is more feeble
near the coast than in the interior of a country ; aud more feeble also
under the equatorial wind from the south-east than under the polar

* Vallfes : Inondations, p. 23.

t Hayes : La Mer Uhre du Pule, p. 224. Wet linen, exposed to the air,

dried at the lowest tinjj^eiatuies ; and a eheet of ice, t-oBpended

by a thread, evaporated away by little and little.

60 EFFECTS OF FORESTS ON HUMIDITY.

wind from the north-east — the former being saturated with moisture,
while the latter has been deprived of it."*

And having stated what the eflFect of this is on the flow and
delivery of rivers, he goes on to say, — " If such be the important
part played by evaporation, it is evident that forests exercise an
appreciable influence on water-courses, according as they promote or
retard, to whatever degree it may be, evaporation. Bat in what do
they exercise this action 1 On this point the whole world seems to
be at sixes and sevens.

" Throughout all time the poets have sung of the cool shade — the
moist shade of extensive woods. A nave of verdure thrown over a
road keeps it moist, and as a consequence protects it or injures it,
according to the climate or the seasons. Tn every page of works on
forestry may be met allusions to the humidity, which is favourable
to the seedlings, and which the shade maintains.

" If any one entertain a doubt, let him follow in the suite of a
forest-guard the day after a storm of rain ; when, although the open
country and a fortiori the roads are already dry, he may procure for
himself a cold bath in penetrating into the clumps of copse-wood.
At his feet the tall herbs are little better than a stream, and on his
head every shaken branch will pour down a douche, which will make
itself be felt." And in explanation he adds in a foot-note, — " Any
one may observe that on the leaves of certain vegetables, but not of
all, the rain-drops take a spheroidal form ; in this state they resist
evaporation energetically, as one may see globular drops run about
on red-hot iron without ebullition. The foliage of other plants has
been dried for a long time, while these pearls sparkle still on the
herbs which bear them. Certain species preserve thus the rainfall
until the agitation of the leaves cause these spheroidal drops to fall."
And he goes on to say, " It seems then natural to believe that forests
oppose themselves to evaporation, and, consequently, acquire for the
ground the product of the rain. But objections are not awanting.

" Attention is called to the circumstance that the foliage of trees
arrests a notable portion of the water falling as rain. When a light
rain-storm follows some days of dry weather, it may be seen that each
tree casts a dry shadow, which on the wet ground of the road is
marked out by a dust-covered patch. The water arrested by the
leaves is lost to the ground underneath ; the tree or the air will
absorb it, and the importance of this is such as is not to be
overlooked.

* Schmit : Qrundriss der Meteorologie,

EXPERIMENTS ON EVAPORATION. 6^;

"The Mardchal Vaillaut has frequently drawn publio attention
to forest hydrology. He instituted experiments to measure the
quantity of rain which is arrested by the foliage of trees ; and the
following are some of the results he obtained ; the observations were
made in the forest of Fontainebleau, during the year 1866 : — *_

QUANTITY OP RAINFALL.
Months. In open air. Sfo'lar&th. P-PO'^on,

millimetres. mm. mm.

January, 35 24.5 or -70

February...... 78-5 63 -81

March, 808 582 -72

April, 67 50.9 -76

May, 46-2 31-5 -68

June, 66 32 -48

July, 105 8 53-8 -50

August, 117 60 -51

September, 1235 65 -51

October, 31 142 -45

November, 47-5 29 ..,-62

December, 61-2 435 -70

859-5 524-7 0-60

" From this it is seen that the leaves arrested in winter 30 %, in
summer 50%, and, on an average, throughout the year 40% of the
rain which fell.

" Under the Epicdas [Picea excelsa, Linh'\ of 35 years' growth,
probably in dense clumps, the pluviom^tre received only 21% of the
years' rain-fall : the tree arrested 79 %. In a forest adjacent to
Versailles, the pluviom^tre, placed under a leafy wood, received 80%
of the year's rain : the foliage arrested only 20%. Under a timber
forest of oaks, of from 70 to 100 years of age, the instrument
received 85% of the year's rain.

" Perhaps there may be ground for some little discussion in regard
to these experiments : the position in which the pluviometre mi'>ht
have a marked influence on the results. Two instruments placed
under an umbiella, one towards the centre, the other at the circum-
ference, under the droppings of the ribs, would give a bad measure-
ment of the mean fall of water on the soil.

* jRewte des Eaux et Fonts. 1867. P. 161.

62 EFFECTS OF FORESTS ON HUMtDlTT.

**M. Mathieu, sub-director of the Forest School, has uniertaksa a
series of experiments under vsry favourable conditious. Of these the
foUowia^ is one wbioh is pirtioularly intorostia^, and one, the results
obtained by which scarcely agree with those of Mirshal Vaillaut.
Two udom^tres were placed at the forest statiou of Ouiq-TranchSes,
the one in the open wood, under a patch of beeches and hornbeims,
of average denseness, and of the age of 42 years ; the other, at a
little distauce, iu the middle of an opea space many hectares ia
extent. It may be well to note tliat the forest udom^tre is of special
construction; that the receiver embraces the stem of one of the
perches of the clump, and presents a surface quite equal to the
projectioa of the top of the tree ; tliat by this means the indications
of the instrument are quite exact, and represent well, without
exaggeration or diminution, the depth of tlie sheet of water received
by the wooded ground ; and that this water, dropping from leaf to
leaf, passes through them, or flows down the trunk.

" Under these conditions the udomHregave, in 1853, the following
quantities of rain : —

MEASUREMENT OF RAIN.
Monthg. Under wood. Outside wood. Proportion.

miliim^tres. mm. mm.

January, 68 73 0-931

February, 37 36 1-025

March, 50 50 1

April, 69 73 -945

May, 8 8 1

June, 48 52 -923

July, 31 34 -911

August, 26..... 37 -702

September, 59 61 -962

October, 118 122 -967

November, 26 28 -928

December, 163 174 -936

Total, 703 749 -939

" It may be astonishing to see in the table that during the months
of February, March, and May the sheltered pluviomfetre received as
much or more rain than the pluviomatre in the open space ; it is
necessary to consider that, either through some caprice of the rain,
or by some such effect of the trees, there fell more water in the wood
than in the adjacent open space. This result, moreover, might

PROPORTION OF EVAPORATION, 63

explain itself quite naturally, and without calling in any special
action of vegetation, if the open space were less accessible to the
rainy wind than was the wooded clump.

" It is worthy of remark that the mean proportion between the
two instruments, which was 0-939 far 1868, had been 0-938 for 1867,
and 0'952 for 1866 ; that is to say, that the proportion varied very
little."

Along with the allowance, which it may be deemed necessary to
make for the quantity of rain which may be arrested by the foliage
and evaporated thence v^ithout reaching the ground, in a rough
estimate of the benefit which trees may bring to the soil by
preventing evaporation thence, it may be deemed necessary to make
some allowance in certain circumstances for the evaporation, through
the stomates of the leaves, of moisture which is dissipated in the
atmosphere, if this be in excess of the difference between what is
evaporated from the soil under the shade and shelter of the wood and
what is evaporated from adjacent open country.

I am disposed to question whether such a case be of frequent
occurrence, or if it be likely to occur at all, but the possibility of its
occurrence must not be ignored. I cannot do more than refer to it
to show that it is not ignored by me.

In a preceding section I have referred to the observations of Mr
Blore on evaporation, under shade and shelter, and in open ground,
at the Cape of Good Hope ; and in connection with a notice of these
observations I had occasion to cite some experiments on evaporation
made by M. Mathieu. A report of these was published by the
French Government in the " Atlas Meteorologique de V Ohservatoire
Imperial, 1867," from which it appears that, during the seven months
comprised between April and October in that year, whilst the
quantity of water evaporated from forest leaves was 3.23 inches, the
quantity evaporated from land clear of forest was 16.29 inches, or
about five times as much.

In April, bafore the development of leaves, if 1,000 represented the
evaporation from the open country, 623 represented the evaporation
from woodland ; but after the trees became clothed with foliage the
amount of evaporation from the woodland was only 130, as against
1,000 of open country evaporation. In October the woodland evapora-
tion was to the open country evaporation as 90 to 100.
The experiments were continued in 1868.

64 EFFECTS OP FORESTS ON HUMIDITY.

At the station of Belle-Fontaine, M. Mathieu measui'ed the evapora-
tion by means of vessels exactly comparable placed outside of a wood,
and under a leafy wood. During the months of January and February
no observations could be made on account of the frost. Bat in the
subsequent months the following results were obtained : —

WATER EVAPORATED.
Months. Outside tlie wood. Under the wood. Proportion,

miUimUres. mm. mm.

March, 33 9 3.66

April, 50 19 .2.63

May, 105 23 4.56

June, 107 19 5.63

July, 95 10 9.50

August, 75 8 9.37

September, 55 11 5.

October, 12 3 4.

November, 2 0 9.

December, 8 4 2.

Totals, 542 106 5-11

From this it is seen that during ten months in 1868 the evapora-
tion was more than five times greater in the open space than it was
in the forest, which consists of high perches, dense and close, of horn-
beams, beeches, oaks, and ashes of sixty-two years' growth.

There are cited by Marsh some valuable observations by Risler on
the evaporation from cultivated soils and the exhalation and exuda-
tion of humidity by field plants and forest trees, given in the Archives
des Sciences ( JbiUiotheque universdLe de Geneve) for Sept. 15, 1869 ;
March 25, 1870; and Nov. 15, 1871, which seem to lead to this
general conclusion, that forests evaporate less than an equal extent of
pasturage, and that if we suppose a mean precipitation of two and a
half millimetres per day, of which two millimetres penetrate into the
soil, the forest takes up less than one half of this supply, the re-
mainder descending into the sub-soil and percolating through earth
and rock until it issues in the form of springs. He found an evapora-
tion of one aud one tenth millimetre per day to be the maximum from
a forest of firs under exceptionally favourable conditions of a fertile
and humid soil and abundance of sunlight.

Risler, in the experiments referred to found that in 1867, not ftir
from Geneva, no water escaped from a parcel of ground thoroughly

MOISTURE ATTRACTED BY MOULD, 65

underdrained at the depth of 1"^ ,20, iu the mouths of July, August,
September, November and December, and but a very trifling quantity
in June and October ; in 1868, very little in May and September and
none in June, July and August, In 1867 the total precipitation was
1066.84 millimetres ; the evaporation, as measured by the difference
between rain-fall and drainage, 733.44 millimetres ; in 1868, these
quantities were 1032.86 and 755,74 millimetres respectively.

M. C6zanne remarks in regard to all the observations cited by him,
— " In conclusion, and with every allowance for the small quantity of
water which is retained by the leaves, the foregoing observations
strengthen the conclusion that, under the same measure of rain-fall,
the soil of the forest receives and retains notably more water than
does uncovered ground.

Sect, IV, — On Moisture being Attracted from the Atmosphere, or other-
ivise retained in the Ground hy Vegetable Mould.

The meteorological effects of forests are, as has been intimated,
somewhat complicated, and the student of these availing himself of
my guidance may be beginning to perceive something of the compli-
cation in which they are involved ; but thus far the unravelling of
different strands has been found to be practicable, and this operation
may be carried a little further without difficulty.

A distinction has been drawn between the effects produced on the
ground by the shade from sunshine, and by the shelter from drying
winds afforded by trees and forests. It is necessary, further, to
distinguish between the effects produced by shade and by vegetable
mould, which exists always, in greater or less quantity, in forest soil,
in consequence of the decay and decomposition of fallen leaves and
and fallen twigs, and broken or decaying rootlets.

In the soil of a forest there generally exists more moisture than
can be attributed to shade, or to shade and shelter combined ; and
much of this is attributable to the attraction of moisture manifested
by this vegetable mould.

By a series of simple experiments this fact may be demonstrated,
the quantity of moisture determined, and the proportion attributable
to each of the effects mentioned approximately ascertained.

Take the weight of a hundred grains or of a hundred drams, or the
weight of a hundred shot of uniform size, of the apparently dry soil

68 EFFECTS OF FORESTS ON HUMmWY.

of ft forest, sheltered and shaded by the trees, and expose it for some
hours to the bright sunshine ; after this weigh it, and most probably
it will be found to have lost weight. This loss will have been
occasioned by the sunshine and open air having caused an evapora-
tion of moisture from the soil, though it appeared to be dry, and the
quantity of moisture so evaporated may be determined by the
weight lost.

Take again the same weight of such forest soil, so dried in the air
and sunshine, and of such dry gravelly sandy soil as you may find on
the road, similarly exposed to the drying influences of the air and sun-
shine ; expose them together on papers for an hour in an oven heated
to such a degree that the papers will be browned, but not burned ;
weigh them again, and probably both will be found to have lost
weight, but the loss of weight sustained by the soil taken from the
forest will probably greatly exceed the loss of weight sustained by
the soil taken from the open field. The loss of weight is occasioned
in this experiment, as in the first, by loss of moisture contained in
the soil, notwithstanding that this was sun-baked and apparently dry.

Had the papers been burned there might also have been burned
organic, vegetable, or animal remains in the soil, occasioning a
loss of weight in addition to that occasioned solely by the loss of
moisture, for which allowance must have been made ;■ but this has
been avoided by the precaution adopted. And the heat prescribed
was to be such as would brown the paper without burning it, to
secure as great a heat as possible short of what would have done
more than merely drive off the moisture contained in the soil. And
if the loss of weight sustained by the soil from the forest so exposed
be in excess of that sustained by the soil taken from the road, this
indicates that it, when apparently dry, contained more moisture than
did that other, which excess was attributable to moisture held fast
by products of vegetable decomposition in the soil.

But this is not all. If equal portions of the two parcels of
thoroughly desiccated soil be spread out on glass, and exposed for a
day or two to the atmosphere, protected from rain or dew (within
doors or without, in a dry room or in a cellar), and these be then
again weighed, they will be found to have gained weight, but in
different degrees, much more having been gained by the forest soil
than by the sandy gravelly soil of the road. This will be done by
their imbibing moisture from the atmosphere, dry as that atmosphere
seemed to be ; and the proof is forthcoming : expose them again in
an oven as before, and the weight gained will again be lost.

PHENOUBNA OF DBLIQUESOBNOS. 67

In this eflfect of vegetable mould we see how forests may
exercise a third influence, over and above and distinct from both
shade and shelter, in maintaining a humidity of soil.

This matter may deserve a little further consideration.

In treating of Rehoisement in France, I had occasion (p. 95) to cite
certain experiments made by Thurmann, made with a view to ascertain
to what extent different minerals could absorb and retain moisture,
and to state results obtained by him showing that cubes of diflFerent
minerals thoroughly dried, weighing each 100 grammes, immersed in
water for five minutes, varied in the quantities absoi-bed by them
from half-a-gramme to from 10 to 30 grammes.

These results have been considered indicative of the absorption of
water being proportional to the state of molecular sub-division of the
material comprising the rock, and they have been resolved into dis-
tinct phenomena — hydroscopicity and capillarity : the former, the
power of each molecule of the rock to retain around it a layer of
moisture difficult to withdraw ; the latter, the power of structures of
molecules of earth to retain in interstices by which they are separated
small globules of water. And thus may the results obtained by the
first-mentioned experiments be accounted for. They indicate greater
hydroscopicity and capillarity to be possessed by the soil of the forest
than is possessed by gravelly and sandy soil of the road — this being,
as may afterwards be proved, an eflfect or consequence of forest pro-
ducts embodied in that soil.

But besides substances which manifest capillarity and hydroscopicity
there are substances which attract and abstract moisture from the
air, some of them doing so to such an extent that they deliquesce or
dissolve in their own brine ; and unless the air be kept excluded from
them, or they be kept in a warm place, where the heat will either
keep the air comparatively diy, or evaporate the moisture attracted
and absorbed by them, you cannot keep them dry. This is signally
the case with the carbonate of potash — the potash of commerce ; it
is manifestly the case with chloride of sodium, or table salt ; it is
also the case, though less manifestly so, with clay ; and to a very
marked degree is it the case with humus, the product of the decay
and decomposition of vegetable matter, and une which abounds in
forest soil from the fall of leaves and twigs.

To this humus mainly may be attributed the great attraction of
the forest soil for moisture, indicated by the gain of weight when,
after being thoroughly desiccated, it is exposed to a dry atmosphere ;

68 EFFECTS OF FORESTS ON HUMIDITY.

and to the great quantity of humus in that soil, the excess of the
quantity of moisture absorbed from the atmosphere over the quantity
absorbed by the dry gravelly sandy soil taken from the road.

The quantities of humus and the quantities of clay, which exercise
similar power, though not to the same degree, in each of the parcels,
can easily be determined.

It may be noted that what is now spoken of is not the deposit of
dew, which depends on a reduction of temperature.

Wherever the difference of temperature between day and night is
great, and the atmosphere is heavily charged with moisture, the
deposit of dew is considerable. In England, Luke Howard, with a
well-constructed rain gauge, found the deposit of dew in one night
towards the end of September equal to "Ol inch of water; and in
the last six days of October he obtained •!! of an inch from copious
dews and mists.

In Algeria, at the stations on the coast, writes Steinmitz, in a
little volume entitled " Sunshine and Showers," after the driest and
hottest days, immediately the sun has set, the soldiers' uniforms
become wet with dew, and in a single night the blades of knives in
the pocket become rusted.

But apart from this deposit of dew, moisture is absorbed from the
atmosphere by the soil. The driest soils contain 13% of moisture.
It has been determined by experiments by Schubler that when a
soil, which weighs about 1000 tons per acre, is pulverised so as to be
freely permeable by the atmosphere, and is exposed to the air after
being thoroughly dried, it will absorb in twenty-four hours, if a sandy
clay, what is equal to 26 tons of water; if a loamy-clay, 30 ; if a stiff
clay, 36 ; if garden mould, 45.

Cezanne states that, '•' In the Roussillon, rain is a rarity ; the in-
habitants can recall periods extending over a year without notable rain;
and that the littoral hillocks behind the buttresses of the Pyrenees
are of a very permeable limestone, but the vine flourishes in this
region, the leaves cover the rocks with verdure, and the grapes swell
with a savoury juice, while along the dusty roads the grasshopper
follows the traveller with its cry, the emblem of aridity and drought.

"It is certainly not from the soil devoid of humidity that the vine
driuks its supply, it is from the atmosphere ; and the vine-growers
do not deceive themselves — it is not for rain that they look, they
know that hope of this would be vain — they cry for the sea breeze,
which will perfectly satisfy them.

MEASURE OP MOISTURE IN SOIL. 69

" On the other hand, in the palus of Bordeaux, the vine is seen
growing, so to speak, with its feet in the water.

" It is then probable that vegetables, or at least some of them, are
endowed with an eclectic power ; they take water where they find it,
they distil away subterranean water when it is in excess, and they
know also how to condense and absorb water from the atmosphere."

I accept the facts, but demur to the reasoning. I think all can be
otherwise accounted for. M. Cezanne cites in a foot-note, in illustration,
the description given by Mr Thomas Baiues of the Markivhoe, a large
watery root, measuring in its greatest circumference 40 inches and
in its smallest 30, with the statement of Mr Baines that when he and
his party, travelling in an arid district of South Africa, felt thirsty the
Bushmen would pull up some of those roots, and by eating of them they
would quench their thirst. I have heard of several different kinds of
such juicy plants growing in the most arid districts of South Africa ;
but never have I heard anything in regard to their natural history,
or their structure, which would warrant the conjecture advanced ;
while the proved afl&nity of soil for moisture supplies a satisfactory
explanation of all the phenomena referred to.

From experiment and observation it has been deduced that pure
sand has little affinity for moisture ; but that such afiinity is
manifested both by clay and by humus in a high degree, and to
these conjointly may be attributed the attractive affinity of the soils
for moisture, indicated by the gain of weight in the second set of
experiments, when the desiccated soils were exposed for a long time
to the air.

To this affinity of soil for moisture attention is given in analyses
of soil in agricultural chemistry. It is in generaV inversely propor-
tionate to the proportion of sand, and directly proportionate to the
quantity of clay in the composition of soil taken from the open country,
in which these constituents greatly preponderate ; but it is also
proportionate in a much higher ration to the quantity of humus in
the soil, and the quantity of this can easily be determined.

If the two parcels of earth last referred to as subjects of experiment
be raised to a red heat in iron spoons, and after all appearance of
brighter incandesence in portions of the mass has ceased, they be
weighed, care being taken to remove all scales of iron or of iron rust,
they will again be found to have sustained a loss of weight ; this is
attributable to the combustion of organic matter, most of which was
humus, or capable of becoming humus, and the loss sustained by the
forest soil will be found much greater than the loss sustained by the

70 EFFECTS OF FORESTS ON HUMIDITT.

other. In the case supposed, the affinity for moisture will be found
to be proportionate to the different results ; but it may be modified
by the proportions of clay, if in either this be greatly in excess — and
this also can easily be determined.

If the two parcels of soil be next drenched with hot water, and this
poured off when discoloured with the muddy matter suspended in it,
and the process be repeated until the water comes off limpid, upon their
being again desiccated in an oven, as before, and weighed, the loss
they have sustained in weight will indicate the quantity of clay which
was in their composition, together with free soluble salts, the quantity
of which may be little or may be much. Thus will have been re-
moved all the materials manifesting a marked affinity for atmospheric
moisture; and in few cases, if any, the results greatly modify the con-
clusion arrived at by the removal of the humus and its constituents.

I prescribe not these proceedings as certain to give precise results,
in absolute accordance with the actual constitution of the soils made
the subject of expei'iment, but as rough and ready experiments which
may be made by the inexperienced, the results of which will indicate,
and to some extent measure, the property of forest soil not only to
retain moisture, but to attract moisture from the atmosphere in a
superior degree to that in which such property is possessed by the
gravelly and sandy soil taken from the highway.

Should any one desire more accurate results, the following course
of procedure may be followed : —

1. Ascertain the quantity of moisture in the apparently dry soil
by the mode of desiccation described, weighing the soil before and
after the operation.

2. Ascertain the affinity for moisture by lengthened exposure of
the desiccated soil to the air anywhere, and subsequently weighing
it to learn what it has gained.

3. Ascertain the quantity of organic matter in the soil by heating it
to incandescence as directed, but doing this in a plantinum crucible,
previou&ly desiccating it as before, and weighing it before and after
this third operation.

4. Drench it with spirit of salt, muriatic acid, or hydrochloric acid,
as it is now generally designated, adding soft water, and continuing
the operation till all effervescence has ceased. Drench it then with
water ; let it settle ; pour ofi" the water when limpid ; desiccate as at
first, and weigh : and the loss of weight will then indicate the
quantity of lime which was in the soil.

DECOMPOSITION OF HUMUS. 71

6. Ascertain the quantity of clay by the operation described.

6. By sifting the residuum through a piece of fine muslin, the sand
may be separated from the gravel, and the quantity of each deter-
mined by weighing them apart.

A comparison of the results will show the difference in the com-
position of the two soils — and in none of the constituents will the
difference be more marked than in the organic constituents and in
the sand and gravel ; the former, composed mainly of humus or the
constituents of humus, having a great affinity for moisture, being
greatly in excess in the forest soil, and the latter, having little or no
affinity for moisture, being almost awanting.

This humus is a product of vegetation, inasmuch as it is a result
of the decay and decomposition of vegetable products ; and it is not
only not decreased but it is constantly being increased by vegetation.
Under no crop is this more manifestly the case than under a crop of
deciduous trees. For this the annual fall of the leaves enables us
without difficulty to account. The shelter afforded by a wood pre-
vents both the fallen leaves, and the dust to which they may be
reduced, from being borne away by the wind, and the shade prevents
the humus from being so decomposed as to be carried off by the air.

With the smaller quantity of humus in the soil not protected by
shelter and shade, it is otherwise. What there occurs is thus stated
in a paper I had occasion to cite in treating of the effect of de-
nudation of the country on the hydroscopicity of the soil,* a paper
on the philosophy of arboriculture, by the Rev. Dr Macvicar, of
Moffat, who was the iirst editor of the Quarterly Journal of Agri-
cidture, issued by the Highland and Agricultui-al Society of Scotland,
and who subsequently resided in Ceylon, where he had opportunities
for prosecuting researches upon which he had previously entered.
The writer remarks, in regard to effects following the destruction of
forests, — " The soil when stript of the clothing which the forest
afforded, and exposed naked to the heat of the sunbeam, changes very
rapidly from the rich mould which the long-continued fall of the leaf
in the forest had made it, and becomes very unproductive. Had
occasional trees in the forest been left to give shade during part of
the day, the destination of the carbon in the mould would have been
to have been slowly converted into carbonic acid, and so to supply
food to the successive crops growing on the soil, as they required it.
But when the sunbeam is left to break in its fall force on the soil all

• " Hydrology of South Africa " (p. 213).

72 EFFECTS OF FORESTS ON nUMIDITY.

day long, it burns the carbon in the soil with great rapidity into
carbonic acid ; and this gas, unless there be in the soil some oxide
having an affinity to it to retain it, goes off in gas, injuring the
salubrity of the air perhaps, and at all events wholly impoverishing
the soil, — for carbonic acid is the principal food of all plants. The
same course of things it might be shown happens with regard to
ammonia ; and thus, both as itself the immediate food of plants and
as that which by oxidation yields nitre, ammonia is lost. Thus the
indiscriminate destruction of forest over any great breadth of country,
if that country has plenty of sunshine, is a great evil."

In correspondence with Dr Macvicar on the subject, he wrote to me,
— " As to the point to which you refer — the rapid generation in the
soil, and the vaporization from it of ammonia and carbonic acid,
under the impact of the tropical sunbeams and breezes — I do not
remember to have seen it dwelt upon by any writer, though both in
the writings of Boussingault and of Liebig it is implied ; and it is an
inevitable consequence of the eremacausis, or the slow combustion of
organic matter. It is familiarly verified by the process of bleaching.
Even with such sunshine as we have in this country the organic
matter which imparts colour to tissues is carried off much more
rapidly in the sunshine than out of it ; and it can only be carried off
as carbonic acid and ammonia : that is, it is not merely changed from
coloured to colourless, as is proved by the loss of weight which the
web has sustained when it is bleached. In this country we have
generally less sunshine than we require, and, except in fallows, the
surface of the soil is never left bare. Hence the effect of the impact
of the sunbeam has been but little considered. But from what I
have observed in the tropics, I am persuaded that its power of
affecting plant food in the neighbourhood, by the destruction of the
fertility of every surface that is left bare, is very great. It intensifies
to a wonderful extent that action of the incumbent atmosphere by
which the carbon and hydrogen in the soil unite with the oxygen and
nitrogen of the air, and give moisture, carbonic acid, and ammonia
almost immediately after, if they be not utilized on the spot where
they are generated, dispersing all but that quantum which the soil
can retain at a temperature of perhaps 140° or 150° F., which is
not much."

CHAPTER III.

Effects of Forests on Marshes.

In studying the effects of forests on marshes there come uuder con-
sideration the drying up of marshes by the growth of forests, the
occasonal appearance of marshes on the destruction of forests, and
also the occasional destruction of forests by the ci'eation of marshes.

The combined consideration of all of these phenomena may be
necessary to a satisfactory view of the first ; but this is susceptible
of satisfactory explanation by itself, and the second may be con-
sidered to be confirmatory of the first, and the third not otherwise
than accordant therewith.

And by the consideration of these several phases of the correlation
of forests and marshes, we may be prepared for the consideration of
the effect of forests, in drying up marshes upon a grand scale through
protracted ages, in rendering what was a marshy land so dry as to be-
come a fit habitation for man, of which Denmark supplies an illus-
tration.

Sect. I. — On the Drying up of Marshes on the Growth of Trees.

We have latterly been considering the effect of arborescent vegeta-
tion in preserving the humidity of the soil ; but we had previously
been considering the effects of forests in increasing the humidity of
the atmosphere ; and previously to that we had under consideration
the phenomena of vegetation on which meteorological effects of forests
affecting humidity of soil and atmosphere depend : moisture being
withdrawn from the soil by the spongioles of the root, trausmitted by
the trunk to the branches and passed off into the atmosphere by the
stomates of the leaves.

It may seem paradoxical to speak of forests both drying up marshes
and keeping the soil moist ; but it is not more so than to speak of a
man blowing both hot and cold. There is a great difference between
moist soil and marsh. All moisture in excess of what can be retained
by shelter and shade and humus in the soil is free to be otherwise

74 EFFECTS OP FORESTS ON MARSHES.

disposed of, and the effect of forests in drying up marshes, viewed ai
an isolated fact, may be proved as satisfactorily as any of the eflfects
of forests which have been under consideration.

I have already alluded to this effect in stating that the allegation
of the South African farmer, that the trees stole the water from the
water leadings, by the sides of which they were planted, was not
altogether without foundation, though the phenomenon on which his
opinion was founded was one which did not prove this, but proved
something very different.

We have had under consideration the fact that very extensive pro-
vision has been made for the evaporation of water from the leaves of
trees : in the case of one tree, the Lilac, so many as 160 thousand
stomates being found on every square inch of the under surface of
the leaf. Whence is the moisture to be so evaporated obtained]
Mainly and almost exclusively, if not entirely so, from the ground.
It seems to follow that what the atmosphere thus gains the earth
must first lose, even though a portion of it may be subsequently
restored. And the quantity thus raised from the ground and given
forth to the atmosphere is very great.

Mr Marsh, whom I have already quoted elsewhere, states : — " The
present estimates of some eminent vegetable physiologists in regard
to the quantity of aqueous vapour exhaled by trees and taken up by
the atmosphere are much greater than those of former inquirers.
Direct and satisfactory experiments on this point are wanting, and it
is not easy to imagine how they could be made on a sufficiently
extensive and comprehensive scale. Our conclusions must therefore
be drawn from observations on small plants, or separate branches of
trees, and of course are subject to much uncertainty. Nevertheless,
Schleiden, arguing from such analogies, comes to the surprising result
that a wood evaporates ten times as much water as it receives from
atmospheric precipitation. In the Northern and Eastern States of
the Union [America] the mean precipitation during the period of
forest growth — that is, from the swelling of the buds in spring to
the ripening of the fruit, the hardening of the young shrubs, and the
full perfection of the other annual products of the tree — exceeds, on
the average, 24 inches. Taking this estimate, the evaporation from
the forest would be equal to a precipitation of 240 inches, or very
nearly 150 standard gallons, to the square foot of surface."

Startled by this, he questions the correctness of the conclusion at
which Schleiden had arrived ; but he states in a foot-note : — " Pfaff,
too, experimenting on branches of a living oak, weighed immediately

EXHALATION OP MOISTURE. 75

after being cut from the tree, and again after an exposure after three
minutes, and computing the superficial measure of all the leaves of
the tree, concludes that an oak tree evaporates, during the season of
growth, eight and a-half times the mean amount of rainfall on an
area equal to that shaded by the tree." Corresponding observations
made by others are not awanting.

Marshal Vaillant writes : — " Even the most humble plants, such as
chickweeds and meadow grasses, evaporate considerable quantities
of water. Independently of all the other actions, which ought not
to be overlooked, this is the chief cause why the abundant summer
rains make so little impression on our rivers. This is why the
gardener uses the hoe so carefully, and why he removes all weeds
which would exhaust the moisture of the soil.

" The intelligent gardener is not deceived, he knows that if any
weed has long numerous roots, like the triticum repens (couch grass),
they do more harm than others, because by spreading to a distance
they deprive a larger extent of ground of its share of moisture. This
is why a paillis, although on account of its dark colour it becomes
sooner warm than turf or other grass plants, does so much good to
cultivated vegetables, by not depriving their roots of moisture.

" The quantity of water exuded by rapidly-growing plants is far
greater than could be supposed possible by people who have not made
direct experiments ; it is especially plants of soft texture with hollow
stems that excite our surprise. A branch of helianthns annuus (a
sunflower), placed in a caraffe full of water, and exposed to the sun,
exhausts the water very rapidly; thus this plant, with its far-
spreading roots, is a very dangerous neighbour to others, and we may
be thankful that the passage of water into the roots does not go on so
quickly as the evaporation by its leaves, otherwise the exhaustion
caused would be much greater than it really is. It is this difference
between the quantity of water transmitted from the soil to the roots,
and from the leaves to the air, that causes the latter to wither in warm
weather. Rain does not penetrate the leaves, but only diminishes
their evaporation, so that an equilibrium is re-established.

" If from herbaceous plants or modest shrubs we turn to our large
forest trees, we may expect that, compared with the weeds of which
we have just spoken, they will transpire a great quantity of water,
which is probably in proportion to the number of leaves and their
extent of surface ; and it is our belief that this summer function of
the leaves is carried on by the trunk and branches during the whole

76 EFFECTS OF FORESTS ON MARSHES.

year. Of the energy and rapidity with which water ascends through
the trunk of a tree, the operation called houcherie, for the preservation
of timber, aifords a remarkable example. In a very short time a
poisonous liquid is transmitted from the base of the trunk to the ex-
tremity of the branches.

"From whence comes the water so rapidly transpired by the
foliage 1 Certainly from the soil ; and as the roots of these vegetable
giants penetrate far — as some say, in some cases, to the same extent
as the branches — it is easy to understand how the ground becomes
dried up and incapable of supplying nourishment to plants of smaller
growth.

" It is therefore impossible for anything to thrive close to, or even
at a considerable distance from, the root of a tree. It is not only the
shade and the want of rain that hinders growth : indeed, plants at
some distance from a large tree are as much shaded as are those
close beside it, and the rain, which seldoms descends vertically,
always moistens such plants more or less, they are also refreshed by
the dew, and, nevertheless, they die or languish. It is because they
grow in a soil which is always dry and deprived of nourishing power.
Certainly the invitation addressed by the oak to the reed in the fable
bespeaks a good disposition ; but had it been accepted the poor reed
would soon have died of thirst. Its tall and powerful protector
would soon have dried up the damp borders of the kingdom of the
wind, which nature has appointed as the habitation of reeds.

" Whoever has uprooted old trees must have remarked to what a
great depth the earth around the roots is exhausted and dried up.
This state of things can be easily acounted for, after the particulars
of the following experiment may have been read.

" We placed in a large jug of water, as tightly closed up as possible
so as to hinder the effect of natural evaporation, the end of an oak
brancii, 1™ 40 centimetres [nearly 5 feet] long, and 4 centimetres
[nearly 2 inches] in circumference at its lower extremity. The
branch was cut off from a tree about 25^" [upwards of 80 feet] high,
add 2™ 63 centimetres [about 9 feet] in circumference at 1°^ [40 inches]
from the ground

After tvrenty-four hours' exposure in the open air at a temperature
of 15° 7" [60° Fahr.] at the minimum, and 25° 7' [77° Fahr.] at the
maximum, the water in the vase diminished 510 grammes [18 oz.].
The sun was shining brightly. In forty-eight hours from the be-
ginning of the experiment the water in the jug had again lost 300
grammes [10| oz.] of its weight. The sun had been very warm, the

EXHALATION FROM LEAVES. 77

thermometer having risen to a maximum of 27° 7" [82° Fahr,], the
minimum having been only 10° 7* [57° Fahr.] ; the wind on this day
and the preceding had been from the north or north-east. Seventy-
two hoin*s after the introduction of the oak branch into the water the
vase had again lost 140 grammes [5 oz.] of its weight. The weather
had been as lovely as the day before, the minimum of the temperature
having been at 12° 5" [54°] and the maximum 25'' [77°]. Thus the
■weight of water evaporated by the branch was, at the end of the first
day, 510 grammes, at the the end of the second, 810, and at the end of
the third, 950 [30 ounces]. The experiment was not cai-ried further.
In the first place, because several of the leaves were withered and
incapable of performing their functions ; secondly, because the water
in the jug was beginning to be affected by being mixed with the sub-
stances which always are deposited by plants when placed in water.

" If we believe that all the leafy parts of a tree will act, as regards
the faculty of transpiration, like the leaves of the above-mentioned
branch : in other words, if we suppose that the quantities of water
expired by the entire tree were in like proportion, we arrive at the
astounding result that an oak like the one described will, in a summer
day, cause the evaporation of more than 2000 killogrammes of water,
more than two cubic metres, [or 440 gallons].

" We are not decided in regard to the value of our experiment, and
we see very weU that our deductions are not free from objections ; but
it must be allowed that supposing that every one-half or one-quarter
of the estimated quantity be omitted, the quantity must greatly
exceed what might have been expected

" A forest should produce on the soil which it covers the effect of
a large umbrella pierced in many places, it may be, but, nevertheless,
arresting and imbibing a certain quantity of rain, of which it deprives
the neighbouring soil. So long as the leaves are imperfectly soaked,
no moisture reaches the ground ; and it can be easily imagined that
a moderate continuous rain would be entirely absorbed by natural
evaporation, and in effect the humidity of the air, even in damp
weather, never reaches the maximum of the hygrometer in the lower
atmospherical strata, and evaporation is never entirely suspended.

" If we further add to these causes of exhaustion that there is little
dew deposited under trees, it can be believed that the ground of a
forest is less favoured as regards the quantity of moisture received
from the heavens than that which is exposed to the open sky.

" And, nevertheless, it is an accepted fact, and that not without
good reason, that the neighbourhood of forests is cold and damp.

78 EFFECTS OF F0BREST3 ON MABSHE8.

This is far from astonisbing when one thinks of the enormous volume
of water transformed by forests into vapour, and the quantity of heat
absorbed in this transformation. This heat must have been obtained
somewhere — perhaps from the soil of the forest and that of the
neighbourhood.

** In the same way, there should be great damp in the neighbour-
hood of forests, especially when the temperature is high, and it
cannot be otherwise on account of the enormous amount of water in
the form of vapour which is discharged by forests into the adjacent
atmosphere.

" This vapour is emitted in much greater abundance during the
day than during the night. Towards night, a little after sunset,
when the general temperature begins to fall, the transpiration not
yet having had time to slacken, and ascending into a colder air,
changes into visible fog, like our own breath in like circumstances
and this fog in its turn becomes a cloud on the following morning,
when the sun warms its particles ; but whether clouds or fogs they
will be cai-ried away by the first breeze, to descend in showers far
from the place of their birth.

" It is evident that the rain of these showers, pumped up, in the
first place, by the tree-roots from the forest soil, if it be sometimes
restored to this soil it is only in part ; so that even in this respect we
can assert that, with regard to water, forests place the soil in a much
worse position than a crop of cereals.

" If these details as to the formation of forest-fogs be correct, such
fogs should be more frequent in calm weather, when the air is
naturally more moist, and especially when the contrast is greatest
between the cool of the evening and the heat of the day. The test
of conditions for the formation of thick forest-fogs is especially com-
plete, at least in our climate, towards the end of summer and the
first half of autumn ; and it is during this period that the phenomenon
is most frequent and noticeable.

" If the transpiration carried on by the leaves were coloured and
perceptible, it would be a grand sight to see great columns of vapour
ascending majestically into the air, diminishing by their height the
distance between the tops of the trees and the stormy clouds ; and as
this vapour facilitates the passage of electricity, by inci'easing the
moisture of the air with which it mingles, the frequency with which
isolated trees are struck with lightning can be accounted for. Per-
haps, also, if attention were turned to this point, the reason would be
discovered why so many people, taking shelter under trees, are struck

EXHALATION FROM LEAVES. 79

by lightning. It is difficult to refuse to believe that these people
were not more exposed to danger in such a situation than if they had
remained in the open field."

These statements I give as the views advanced by Marshal Vaillant.
There are points on which my own views are somewhat different; but
with regard to the grand fact, that the emission of moisture by the
leaves of the forest is very great, we are at one.

With what is known of the affinity of humus and of clay for mois-
ture, it may be considered probable that not a little of the moisture
evaporated by the stomates may be re-absorbed by the soil, though
never precipitated as rain. But even supposing that this should have
happened, not once, but times innumerable in the course of a specified
period — and thus much of the moisture evaporated should be sub-
stantially the same moisture, passing again and again and again
through the circuit, evaporated, passed through the stomates, ab-
sorbed by the air, thence absorbed by the soil, and thence absorbed
by the rootlets to be passed on by endosmosic action again to the
leaves, to go through the same round again and yet again — it is not
unreasonable to suppose that a large portion, a very large portion,
must be taken from the soil.

The experiments founded on by Pfaff, like that of Marshal Vaillant's,
give the result of evaporation which could not have been sustained in
this way, for the branch was severed from the tree. I have no means
of verifying his calculation resulting in the conclusion that the quantity
of moisture passing out by the stomates in the time specified must have
been equal in quantity to eight and a-half times the whole quantity of
rain which fell on the spot in the course of the period specified ; but
with what I happen to know of vegetable physiology his conclusion in
no way startles me.

By Dr Asa Gray it is remarked : — " The quantity of water exhaled
from the leaves during active vegetation is very great. In one of the
well-known experiments of Hales, a sunflower three and a-half feet
high, with a surface of 5,616 square inches exposed to the air, was
found to perspire at the rate of twenty or thirty ounces avordupois
every twelve hours, or seventeen times more than a man. A. vine,
with twelve square feet of foliage, exhaled at the rate of five or six
ounces a-day ; and a seedling apple tree, with eleven square feet of
foliage, lost nine ounces a-day. The amount varies with the degree
of warmth and dryness of the air, and of exposure to light ; and is
also very different in different species, some exhaling more copiously

80 EFFECTS OP FORESTS ON MARSHES.

even than the sunflower. But when we consider the vast perspiring
surface presented by a large tree in full leaf, it is evident that the
quantity of watery vapour it exhales must be immense."

Of the moisture thus evaporated and passed into the atmosphere a
very great quantity must have been withdrawn from the soil and
dissipated, and thus even a marsh might in course of time be dried up.

Of this effect let me give one illustration, one which was communi-
cated to me by a distinguished agriculturist in Berwickshire, not less
distinguished for his knowledge of the science and literature of agricul-
ture than he is for the practical application he has made of the know-
ledge he possesses. On the farm in his possession, and which has been
long in the hands of himself and his family, there is a rising ground
at the base of which there was a piece of waste land, which, though
not a bog, was characterised by its large and luxuriant crop of rushes,
and into which sunk the feet of horses, if not of men, when they got
upon it, leaving footprints wet, if not filled with water, and there was
adjoining this a corner of enclosed cultivated land which it was
attempted to make dry by drains, but the attempt was vain.

Shortly after 1820 the top of the rising ground was planted with
firs and larch. The plantation covered a space of 20 acres. From
this time both the swampy waste land and the enclosed drained but
damp land became more dry, and at length became perfectly so.
Some forty years after the planting of these trees a furious gale pro-
duced great devastation in the plantation, uprooting or breaking over
most of the trees and leaving standing only here and there one. The
scene was unsightly, and ultimately the whole were felled and the
land cleared ; but immediately the low-lying ground became swampy
as before, and this was its condition when I visited the locality some
eight years thereafter.

The phenomena were accounted for by my friend and informant by
the supposition that there must have been a fissure in the rising
ground, from which the water oozed out, formerly and now ; but that
the rootlets of the trees, during the growth of these, absorbed the
moisture, and though their doing so may have increased the humidity
of the atmosphere enveloping the trees, it prevented the percolation
of the moisture into the ground below, which was previously so wet ;
but the removal of the trees allowed it, in oozing out, to descend to
the lower-lying soil as before.

To this explanation I offer no objection — an examination of the
rock alone would enable me to test the correctness of it. At the

MAPSHES APPEARIKO IN FORESTS. 81

same time, another explanation of the cause of the phenomena
suggested itself to me when the details were given, namely : that
before the rising ground was planted much of the moisture falling as
rain upon the upper part of it spread under the surface, being pre-
vented by rock or clay from sinking, and oozed out at the lower level;
but after the plantation was formed less of the rain-fall reached this
impervious layer.

But in either case all may be accounted for without prejudice to
the doctrine now under consideration. The planting of the trees was
followed by the desiccation of the swamp ; the destruction of the
trees, by its restoration.

Sect, II. — On the Occasional Ajyjyearance of Marshes on the
Destruction of Forests.

In the case of the disappearance of a swamp on the planting of an
adjacent rising ground with trees, and the reappearance of the swamp
on the destruction of the trees, the one phenomenon may be con-
sidered the counterpart to the other, and both of them in accordance
with the exposition which has been given of the absorption of moisture
from the soil by the roots, and its emission into the atmosphere by
the leaves. Other cases of the destruction of woods having been
followed by the appearance of swamps have been brought under
my notice.

In Russia, some yeai-s ago, in the course of conversation on the state
of the forests with an intelligent lady, the niece of a forest official, I
learned that there, as elsewhere, when ground is cleared of firs and
pines, as it often is by extensive fires, it often happens, so often that
in some districts it may be said that generally, there spring up birches
in great abundance ; and, she added, that in some cases the clearing
away of a wood converts the groiind on which it grew into a morass,
which, when it is replanted, is commonly replanted with willows.

I accept the statement as made. I pass at present the growth of
birches where previously grew the pine and the fir, but with the
intention of reverting to it afterwards. I call attention to the morass,
and suggest the enquiry, How came it to pass that there was no
morass there before ?

I consider there was none before, most probably because all the
water which went to the subsequent creation and maintenance of the
morass which subsequently appeared was raised by the trees and
passed into the atmosphere, in accordance with what has been

82 EFFECT OF FORESTS ON MARSHES.

advanced ; and that this was the case I have no doubt. But along
with this there may have been combined another operation, more
simple, mechanical, and intelligible, which must not be overlooked.

I have never heard particulars of a case which seemed to run
counter to the exposition which I have given, of which I have not
been able to show that it was compatible, or consistent, with the
supposition that the operation was such as I have supposed. But
there is another operation, noticed by Becquerel, to which Marsh
considers that sufficient importance has not, until very recently, been
generally ascribed, namely, the mechanical action of roots as con-
ductors of the superfluous humidity of the superficial earth to lower
strata. " The roots of trees," says he, " often penetrate through
sub-soil almost impervious to water, and in such cases the moisture,
which would otherwise remain above the sub-soil, and convert the
surface earth into a bog, follows the root downwards and escapes
into moi'e porous strata, or is received by subterranean canals or
reservoirs. When the forest is felled, the roots perish and decay, the
orifices opened by them are soon obstructed, and the water, after
having saturated the vegetable earth, stagnates on the surface and
transforms it into ponds and morasses. Thus, in La Brenue, a tract
of 200,000 acres resting on an impermeable sub-soil of argillaceous
earth, which ten centuries ago was covered with forests, interspersed
with fertile and salubrious meadows, has been converted by the
destruction of the woods into a vast expanse of pestilential pools and
marshes. In Sologne the same cause has withdrawn from cultivation
and human habitation not less than 1,100,000 acres of ground, once
well-wooded, well-drained, and productive."

It is with the fact that such results have followed such proceedings
that we have to do. From the facts alone we may leai'n wisdom,
though we should be baffled in attempting to trace the process by
which the results have been produced, and explanations offered by
others may appear to us unsatisfactory.

We have learned that food invigorates us and sleep refreshes,
and we act upon the knowledge of the facts, though we may be
unable to explain how it is that these results are produced. And
we find that thus the knowledge of these facts has been utilised in
Russia, where a morass appearing on the destruction of a forest is
replanted with willows. Pines and firs grew there before ; but
pines and firs would not grow now, and thus is brought before us
another view of the subject : not only has the destruction of

FORESTS DESTROYED BY MARSHES. 83

forests given rise to the appearance, on the spot or near it, of a
morass, but a morass otherwise produced has brought about a
destruction of forests.

Sect. III.— -On the Occasional Destruction of Forests hy the Creation of
Marshes.

The cases of forests having been destroyed by the creation of
marshes are numerous. There is nothing in this which is otherwise
than in accordance with the views of the meteorological effects of
forests which have been advanced ; but it may be well that this
should be shown, and it may be not improper that in doing so the
phenomena should be brought under consideration in more than
one of the phases which they present,

1 have, in the pi-eceding section of this chapter, given my explana-
tion of the fact communicated to me that in some cases in Russia
the clearing of the portion of a forest by a forest fire, or by a hurri-
cane, has been followed by the conversion into a morass of the ground
on which it grew ; and I have brought forward other facts suggestive
of how it may be that the results followed. But these exhaust not
the means by which morasses are produced in forest land.

In forests we meet with swamps which appear to have destroyed
trees growing on the spot, but which may have been themselves pro-
duced by the destruction of other trees through a process in no respect
similar to any which have been noticed.

I submitted the account I have given of the facts communicated to
me by my friend in Russia to an intelligent English engineer who had
resided much in the interior of the country, who was a man of careful
observation, one who reasoned on what he saw, and one from whom
I had received much information in regard to forests in Russia. He
returned my statement with the following annotation : — " In the
interior there occasionally occur great hurricanes, tearing all before
them and blowing down large spaces of the forests, laying the trees
with their roots attached to tiiem in all directions, and being in many
cases far from towns or villages the blown down trees are never
taken away, but decay where they have fallen, as I have seen. When
the ground is level, the little river is, from the fallen trees, raised in
its bed, or, as is often the case, is changed in its course. There is
thus always more of the space kept longer under water in the spring
than formerly, and during the summer a rank vegetation springs up,

84 EFFECTS OP FORESTS o!J MARSHES.

which tends also to keep the ground damp and watery. This, along
with the decaying wood, soon gets into a complete marsh, and will
eventually become what is called in Britain a peat moss.

** In cases where these hurricanes have destroyed the forest near to
inhabitated districts, and the land is low-lying, the space is cleared
and turned often into meadow, which is what the Russians like — good
meadow land. Their method of getting the hay from the soft and
marshy land is to put it up into ricks in some raised part of the
meadow, inclose it round with a wicker fence, and when the winter
sets in they take it home in their sledges, in the same way as their
wood is all taken to its destination, advantage being taken then of
sledges on the snow, where there are often no roads in summer ; and
also in the winter time, the peasant farmers having nothing do on
their land are thus able to get their rye, etc., conveyed to the nearest
market ; and having then plenty of time, some of them go to the
large towns and factories, and work there during the winter, returning
home in the spring, generally about the Easter holidays."

I have given the annotation entire, because to me it speaks
throughout of the abundance of moisture existing when the forests
have been destroyed. The allusions to what is done in leading rye and
leading wood speak of the abundance of water in the ground kept
comparatively dry by the forest, but accumulating when superficial
drainage is prevented.

My correspondent assumes, and not without reason, that in the
cases alleged the water level may have been raised by the damming
up of an outlet ; and I accept the explanation as one given by an
intelligent observer, living in the country and ftimiliar with the facts.
His statement is suggestive of much which might illustrate the
operation of trees in drying marshy land, utilizing and dispersing the
excess of moisture, and fitting the land, otherwise compai'atively use-
less to man, for bringing forth herbs meet for them by whom it is
dressed. But at present we have to do with the one fact that thus
also morasses may be produced, along with the effects referred to ;
and of this other illustrations may be given.

In the Northern States of America, and in the Dominion of
Canada, we meet occasionally with extensive patches of weird-like
trees, standing leafless and dead in a shallow waste of waters, miles
in extent, produced by the accidental or designed damming up of
some streamlet it may be by which it had previously been drained.
It may have occurred through some such accident as my friend in

THE BOIS BRULE. 85

Russia has suggested ; it may have occurred iu connection with some
endeavour to divert into another channel the waters of the same or
some other water-course ; it may have occurred in consequence of the
damming up of some outlet from a lake which it was sought to
enlarge as a reservoir for the supply of a canal, or a mill-lade, or some
other purpose ; or it may have been the effect of the woi'k of a
beaver, for cases of all such occvirrences can be cited. But, however
produced, the consequence to that portion of the forest which is laid
under water, though only to the depth of one or two feet, is the same
— the trees are killed as if girdled by fire, or by the woodman's axe,
and, most probably, by a similar operation, through the decay and
destruction of the bark and sapwood at the water-line, or between
wind and water, promoted by alternate exposure to each by the
ripple, and the consequent severance of the communication between
rootlet and leaf, or it may be by such a severance being occasioned by
the rupture and decay of vessels through which that communication
was maintained.

A graphic sketch of the destruction thus wrought occurs in
an account given by Gosse of a forenoon's excursion, which he
made in Canada to the Bois Brule, a large tract of land which lay at no
great distance from his residence, but was so hidden in the recesses of
the woods, and so out of the way of any travelled road, that it was
not often visited except by the trapper. The first quarter of a mile
lay through what he calls a very rough slash. " Such a labyrinth of
fallen timber we had to penetrate," says he, " climbing over the
trunks, and scrambling through the dry branches of the prostrate
trees, often falling through ; and, to make the matter worse, these
were concealed by the tall Indian wickup, epilohkcjn latefoUum, with
which the ground was absolutely covered, and, as the long seed-pods
were just bursting, our every movement dispersed clouds of the light
downy cotton, which, getting into our mouths and nostrils, caused us
considerable inconvenience. Presently we descended the steep bank,
and walked, or rather scrambled, up the rocky bed of the stream, by
means of the stones which were above water, though, as they were
wet and slimy, we occasionally wetted our feet. Thus we went on
sometimes in the stream, sometimes among the alders and underwood
of the banks, for about a mile and a-half. We were much surprised
in going up this brook, about a mile up, at coming upon a ruined
building, which had been erected over the stream at a craggy fall, the
timbers of which had fallen down, and some of them had been
carried a considerable distance down by the freshets, I supposed it

Ob EFFECTS OF FORESTS ON MARSHES.

must have been a mill, but wondered at its situation, so far from any
road. I have since been informed that it was a saw-mill, and that
there was a good road to it, but this road being now overrun with
bushes and young trees, escaped our notice. The mill has been disused
nearly twenty years. On the borders of the brook I met with seed-
vessels of the touch-me-not, impatiens nolli tangere, the handsome
sub-conic scarlet fruit of the white and the red death, trillium
picium and T. foetidum, the large umbelled bright blue berries
of smilacina horecdis, and many others. In pressing through the
bush we got our clothes bedaubed with a nasty substance, which
we discovered to proceed from thousands of the aphis lanata (?)
which we had crushed ; they were so thickly clustered round
the branches of the alders as to make a solid mass half-an-inch
thick, covered with ragged filaments of white down. We were
getting tired of the ruggedness of our path, when we suddenly
came upon a new and very good bridge across the brook, made
of round, that is, unhewn logs, which connected a good broad
path, from which the fallen trees and encumbrances had been cleared
away, and which had evidently been used for drawing out mill-logs in
winter with sleds. This we followed. The sides of the road were
lined with the stumps of large spruces and hemlocks, which had been
felled the previous winter ; and the road itself was strewn with the
chips of the axe-men. The course lying through a cedar swamp, the
ground was mossy, and in some places wet ; here the scarlet stone-
berry was abundant, as well as the berries mentioned before. The
iovmer, framria canadensis, is a low and pretty plant, having a white
flower, resembling that of a strawberry, and four large oval green
leaves on the ground ; at present they were crowned with the little
cluster of bright red berries, which were ripe, and we ate many —
they were farinaceous and agreeable. This plant is common in
Newfoundland. We continued to follow this path till it appeared
almost interminable, though its tedious uniformity made it seem
longer tlian it really was, as I suppose we did not walk more than a
mile and a-half on it when I perceived by the increasing light among
the trees that we were approaching a large opening.

" We now pi'essed eagerly on, and found that we had reached the
borders of the Bride, which was not a clearing, as I had expected, but
was covered with a stunted and ragged gi'owth of moss-grown spruce,
from eight to twelve feet in height, exactly resembling the small
woods of Newfoundland. On the borders of the large marshes I
found also the same plants that inhabit such situations in that

THE B0I8 BRULE. 87

country, and which I now saw for the first time in Canada. I also
recognised numbers of another old acquaintance, an exceedingly
curious plant, the Indian cup or pitcher-plant, sarracenia purptirea."
Some of the plants he describes, and then goes on to say, " The road
by which we had approached did not enter the Brule, but merely
touching its edge, went straight on, entering the tall woods on the
other side. We penetrated a few roods into the Brule, to see if there
were any clearing, but could perceive no change in the ugly, dead,
half-burnt spruce, and therefore returned. This singular piece of
ground contains some thousands of acres, and is said to owe its origin
to the beavers, which were formerly numerous, damming up the
streams, which, overflowing and spreading over the flat-lands, killed
the growing timber. It is a resort of wolves, bears, and other wild
animals, though we perceived no sign of life in the stillness which
pervaded the solitude ; nor, indeed, in the whole journey, with the
exception of one or two little birds, which were not near enough to
be identified, and a few insignificant insects in the forest. Having
satisfied our curiosity we began to return as we came, until we
arrived at the bridge, when, instead of retracing the course of the
stream, we crossed the bridge and continued to pursue the road,
which, for some distance, led us through towering spruces and
hemlocks, as before. On a sudden the character of the woods
changed : we found the sides lined with young maple, birch, beech,
&c., which met overhead at the height of about twelve feet, forming
a very perfect and regular continued Gothic arch, or rather a long
series of arches. This long avenue was the most pleasant part of our
walk, and the more so because it was quite unexpected. We
presently opened into a large field, which had been just mown, and
here we were rather laughably bewildered : the place was a ten^a
incognita ; we had never before seen it, nor could we i-ecognise any
object, so as to guess at our whereabouts. There appeared to be no
outlet through the woods by which the field was environed. In one
part was the skeleton of an old log-house without a roof, and a
portion of the field was planted with potatoes. We at length saw
a path through to these potatoes, on which we walked till we came to
the brow of a hill from whence we perceived familiar objects. It
commanded an extensive view : the beautiful and winding Coatacook
was at our feet with its bridge. Smith's mills and all that neighbour-
hood ; beyond a broad belt of the forest was visible Tilden's Tavern
and the road leading from Hatley to Stsrbrooke, and the forest again
behind all. We now left the path, taking a short cut over the hill,

88 EFFECTS OP FOBESTS ON MARSHES.

coming down by Bradley's mill, and so home, much pleased, notwith-
standing the little disagreeables, with our little excursion."

In regard to the effects of the work of the beaver, it is remarked
by Marsh, " I am disposed to think that more bogs in the Northern
States owe their origin to beavers than to accidental obstructions of
rivulets by wind-fallen or naturally decayed trees ; for there are few
swan^ps in those States, at the outlets of which we may not, by
careful search, find the remains of a beaver dam. The beaver some-
times inhabits natural lakelets and even large rivers like the
Mississippi, when the current is not too rapid, but he prefers to owe
his pond to his own ingenuity and toil. The reservoir once con-
structed, its inhabitants rapidly multiply so long as the trees, and
the harvests of pond lilies and other aquatic plants, on which this
quadruped feeds in winter, suffices for the supply of the growing
population.

" But the extension of the water causes the death of the neighbouring
trees, and the annual growth of those which could be reached by
canals and floated to the pond soon becomes insuificient for the wants
of the community, and the beaver metropolis now sends out
expeditions of discovery and colonization. The pond gradually fills
up, by the operation of the same causes as when it owes its existence
to an accidental obstruction, and when, at last, the original settle-
ment is converted into a bog by the usual processes of vegetable life,
the remaining inhabitants abandon it and build on some virgin brook-
let a new city of the waters."

And he adds in a foot note : — " I find confirmation of my own
observation on this point (published in 1863) in the ' North West
Passage by Land,' of Milton and Cheadle, London, 1865. These
travellers observed • A long chain of marshes formed by the damming
up of a stream which had now ceased to exist,' chap. x. In chap. xii.
they state that ' Nearly every stream between the Pembina and the
Attrabasca — except the large river M'Leod — appeared to have been
destroyed by the agency of the beaver,' and they question whether
the vast extent of swampy ground in that region ' Has not been
brought to this condition by the work of beavers, who have thus
destroyed, by their own labour, the streams necessary to their own
existence.

" But even hero nature pi'ovides a remedy, for when the process of
consolidation shall have been completed, and the forest re-established
upon the marshes, the water now diffused through them will be

MARSITES OCCASIONED BY LEAVES. 89'

collected in the lower or more yielding portions, cut new channels for
their flow, become running brooks, and thus restore the ancient
aspect of the surface.

" The authors add the curious observation that the beavers of the
present day seem to be a degenerate race, as they neither fell large
trees nor construct great dams, while their progenitors cut down trees
two feet in diameter and dammed up rivers a hundred feet in width.
The change in the habits of the beaver is probably due to the diminu-
tion of their numbers since the introduction of fire-arms, and to the
foot that their hydraulic operations are more frequently interrupted
by the encroachments of man.

" In the valley of the Yellowstone, which has but lately been much
visited by the white man, Hayden saw stumps of trees thirty inches
in diameter which had been cut down by beavers. *

" The American beaver closely resembles his European congener,
and I believe most naturalists now regard them as identical. A
difference of species had been inferred from a difference in their modes
of life, the European animal being solitary and not a builder, the
American gregarious and constructive. But late careful researches
in Germany have shown the foi^mer existence of numerous beaver-
dams in that country, though the animal, having become too rare
to form colonies, has of course ceased to attempt works which require
the co-operation of numerous individuals, t

" On the question of identity, and all others relating to this interest-
ing animal, see L. H. Morgan's important monograph, " The American
Beaver and his Works," Philadelphia, 1868. Among the many new
facts observed by the investigator is the construction of canals by the
beaver to float trunks and branches of trees to his pond. These
canals are sometimes 600 or 700 feet long, with a width of two or three
feet, and a depth of one to one and a-half."

It may be considered by some of my readers that the natural
history of beavers can scarcely be considered the meteorological
effects of forests. The same may be alleged of all that is being
advanced in this chapter relating to the effects of forests on the
humidity of the ground. I deem it proper to treat the subject thus
freely, partly with a view to anticipating and obviating objections
which may suggest themselves to conclusions drawn, and partly

* " Geological Survey of Wyoming" (p. 135).
t Schleiden : " Fur Baim und Walcl'' Leipzig, 1870 (p. 68).

90 EFFECTS OP FORESTS ON MARSHES.

because it is the effect on the soil of the meteorological effects of
forests which chiefly concerns us at present in the discussion of these.

Sect. IV. — On the Desiccating Effects produced on Marshes hy Forests
in Prolonged Periods.

Reference is made by Marsh to a recuperative operation, whereby
even the bog produced by the destruction of a forest regains, after a
time, its former aspect, and in this the desiccating effect of vegetation
comes again into play, pi'omotes the work, and expedites the result.
In Denmark we see what may thus be accomplished. We there
meet with a land, which, at one or more periods of its existence as
land, must have been over a great extent of its surface covered by
morasses and marshes, and peat bogs, but which is now so dry as to
be habitable, and cultivated by man, giving him in return for his
labours fields of increase ; and the peat bogs supply extensive
indications that forests must have played an important part in
producing the change.

From Bogens Indrandring i de BansJce Skove, by Chr. Vaupell, we
learn that a careful examination of the peat mosses in North
Sjselland, which are so abundant in fossil wood that within thirty
years they have yielded above a million of trees, shows that these
trees have generally fallen from age and not from wind. They are
found in depressions on the declivities of which they grew, and
they lie with the top lowest, always falling towards the bottom of
the valley.

The origin of these bogs dates from pre-historic times ; but the
origin of other bogs has been studied, and the result has been given
in part in the preceding section.

Marsh, in his valuable treatise on " The Earth as Modified by
Human Action," which I have already cited, says, " Bogs generally
originate in the checking of water-courses by the falling of timber or
of earth and rocks, or by artificial obstructions across their channels.
If the impediment is sufficient to retain a permanent accumulation
of water behind it, the trees whose roots are overflowed soon perish,
and then by their fall increase the obstruction, and, of course,
occasion a still wider spread of the stagnating stream. This process
goes on until the water finds a new outlet, at a higher level, not liable
to similar interruption. The fallen trees not completely covered by
water are soon overgrown with mosses ; aquatic and semi-aquatic
plants propagate themselves and spread till they more or less com-

DRYING UP OP BOGS. 91

pletely fill up the space occupied by the water, and the surface is
gradually converted from a pond to a quaking morass. The morass
is slowly solidified by vegetable production and deposit, then very
often restored to the forest condition by the growth of black ashes,
cedars, or, in southern latitudes, cypresses and other trees suited to
such a soil, and thus the interrupted harmony of Nature is at last
re-established."

In continuation of the passage I have cited, Mr Marsh goes on to
say, " In counti-ies somewhat further advanced in civilization than
those occupied by the North American Indians, as in mediaeval
Ireland, the formation of bogs may be commenced by the neglect
of man to remove from the natural channels of superficial drainage
the tops and branches of trees felled for the various purposes to
which wood is applicable in his rude industry ; and when the flow
of water is then checked, nature goes on with the processes I have
already described. In such half-civilised regions, too, wind-falls are
more frequent than in those where the forest is unbroken, because when
openings have been made in it for agricultural and other purposes
the entrance thus afforded to the wind occasions the sudden over-
throw of hundreds of trees which might otherwise have stood for
generations, and have fallen to the ground only one by one, as
natural decay brought them down. Besides this, the flocks bred by
man in the pastoral state keep down the incipient growth of trees on
the half-dried bogs and prevent them from recovering their primitive
condition."

Denmark supplies many illustrations of the effect of vegetation,
herbaceous and arborescent, in filling up and drying up marshes in
prolonged periods extending back into pre-historic times.

By numerous successive growths of aquatic and semi-aquatic plants,
herbs, and trees, bogs have there been filled up and dried up in the
course of ages, and at length rendered, as now, so dry as to be fit
habitation for man. And simultaneously with what has been
efibcted by the abstraction of water by the spongioles, and emission
of it by the stomates, an influence modifying the process of desiccation
otherwise produced, intensifying or moderating it, may have been
going on.

Marsh, citing as his authority a work by Wilhelm, entitled " Ber
Boden tond das Wasser" a work published in Vienna in 1861, and a
work by Krecke, entitled " Ilet Klit)iai van Nedeiia7id," sajs : — The
relative evaporating action of earth and water is a very complicated

92 EFFECTS OF F0REf>r8 OX MARSHES.

problem^ aai the results of observation oa the subject are con-
flicting. Schuebler found that at Geneva, the evaporation from
bare loose earth in the months of Dscember, January and February,
was from two and a-half to nearly sis times as great as from a like
surface of water. In the other months, the evaporation from water
was from about one and a-half to six times as great as from the
earth. Taking the whole year together the evaporation from the
two surfaces was 199^^ lines from earth, and 536j-V lines from
water. Experiments by Van der Steer, at the Holder, in the years
1861 and 1862, showed for the former year, an evaporation of 602'9
millimetres from water, 1399-6 millimetres from grounds covered
with clovers and other grasses ; in 1862 the evaporation from water
was 584-5 millimetres; from grass-ground 875-5." It is these latter
observations with which we have to do, and these indicate that from
the bog evaporation would proceed more rapidly than it would from a
lake of the same extent similarly situated.

Such seem, then, the effects of forests on swamps and of swamps on
forests. The moisture withdrawn from the ground and passed into
the atmosphere by the trees, if in excess of what is supplied from
a higher level, and of what also falls on the spot, as rain, snow, or
dew, must render them dry, and to the same extent produce the
meteorological effect of increasing the humidity of the air ; but at
the same time, by shade, and by shelter, and by covering the ground
with fallen trees, and broken twigs, and by the humus produced from
the decay of these, the forests prevent extreme desiccation. And the
occasional appearance of marshes on the destruction of forests, even
when attributable to the stoppage of an outlet, may indicate what they
have thus accomplished.

CHAPTER IV.

On the Effects of Forests on the Moisture over a Wide
ExPxVNSE OF Country.

The observatious which we have had under consideration show
that forests, in common w4th other products of vegetation, withdraw
moisture from the ground, and that they do so to such an extent as
to carry off the water of swamps and to prevent the formation of
these increasing the atmospheric moisture in their immediate vicinity
to such a degree that it may be felt, making houses damp, even iu
their innermost chambers, and that it may be seen in clouds and fogs
and drizzling rain ; and yet, that they keep the soil moist compared
with the soil beyond their shade and shelter, wherever that shade
and shelter fall ; while the ground is at the same time enriched with
vegetable mould, the product of the fallen leaves and other dehris.

But when we extend our study to the effects of forests on the
humidity of soil and climate over a wide expanse of country, we find
that observations have been made which seem to show that in some
cases the extensive destruction of forests, over a great expanse of
country has not perceptibly affected the quantity of the rain and
dew, and hail and snow, which has there fallen from heaven ; while,
on the other hand, there are lands which were once populous and
fertile, but are now arid and sterile — the aridity of which is alleged
to be the cause of their sterility, and to be a consequence of the
destruction of forests.

On thus extending our field of observation we meet with additional
facts, which, if all the circumstances and conditions of each were
known, might be easily reconciled, notwithstanding apparently an-
tagonistic conclusions to which they sometimes seem to lead.

I shall cite some of the individual or separate facts which are
known, illustrative of the general facts now stated ; and either as I
advance or subsequently, as may appear at the time most important,
1 shall advert to the modus operandi of the means whereby the results
observed may have been brought about.

9i EFFECTS OF FORESTS ON MOISTURE

Sect. I. — Gases in which the Extensive Destruction of Forests does not

appear to have Perceptibly Affected the Quantity of the

Rainfall over a Wide Expanse of Country.

The subject of this chapter is the effect of forests ou the moisture
over a wide expanse of country, that of this sectiou is only the
apparently negative effect, in certain cases of the extensive destruc-
tion of forests, on the rainfall. Attention is called to the difference,
that it may be noted. The rainfall is treated neither as the source
nor as the measure of the moisture, but solely as one of the indications
of the humidity of the atmosphere, it being the indication of this to
which most importance is generally attached, and that which is most
generally referred to in popular discussions on the meteorological
effects of forests.

Both Europe and America supply illustrations of apparently little
effect having been produced upon the deposit of moisture in the form
of rain over a wide expanse of country by the extensive destruction
of forests.

There are many indications of Europe having been formerly
covered much more extensively and densely with forests than now.
In France, the destruction of these forests within the last two
hundred years as well as before has been considerable, yet there does
not appear to have been within that time any very great diminution of
the rainfall over some extensive districts in which observations on the
rainfall have been made.

This point has been discussed at considerable length by M. Cezanne,
in h\.^Se(j[uel to Etude sur les Torrents des Ilautes Alpes, par Alexandre
Surell. It is mentioned by him that some writers on the subject, to
whom he afterwards refers more particularly, in endeavouring to demon-
strate the action of forests on the rainfall, have adduced as proof that
the destruction of forests, and the extensive plantation of these, have
both of them affected the regime of the rainfall in France; some, that
the rainfall has increased at Viviers contemporaneously with the de-
hoisement or destruction of forests on the mountains of the Cevennes j
others, that it has increased at Bourdeaux contemporaneously
with the rehoisement, or replanting of forests, on the Laudes : facts,
if facts they be, which, though not incompatible with each other,
point to different conclusions. In reference to these observations,
M. Cezanne writes : — " If facts of this kind were clearly established,
they would be unanswerable ; but before admitting them wc must

OVER A WTPF. EXPANSE, 95

betake ourselves to the records of the rainfall and enquire whether
either of these two conflicting assertions have any value.

" In France, the earliest series of pkiviometric observations is that
of r Observatoire. It was begun in 1689 by Phillippe de la Hire, in
accordance with an express order given by Colbert to the Academy,
in view of the requirements of the hydraulic works at Versailles, to
ascertain what quantity of water the rain falling on the plains around
could supply to the projected reservoirs.

" It has been repeatedly interrupted, and again resumed. And
a summary of the record is given in the following table, taken
from a valuable collection of pluviometric observations publi shed
by M. Raulin, Professor of Geology in the Faculty of Sciences at
Bourdeaux : — *

TABLE OF MEAN ANNUAL RAINFALLS IN DECADES, ACCORDING TO THE
rLUVIOMETRB ON THE TERRACE OF THE OBSERVATORY AT PARIS.
Periods. Number of Years. Rainfall. Difference. Names of the Observers.

1688-1700 10 517- )

1701-1710 10 480-6- 36-4 V Lahire, 1688 to 1718.

1711-1720 10 464-9- 15-7 j

1721-1730 10 378-3- 86-6),, ia- n a- a t? u

1731-1740 10 411- + 327lM^rald,^ran^J7.^,d/F^^^^

1741-1750 10 425-5+ 11-5 j 1709 to 1.54.

1773-1780 8 537-6 + 114-1). * ai t> ^ ittq

i^oi ^'•ar\ in nnr n qo t ' Jeaurat, Alex. Bouvard, 1773-
u81-l<90 10 506-9- 32-/ V ' ,^^,0

1791-1798 8 413-7- 93-2 j ^''^^•

1804-1810 7 518-3 + 104-6]

1811-1820 10 496-5- 21-8 |

1821-1830 10 498-6+ 2-1 | ^^ , , t ^r •

1831-1840 10 509-3+ 10-7 Bouvard, Arago, Le Verrier.

1841-1850 10 529-3+ 20-

1851-1860 10 520-3- 9- J

" The column of difference shows that the variation followed no law
of continuity. The long-continued series of observations presents us
with three separate periods, and these give respectively for the annual
mean, during 65 years, 1688 to 1754, 448-6 millimetres; 26 years,
1773 to 1798, 489-6; 57 years, 1803 to 1860, 512-0.

" Many authors have appealed to these numbers to prove that the
rainfall in Paris is now [not less, but] greater than formerly; but this
has been met by the following considerations : In pluviometric observa-

* Bourdeaux, Chaumas. 1864.

96 EFFECTS OF FORESTS ON MOISTURE.

tions all eirors made are errors of deficiency, arising from the escape
of water by evaporation, by infiltration, by spilling, and from neglect,
etc. ; and doubtless the first observers did not attach any great im-
portance to those measures "which, in the absence of other correspond-
ing observations made elsewhere, could not lead to any generalization.

"Thus Father Cotte, quoted by M. Raulin, writes in 1804: — 'I
may observe that the udomfetre used at the Observatory of Paris has
been found to be so defective that they have been obliged to give up
the use of it for some years ; they have now set up a new one, which
is much more exact. The water is received and measured on the
platform of the building, 27 metres [90 feet] above the ground, instead
of measuring it, as formerly, in one of the apartments on the first
storey, so that it ran through a pipe 63 feet long from the platform
where it was received to the reservoir, which necessarily occasioned
a loss.'

" From these diflferent causes it is impossible to compare satis-
factorily the series of observations from 1688 to 1754 with the series
made from 1803 to 1860. It is possible that if the two series of
observations had been made with the same instrument, and with the
same precision, the latter might have shown a diminished instead
of an augmented mean.

"Arago said, on this subject, in 1853*: — ' There is no reason to
suppose that the climate of Paris is either more or less rainy than it
was 150 years ago. The small augmentation presented by the
numbers in the later groups do not in fact exceed variations observ-
able in the earlier periods.'

'* It is known that in 1817 a second udometre was placed on the
ground of the court, and that ever since it has constantly received
quantities of water a Httle in excess of what was received by that on
the terrace, as may be seen from the following numbers : —

Measurement of Water Annually

Period. Received Proportion.

On the Terrace. On the Ground.

a b a-b.

miUimt'tres. mm. mm.

1821-1830 498-6 551-9 MO

1831-1840 509-3 584-8 1-14

1841-1850 529-3 627-8 MS

1851-1860 620-3 577-1 1-40

* Arago : " CEuvres completes Melanges (p. 420j.

OVER A WIDE EXP ANSE IN FRANCE. 97

" It was long believed that this difference was owing to this — ^that
the drops of rain increased in bulk by aggregation during their fall ;
it is agreed now that the relatively lesser amount collected in
the pluviometre on the terrace is attributable to atmospheric eddies.
But, if it be so, the topographical modifications to which the vicinity
and approaches to the Observatoire have been subjected since 1688
may suffice perhaps to explain the augmentation of the actual means.
This idea natm-ally suggests itself when astronomers are heard com-
plaining that, in consequence of the multiplication of street carriages
and other conveyances, of gas lights and of hells, certain researches
have become impossible in the Observatoire of Paris, so that it is
necessary to remove it to the country, and it is imperatively
necessary to decentralize the study of astronomy.

" In short, it may be admitted in regard to Paris, that if the
rainfall be different from what it was during the last century, the
variation is so inconsidei*able that doubts are entertained as to what
the character of the variation is."

Similar comments are made on observations made at Bourdeaux.

" The observations which we possess for the city of Bourdeaux are
summarised in the following table, the numbers given in which are
taken, in like manner, from the valuable collection of M. Raulin : —

TABLE OF MEAN ANNUAL RAIN-FALLS AT BOURDEAUX, IN DECADES.
Periods. Number of Years. Rain-fall. Difference. Names of the Obserrers.

1714-1720 7 659-1 ]

1721-1730 10 737-5+ 78-4 |

1731-1740 10 735-1- 2-4 I ^^ - ,,

1741-1750 10 693-6- 41-5 \ ^'^'"^^^^^^ ^'^^^^^ ^^^ s^"'

1751-1760 10 670-0- 23-6 |

1761-1770 10 647-8- 22-2 J

1842-1850 8 .849-2 + 207-3 )

1851-1860 10 795-2 - 54-8 /

1776-1786 10 641-9- 5-9 Guyot and De la Mothe.

Abria.

1851-1860 10 820 Petit-Laffitte.

General average, 719 millimetres.

" The column of differences here shows still that the variations do
not follow a law of continuity. For the first series of 67 years the
annual mean is 684-7 millimetres, while for the new series,
1842-1860, this mean rises to 820, an augmentation of 20%.

H

98 THE EFFECTS OF FORESTS ON MOISTURE

"AqcI it is remarkable in this table that for the years 1851-
1850, two different observers obtained quantities of water notably
differe nt."

The work of M. Raulin presents other examples of such anomalies.
To these I shall afterwards have occasion to refer in the further pro-
secution of the study of the subject ; but from the recorded observa-
tions, the destruction of forests in the districts I named does not
appear to have greatly affected the deposit of moisture throughout
the districts referred to.

Corresponding results have been yielded by a study of the records
of observations made in the United States of America.

In North America we have a country which within comparatively
recent times was extensively covered with forests in regions which
have now been in a great measure cleared of them. To observations
which may indicate any changes upon the rainfall over extensive
districts which may thus have been produced attention has been
given, and is being given, by fhe Smithsonian Institution, under the
direction of the Secretary, Professor Joseph Henry, at Washington.
Under his direction there are being collected, collated, tabulated, and
otherwise utilised, meteorological observations made throughout the
United States, observations made at sea, and collected at the United
States Naval Observatory, observations made by Arctic and Ant-
artic explorers, and observations made at several hundred stations in
other parts of the world.

Observations on the winds of North America have been tabulated
and published, and have been largely made use of by the English
Board of Trade in constructing wind charts of the Northern Ocean.
In 1872 Professor Coffin was engaged in the tabulation of observa-
tions in parallel zones of latitude 5^^ in breadth, the whole world over,
from the North Pole to the South. And at that time it was reported
by Professor Henry : —

" The temperature observations ai*e still in progress of reduction,
two computers being engaged upon the work. The progress of their
labours has, however, frequently been interrupted by calls from
different portions of the country for reports on the climate of
different districts.

" The following is an account of the present condition of this part
of the general reductions :

" The collection and tabulation, in the form of monthly and
annual means, of all accessible observations of the atmospheric tern-

OVER A WIDE EXPANSE. 99

perature of the American continent and adjacent islands, have been
completed to the close of the year 1870, and extensive tables
representing the daily extremes, or the maximum and the minimum
at the regular observing hours, have been prepared.

" An exhaustive discussion of all the observations available for the
investigation of the daily fluctuations of the temperature has been
made, and this part of the work is now ready for the printer.

" The discussion of the annual fluctuations of the temperature has
been commenced and carried as far as the present state of other parts
of the discussion would permit.

" The construction of a consolidated table giving the mean results,
from a series of years, for each month, season, and the year, at all
of the stations, which will probably exceed 2,500 in number, has been
begun and completed for that part of the continent lying north of the
United States, and also for several of the States. This is perhaps the
most laborious, as it is one of the most important parts of the dis-
cussion. In many of the large cities there are numerous series, made
by various observers, at different hours, all of which have to be
brought together, corrected for daily variation, and combined to
obtain the final mean. To give some adequate idea of the time and
labour involved in the preparation of these tables, it may be
mentioned that, in the State of New York alone, there are about
three hundred series, which are derived from nearly two million
individual observations.

" The principal sources from which the general collection of
results has been derived, may be enumerated as follows : —

" 1. The registers of the Smithsonian Institution, embracing
upward of three hundred large folio volumes.

" 2. The publications of the Institution, Patent-Office, Department
of Agriculture, and public documents.

" 3. All the published and unpublished records of the United
States Army, United States Lake Survey, and United States Coast
Survey.

" 4. The large volume compiled by Dr Hough, from the observa-
tions made in connection with the New York University System,
the records made in connection with the Franklin Institute, and
those obtained from numerous observatories and other scientific
institutions,

•' 5. The immense collection of printed slips, pamphlets, manu-
scripts, (fee, in the possession of the Smithsonian Institution.

" The work Las been somewhat retarded by the collection and

100 EFFECTS OP FORESTS ON MOISTURE

tabulation of the rain-fall, to the end of 1870, for the Smithsonian
stations, and to the end of 1871 for the United States military posts,

** Beside the discussion of the observations on temperature, rain,
and wind, there remain those relative to the pressure of the atmos-
phere, and its humidity ; also those which are classed under the head
of casual phenomena, such as thunder-storms, tornadoes, auroras,
meteors, early and late frosts, progress of vegetation, opening and
closing of rivers, &c. These will be put in hand as soon as the funds
of the Institution which can be devoted to meteorology will permit
the requisite expenditure."

From this statement some idea may be formed of the magnitude of
the work, of the extent of the resources provided for the prosecution
of it, and of the energy with which it was being carried out.

The documents by Dr Hough, referred to, were published in two
large volumes, the first entitled '' Eesults of a Series of Meteorological
Observations, made in obedience to instructions from Regents of the
University of the State of New York, from 1826 to 1850 inclusive,"
and the second entitled " Second Series of Meteorological Observa-
tions, embracing Observations from 1850 to 1863, with Records of
Rainfall, and other Phenomena, to 1867 inclusive."

In 1872 were published " Tables and Results of the Precipitation
in Rain and Snow in the United States, and at some Stations in
Adjacent Parts of North America, and in Central and South
America," collected by the Institution, and discussed under the
direction of Professor Henry by Mr Charles A. Schott. And, in an
examination of these, I fail to discover any intimation of any change
in the quantities of rain falling having followed the clearing of any
district from which observations w^ere collected, and the stations were
790 in number.

Simultaneously with the collecting of these observations by the
agents of the Smithsonian Institution, special attention was being
given by Mr Draper, Director of the Meteorological Observatory in
the Central Park of New York, to the alleged effects of forests and of
the destruction of these on the rain-fall. And in his report to the
Board of Commissioners of the Department of Public Parks for the
same year, 1871, he makes the following statement, in reply to the
question. Does the clearing of land increase or diminish the fall of
rain : —

" Much solicitude is publicly felt as regards the supposed di-
minished quantity of water which fell last year, a point of the
highest concern. There is a general impression that this alleged

OVER A WIDE EXPANSE IN AMERICA. 101

deficiency was to such an amount as to endanger a due supply to the
city for the current year. And not only this, it has also been
asserted that, for several years past, there has been a steadily
occurring diminution in the rainfall. Whilst the quantity of water
has thus been becoming less and less, the demand has been becoming
greater. Not only has the population of the city increased, but also
that of the suburban districts, which derive their supplies from the
same water-gathering grounds that we do.

" I therefore supposed, since our registering rain-gauge furnishes
very reliable measures, that it would be useful to examine this sub-
ject critically. But since we have had these gauges in operation only
about three years, and as the investigation proved to be full of
interest, I was led to draw upon other additional sources of informa-
tion, selecting such as seemed to be of the most trustworthy kind.
By the aid of these, the examination has been extended as far back
as 1836, and with the following results: —

" 1st. As respects the indications given by our own instruments,
which may be thoroughly relied on for the years 1869, 1870, 1871.

" For the first of these years, 1869, the total rainfall was 46-82
inches, distributed as follows : During the first quarter, 15-06 inches;
second quarter, 10-24 3 third quarter, 7-72; fourth quarter, 13-80 —
total, 46-82.

" For 1870, the total rainfall was 42-32 inches, distributed as
follows: During the first quarter, 12-86 inches; second quarter,
10-29; third quarter, 9-39; fourth quarter; 9-78 — total, 42-32.

For 1871, the total rainfall was 52-06 inches, distributed as
follows: During the first quarter, 10-33 inches; second quarter,
14-12 ; third quarter, 14-21 ; fourth quarter, 13-40— total, 52-06.

" So far as these years are concerned there does not appear any
evidence of a decrease. On the contrary, in the last there is a very
considerable excess over either of the others.

" Extending our examination to preceding years as far back as the
beginning of 1836, and grouping those years into three periods each
of ten, and one of six years, the statement comes to this : First
period, from 1835 to 1846, 39-5 inches ; second period, from 1845 to
1856, 47-0; third period, from 1855 to 1866, 52-0; fourth period,
from 1865 to 1872, 52-0. This would make the annual rainfall
throughout these 36 years, 47-62 inches. That of the last three
years 47-06.

"These numbers being substantially the same, it may be con-
cluded that, though there are large variations from year to year, aa

102 EFFECTS OF FOHESTS ON MOISTURE

shown by a synoptic table, these, on the whole, will neutralize one
another when very long periods of time are considered.

" In the foregoing tables the numbers from 1836 to 1854, inclusive,
are derived from the observations made by the Military Officers at
Fort Columbus, New York Harbour ; those for the next twelve years
are from the records of Prof. Morris, in New York City ; and the
remainder are from the registers of this observatory. It is of course
assumed that the i-ainfall at Fort Columbus, that in New York City,
and that in the Central Park are the same, an assumption which is,
I suppose, under the circumstances, admissible.

" The amount of rainfall not only influences in a predominant
manner the growth of plants, and, therefore, agricultural pursuits
determining the profitable cultivation of many different crops, but it
also exerts an influence on several manufacturing operations. If,
therefore, the above statement be correct, no apprehension need be
entertained .of a permanent disturbance in these particulars. Al-
though in the last thirty-six years great changes have been made in
all those portions of the United States intervening between the
Mississippi and the Atlantic Ocean, large surfaces having been cleared
of the primeval forests and brought under cultivation, their physical
character and aspect having therefore been essentially altered, no
corresponding diminution can nevertheless be traced in the mean
amount of water that has fallen. On the contrary, as seen in the table
given and in the synoptic chart, there has been an actual increase. It
appears, therefore, that the wide-spread public impression that the
clearing of land diminishes the volume of rain is not founded on fact,
and in truth this is no more than might have been expected from a
correct consideration of the meteorological circumstances under which
rain is produced.

"It is the belief of European Meteorologists that the mean rainfall
on the western portion of that continent varies little, if at all, when
periods of many years are considered. In England there are rainfall
records reaching back to 1677. Since 1725 these records are un-
broken ; at present there are more than 1,500 rain-gauge stations in
that country. The Scotch observations extend to 1731, the Irish
to 1791.

" A discussion of the observations made at the Royal Observatory
at Greenwich, in 1859, led to the conclusion that the annual fall of
rain, as compared with that previous to 1815, was becoming smaller;
but more extended observations, taken from gauges at stations widely
separated, led to the opposite conclusion, viz., that there was a per-

OVER A WIDE EXPANSE, 103

feet compensation, the decrease at one place being compensated by
the increase at another.

"This conclusion was strikingly illustrated by the Continental
observatories. The rainfall at Paris was found not to have altered
in 130 years, and though the observations of fifty years at Marseilles
gave a decrease, those for fifty-four years at Milan gave an increase.

" Even in the same locality this principle of compensation may be
noticed. Thus the rainfall in England, in the ten years from 1850
to 1859, was found by Mr Symons to be five per cent, less than
during the previous forty years, but during the following six years it
was five per cent, above the mean of the preceding ten.

" It may, however, be supposed that conclusions which apply to
the old-settled countries of Europe, in which but few important topo-
graphical changes, through agricultural or other operations, have
taken place for many years, will scarcely apply to America, wherein
the clearing of land and agriculture surface-changes have been occur-
ring on a very extensive scale. The foregoing conclusions, however,
show us how insignificant is the meteorological result which these
variations produce."

The observations are cited as evidence that there are cases in
which the extensive destruction of forests does not appear to have
perceptibly affected the quantity of the rainfall over a wide expanse
of country ; and these observations are brought forward as
observations not less necessary to be taken into account, in
considering the effects of forests on the humidity of the climate,
than are those which have previously engaged our attention.

SacT. II. — Cases in which the Extensive Destruction of Forests

appear to have heenfolloioedhy a marked Desiccation

of Land and Aridity of Climate.

Lawyers have been credited with the hon mot that the case being
altered that alters the case, but the principle holds true in science
as well as in law ; and it seems to be a truth of universal application.
Along with the recorded observations which have been cited as cases
in which the extensive destruction of forests does not appear to have
perceptibly aflFected the quantity of rain falling over a widely-
extended country, there are other cases in which the extensive
destruction of forests appears to have been followed by a marked
desiccation of land and aridity of climate ; and these are so

104 EFFECTS OF FORESTS ON MOISTURE.

numerous as almost to justify the declaration that, in times past,
wherever civilised man has gone, what he found a wilderness he has
left a desert, dried up and desolate, through the reckless destruction
of the forests and the bush.

In treating of the hydrology of South Africa, of the former hydi'O-
graphic condition of the Cape of Good Hope, and of the causes of its
present aridity, I have given copious details in regard to the destruc-
tion of herbage and trees which has been going on in South Africa
from the time when it was first visited by Europeans to the present
(pp. 167-170), with details of the condition to which forests have been
reduced by reckless felling of timber trees (pp. 171-175), with details
of the extensive destruction of forests by fire (pp. 175-194), and with
details of the consequence of the destruction of herbage and trees on
the desiccation or diminution of the water supply in thfi basin of the
Orange River, given by Mr J. Fox Wilson in a paper read befoi-e the
Royal Geographical Society, with remarks on the same by Dr Living-
stone, Sir Roderick Murchison, Dr Kirk, Mr Galton, Colonel Balfour,
and Lord Stratford de RedchfFe (pp. 197-207), and corresponding
testimony by Dr Rubige, and others, at the Cape of Good Hope.

Of the extreme aridity of South Africa, beyond the colonized
portion of it, I have given illustrations in accounts given by Dr
Livingstone of his experience at Kolobeng, in accounts given of the
great suff'eriDgs of Mr Helmore and his family in travelling in the
interior, under which the whole of them succumbed and perished,
and in accounts given by Mr M'Kenzie of his experience in travelling
to Shooseng (pp. 216-223), and in accounts given by Dr Moffat of
his experience in a journey to Griqua Town (pp. 253-256) ; and of
the aridity of soil and climate within the colony I have given corre-
sponding illustrations in the same volume (p. 8 and p. 227).

In bringing forward these facts thus detailed I made obvious my
belief that though only the sequence of desiccation to the destruction
of forests and herbage and grass could be proved, they were connected
as cause and effect. Such was also the opinion of, I believe, all
whose testimony I thus adduced. To establish this point was the
object of the paper prepared for the Geographical Society by Mr Fox
Wilson ; and thus has Dr Moffat borne testimony to the fact : he
relates that on his settlement at Latakoo, " The natives were wont
to tell of the floods of ancient times, the incessant showers which
clothed the very rocks with verdure, and the giant trees and forests
which once studded the brows of the Hamhana hills and neighbour-
ing plains. They boasted of the Kurun^an and other rivers, with

PBSICCATION OF SOUTH AFRICA. 105

their impassable torrents, in which the hippopotami played, while the
lowing herds walked to their necks in grass, filling their mdkukas
(milk sacks) with milk, making every heart to sing for joy." And he
mentions that, " Independent of this fact being handed down by their
forefathers, they had before their eyes the fragments of more fruitful
years in the immense number of stumps and roots of enormous
trunks of acacia giraffce, where now scarcely one is to be seen raising
its stately head above the shrubs ; while the sloping sides of hills
and the ancient beds of rivers, plainly evinced that they were
denuded of the herbage which once clothed their surface. Indeed,
the whole country north of the Orange River lying east of the
Kalagari desert, presented to the eye of a European something like
an old neglected garden or field." Dr Mofi'at found no difl&culty in
accounting for this, " The Bechuanas, especially the Batlapis, and
the neighbouring tribes," says he, " are a nation of levellers ; not
reducing hills to comparative plains, for the sake of building their
towns, but cutting down every species of timber, without regard to
scenery or economy. Houses are chiefly composed of small timber,
and their fences of branches and shrubs. Thus, when they fix on a
site for a town, their first consideration is to be as near a thicket as
possible. The whole is presently levelled, leaving only a few trees,
one in each great man's fold, to afford shelter from the heat, and
under which the men work and recline.

'* The ground to be occupied for cultivation is the next object of
attention. The large trees being too hard for their iron axes, they
burn them down by keeping up a fire at the root. These supply
them with branches for fences, while the sparrows, so destructive to
their grain, are thus deprived of an asylum. These fences, as well
as those in towns, require constant repairs, and, indeed, the former
must be renewed every year ; and by this means the country for
many miles around becomes entirely cleared of timber ; while in the
most sequestered spots, where they have their outposts, the same
work of destruction goes on. Thus, of whole forests, where the
giraffe and elephant were wont to seek their daily food, nothing
remains.

" When the natives remove from that district, which may be after
only a few years, the minor species of the acacia soon grows, but the
acacia giraffce requires an age to become a tree, and many ages must
pass before they attain the dimensions of their predecessors. In the
course of my journeys I have met with trunks of enormous size,
which, if the time were calculated necessary for their growth, as well

I

106 EFFECTS OP FORESTS ON MOISTUEB.

as their decay, one might be led to conclude that they sprung up
immediately after the Flood, if not before it. The natives have also
the yearly custom of burning the dry gi-ass, which on some occasions
destroys shrubs and trees even on the very summit of the mountains.
To this system of extermination maybe attributed the long succession
of dry seasons." " To the same cause," says he, " may be traced the
diminution of fountains, and the entire failure of some which formerly
afforded a copious supply, such as Griqua Town, Campbell, and a
great number of others which might be mentioned. It has been
remarked that since the accidental destruction of whole plains of the
Olea similis (wild olive) by fire, near Griqua Town, as well as the
diminishing of large shrubs on the neighbouring heights, a gradual
decrease of rain has succeeded in that region."

In treating of these, the secondary causes of the desiccation of
South Africa, I had occasion to quote, from Marsh's treatise on " The
Earth as Modified by Human Action," the following statement, which
I followed up with the remarks and quotations from the same and
other authors, which follow : —

" ' Whenever a tract of country, once inhabited and cultivated by
man, is abandoned by him and domestic animals, and surrendered to
the undisturbed influences of spontaneous nature, its soil sooner or
later clothes itself with herbaceous and arborescent plants, and at no
long interval with a dense forest growth. Indeed, upon surfaces of a
certain stability, and not absolutely precipitous inclination, the
special conditions required for the spontaneous propagation of trees
may all be negatively expressed, and reduced to these three : —
exemption from defect or excess of moisture, from perpetual frost,
and from the depredations of men and browsing quadrupeds. When
these requisites are secured, the hardest rock is as certain to be over-
grown with wood as the most fertile plain, though for drier seasons
the process is slower in the former than in the latter case. Lichens
and mosses first prepare the way for a more highly organized vege-
tation. They retain the moisture of rains and dews, and bring it to
act, in combination with the gases evolved by their organic processes,
in decomposing the surface of the rock they cover ; they arrest and
confine the dust which the wind scatters over them, and their final
decay adds new material to the soil already half-formed beneath and
upon them. A very thin stratum of mould is sufficient for the
germination of seeds of the hardy evergreens and the birches, the
roots of which are often found in immediate contact with the rock,

EFFECTS OF DESTRUCTION OF FORESTS. 107

supplying their trees with nourishment from a soil deepened and
enriched from the decomposition of their foliage, or sending out long
rootlets into the surrounding earth in search of juices to feed them.'

" But with all the provisions which have been made for the produc-
tion of forests, and for the restoration of small portions which have
been destroyed, it is possible for man to counteract these ; and he
has done so. But what have been some of the consequences which
have followed ?

" According to a summary of some of these given by Marsh, ' With
the extirpation of the forest all is changed. At one season the earth
parts with its warmth by radiation to an open sky ; receives, at
another, an immoderate heat from the unobstructed rays of the sun.
Hence the climate becomes excessive, and the soil is alternately
parched by the fervours of summer, and seared by the rigours of
winter. Bleak winds sweep unresisted over its surface, drift away
the snow that sheltered it from the frost, and dry up its scanty
moisture. The precipitation becomes as irregular as the tempera-
ture ; the melting snows and varied rains, no longer absorbed by a
loose and bibular vegetable mould, rush over the frozen surface, and
pour down the valleys seawards, instead of filling a retentive bed of
absorbent earth, and storing up a supply of moisture to feed
perennial springs. The soil is bared of its covering of leaves, broken
and loosened by the plough, deprived of the fibrous rootlets which
held it together, dried and pulverized by sun and wind, and at last
exhausted by new combinations. The face of the earth is no longer
a sponge, but a dust heap ; and the floods which the waters of the
sky poured over it hurry swiftly along its slopes, carrying in suspen-
sion vast quantities of earthy particles, which increase the abrading
power and mechanical force of the current, and, augmented by the
sand and gravel of falling banks, fill the beds of the streams, divert
them into new channels, and obstruct their outlets. The rivulets,
wanting their former regularity of supply, and deprived of the
protecting shade of the woods, are heated, evaporated, and thus
reduced in their former currents, — but swollen to raging torrents in
autumn and in spring.

" * From these causes there is a constant degradation of uplands,
and a consequent elevation of the beds of water-courses, and of lakes,
by the deposition of the mineral and vegetable matter carried down
by the waters. The channels of great rivers become unnavigable,
their estuaries are choked up, and harbours which once sheltered
large navies are shoaled by dangerous sand-bars.'

108 EFFECTS OF FORESTS ON MOISTURE.

" The earth stript of its vegetable glebe grows less and less
productive, and consequently less able to protect itself by weaving a
new net-work of roots to bind its particles together, a new carpeting
of turf to shield it from wind and sun and scouring rain. Gradually
it becomes altogether barren. The washing of the soil from the
mountains leaves bare ridges of sterile rock, and the rich organic
mould which covered them, now swept down into the dai-k low
grounds, promotes a luxuriance of aquatic vegetation that breeds
fever and more insidious forms of mortal disease by its decay, and
thus the earth is rendered no longer fit for the habitation of man. . .

" The efi"ect of the destruction of forests upon the climate has been
questioned, but the facts remain. And so has it been seen again and
again in the history of the nations. The term savage, from its etymo-
logical derivation, speaks of a sylvan life ; and from the sylvan or
savage life to that of the civilized or city life, the progress of man
may be traced, to some extent, by the destruction of forests. The
one has, until attention was given to consequences which have
followed the destruction of forests, been the accompaniment or com-
plement of the other, operating sometimes as a cause, manifesting
itself sometimes as a consequence — if both be not con-sequences of a
common cause. But it is possible that the destruction of forests may
be carried too far. According to the testimony of Dr Hooker, cited
in the preface, ' In the estimation of an average Briton forests are of
infinitely less imjJortauce than the game they shelter, and it is not
long since the wanton destruction of a fine young tree was considered
a venial ofi'ence compared with the snaring of a pheasant or x'abbit.
Wherever the English rule extends, with the single exception of India,
the same apathy or inaction prevails. ... In Demerara the
useful timber trees have all been removed from accessible regions,
and no care or thought of planting others ; from Trinidad we have
the same story ; in New Zealand there is not now a good Kami pine
to be found near the coast ; and I believe that the annals of almost
every English colony would repeat the tale of wanton waste and
improvidjgnce.'

" In view of this waste, Schleiden, to whom I have already referred,
writes, if not in the words, yet following in the train of thought of
one of the noblest veterans of our science, the venerable Elias Fries,
of Lund : ' A broad band of waste land follows gradually in the steps
of cultivation. If it expands, its centre and cradle dies, and on the
outer borders only do we find green shoots. But it is not impossible
it is only difficult, for man, without renouncing the advantage of

SPREAD OF DEVASTATION. 109

culture itself, one day to make reparation for the injury which he has
inflicted : he is appointed lord of creation. True it is that thorns and
thistles, ill-favoured and poisonous plants, well named by botanists
' rubbish plants,' mark the tract which man has proudly traversed
through the earth. Before him lay original nature in her wild but
sublime beauty. Behind him he leaves the desert, a deformed and
ruined land ; for childish desire of destruction, or thoughtless
squandering of vegetable treasures, have destroyed the character
of nature ; and man himself flies terrified from the arena of his actions,
leaving the impoverished earth to bai'barous races or animals, so long
as yet another spot in virgin beauty smiles before him. Here again,
in selfish pursuit of profit, consciously or unconsciously, he begins
anew the work of destruction. Thus did cultivation, driven out,
leave the East, and the deserts pei'haps previously I'obbed of their
coverings ; like the wild hordes of old over beautiful Greece, thus
rolls this conquest with fearful rapidity from east to west through
America, and the planter often now leaves the already exhausted
land, the eastern climate become infei'tile through the demolition of
the forests, to introduce a similar revolution into the far west. But
we see, too, that the nobler races, or truly cultivated men, even now
raise their warning voices, put their small hand to the mighty work
of restoring to nature her strength and fulness in yet a higher stage
than that of wild nature ; one dependent on the law of purpose
given by man, arranged according to plans which are copied from
the development of manhood itself. All this, indeed^ remains at
present but a powerless, and for the whole, an insignificantly small
enterprise, but it preserves the faith in the vocation of man and his
power to fulfil it. In future times he will and must, when he rules,
leads, and protects the whole, free nature from the tyrannous slavery
to which he now abases her, and in which he can only keep her by
restless giant struggles against the eternally resisting. We see in
the gray cloudy distance of the future a realm of peace and beauty
on the earth and in nature, but to reach it must man long study in
the school of nature, and, before all, free himself from the bonds of
that exclusive selfishness by which he is actuated." '

In 1847 was published Klima ttiid Plantzen Welt in der Zeit, by
C. Fraas. It was published at Landshut. In this work the writer
endeavoured to show, by the history of vegetation in Greece, not merely
that clearing and cultivation have affected the climate, but that change
of climate had essentially modified the character of vegetable life.

110 EFFECTS OF FORESTS ON MARSHES,

In the same year, 1847, Becquerel published a work, entitled
Elements de Physique Terrestre et de Mineralogie, and six years later,
in 1853, he published another work, entitled Des Climats et de
Vinjliience qu exercent les sols Boises et non-hoissees, and in a paper
addressed to the Academy of Sciences he examines the subject of
forests both as to their commei'cial importance, and as to their
influence on climate. In this paper he casts a rapid glance at the
effects produced by the destruction of forests from the remotest ages
to our time.

Forests, he shows, existed on the globe long befoi'e the appearance
of man, a fact proved by the immense coal deposits which are to be
found in every part of it, even in the polar regions. These deposits
consist of Equisetacea, Sigillaria, &c., particularly also of ferns of the
size of trees, instances of which are now only to be met with under
the tropics. In most parts of the old continent, the primitive life of
man was, as he shows, passed in forests, and increase of population
was the cause of the first attacks upon them ; but the greatest
devastations only date from the period when great conquerors cut
down and burnt the forests in which the peoples they wanted to
subdue had taken refuge. From the Ganges to the Euphrates, from
that to the Mediterranean, an extent of ground 1,000 leagues in
length and several hundred broad, was ravaged by wars during the
lapse of thirty centuries. Nineveh and Babylon, so celebrated for
their civilization. Palmyra and Balbeck, renowned for their opulence,
now offer nothing but ruins to the exploring gaze of the traveller, in
the iTdidst of deserts and s^vamps, once covered by luxuriant forests.
From the time of Sesostris to that of Mehemet II., Asia Minor was a
constant scene of unrelenting wars leading to similar results. The
land of Canaan, so highly praised in the Bible, is now little more
than a desert, and the whole coast of Africa along the Mediterranean
tells a similar story.

Turning from historical considerations to the present state of forests
in France, he shows that similar operations, though not to the same
extent, were being cfirried on there, which could only tend to produce
similar effects.

By Mr Marsh, who has himself given much attention to the
subject, it is stated that the subject of climatal change, with and
without reference to human action as a cause, has been much dis-
cussed by Moreau de Jormis, Dureau de la Malle, Arago, Humboldt,
Fuater, Gasparm, Becquerel, and many other writers, in Europe, and

DEVASTATION OF THE EAST. Ill

by Noali Webster, Ferry, Drake, and others, in America, and his
work cited is a valuable repository of infonnation, collected by
him from their works and other sources, combined with observations
made by himself, and conclusions at which he has arrived, all of
which are in accordance with those here stated.

Besides the writers now named, Professor Laurent, of Nancy
Forest School, has given attention to the s'lbject, and has traced the
desolation which has been brought on the former homes of teeming
life in the East to the destruction of trees. And a writer in the
Edinburgh Review, for October 1875, on the subject of forest manage-
ment, citing the work of Professor Laurent, says, " Babylon, Thebes,
Memphis, and Carthage, now waste and even pestilential, were
formerly the very hives of human life. The remains of conduits
canals, cisterns, and pools, throughout Palestine, and especially
through the now desert couutiy east of the Jordan, are such as to
explain the accounts on record of the former population of these
regions. So thorough has been not only the change of climate, but
the denudation of soil, caused by the cutting down of the olives,
palms, and other trees of Palestine during the Roman war, that it
would be impossible to attach any credit to the most venerable
accounts of the former fertility, beauty, and population of the Holy
Land — its brooks and fountains gushing out of valley and hills, being
now replaced by bare and solid rock— without the knowledge that we
have acquired of the fatal effect of the destruction of timber." This
may be considered by others, as it is by me, questionable, but it
may be received as indicative of the conviction of the writer, that
the connection of the destruction of the forests, eighteen hundred
years ago, with the present aridity, as cause and effect, is established
beyond all question.

It is alleged by Mr Draper, while reporting his conclusions from
an extensive collating of meteorological records in Amei'ica, which
wei-e to the effect that there had been no diminution of the rainfall in
the districts in which these observations had been made, that, —
"Against this conclusion, which is based essentially on recorded
instrumental observations, I cannot admit the force of any alleged
historical facts ; " and expressing an opinion that the devastation of
ancient empires which is attributable in part to drought, is attribut-
able in a great measure to war, and consequences of war other than
the destruction of forests, he says, — " It is useless to draw any

112 EFFECTS OP FORESTS ON MOISTURE

inference from the present desolate condition of the regions of the
Euphrates and Tigris, or of the Holy Land, as contrasted with their
amazing fertility in the olden days ; " and, " changes such as these
have nothing to do with changes of climate." But, with the mass of
testimonies which I have piled around me to effects which have
followed immediately on the destruction of forests, I cannot assent to
the sweeping statement I have quoted. It may be freely admitted
that devastations occasioned by war may be followed by drought,
without compromise to the allegation that the destruction of forests
may be followed by drought. The devastations of war may include the
destruction of forests, ajid it so happens that facts are not awanting
illustrative of the devastations of war being followed by an opposite
effect, with results corresponding to what might be expected therefrom.

When Humboldt visited South America he was led to consider
what could be the cause or occasion of a process of desiccation which
was brought under his notice. To quote from a statement by Boussin-
gault, which is cited by Mr Marsh : — " ' The rivers which rise within
the valley of the Aragua, having no outlet to the ocean, form, by
their union, the Lake of Tacarigua or Valencia, having a length of
about two leagues and a-half [or seven English miles].

" ' At the time of Humboldt's visit to the valley of the Aragua, the
inhabitants were struck by the gradual diminution which the lake
had been undergoing for thirty years. Tn fact, by comparing the
descriptions given by historians with its actual condition, even
making large allowance for exaggeration, it was easy to see that the
level was considerably depressed. The facts spoke for themselves.
Oviedo, who, toward the close of the sixteenth century, had often
traversed the valley of the Aragua, says positively that New Valencia
was founded, in 1555, at half a league from the Lake of Tacarigua ;
in 1800, Humboldt found this city 5,260 metres [or three and a-half
English miles] from the shore.

" ' The aspect of the soil furnished new proofs. Many hillocks on
the plain retain the name of islands, which they more justly bore
when they were surrounded by water. The ground laid bare by the
retreat of the lake was converted into admirable plantations ; and
buildings erected near the lake shewed the sinking of the water from
year to year. In 1796, new islands made their appearance. A
fortress built in 1740 on the island of Cabrera, was now on a
peninsula ; and, finally, on two granitic islands, those of Cura and
Cabo Blanco, Humboldt observed among the shrubs, some mHrea
above the water, fine sand filled with helicites.

OBSERVATIONS IN SOUTH AMERICA, 113

" ' These clear and positive facts suggested numerous explanations,
all assuming a subterranean outlet, which permitted the discharge of
the water to the ocean. Humboldt disposed of these hypotheses,
and did not hesitate to ascribe the diminution of the waters of the
lake to the numerous clearings which had been made in the valley of
Aragua within half a century.'

" Twenty-two years later, Boussingault explored the valley of Ara-
gua. For some years previous, the inhabitants had observed that the
waters of the lake were no longer retiring, but, on the contrary, were
sensibly rising. Grounds, not long before occupied by plantations,
were submerged. The islands of Nuevas Aparecidas, which appeared
above the surface in 1796, had again become shoals dangerous to
navigation. Cabrera, a tongue of land on the north side of the
valley, was so narrow that the least rise of the water completely
inundated it. A protracted north wind sufl5ced to flood the road
between Maracay and New Valencia. The fears which the inhabi-
tants of the shores had so long entertained were reversed. Those
who had explained the diminution of the lake by the supposition of
subterranean channels were suspected of blocking them up, to prove
themselves in the right.

*' During the twenty-two years that had elapsed, the valley of
Aragua had been the theatre of bloody struggles, and war had
desolated those smiling lands and decimated their population. At
the first cry of independence a great number of slaves found their
liberty by enlisting under the banners of the new republic ; the great
plantations were abandoned, and the forest, which in the tropics so
rapidly encroaches, had soon recovered a large proportion of the soil
which man had wrested from it by more than a century of constant
and painful labour."

In this case war seems to have produced a contrary effect to that
attributed to it, in other circumstances, by Mr Draper.

Boussingault proceeds to state that two lakes near Ubate, in New
Granada, had formed but one a century before his visit ; that the
waters were gradually retiring, and the plantations extending over
the abandoned bed ; that, by inquiry of old hunters, and by examina-
tion of parish records, he found that extensive clearings had been
made and were still going on.

" He found, also, that the length of the Lake of Fuquend, in the
same valley, had, within two centuries, been reduced from ten
leagues to one and a half, its breadth from three leagues to one. At

114 THE EFFECTS OF FOKESTS ON MOISTXTRE,

the former period the neighbouring mountains were well wooded, but
at the time of his visit the mountahis had been almost entirely
stripped of their wood. He further adds that other cases, similar to
those alrei.dy detailed, might be cited, and he proceeds to show, by
several examples, that the waters of other lakes in the same regions,
where the valleys had always been bare of wood, or where the forests
had not been disturbed, had undergone no change of level."

The following statement is also made by Boussiiigault : — *' In the
island of Ascension there was an excellent spring, situated at the foot
of a mountain originally covered with wood. This spring became
scanty, and at last dried up, after the trees which covered the
mountain had been felled. The loss of the spring was ascribed, and
rightly so, to the cutting down of the timber. The mountain was
therefore planted anew, and a few years afterwards the spring re-
appeared by degrees, and by and by flowed with its former abundance.

" The metalliferous mountain of Marmato is situated in the province
of Popayan, in the midst of immense forests. The stream along which
the mining works are established is formed by the junction of several
small rivulets, which take their rise in a country thickly wooded.

" In 1826, when I visited the mines for the first time, Marmato
consisted of a few miserable cabins, inhabited by negro slaves. In
1830, when I quitted the country, Marmato was covered with work-
shops, had a foundry of gold, machinery for grinding and amalga-
mating the ores, and a free population of nearly 3000 inhabitants.
In the course of these four years an immense quantity of timber had
been cut down, for the construction of machinery and of houses, as
well as for fuel and the manufacture of charcoal. But the clearing
had scarcely been two years effected before it was perceived that the
quantity of water for the working of the machinery had notably
diminished. The volume of water was measui-ed by t!ie work done
by the machinery; and actual gauging at different times showed the
progressive diminution of the water. Now, in the island of Ascension,
and at Marmato, it is improbable that any merely local and limited
clearing away of the forest should have had such an influence on the
constitution of the atmosphere as to cause a variation in the mean
annual quantity of rain. Besides, as soon as the diminution of the
stream at Marmato was ascertained, a rain-gauge was set up, and in
the second year of observation showed a larger quantity than in the
first year, though the clearing had been continued, and though there
was no appreciable increase in the size of the running stream.

" Two years' observations are insufficient to show any definitive

OBSERVATIONS BY BOUSSINGAULT. llS

variation ia the annual average quantity of rain. Bat, so far as they
go, they show that at Marmato the mass of running water had
diminished, in spite of the larger quantity of rain which fell. It is
therefore probable that local clearings of forest land, even of very
moderate extent, cause springs and rivulets to shrink, and even to
disappeai', without the effect being ascribable to any diminution in
the amount of rain that falls."

These observations are advanced by Boussingualt in connection
with the statement that, — " In many localities it has been thought
that, within a certain number of years, a sensible diminution has been
perceived in the volume of water of streams utilized as a motive-
power ; at other points, there are grounds for believing that rivers
have become shallower, and the increasing breadth of the belt of
pebbles along their banks seems to prove the loss of a part of their
water ; and, finally, abundant springs have almost dried up. These
observations have been principally made in valleys bounded by high
mountains, and it has been noticed that this diminution of the waters
has immediately followed the epoch when the inhabitants have begun
to destroy, unsparingly, the woods which were spread over the face of
the land.

" And here lies the practical point of the question ; for if it is once
established that clearing diminishes the volume of streams, it is less
important to know to what special cause this effect is due."

In a report by Dr Hough, President of the United States Associa-
tion for the Advancement of Science, in 1871, are references to
climatic conditions there, attributed to the destructions of forests ;
and, in this connection, referring to the painful accounts which the
journals were then giving of the distress in India from famine, he
says, — " From a careful study of this subject, with such data as are
accessible in late reports, we cannot doubt that this calamity is
largely due to the fact that the forests have within recent years been
swept off, by demands for railroad and other uses, much more rapidly
than formerly, and that the exposure to winds and sun, thus
occasioned, may have largely contributed to these painful results."

Mr Marsh, in a foot-note supplying indications of what may be
called secular desiccation, in regard to which he had said, " After a
district of country has been completely or even partially cleared of its
forest growth and brought under cultivation, the drying of the soil
under favourable circumstances, goes on for generations, perhaps for

116 EFFECTS OF FORESTS ON MOISTURE

ages," says, — " In many parts of New England there are tracts,
many square miles in extent, and presenting all varieties of exposure,
which were partially cleared sixty or seventy years ago, and where
little or no change in the proportion of cultivated ground, pasturage,
and woodland has taken place since. In some cases, these tracts
compose basins apparently scarcely at all exposed to any local
influence in the way of percolation or infiltration of water towards or
from neighbouring valleys. But in such situations, apart from
accidental disturbances, the ground is growing drier and drier from
year to yeai-, springs are still disappearing, and rivulets still
diminishing in their summer supply of water. A probable explana-
tion of this is to be found in the rapid drainage of the surface of
cleared ground, which prevents the subterranean natural reservoirs,
whether cavities or merely strata of bibulous earth, from filling up.
How long this process is to last before an equilibrium is reached,
none can say. It may be for years ; it may be for centuries.

"Livingstone states facts which strongly favour the supposition
that a secular desiccation is still going on in Central Africa, and
there is reason to suspect a like change is taking place in California.
When the regions where the earth is growing drier were cleared of
wood, or, indeed, whether forests ever grew there, we are unable to
say, but the change appears to have been long in progress. A
similar revolution appears to have occurred in Arabia Petraea. In
many of the wadis, and particularly in the gorges of the Wadi Feiran
and Wadi Esh Sheikh, there are water-worn banks showing that, at
no very remote period, the winter floods must have risen fifty feet in
channels where the growth of acacias and tamarisks and the testi-
mony of the Arabs concur to prove that they have not risen six feet
within the memory or tradition of the present inhabitants. Recent
travellers have discovered traces of extensive ancient cultivation, and
of the former existence of large towns in the Tih desert, in localities
where all agriculture is now impossible for want of water. Is this
drought due to the destruction of ancient forests, or to some other
cause ?

" For important observations on supposed changes of climate in our
Western prairie region, from cultivation of the soil and the introduc-
tion of domestic cattle, see Bryant's valuable Forest Trees, 1871,
chapter v., and Hayden, Preliminary Report on Survey of Wyoming,
p. 455."

Mr Marsh adds : — " Some physicists believe that the waters of our
earth are, from chemical or other less known causes, diminishing by

REPLANTING FOLLOWED BY HUMIDITY. 117

entering into new and inorganic combinations, and that the element
will finally disappear from the globe." I do not know anything of
the facts or the reasonings on which this opinion rests.

If it be necessary, in considering the effects of forests on the
humidity of the climate, to take into account cases in which the
extensive destruction of forests does not appear to have powerfully
aflfected the quantity of the rainfall over a wide expanse of country,
it is no less necessary to take into account other cases in which the
extensive destruction of forests does appear to have been followed by
a marked desiccation of land, and aridity of climate. They are facts
perfectly compatible with each other, and the establishment of either
is neither a disproof of the other, nor does it invalidate the testimony
on which it is received, though it may prompt to a more strict
scrutiny of what is said, and of the credibility of this, than might
otherwise have been given to it. Let it suffice here to state that the
objections to which such statements are open are these, first, that
they are vague and general, and, second, that they relate to effects
which may have been otherwise produced than in accordance with the
supposition advanced ; and what is considered the cause may have
been in reality the effect, for anything to the contrary advanced in
the statements made.

Sect. III. — Cases in ivhich the Destruction of Trees has been followed

hy Desiccation, and the Replanting of Trees followed by

the Restoration of Humidity,

In treating of the Hydrology of South Africa, in a separate
volume already referred to, I had occasion to cite St. Helena as a
South African Island supplying illustrations of corresponding effects
produced on the climate both by the destruction of trees and by
extensive sylviculture.

From a note appended by Emsmau to his German translation of
a work on meteorology in relation to cosmical phenomena by Foissac,*
it appears that in the beginning of the sixteenth century the forests
of St. Helena must have been extensive, for it is stated by him, on
the authority of the introductory chapters in Beatson's St. Helena,
that it was the goats which destroyed the beautiful forests which,

* Meteorologie mit RUcksight auf die Leiiere vom Kosmos. Deuich von
A. U. Emsman, Leipzig, lb59.

118 EFFECTS OF FORESTS ON MOISTURE.

three hundred and fifty years ago, covered a continuous surface of not
less than two thousand acres in the interior of the island, not to
mention scattered groups of trees.

While I was at the Cape I wrote to St. Helena for information on
the subject, and in reply his Excellency, H. R. Janisch, now Governor
of the island, at once supplied me with the following information,
embodied in notes published on the Natural History of St. Helena : —
" Viewed from the sea the island offers little or nothing to the eye
but an assemblage of lofty and barren hills, intersected in all
directions with deep and narrow valleys, in many cases little better
than ravines, and generally devoid of vegetation, excepting here and
there patches of prickly pear, samphire, and profitless weeds, the
wooded peaks in the interior being in most positions hidden from
view by the almost perpendicular cliff's running down to the sea.
Bat when first discovered, in 1502, it was in the valleys almost
covered with trees right down to the water's edge. These trees
appear to have been principally gum-wood, ebony, and red-wood."
Tiie gum-wood flourished nearest to the sea ; the ebony and red-
wood covered the slopes of the mountain ; while the hill tops appear
to have been covered with the cabbage tree and ferns — the former
(areca oleracea) presenting from a little distance the appearance of a
tree bearing stocks of cabbage, or of brocoli, at the extremities of its
branches. While such was the state of vegetation, it must have been
an island well watered everywhere.

Bat the earlier governors and settlers made sad havoc among the
trees ; and herds of goats and of swine being allowed to run loose on
the land, young growing trees, which might have supplied the waste,
were destroyed, and the island became almost denuded. All the
ebony trees have long since disappeared : the last, a tree remarkable
for its excessive hardness, size, and density, was found on Deadwood.
The red-wood is now scarce, and, like the ebony, would altogether
have disappeared, had not Governor Byefield caused two young trees
to be set at Plantation House, from which two all at present on the
island have been propagated. And a comparison of the cabbage trees
of the present with the remains of those of the past tell of a stunted
growth. What was the consequence of this extensive destruction of
trees? "Incidentally we find," says my correspondent, "in the
records of the last century, accounts of repeated and almost periodical
visitations of very severe drought, occasioning ruinous losses of cattle
and crops."

Towarda the close of the last century, however, the denudation of

RAINFALL IN ST. HELENA. 119

the island had been carried so far that wiser governors saw it to be
necessary to adopt some strenuous measure to restore the vegetation.
Nurseries were made, and experienced gardeners were introduced by
the Company, and trees from all parts of the world were introduced
and flourished. Prizes were given for the number of trees reared,
irrespective of their character. The cluster-pine (pinus pinaster) was
sown very extensively, and several plantations of this tree remain in
a thriving condition. But a variety of other forest trees, greatly pre-
ferred both for beauty and use, were planted about the same period
and have flourished well. In regard to the results, my correspondent
writes : — " For many years past, since the general growth of our trees,
we have been preserved from this scourge ; and droughts, such as
were formerly recorded, are now altogether unknown. We have no
means, however, of otherwise comparing the rainfall of the two periods,
as no tables, or even estimates, of the rainfall can be had for the
earlier dates. Our fall of rain now is equal to that of England, and
is spread almost evenly over the year. The showers fall more heavily
in two or three months of the year. But this period, though called
on this account the rainy season, is in no way to be compared to
what is understood by an inter-tropical rainy season."

Meteorological observations are or were kept at Longwood and at
Plantation. I have at command only the record of the rainfall from
1841 to 1848. The amount of rain which fell in these years was : —

1841, 68-925 1845, 19-509

1842, 90-458 1846, 26-556

1843, 37-189 1847, 42-441

1844, 20-026 1848, 45-630

The communication I have cited not only tells of the former
abundance of vegetation and moisture, and of frequent long-continued
droughts having followed the reckless destruction of forests, but it
tells of the replenishing of the island with trees under the fostering
care of the East India Company towards the close of the last
century ; and that subsequent to that, droughts such as had been
previously recorded had been for a long time altogether unknown.
But it was further added : — " Since the transfer of the Island from
the Company in 1836 the matter has been much neglected. The
liberal expenditure and prizes of the East India Company came to an
end. The business men of our population require, whether the profits
be large or small, that the returns shall be quich ; and they have no
idea of casting upon waters seed that cannot be found after so many

120 EFFECTS OF FORESTS ON MOISTURE.

days. The result has been that, for the last thirty years, in place of
every score cut down hardly one tree has been planted beyond the
supply of self-sown plants. Our Governor has, however, given much
attention to this since his arrival ; and he is anxiously endeavouring
to introduce and propagate the best trees he can obtain, and as yet
his experiments have been very successful and encouraging." This
was written in 1865.

Blanqui in a volume entitled Voyage in Bulgarie, published in 1843,
says that, — " In the Island of St. Helena, where the wooded surface
has considerably extended within a few years, it has been observed
that the rain has increased in the same proportion. It is now in
quantity double what it was during the residence of Napoleon." In
this we find a corroboration of what was reported by Mr Janisch in
regard to the consequence of extensive plantings encouraged by the
East India Company previous to 1836.

The Island of St Helena is of volcanic origin. It is said to have been
discovered by the Dutch in 1502. " Viewed from the sea, as it is
approached, there is nothing inviting in its appearance; one large
mass of rock with deep ravines running down into the sea, divested
apparently of all vegetation, and presenting inaccessible rugged cliffs,
some of great height, is all at first that the eye beholds ; but as one
nears the shore in the interior at certain places may be seen, peeping
from out the rock, a few trees to tell that all is not barrenness
within."

In the " Notes on the Natural History of the Island of St. Helena "
sent to me, it is stated.

" The greater part of the Island is now bare of trees and verdure,
many mountains having little upon them beyond samphire and a few
scrubby weeds, which alone save them from absolute sterility,
especially in the dry season, when the shallow soil is utterly parched
up. Other mountains are capable of afFoi'ding a very limited supply
of food for sheep, which traverse their loftiest peaks and most intricate
paths in search of their scanty fare.

" Some few of the hills are tolerably well wooded, and the loftiest
of the whole, Diana's Peak, 2700 feet high, is clothed to the very
summit

" The cultivated parts of the Island, particularly in the neighbour-
hood of Plantation, as seen from High Knoll, remind the stranger very
much of England, especially of parts of Devonshire.

" lllusiou or likeness is further carried out by the large quantities

PLANTS ON PT. HFLKNA, 121

of luxuriant furze and scrambling brambles seen in full bloom down
the slopes of the hill, along the lanes and bye-roads.

" The furze appears to have been introduced into the Island during
the early part of the last century, and has proved very useful to the
inhabitants by furnishing them with a plentiful supply of fire-wood.
It does not appear to be used here as it is in the north of England,
for the purpose of watling in the walls, for making warm and comfort-
able outbuildings for fai-ms and other purposes.

** When used this way, it is merely twisted between the upright
posts supporting the building, and if closely worked it makes a warm
building.

" There are several plantations in the Island pretty well stocked
with good sized trees, principally pine and fir, which grow very well
here, but for timber purposes the wood is too coarse and open in
texture, resulting most likely from its rapid growth. The wood will
answer for common purposes when protected from the weather, but
otherwise it appears soon to decay and to be subject to rot.

" These trees, however, are a great ornament to the Island, and
add much to its English appearance, as they are the predominating
ones, and give character to the scenery.

" The Scarlet Geranium grows wild and very luxuriantly among the
rocks, and in some places may be seen whole hedges of it ; the
nasturtion also grows wild, and water cresses are found in the valley
streams, as well as many other plants common to England.

" Barilla, called here samphire, is very abundant in most parts of
the Island ; and the true samphire is found in many places, but does
not appear to be much used. Fruit of many kinds grows very well
here ; the pears are large, plump, hard, and juicy, and are seen on the
tree at the same time as the blossoms. Peaches are good and
plentiful, their beautiful blossoms being often seen in the hedges ;
the fig thrives pretty well, as also Oranges and Lemons, and the
useful Plantain. Coffee has been tried and succeeded, it is considered
to be very good in quality and flavour. Cotton grows wild, as well
as the castor-oil plant.

" The Port Jackson Willow thrives exceedingly well, and will ulti-
mately be valuable for supplying firewood, as it grows quickly and
throws up much underwood ; and is a veiy ornamental tree in all its
aspects, especially pleasing to the eye when full of its yellow catkins.

" The Cape Gooseberry is a useful fruit, and forms an excellent
substitute for the English Gooseberry which it much resembles in
taste when cooked ; it is the more useful from the fact that the

122 EFFECTS OF FORESTS ON MOISTURE.

English Gooseberry does not thrive well here, but runs into an un
fruitful shrub.

" The trees most cultivated in Jamestown are the Margossa and
the Banian, neither of which are of any great use except for a little
shelter from the sun; the Banian is more curious than beautiful.
The Date, Cocoa Nut, and Cypress are seen in some of the gardens, and
the long leaf of the Plantain mostly accompanies them wherever
water can be obtained.

" A great variety of plants, the natives of different regions, may
be seen growing equally well on St. Helena, the configuration of which
affords a considerable range of climate. The following list of the
exotic trees and shrubs now growing on the island may prove not
uninteresting : —

" Common Oak, Mosscup Oak, Evergreen Oak, Cork Tree, Abele
Tree, Weeping Willow, Pineaster Fir, Spreading Fir, Dwarf Fir,
Norfolk Island Pine, Chili Fir, Cape Yew, Casuarina, Cypress (two
kinds), Arbor Vitce, Eucalyptus, Banian (four kinds), Indian Rubber
Tree, Eiythrina Cape Coral Tree (three kinds), Sophora, Margossa,
Gamboge, Terminalia (Bengal Almond), Pittisporum, Wild Olive,
Black Fruited Olive, Magnolia, Liliodendron, Silk-worm Mulberry,
Cliiua Weeping Birch, Mun-aya, Sago Palm, Palmetto, Dragon Palm,
Fan Palm, Iron Wood, Holy Thorn, Myrtle (three kinds), Bauhinia,
Locust, Bois Noir, Teak, Cinnamon, Laurel, Bay, Barberry, Protea,
Gum Benzion, Coffee Shade, Wild Fig, Wattle of New Holland,
Gelega, Altheea Frutex, Chinese Rose Hibiscus (^Shoe Black), Change-
able Rose (two kinds), Single Red Hibiscus, Single Purple Hibiscus,
White Flowered Hibiscus, Yellow Tahitian Hibiscus, Mimosa
(various,) Acacia (various), Port Jackson Willow, Buddlea, Candle
Nut Tree, Yansheu, China Rose Apple, Spice Tree, Psoralea, English
Privet, Sea Grape, Coral Tree (Jatrapa), Rock Rose, Travellers Joy,
Oleander, Fiddle Wood, Pola Gola, Spanish Broom, Velvet Thorn,
Cassia, Grewia, Datura Arborea, Scarlet Cordea, Soap Berry, Screw
Pine, Date Plum, Sweet Olea, Tea, Coffee, China Privet, Jasmine
(2 kinds). Holly, Banksia, (3 kinds), Elder, Cotton (2 kinds), Cytisus,
Ash, Barbados Pride, Lion's Tail, Osteospernum, Castor Oil, May,
Azalea, Gardenia (Cape Jasmine), Tutsan, Verbena, Furze, Wild
Bringal, Bamboo (3 kinds). Bamboo Reed, Plumbago, Camellia,
Fuschia, Madagascar Creeper, Passion Flower (5 kinds). Ivy, Wood-
bine, Melostroma.

" Fruit-bearing Plants : — Peach, Apple, Pear, Cape Plum, Mango,
Chirimoya, Orange (Sweet), Orange (Seville), Lemon, Lime, Shaddock,

RAINFALL ON ST. HELENA. l'?3

Citron, Quince, Filbert, Grape, Pomegranate, Cocoa Nut, Date,
Water Lemon (purple), Rose Apple, Pine Apple, English and Spanish
Mulberry, Loquat, Banana, Apricot, Guava, Litchi, Melon, Cherry,
Indian Walnut, Chesuut, Fig, Papau Apple, Tamarind, Strawberry,
Wild Raspberry, English Raspberry, Blackberry, Cape Gooseberry
(Tomatita, vulgarly called Bilberry."

Ships entering the harbour approach it on the eastern side of the
Island, to windward, and may sail with safety close on shore, the
water in the roadstead being deep, and there they may ride at anchor
at all times with perfect safety, there rarely being any wind so strong,
or sea so violent as to endanger their security. Opposite the
anchorage is the town of St. James. At the extreme end of the town
are a few pretty forest and vegetable gardens ; and at the termina-
tion of James' Valley is a waterfall, beneath which is a beautiful
spring whence comes all the water used for the supply of the town
and shipping. The water is clear and good. It is calculated that
seven thousand tons of water are daily discharged into the sea. The
number of springs in the Island are said to exceed two hundred.

I accept with faith the statements made to me, in regard to the
changes remarked at St. Helena as following the destruction and
replenishing of trees, mainly because of their general accordance
with what has been observed elsewhere ; but also in a great measure
from confidence in popular observations in regard to facts even
when I cannot assent to popular expositions of these facts as to
cause and ejQFect.

The following remarks are results obtained from observations
made by rain gauges kept at St Helena : —

The total amount of Rain which fell at Longwood in the year 1848
was 45-630 inches, which appears to be rather more than the average
of eight years previous, which amounts only to 43 '8 inches.

The month of October, during 1848, was the driest month of the
year, being only 0-126 of an inch. January is the nest driest mouth
0-720, and December 0-758 ; the two wettest tnonths being June
7-150 and July 9-245 inches.

Upon comparing the Registers kept at Longwood and Plantation
for 1847, it appears that the fall of rain was greatest at Plantation, it
there being 45-892 inches, and at Longwood 42*364 inches; January
and December being the two driest months of the year, June and
September being the two wettest months, when the sum of the two
mouths are taken. At Plantation the two wettest months were

124 EFFECTS OF FORESTS ON MOISTURE.

June and July; at Longwood tlie wettest montlis being June and
September.

The amount of Rain which fell for the undermentioned years, was :

1841, 68-925 inches. 1842, 90*458 inches.

1843, 37-189 „ 1844, 20-026 „

1845, 19-509 „ • 1846, 26-556 „

1847, 42.411 „ 1848, 45-630 „

giving the mean annual fall, 43-813 inches.

Upon Examining the Monthly Register for these eight years, it
appears that October, November, December, and January, give the
mean driest months. The four wettest being March, May, June,
and July. The December of 1846 being the driest month of the
Avhole 96 months ; and the February of 1842 being the wettest month
of the whole period.

Professor Playfair states, that when the annual fall exceeds 25
inches, the climate is to be classed as moist : if so, St. Helena must
certainly be classed as a moist climate, because this standard, com-
pared with St. Helena's average of eight years, is nearly in the pro-
portion of 25 to 43. The Professor also " supposes" the annual fall
of Rain near London at 24 inches ; if so, St. Helena far exceeds London
in its fall of Rain, this being more than half as much again at St.
Helena as it is at London.

The four following observations, being the quantities of Rain
received at the respective stations for a period of nine months in
1841, are quoted as a confirmation of the theory that woods and
mountains tend to precipitate Rain : —

1, At 2644 feet elevation 22-63 inches.

2, At 1991 „ 27-11

3, At 1782 „ 43-42

4, At 414 „ 7-63

The whole four stations being comprehended within a circle of little
more than a mile radius.

These statements I give as I have received them. So much
depends on the locality and circumstances in which observations by
the rain gauge are made that I am unable to say whether they tend
to strengthen or to weaken the conclusion to which I have come.

The Island of Mauritius supplies analogous facts. In a history of
that Island, embodied my informant believes in Thornton's History
of India, the author observes that when we obtained possession of it
our countrymen thought it absurd that the beautiful land on the

STATE OP MAURITIUS. 125

summits and slopes of the mountains should be abandoned to forests
and jungle, and so cut them down, upon which the water supply
began to fail. Reflection soon taught the authorities the cause of
this failure ; upon which the hills were again planted with trees, and
the rivers and streams resumed their former dimensions.

Mr Marsh writes : — " The Island of Mauritius lying in the Indian
Ocean in about 20° N. L., is less than forty miles long by about
thirty in breadth. Its surface is very irregular, and though it con-
sists, to a considerable extent, of a plateau from 1200 to 1500 feet
high, there are three mountain peaks ranging from 2300 to 2700
feet in height. Hence, though the general climatic influences are
everywhere substantially the same, there is room for a great variety
of exposures and of other purely local conditions. It is said that
the difference of temperature between the highest and lowest stations
does not exceed eight degrees F, while, according to observations at
thirty five stations, the rainfall in 1872 varied from thirty-three
inches at Gros Cailloux to one hundred and forty six inches at Cluny.
Nature, September 24, 1874. This enormous difference in measure-
ment is too great to be explained by possible errors of observation or
other accidental circumstances, and we must suppose there are, in
difi'erent parts of this small island, great differences in the actual
precipitation, but still much of this variation must be due to causes
whose range of influence is extremely limited."

Mr Meldrum, Director of the Mauritius Observatory, read a paper
before the Scottish Meteorological Society in July, 1866. In this he
stated that for some years before there had been severe droughts in
the island, and recently there had been severe outbreaks of fever,
which had carried off one-tenth of the population. A careful analysis
of meteorological observations that had been made showed that from
1861 to 1866 there had been a great diminution in the rainfall. So
far as could be discovered, the rainfall was less than during any
similar period since the island was discovered. This could only be
explained by the cutting down of large forests in the interior, no less
than 70,000 acres having been denuded of trees during the ten years
from 1852 to 1862. Mr Meldrum concluded by saying that the
calamities which had so seriously affected the people of the Mauritius
seemed to be self-inflicted ; and that the proper remedy was to
restore the forests of which the once salubrious and beautiful island
had been deprived. And in a communication published in the
Journal of the English Meteorological Society for that year there is
given additional information on the subject. In this he states,

126 EFFECTS OF FORESTS ON MOISTURE.

"That the rainfall in that island during the five years 1862-66 was
considerably le^s than during any previous five years of the whole
period since 1853 ; " — " that during the first five years, from 1853-
57, the relative humidity of the air was 72'1, whilst during the last
five years, 1862-66, it was only 68*2 ;" — " that the vapour pressure,
which in the earlier of these quinquennials was '657, had fallen
during the latter given quinquennial to •638."

Notwithstanding these facts, he says : — " In no former year of the
period of fourteen years did such floods occur as in 1861 and 1866,
or such severe droughts as in 1865 and 1866." And to account for
these facts, he says : — ■" That the decrease of rainfall, humidity,
and vapour pressure, and the occurrence of floods and droughty may
in some measure be due to the cutting down of the forests, which
commenced on an extensive scale about 1852, was vigorously carried
on till 1862, and is being still prosecuted, though to a smaller
extent."

One chief cause of the cutting down of the forests in the Mauritius,
Mr Meldrum states thus : — " Proprietors of forests in high and
remote parts of the island, where the climate was as yet too damp
and rainy for the sugar-cane, engaged in the work because they
believed that their land would thereby become more fit for such
crops ; for it was very well known that the climate became drier in
proportion as the forests were cut down. Upon the whole, I think,
at least 70,000 acres, or about one-sixth of the entire area of the
island, have been denuded of forests since 1852, and that, too, on the
central and elevated parts of the island, at or near the sources of the
rivers."

He points out how, by the lowering of lakes, and the complete
desiccation of others, malaria resulted, and a deadly epidemic. And
the remedy which he suggests is, " to restoi'e, as far as practicable,
certain portions of the forests of which this once salubrious and
beautiful island has been deprived."

In 1871, a report was issued by Dr H. Rogers, of Mauritius, " On
the Eff'ects of the Cutting down of Forests on the Climate and Health
of Mauritius." This report I have not seen ; but in a lecture on Forest
Culture in its relation to industrial pursuits, delivered in Melbourne
on the 22d June, of that year, by Baron von Miiller, Government
Botanist in Victoria, there was given the following resume of its
contents, with the remarks which follow : So late as 1861 the Island
was resorted to by invalids from India, as the " pearl" of the Indian
Ocean — it being then one mass of verdure. But when the forests

PLANTING ON MAURITIUS, 127

were cleared, to gain space for sugar cultivation, the rainfall
diminished ; the rivers dwindled down to muddy streams ; the water
became stagnant in cracks, crevices, and natural hollows, while the
equable temperature of the Island entirely changed ; drought was
experienced in the midst of the ocean, and thunder showers were
rarely any longer witnessed. The lagoons, marshes, and swamps,
along the sea-board were no longer filled with water, but gave off
noxious gases ; while the river waters became impure from various
refuse. After a violent inundation in February 1865, followed by a
period of drought, fever of a low type set in. Against this the
remedies employed in ordinary febrile cases proved utterly valueless.
From the waterless sides of the lagoons pestilential malaria arose.
Exposed to this the labourers fell on the field, and in some instances
died within a few hours. Scarcity of food among the destitute
classes, and inadequate sewage arrangements, predisposed also to the
dreadful effect at the time. It is alleged, and maintained, that
marshes should either be drained out completely, or kept constantly
submerged. And Dr Rogers insists that, for sanitary reasons alone,
the plateaux and high lands of Mauritius must be replanted with
trees.

To what extent this may have been done, and with what results,
remain to be seen.

In Chambers' Journal it was mentioned in the beginning of 1875,
apparently on the authority of the transactions of the Royal Society
of the Mauritius, that with a view to check the increasing dryness of
the climate 800,000 trees had been planted, and 150,000 seed holes
prepared on barren mountain slopes and other waste places. And
we have the following statement in regard to what appears to have
been a prior application of the remedies proposed : — " The hills were
again planted with trees, and the rivers and streams resumed their
former dimensions." *

*A letter from Mr A. St. John, who had given attention to the subject, and had been
asked by Mr Fox Wilson for testimony which he might adduce in bis paper " On the
Desiccation of the Basin of the Orange River," in support of views held by them both,
has been put into my hands. In this it is said;— "It is Thornton, I believe, in hia
• History of India,' who gives an account of the drying up of the springs in the
Mauritius ; and the Journal of the Indian Archipelago, published by Logan at

Singapore, supplies information about the Island of Penang I am

confident of the information retained in my memory, though I may not always be able
to point out the source from which it was obtained ; for example, I am perfectly sm-e
that the writer, who as I have stated I think is Thornton, that gave the history of our
conquest of the Mauritius, observes, that, when we obtained possession, our country-
mea thought it absurd that the beautiful land on the summits and slopes of the

12S EFFECTS OF FORESTS ON MOISTURE.

Reference is made to the Island of Ascension by Boussingault, in
his work entitled Economie Rurale considerie dans ses Ba2:)ports avee
la Ckimie la Physique et la Mineralogie, in a passage which has been
cited, in which he says : — " In the Island of Ascension there was an
excellent spring situated at the foot of a mountain originally covered
with wood. This spring became scanty, and at last dried up, after the
trees which covered the mountains had been felled. The loss of this
spring was ascribed, and rightly so, to the cutting down of the timber.
The mountain was therefore replanted, and a few years afterwards
the spring reappeared by degrees, and by and by flowed with its
former abundance."

When I was at the Cape of Good Hope, the Hon. Mr Barrington,
of Belvidere, on the Knysna, wrote to me in regard to Ascension, that
on that island, the driest of the dry — spoken of sometimes as a heap of
cinders, which only could be maintained as a naval station by sending
to it water in tanks from England and from the Cape — trees and
culinary vegetables had been planted, and had been grown with
success, through instructions supplied by Sir Wm. Hooker from Kew ;
and that, since this had been done, not unfrequenlly had the island
been seen capped with a cloud, and little runneb of water had been
seen trickling down the sides of the rock. I have always understood

mountains should be abandoned to forests and jungle ; and so cut them down, upon
which the water supply began to fail. Reflection soon taught the authorities the cause
of this failure ; upon which the hills were again planted with trees, and the rivers and
streams resumed their former dimensions,"

In the same letter the writer says :-" I have deferred answering your letter in the
hope of being able to consult some of the works which supplied a portion of the
material for my article ' On the Failure of Springs ;' but I have not been able to do
what I intended. What I say of the drying up of four hundred springs in Persia is on
the authority of Tavernier ; but as the copy I possess of that traveller has no index, I
cannot at once find the passage, though perfectly certain that it occurs in his account

of the Northern Provinces Formerly, in my ' Manners and Customs of

Ancient Greece,' (II, 370), I pointed out the disforesting of the mountains as the cause
of the drying up of streams and rivulets in several parts of the country, and of the
diminishing of nearly all the rivers. Demoeritus, many centuries before Christ, had
made the discovery that woods and forests are necessary to the maintenance of springs ;
and in the last century, Volney contended that the Sahara might be rendered fertile by
planting it with such firs as would grow in sand, which would attract and retain
moisture. I make not the least doubt that in the Transgariep portions of Southern
Africa, to which you refer, the diminution of moisture was occasioned exclusively by
the cause you point out, and not by any cosmical changes, as imagined by Livingstone,
Should the Government, as far as its authority extends, ordain that whenever trees are
cut down others should be planted in their place, and generally encourage the multi-
plication of woods and forests, I make no doubt that that whole region would be
abundantly supplied with moisture."

STATE OP ASCENSION. 129

that the copious supply of water in Capetown was derived, not from
rainfall and surface drainage, but from the percolation, through the
four thousand feet thick filtering stone, of moisture absorbed from
what is called the Table-cloth, often seen on Table Mountain when
the south-east wind blows in the summer months ; and there seemed
to me nothing unreasonable in the information supplied by Mr
Barrington. He derived his information from the late Commodore
Burnet, who had been stationed at the Island, who stated that for a
long time the garrison and the shipping had had a good supply of
water ; and he (Mr Barrington) stated that when he himself saw it,
which was in 1861, the summit was enveloped in mist the whole day.

I subsequently obtained through Dr Hooker, who had succeeded
his father as Director of the Royal Gardens at Kew, a copy of the
report made in 1862 by Capt. Barnard when in charge of Ascension,
with a lithographic plan of the Island, illustrative of what had been
then accomplished, which had been published at his suggestion by
the Lords of the Admiralty, that the public might know something
of the altered " condition of that curious and now important island,
due to the encouragement given by the Admiralty, through the
instrumentality of Commodore Burnet, and more recently by the
intelligence and zeal of Capt. Barnard and his indefatigable assistant,
Mr Bell." And he goes on to say, in support of his suggestion : — " I
doubt if there is any spot in the world where a comparatively barren
rock, — destitute of all natural useful vegetation, exposed to the most
terrific and injurious sea breezes, — has been, or could have been,
brought into such a state of useful cultivation."

The plan shows a great many patches, measured as many of them
by poles as by acres, but measuring in the aggregate twenty-nine
acres, covered with furze and shrubbery, and upwards of twenty-seven
acres of land under cultivation, bearing crops of potatoes, sweet
potatoes, cabbage, carrots, pumpkins, turnips, endive, beans, leeks,
grass, pine apples, bananas, guavas, figs, oranges, shaddocks, mul-
berries, and sugar-cane.

It appears that a number of seeds consisting of acorns, horse
chesnuts, Spanish chesnuts, etc., which had been previously sent,
had been spoilt, probably by being stowed away on ship-board in a
damp hold ; but simple measures were adopted to prevent the recur-
rence of this, and by terracing, excavating, and levelling every little
patch capable of cultivation, the most was made of every advantage
which could be commanded on the island.

The whole report by Captain Barnard is full of details illustrative

130 EFFECTS OF FOBESTS ON MOISTURE,

of that indomitable energy and contrivance which we proudly allege
to be characteristic of our nation.

This I shall immediately quote at some length ; but what chiefly
concerns us is that, apparently by vegetation, there was secured
sufficient humidity to promote vegetation, and this in such abundance
that a cloud capped the mountain supposed never to have been seen
so capped before, and rills of water ran down rocks supposed never
to have been bedewed with such tears within the memory of man.
When every allowance has been made for suspected exaggeration of
previous aridity, and of humidity attained, there remains still a fact
to encourage the hope that by the extension of forests an increased
humidity may be secured.

In 1864 there were published by the Government the following
observations on Ascension, by Captain F. L. Barnard, R,N. : —

"Ascension is in latitude 7^ 56' S. and longitude 14° 24' W. It
is about 7 1 miles in length and 6 miles in breadth, and is within the
immediate influence of the S.E. trade wind. The island is entirely
volcanic, the surface being broken into mountains, hills, and ravines.
It was discovered by the Portugese in 1501, but remained uninhabited
until after the arrival of Napoleon at St. Helena, when it was
occupied as a post by Sir George Cockburu, and placed on the
establishment of a sloop of war, under a lieutenant. In 1822 the
naval garrison was relieved by a detachment of marines under Major
John Campbell ; since which it has gradually been increasing in
importance, and I propose tracing its rise, progress, and present
capabilities from valuable notes left by my predecessor Captain W. F.
Burnett, C.B., and the records in office.

" But little information remains on record between 1815 and 1824,
in which latter year Lieut.-Col. Nicolls arrived to take command. The
number then victualled was 59. Mules and donkeys were the only
draught animals, and sheep and bullocks were then first applied for.

" The supply of water was scanty and precarious, and even in 1829
it depended on drips in the banks, and the rain that was collected in
casks and a few old tanks. Three carts, six oxen, and three drivers
were employed daily in transporting about 360 gallons a distance of
six miles, and even this quantity was liable to a considerable
diminution after long droughts. When Dampier's vessel, the
'Roebuck,' foundered near Ascension in 1701, he discovered springs
or drips by watching where the goats went to drink; and in 1824
attention was called to three of these, viz., Middleton's, the Mountain

WATER OIS ASCEiSblOi^. 131

or Breakneck, and Dampier's. Iron water pipes were applied for to
lay down between the Mountain and garrison, where there were tanks
capable of containing 40 tons only.

" In July 1825 a boring machine arrived, and tanks and reservoirs
were commenced on a large scale ; but the latter, from subsequent
accounts, seem to have been mere excavations, from which the water
soaked away in a few days.

"Boring was first commenced in 1826 above Middleton's springs,
by Colonel Nicolls, without any important results. In 1829, Captain
Bate reported the possibility of supplying the African squadron with
water, proposing certain measures, and Captain Brandreth, R.E.,
was instructed by the Admiralty to make a survey and report of the
island. He found that the auger of the boring machine had been
introduced nearly horizontally in the dii-ection of the substratum,
which would merely have the effect of causing the stream to flow
more freely without arriving at the source of the spring. Captain
Bate had also bored near high-water mark by the advice of a foreign
naturalist, and from the wells then made the present supply of salt
water is derived. Unsuccessful borings were made in the low lands,
and others were recommended in the Mountain district. Captain
Brandreth reported favourably on Captain Bate's propositions, and
returned to Ascension in 1830. Finding that the stock of water was
reduced to 40 tons in consequence of a drought during twelve or
fourteen months, he pressed for further experiments in boring, and
fixed on a spot high up in the Mountain district, on the weather side,
at the bottom of a ravine, the sides of which were 80 feet in height.
The strata consist of volcanic matter on beds of clay. The
experiment succeeded, and at the depth of 25 feet from the surface
a spring was found ; the shaft was sunk 60 feet, and still yields (in
1864) from three to four tons daily, even after a long drought. A
second shaft was subsequently sunk about 100 yards from the first,
and produces an occasional supply only. In the latter end of 1830
the main water pipes were partly laid down.

" Palmer's springs were discovered 500 feet below the drips in
Breakneck, and were said to produce 2,000 gallons in 24 hours Two
large reservoirs were constructed by building up a deep gorge in
terraces, which receive the water from an extensive rocky valley, but
there is no spring in my opinion. Drinking troughs have been con-
structed here and at Middleton's ; they supply the island-bred cattle,
9.nd wild animals with water, which at the latter is brackish, and
does not agree with imported beasts. The marines used to take it

132 EFFECTS OF FORESTS ON MOISTURE.

medicinally in cases of dysentery. There is a neat cottage at
Palmer's, in which a man and his wife reside, and take care of a
garden producing chilies and pumpkins,

" In December 1831 the main pipes were finished, being led from
Bate's tank at Dampier's, 5 miles distant from the garrison, and 1000
feet above its level, and the same depth below the Mountain tank.

"In January 1832 an octagon iron tank, capable of containing 20
tons, was placed under the drip in Breakneck Valley, and in the same
year a tnnnel was cut through the mountain about 930 feet long, for
pipes to convey the water, which was pumped by horse power, and
forced up 140 feet into an iron tank above the level of the reservoir
on the other side of the mountain. The tunnel is sufficiently wide
and high to admit of people walking through with ease, and is a
wonderful proof of the perseverance and skill of the marines, who,
under Captain Payne, executed it in the short period between 19th
May and 3rd October of the same year. The principal and only
certain supply of water is obtained through this.

"InFebruary 1847 there was a great scarcity of water, and distilling
was first commenced with Clark's apparatus, but as salt water was
obtained from a well sunk in the square, affected by the ebb and flow
of tide, the supply was limited and uncertain.

" I found the drips in 1861 much in the same state as they appear
to have been in 1832, and shall describe the present water resources
of the island, the steps that have been taken to improve them, and
the plans I would suggest to ensure an adequate supply.

" The drips and wells in Breakneck Valley are the only sources that
never entirely fail, although the yield is considerably less after a long
drought ; the drips are caused by the rain and wet fogs, arrested by
the steep sides of the ravine, and percolating through the cinder to
strata of rock, which crop out and form ledges. Under these, lengths
of zinc and iron sheeting were placed, conducting the water in driblets
to a small cemented trough over the octagon tank, which occasionally
overflowed after heavy rains, and at all times the labour of forcing a
column of 140 feet of water was very distressing to animals, and
absorbed much labour.

" In the latter end of 1863, a wind engine of 1| horse power, by
Bury and Pollard, was erected near the octagon tank ; the pipes were
connected throughout their whole extent, as they were found to be
too much on a dead level to carry ofi" the water forced up, and we had
the satisfaction of finding that it worked admirably, and was capable
of doing much more when required.

SUPPLY OF WATER ON ASCENSION. 133

" Extensive troughs lined with Roman cement have replaced the
odds and ends of old sheeting, preventing waste and increasing the
yield of water.

" The wells which were sunk in the spots selected by Captain
Brandreth are worked by hand pumps daily, and produce sufficient
water for the consumption of the Mountain after many months of
drought. I am, therefore, of opinion that the upper one is supplied
by a bona fide spring, and without it much inconvenience would be
frequently experienced.

" The roofing surface has of late been greatly increased, and iron
tanks have been placed in convenient places for the supply of the cow-
house and stables, by which both manual and horse labour are saved.
" Finding that a considerable rush of water from the mountain roads
found its way into Dampier's tank in a very muddy state, large
cisterns have been constructed, with underground drains between
them, the last being connected with the main pipes just below the
Mountain reservoir. A great mass of mud and cinder is deposited by
these means, and the water eventually reaches its destination in a
comparatively clean state. In connection with this arrangement all
the upper roads, which were composed of soft light cinder, liable to
be washed away, are being paved with durable stone.

** The drip at Dampier's is scarely worth taking into account, as it
dries up soon after the rain ceases, and produces nothing when most
required.

" To prevent the waste necessarily caused by frequently running
down small quantities of water from the main tank at Dampier's
(Bate's), drinking troughs have been sunk on the spot and are supplied
by means of a small fire engine.

" The cattle that are not being stall-fed are driven in every morn-
ing for food and water ; and there have been no losses amongst the
imported cattle since this system has been adopted.

"In 1861 Dr. Normanby's distilhug apparatus arrived in H.M.S.
* Isis,' and in the beginning of 1863 pipes were laid down to it from
the sea, affording an ample supply of salt water, which is pumped up
a height of 25 feet by means of a simple and ingenious contrivance
of Mr Smith, the superintending engineer. A small eccentric on the
shaft of the donkey engine works a number of levers which pump the
salt water into a tank, and the fresh water into a reservoir when the
receiver is full. By attaching a strap to the fly-wheel a chaff cutter
is also worked in an adjacent building. The produce of water is
about one gallon per minute,

134 EFFECTS OP FORESTS ON MOISTURE.

" Such are the water resources of the island, which have not more
than kept pace with the increase of the population, from 59 in 1854 ;
to an average of 550 in 1863; and after three years' experience and
much painful anxiety, with the necessity of reducing the allowance
to a gallon for each person during upwards of six mouths, I would
urge the paramount necessity of ensuring an adequate supply."

The details of hydraulic works proposed by Captain Barnard I do
not deem it necessary to quote. After giving them, he proceeds : —
" I have found but little reliable information respecting the former
cultivation of the island ; but with the assistance of memoranda left
by Captain Burnett, records, and my own experience, I shall describe
its present state and capabilities of improvement.

" Like Captain Brandreth, I shall divide the island into four parts,
with reference to its agricultural capabilities.

" The first, consisting of about 200 acres, on the highest lands round
the Peak.

" The second, of about 800 acres, lying below the Peak, from 2,200
feet to 1,400 feet above the level of the sea.

" The third part, comprising tracts of cinder and ashes, with inter-
vening watercourses about the lower lands.

" The fourth takes in extensive beds of lava and cinder, not likely to
undergo any change, but which produce purslane and other food, on
which herds' of wild goats feed and keep in good condition.

*• This part comprises the Peak of Green Mountain, with all it
surrounding ravines and hollows, from a height of 2^820 feet to Elliot's
Pass, about 2,200 feet above the level of the sea. At the summit is
a small piece of table land, on which the Bei'mudian cedar, guava,
hibiscus, and other shrubs flourish ; it is frequently enveloped in mist,
and with the exception of a running grass gathered by the Africans
for the cows, it is covered with a long wiry sedge used for stable
bedding only. Orange trees brought with great care from Rio and
the Gape of Good Hope, have been tried on the N.E, side, where the
soil is deep and good, but without success ; they appeared to flourish
for a season, but soon began to droop and wither away ; consequently
all that retained any signs of life were transplanted into a nursery,
where they must remain until the weather is favourable for putting
them into sheltered spots in the ravines where lime trees flourish.
Numbers of trees and shrubs have been planted by the sides of the
path leading to the Peak since Mr Bell's arrival in 1857. They look
healthy aad strong, and the more tender ones are protected by tree

PLANTING ON ARCENSTON, 135

guards. A list of them is annexed. . , . , A tin trough
placed under one of the wattles for the pheasants to drink from, has
water in it during the driest seasons, affording a proof of how much
moisture is attracted by planting. The above is enclosed on the
sides accessible to cattle by a fence of cask staves.

" We now come to a second enclosure planted with a double row
of pinus excelsa, which are growing well. Buddlea, vites trifolia,
gorse, broom, and brambles, border the path in one thick mass, with
the beautiful crimson flower of the hibiscus peeping through the
foliage. Between the base of the High Peak and the Little Peak is
a bare ridge exposed to the strong trade wind, producing sedge and a
few stunted shrubs. The Little Peak is enclosed by a bank and
ditch, and is cultivated all over, producing light and uncertain crops
of English or sweet potato. To leeward of and below it, shrubs grow
luxuriantly, and an excavation has been converted into a nursery, but
the soil is dry and porous, and tender plants do not survive even a
short drought in it. Pine apples have been planted, and will probably
succeed here. There is also a fine lime tree, whose roots have found
their way into a fissure in the cinder; it consequently flourishes,
whilst every attempt to grow others near it has failed.

" All the first division is planted suflficiently, and nothing is
required but attention to the growing trees and shrubs, and keeping
the fences in repair. It is surrounded by Elliot's Pass, a road cut
out of the solid cinder, and passing horizontally quite round the
Mountain, which at several points is tunnelled through. It affords
great facilities for planting the sides of the mountain and ravines — is
a convenient path for the shepherds, and a pleasant walk of about
three miles, lined with blackberiy bushes bearing plenty of fruit, and
numbers of trees and shrubs.

" The ravines present the appearance of dense thickets, bramble,
buddlea, vitex, etc., having completely clothed them. Thousands of
small birds flock about the bushes, and are increasing wonderfully ;
they consist almost exclusively of avadavats introduced by Captain
Burnett. This pass was commenced in 1839 by Lieutenant Wade,
Royal Marines, and completed in January 1840. In 1861 about 600
yards of the path on the weather side were considerably widened by
Captain Barnard.

" The second and most important division commences below
Elliot's Pass, adjoining which are the farm buildings, consisting of a
a cow-house, fodder store, and stock yards, with slaughtering triangle,
and every convenience for stall-feeding oxen, penning sheep, and

136 EFFECTS OF FORESTS ON MOISTURE.

saving manure for the cultivated lands, a great part of which in 1861
had been constantly cropped with sweet potatoes and its fertilizing
powers extracted. The farm buildings were so scattered and ill
arranged that no great body of manure could be collected. All the
slaughtering was carried on in the garrison, and the ofFal thrown into
the sea. I made a complete change in the system ; built a fodder store,
demanded chaff cutters and oil-cake crushers, formed large yards,
adjoining the cow-house by excavating, did away with detached sheds,
and connected a sufficient number of iron tanks to ensure a constant
supply of water on the spot.

*' All crops are most uncertain excepting sweet potatoes, which,
unfortunately, are not generally liked as a vegetable, and cannot be
used in soup. Regular and large sowings of English potatoes are
now made, and several good crops have been obtained ; the arrange-
ment for thoroughly manuring the ground once in two years evidently
tending to restore fertility to the soil, for the sweet potatoes even
come to perfection in less time than they did before. Great losses
must be expected from the ravages of caterpillars and long droughts,
but the system should be persevered in, if only for the purpose of
introducing something like rotation of crops, not hitherto much
studied. The best seed potatoes have been obtained from the Cape
of Good Hope ; they are red, and about the size of walnuts. Some
from Loanda have also turned out very well. Supplies according to
demand are sent by the contractors for cattle from Table Bay eveiy
two months. The seed saved on the spot is worthless. Pumpkins
grow to a large size in the weather gardens, weighing upwards of
80 lbs. ; they are propagated from cuttings. Great efforts have been
made to grow cabbages in large numbers, but the caterpillars destroy
nearly all the seedlings, and there are never sufficient for a general
issue. French beans succeed better than any other vegetables when-
ever the droughts do not last long ; about two out of three sowings
fail. Now and then a fair crop of turnips may be got, but carrots
are a long time in growing, and never attain even a moderate size.
The New Zealand spinach grows wild amongst the other crops, and at
times is gathered in large quantities. No other vegetables are grown
in the sheep walk or weather gardens.

" Guano has been twice obtained from Boatswain Bird Island, and
seemed to produce good crops of sweet potatoes, but stable and farm
manure is better, and more easily obtained.

" In the Home gardens about the Mountain cottage, leeks are pro-
duced plentifully, as well as French beans, lettuce, endive, and herbs.

PLANTING ON ASCENSION. 137

Pine apples have been propagated successfully of late years, and are
well flavoured.

" All the ground available for planting is in detached patches, and I
find, on searching the records, that detailed descriptions of that under
cultivation, up to the end of 1859, have been forwarded to the Secretary
of the Admiralty. Since I took charge in July 1861, I have turned
my attention to the possibility of breaking up new ground and culti-
vating English potatoes, cabbages, and the vegetables usually issued
with fresh meat. The difficulty of finding any sufficiently level and
sheltered is great, and I have had recourse to excavating on the side
of the mountain. One piece now in progress, on the same level with
the home gardens, will have a back of 44 feet. I have also converted
what was formerly a stock yard into a garden, and have a very
promising crop of Jersey potatoes well up. As we can find labour, I
purpose terracing a very promising piece of ground under the weather
gardens, above a patch on which cabbages have been successfully
raised. My predecessor enclosed a space on a rather steep slope,
containing about an acre, which will be broken up, if the dry weather
lasts ; it will be fit only for the sweet potato, which is the staple
produce of the island, and flourishes even in the driest seasons, but it

is not prized by the men There is no limit to

the broken ground available for the planting of shrubs, and during
the dry season a party is constantly employed digging holes four feet
wide, thi'ee deep ; there are upwards of 1,000 now open for the
reception of the Australian wattle, to be planted between Michaelmas
and Lady-day. This shrub has been most successful at Ascension,
and in a few years will change the aspect, and probably the climate,
of the island, from its rapid growth and facility of propagation. I
lately measured one that was planted last November twelvemonths,
in the shape of a small layer, and it is now from six to seven feet
high, covering a circle with a circumference of 36 feet; about 1,000
of these have been planted within the last three years.

'■' Mr Bell fortunately hit upon the simple plan of laying the small
branches into preserved meat tins, butter firkins, and boxes, in which
they can be carried to any distance ; they already flourish much lower
than any other tree or shrub, and had we not lost our last season
from an unusual drought, many more would have been planted lower
still ; there are upwards of 1,000 now ready. I have entered into
the above details to show that the wattle has greatly reduced our
requirements, and I constantly receive, from private sources,
loquats, guava, orange, lime, and wild fruit trees, from the Cape of

N

138 EFFECTS OF FORESTS ON MOISTURE.

Good Hope and the coast. The date palm, coffee bush, and custard
apple look healthy and strong in their seed beds, and thousands of
young shrubs and trees, from the Peak down to the level of the home
gardens, are making rapid growth, whilst the furze, bramble, and
other shrubs fill the deep ravines and fissures with a luxuriant foliage,
affording good cover for game. Pine apples have arrived to great
perfection under Mr Bell's treatment, and we are making fresh
plantations from time to time.

" Of all things we most require conifers, and find that various
attempts have been made by my predecessor to obtain seeds. The
following advice in a letter from Dr Lindley to the Comptroller of
Victualling, dated Acton Green, August 20, 1860, if acted upon would
be of great service to the island : — ' Mr Bell finds by experience that
of all trees the most useful to plant on the mountain slopes are
conifers. In this I concur, and I would advise their Lordships to
send out a supply of Chilian Araucarian and Norfolk Island pines,
most especially the former, which form forests on the southern face
of the Chilian Andes in precipitous places, where they bid defiance to
storms. Ally quantity of the seeds (Chilian Araucarian Pine) could
be procured tlu'ough the English Consul at Valparaiso, Mr Rouse,
who, however, should be instructed to take care that the seeds are
fresh. The Indians bring them to market, but sometimes so old
that they will not grow.'

" I hope to be able to get Norfolk Island pine cones, and Australian
trees and plants through my predecessor, Commodore Burnett ; they
all do well at Ascension.

" The Bermudean cedar grows most luxuriantly at the Peak, and
a parcel of the seed would be most acceptable. Scai'cely any trees
or shrubs bear seed here.

" As Sir William Hooker takes a lively interest in the cultivation
of the island, he may like to know what steps have been taken to
carry out his valuable suggestions, as well as those of Dr Lindley
and Dr J. D. Hooker, which I have found amongst the Records.

" Finding a great scarcity of manure, and no facilities for carting
it up from the garrison, I shortly after my arrival commenced stall
feeding, and slaughtering the oxen at the Mountain, and have now a
most valuable heap of manure ready for our worn land.

" I next pi'ocured a quantity of guano from Boatswain Bird Island ;
this, from its great poi'tability, will be a great boon to us if it succeeds,
which I have every hope of its doing from the healthy green and
luxuriant foliage of a large breadth of sweet potatoes manured with it.

PARA GRASS ON ASCENSION. 139

" Mr Bell frequently accompanies me in searching for eligible spots
for establishing fresh patches of vegetable ground, and by the aid of
terracing, as we can command labour, I feel confident that an ample
supply of cabbages, leeks, and at times potatoes, can be commanded.

" Mr Bell having represented to me that numbers of young shrubs
and trees required protection when first planted out, I have caused a
lai'ge number of guards to be constructed from firewood and the hoops
that come off the trusses of hay; they answer most admirably.

" These plans, combined with the system of layering adopted by
Mr Bell, and the breaking up of new ground, will, I feel convinced,
do all that is possible for the cultivation of the Mountain, which ia
capable of spade labour only.

" The cones of the pitch pine from the Bahamas ordered by their
Lordships to be forwarded to Ascension, upon Sir William Hooker's
recommendation, will, in all probability, succeed, and I shall be glad
to get them.

*' Having described our requii'ements and plans for the cultivation
of the mountain, I think an account of an experiment on a large
scale, which we are making on the north-east plains, may be
interesting to Sir William Hooker.

"In a document from Mr Bell to Captain Burnett, dated October
1859, I find these plains described as having been cleared and culti-
vated twenty years before, but in consequence of the loss of horses,
and frequent failures of the crops, they were abandoned and con-
sidered barren and useless.

"However, on searching the records last year, a letter was dis-
covered bearing date 31st August 1849, from the Secretary of the
Admiralty, acquainting the captain in charge that Sir William Hooker
intended to forward a case of most excellent grass for fodder, known
by the name of ' Para;' accompanying this letter was a description
of the grass and its habits.

"At Ascension it is doing wonders, increasing in the most
astonishing manner, and growing down all weeds and inferior grasses
wherever it is once established. Patches of it were tried on the No. 2
plains, and made not only rapid growth but resisted a drought of
several months, though exposed to a tropical sun and the full force
of the south-east Trade.

" Ploughs and harrows having been promptly supplied at my

request, w^e took advantage of a spare team, and a colt that required

breaking in, to plough and harrow these plains, and, much to our

atisfaction, found them to be covered with a rich friable loam.

140 EFFECTS OP FORESTS ON HUMID1TT=

With protection, crops of every description might be grown here,
but, in the absence of horse and manual labour, to collect the rocks
and boulders which abound on the surrounding hills, and would form
excellent dry walls and well-sheltered enclosiu-es, we are planting
from six to eight acres with Para grass in fine showery weather. If
it succeeds, we could have fine pasture lands for cattle in a short
time, and there is every facility at hand for constructing drinking
troughs. I am also trying a small patch with English potatoes,
fenced for the purpose. The method Mr Bell is adopting for planting
this grass is by cutting turf into junks, which are carried to the spot
in bread bags, on the heads of Africans, and trod in at equal distances ;
the runners grow by inches in one week after rain, and form a perfect
mat which no animal can root up. Men are daily employed collecting
Para grass for the beasts and cattle, both at the mountain and at the
garrison, and it materially saves the expensive oat straw sent from
the Cape. If Sir William Hooker could obtain a bag of the seed it
would help us greatly. Should it at any time be thought advisable
to bring a much larger breadth into cultivation for vegetables than
can be obtained at the Mountain, I could fence in many acres on the
weather slope of a valley formed by two ridges of these plains for the
expense of about four additional rations for donkeys to draw the
stones on sleighs, but with our present command of labour I could
not attempt it. If the Para gi-ass succeeds, there are other large
plains, containing hundreds of acres, capable of being converted into
pasture land.

" In conclusion, I think it due to Mr Bell to state that the whole
of the farming and gardening operations under his care are carried
on in a most systematic and skilful manner. He combines the
experience of three years with considerable tact in managing the
Africans.

" I dwell upon this more particularly, as there appears to be a
growing interest in the cultivation and general improvement of
the establishment at Ascension, and operations might be more
readily and economically undertaken at present than with a new
gardener, who would have everything to learn ; and, on my part, I
am quite willing to devote as much attention to this branch of my
duties as I can possibly spare."

There was appended the following Table, showing the quantity of
cultivated ground on the island of Ascension, in what way laid out,
and present crop : —

LAND UNDER CULTURE ON ASCENSION,

141

Name of garden and En-
closure.

In what way laid out.

Present Crop in the CultiTated

>

1

^

2

1

>

i

1

8
10

21
12

9
24
29

1
13
23

20

16

3

4
3

38
34

9

1

_

8

12
13
13
8

5

10

3

19
16

8

The High Peak . .
Little Peak . .

Weather Gardens .
Sheep Walk . .

Home Gardens

Outer boundary of the

Home Garden .
Hospital Garden .
Sugar Cane Patches .
Caldwell's Fruit Ravine
Jumper's Ravine .
Broad Ravine . .

Narrow Ravine

Black Rock Ravine

Tobacco Garden Ravine
Hospital Eavine .
Weather Patches . .
Mulberry Run
Cane Eavine
Palmer's Springs .
Detached patches and
Elliot's Pass

6

1

2

15

3

3

3

2

1
2

?9

38

9

16
4

1

19

15

20

17

i

7
12

1

1
1

1

3
2

1
2

English potatoes ; seed obtained
from Jersey.

Sweet and English potatoes, Cab-
bage, carrots, pumpkins, and
turnips; three acres fallow.

Sweet potatoes and two small
grass paddocks, pine apples,
bananas, &c., endive, French
beans, and carrots.

Leeks, herbs, seedling date palm
and coffee, &c., <&c. ; one acre
fallow.

Turnips and English potatoes.

Cuttings of shrubs.

Sugar cane.

Guavas.

Bananas.

Bananas, oranges, and shad-
docks.

Bananas, shaddocks, and large
pandanus.

Bananas (the principal banana
ravine).

Bananas and flg bushes.

Bananas.

Bananas and mulberries.

Bananas and sugar cane.

Bananas and sugar cane.

Bananas and pumpkin.

Bananas.

Totals .

29

-

-

4

27

1

0

25

June 16th 1862.

(Signed) F. L, BARNARD, Captain in charge of Ascension.

In the observations published in 1864, it is stated, "Much might
be done to improve and add to the area of the cultivated land.
. . . I consider that the cultivation of the mountain has reached
a new stage ; the buddlea, vitex, and quick-growing underwood have
done their work as pioneers, and made good soil where coflfee and the
various ornamental and useful trees and shrubs that are ready for
transplanting should be put.

" Already a large piece of ground adjoining the cattle yards is
being enclosed with a strong fence formed of branches of Ascension
trees and underwood. It is planted with Para grass, and will be most
valuable for sick cattle, as well as the sheep, at the half-yearly
musters, when they invariably suffer greatly from running at their

142

EFFECTS OF FORESTS ON MOISTURE.

noses, after being kept a day or two on dry food. The yearly saving
in fodder will be at least £50."

There is given the following table of observations : —

^

-3 S

.

«o

0

CO

t-

s

II

1'

<»

-*
w

1

g
§?

00

a .

CO

<N

^

10

-

■5=3

d

0

— <

op

T"

ȣ

•S

0

05

>b

JS

' CO

t!

0

0

C5

<u S

•n

CO

CJ

M

m

1

CI

cb

00

IJ
t-

^

Is

^

05

0

^ 1
S

ai

C5

00

?D

l^

0

'*

00

CO

<N

II

jS

IM

cq

«

0

^

C<5

(M

§5

g

0

C5

CO

a^.

10

•*

0

»o

0

Is

.s

CO

0

t^

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TREES GROWN ON ASCENSION. 143

There is appended also the following list of botanical names of
trees and shrubs growing on the Peak : — Juniperus Bermudiana,
Podocarpus sp., Brugmansia suaveolens, Brugmansia sanguinea,
Ficus (four species), Casuarina (two species), Acacia, four species,
including the Wattle, Tlex sp., Alpinia nutafts, Pinus excelsa, Pinus
pinea, Vitex trifolia, Bignonia (Stoniby sp.), Hibiscus (five varieties),
Clerodendron fragrans, Coffea Arabica, Buddlea (Ascension gum
bush), Eriobotrya Japonica (the loquat), Quercus robur (English
oak), Cedrus Deodara (one plant), Cupressus torulosa, Widdringtonia
juniperoides, Fourcroya gigantea, Hakea sp., Virgilia Capensis,
Eucalyptus (four species), Nei'ium oleander, splendens, Phytolacca
decandra, Myrica cordifolia, Leucodendron argenteum, Melaleuca
hypericifolia, Rhus laevigata, Schottia latifolia, Pandanus odoratis-
simus. Fruits — The banana, peach, lime, orange, fig, loquat, and
guavas, the latter being the only kind that produces fruit. Respect-
ing the natural grasses on the Peak, it is said, — " What appears to be
grass is in reality not grass at all, being only sedges, near relations
to the English rush."

I consider that the preservation of the water under the wattle, to
which reference is made, may be accounted for otherwise than by
supposing that the moisture is attracted by vegetation ; but the fact
of the connection between plantations and moisture, resulting in an
increase of the former being accompanied by an increase of the latter,
remains the same whatever theory or hypothesis may be entertained
in regard to the modus operandi.

In the Report of Kew Garden, for 1864, it is stated, "that from
Ascension there continued to be received encouraging accounts of the
increased fertility and moisture of the island, consequent on the
extension of the plantations." And in the Report for 1865, it is
stated, — " Of once sterile Ascension Island, which we continue to
supply with plants, Captain Barnard reports that it now possesses
thickets of upwards of forty kinds of trees, besides numerous
shrubs and fruit trees, of which, however, only the guava ripens.
These already afford timber for fencing cattle-yards. When Mr
Hooker visited the island in 1843, owing to want of water, but
one tree existed on it, and there were not enough vegetables
produced to supply the Commandant's table ; whereas now, through
the introduction of vegetation, the water supply is excellent, and the
garrison and ships visiting the island are supplied with abundance of
vegetables of various kinds." Later reports I have not seen.

144 EFFECTS OF FORESTS ON MOISTURE.

It is remarked by Marsh, that " it has long been a popularly settled
belief that vegetation and the condensation and fall of atmospheric
moisture are reciprocally necessary to each other, and even the poet

sings of

Afric's barren sand,
Where nought cau grow, because it raineth not,
And where no rain can fall to bless the land,
Because nought grows there." *

Here we have an illustration of the converse fact : one measure of
humidity promoting vegetation, and vegetation not only arresting the
desiccation but so reversing the process that an increased humidity
is the consequence.

Sect IV. — Cases, Illustrative of Effects of Forests on Humidity,
correspondinng to such as have been adduced.

Besides the cases which have been brought forward as indicative of
the effects of forests upon the humidity of a country, there are others
which point to the same conclusion, which may be adduced, not as
corroborative testimony, but as independent facts, which are in
accordance with what has been alleged. Continuing observations
made on the Islands and Continent of Africa, I cite first the case of
Madeira.

Madeira does not, like St. Helena and Ascension, supply evidence
of a restored or newly produced humidity following the planting of
trees; but it supplies testimony to the effects of trees on the humidity
of the atmosphere and soil, which is of importance.

Washington Irving, in his " History of Columbus," refers to an
ancient document which is believed to have been drawn up by one of
the first discoverers of Madeira, about the year 1378. According to
this document, — " The country was delightful. The forests were
stately and magnificent. There were trees laden with excellent
fruits. The waters were cool and limpid. On penetrating a little
distance they found a beautiful sheltered meadow, the green bosom
of which was bordered by laurels and refreshed by a mountain stream,
whieh ran sparkling over jiebhles.'"

In accordance with this statement is the following glowing descrip-

* " Det golde Strog i Afrika.

Der Intet voxe kan, da ei det regner,
Og, omvendt, ingen Regn kau falde, da
Der Intet Toxer."
Faludam-Musllek, Adam Homo, ii, 408.

FORMER CONDITION OF MADEIRA. 145

tiou of wood and waters, giveu iu au uupublished aucient manuscript,
cited by Dr Graham in a work entitled " Climate and Resources of
Madeira," published iu 1870 : — " The island of Madeira at the period
of its discovery presented a most lovely picture of nature : a vegeta-
tion truly astonishing covered it with trees, reaching to a prodigious
height, — the majestic cedar, laurel, til, besides others, forming one
continuous and impenetrable forest. Evergreens and creeping plants
wove their festoons from branch to branch, giving new shade to a
land all clothed with vegetation, and new force to inumerable springs
of pic7'e and salubrious water" But tradition tells of a great forest
fire having swept over a great extent of the island ; and after that,
it was alleged, all was changed.

Mr Milne H )me, Chairman of the Council of the Scottish
Meteorological Society, in a paper submitted to this Society, entitled
" Suggestions for Increasing the Supply of Spring Water at Malta,
and Improving the Climate of the Island," says, — ' Some valuable
facts are supplied from the island of Madeira, It has been shown that
the annual fall of rain there is, on an average, thirty or thirty-two
inches, being about thirteen inches more than at Malta. Can one
reason be that, whilst Malta is treeless, Madeira is still partially
wooded ? Dr Graham says, — ' The north side of Madeira is still well
clothed ; and, although there are perhaps few trees which can aspire
to the dimensions handed down to us in the relics of former days, the
dark and ancient foliage still covers both hill and valley.'

" Dr Graham refers to the dimensions of the trees of a bygone
age in Madeira. There can be no doubt that when first colonized
the island had been completely covered with wood. Its name, as
given by the Portuguese, was originally Materia, in allusion to the
inexhaustible materials it supplied for ship-building and the con-
struction of houses."

Dr Graham quotes from an unpublished ancient manuscript the
glowing description of its woods and waters, which has been given
above ; and referring to those statements of an old date, he goes on
to say, — " It seems evident, from these descriptions, that Madeira
when first colonized was much better supplied with both wood and
water than at present ; and the conclusion seems not unreasonable,
that the better supply of water was in consequence of the larger
extent of wood." Citing these passages, Mr Milne Home goes on to
say, — " Dr Graham expresses a decided opinion to that efi'ect. He
condemns unsparingly the selfishness and folly of the first colonizers,
who, in order to get land for the culture of the sugar-cane and vine,

0

146 EFFECTS OF FORESTS ON MOISTURE.

set fire to the woods, and produced a conflagration which lasted seven
days."

Dr Graham says, — " The forests of Madeira have been continually
receding with the increase of fuel requirement, and the replanting of
the land thus laid waste has been long and culpably neglected.
Recently, however, the introduction of the pine tree has to a very
great extent stemmed the progress of reckless destruction. The pine
grows easily and rapidly, occupying lands ill-suited to other kinds of
cultivation." And in another couneution he says, — " The recession
of nature's woods has been in late years compensated by the advance
of the introduced species."

He reports his observations on the arrest of the water of fogs and
clouds by the leaves of the coniferse, and other trees, which act almost
like a sieve, draining it out ; and he remarks, " when the hills were
completely wooded, at the time of the colonization, it is quite
probable that the humid mists, continually passing over the moun-
tains, were intercepted, and that the rivers which now, soon after
rain, dwindle down to tiny streams were then more constantly full."
And he further remarks : — " On the eastern side of the basin of
Funchal, the upper lands have been almost entirely cleared of trees.
The rain water descends impetuously in a torrent, leaving a tiny
stream, which flows steadily so long as the sky is overcast, but
ceases altogether after one day of sunshine. I do nut think the rains
are now heavier or more fitful than in former times ; but there are
now no woods on the south side to restrain the drops, which unite to
denude the rocks of their soil, and to form the mighty torrents
witnessed every winter. I do not doubt that the planting of trees in
the villages at the head of the main ravines would lead rapidly to a
nearly constant supply of water in a region where it would be useful.'
The facts reported and the conclusions drawn from them are all in
accordance with what has been reported in regard to St Helena and
Ascension.

By Blanqui, in his Voyage en Bulgarie, already cited, it is alleged
that " the terrible droughts which desolate the Cape Verd Islands
must be attributed to the destruction of the forests." And he says
that, " in Egypt, recent plantations have caused rains which hitherto
were almost unknown."

I have repeatedly met with a reference in different forms to
observations which have been made, or are alleged to have been
made, in Alexandria and Egypt, in accordance with those which have

THE CONDITION OF EGYPT. 147

been brought forward in this and in the preceding section of this
chapter ; but I consider them open to question.

A writer in the " Edinburgh Review " whom I have already cited,
after making some remarks on the desiccation of Palestine, as a con-
sequence of the destruction of the olives, palms, and other trees,
during the Roman war, goes on to say : — " Even as to that country,
of which it was said, two thousand four hundred years ago, that the
family of Egypt have no rain, the United States Commission of
Agriculture, for 1871, reports: — 'In Upper Egypt, the rains which
eighty years ago were abundant, have ceased siuce the Arabs cut
down the trees along the valley of the Nile towards Lybia and Arabia.
A contrary effect has been produced in Lower Egypt, from the
planting of the Pacha. In Alexandria and Cairo, where rain was
formerly a rarity, it has since that time become more frequent." But
this statement appears to be open to question.

It is stated by Cezanne that Clot Bey has, in his work entitled
Aper^u general sur V Egypte (vol. i, p. 22), shown that the plantations
in Egypt have not rendered rains more frequent. And he states that
at Cairo, the mean number of days on which it rains in the course of
the year is twelve, and the rain-fall 34 millimetres.

On this subject Mr Marsh remarks ; — " The alleged augmentation
of rain-fall in Lower Egypt, in consequence of large plantations by
Mehemet All, is very frequently appealed to as a proof of this in-
flaeace of the forests, and this case has become a regular common-
place in all discussions of the question. It is, however, open to the
same objection as the alleged instances of the diminution of precipi-
tation in consequence of the felling of the forest.

" This supposed increase in the frequency and quantity of rain in
Lower Egypt is, I think, an error, or at least not an established fact
I have heard it disputed on the spot by intelligent Franks, whose
residence in that country began before the plantations of Mehemet
Ali and Ibrahim Pacha, and I have been assured by them that
meteorological observations, made at Alexandria about the beginning
of this century, show an annual fall of rain as great as is usual at this
day. The mere fact that it did not rain during the French occupation
is not couclusive. Ha\ing experieucsd a gentle shower of nearly
twenty-four hours' duration in Upper Egypt, I inquired of the local
governor in relation to the frequency of this phenomenon, and was
tol.i by him that not a drop of rain had fallen at that point for more
than two years previous.

" The belief in the increase of rain in Egypt rests almost entirely on

148 EFFECTS OF DESTRUCTION OF FORESTS

the observations of Marshal Marmont, and the evidence collected by
him in 1836. His conclusions have been disputed, if not confuted,
by Jomai-d and others, and are probably 'erroneous. See Foissac,
Meteorologie, German translation, pp. 634-639."

The Imperial Academy of Science has expressed a wish that the
Government of Austria would apply to the Viceroy of Egypt for ex-
tracts from the observations which have been made on the rise of the
Nile gauge above Cairo for 3000 years and more, especially for ex-
tracts from the records of the last 200 years. Should these be
supplied, we may hope that some light may be incidentally cast upon
some of the questions at issue.

South Africa has also its tale to tell. Mr Tuck, superintendent of
the Botanic Garden at Giahamstown, in writing to me before I left
the colony, communicated the following notice of what he had observed
in the course of the summer, that of 1864-1865 : — " This season has
been unusually hot and dry along the coast ; and all arouud Grahams-
town we have been unable to grow anything all this summer for
want of rain. The springs are all failing.

" You may perhaps know the place of Mr J. J. Stone, on the top of
the hill on the Cowie road, towards the sea, marked out by a
quantity of Gum trees, on the ridge of the high hills to the south-
east of Grahamstown ; well, all through the summer we have had
only light misty rain, just enough to damp the grass, and not enough
to wet the ground, but these trees of Mr Stone's have there converted
the mist into rain. They have scarcely felt any effects of the dry
weather ; the vegetables and flowers have there grown all the summer
without watering ; there the tanks have always been full : and that
is the only place of which I have heard that it has been so within
five and twenty or thirty miles of Grahamstown."

I have had occasion to cite the statements made by Boussingault
(ante p. 113) in regard to changes in the Lake of Tavarigua, in the
vicinity of New Valencia, in South America, otherwise they also might
have found a place here, as they show that a destruction of forests
had been followed by a lowering of the waters of the lake, and the
reproduction of the forests, consequent on the abandonment of culti-
vation, had been followed by a replenishing of the lake.

By Dr Hough, who has given much attention to the subject in
America, it is stated, that " some twenty-five years ago the Danish
sland of Santa Cruz was a garden of freshness, beauty, and fertility.

IN VARIOUS COUNTRIES. 149

Woods covered the hills, trees were everywhere abundant, and the
rains profuse and frequent. A recent visitor who sought the Island,
with which he had been familiar in the time of its greatest beauty,
for the sake of botanical study, a year or two since, found a third
part of it reduced to a desert. The short copious showei's had
ceased, and the process of desiccation was gradually extending over
the island. An attempt to restore the former fertility, by means of
planting, was made too late. One planter had set a thousand trees,
but every one of them failed."

" The island of Curacoa," again says he, " was, within the memory
Of living persons, a garden of fertility. But now whole plantations,
with their once beautiful villas and terraced gardens, are nothing but
an arid waste ; and yet, sixty miles away, along the Spani^ Main,
the rankest vegetation covers the hills, and the burdened clouds
shower down abundant blessings,"

A writer in the Edinburgh Review, whom I have already had
occasion to quote, citing as his authority, I presume, Dr Robert
Brown, says, " ' By the destruction in France of a great extent of
forest,' writes Dr Brown, ' in order to replace them by cultivated
fields, the temperature has become very irregular ; heavy rains,
storms, and dryness, have each done their work upon the soil, and
made crops every year more and more uncertain.' In the Vosges,
the destruction of forests has gone so far that agriculture has suflFered,
the soil has become arid, and inundations are frequent. In the
Department of the Gard, in 1837, no rain fell for nine months.

" Nismes, named from the forests which once surrounded it, is now
amid an arid waste. At Beziers. the Agricultural Society reported in
1797 that the forest which once sheltered the place having been
destroyed, the loss of the olive crop was the consequence. The
authorities of the Izere reported, in 1793, that the destruction of the
foresCs had altered the temperature, augmented dryness, and seriously
.affei^ed the crops. From Provence, from the valley of the Moselle,
from that of the Haute Garonne, from the Herault, and from the
Eastern PyKenees, come complaints of the same nature. The regular
rain-fall has been diminished, the temperature has changed and
become fuficertain, asiid partial and irregular storms have proved
curses rather than blessings wherever the forests have been ruthlessly
swept away."

These statements also are all of them in accordance with what
has been reported with greater detail in regard to St. Helena and
Ascension.

CHAPTER V.

Local Effects of Forests on the Rainfall.

In preceding chapters the principal subject has been the effect of
forests on humidity, and any mention made of rain has been only in-
cidental. In tiiis chapter that prominence is given to this ; and it is
the local effects in contradistinction to the effects of forests, or of the
destruction of these over a wide expanse of country, which is brought
under consideration.

In these preceding chaptei's oftener than once mention has been
made of the rainfall as supplying indications of humidity, or of com-
parative aridity ; and looking at these we have found that though the
desiccation of some countries has followed the destruction of forests,
in others no appreciable effect has been produced on the quantity of
rainfall over a wide expanse of country. But we have found marked
effects on the humidity of both soil and climate pi-oduced over a more
limited range, both by the destruction of forests and by the planting
of trees where they were not before, or where they had been destroyed.
And by further limiting and localising our observations we may be
able, with advantage, to follow up the observations which have been
made, and ascertain more satisfactorily the meteorological effects of
forests in relation to moisture. As a preliminary to the consideration
of the effect of forests on the rainfall, it may be well to consider how
rain and rivers are produced.

It may be hundreds are prepared, if asked, Whence comes the rain 1
and, Whence come the rivers 1 to tell that the rain comes from the
clouds, and the rivers, from springs among the hills. But we require
to go a little further in our consideration of the matter before we can
determine the effects of forests and of the destruction of forests on
the rainfall and on rivers. Whence come the clouds 1 Oh, from the sea.
And how do they spring from the sea 1 — And how are they formed 1 —
And how can the formation of them be affected by forests, or by land
denuded of forests, as in some cases both the rainfall and the rivers
appear to be 1 — And wliy is it so in these cases and not in others ?

These and a hundred other questions suggest themselves on our

ON THE PRODUCTION OP RAIN. 151

entering on this n3w phase of enquiry. And in view of these, it
seems expedient to begin at the beginning; and by anticipating,
prevent the questionings which might have no end if a different
course were followed.

Sect. I. — On the Production of Rain.

In consequence of the comparative heat in the tropics the air there
expands, and colder air of greater density flowing in over the surface
of the earth or sea, the expanded air is borne upwards from below,
till, cooled at a higher elevation, it begins to descend, to the north
and to the south of the equatorial region ; but, excepting in excep-
tional circumstances, it reaches not the earth again until it has been
cooled down to the temperature of the air at that lower level. This
process going on continuously, there are produced two sets of cun-ents
in the atmosphere : one from the Northern Artie regions, sweeping
along, over earth and sea, towards the equator, occasioning the north-
east Trade Winds, and the north winds and east winds so dreaded by
the suflferers from rheumatism in the northern hemisphere ; and
another from the Southern Antartic regions, sweeping along in like
manner, on or near the surface of the globe, towards the equator,
occasioning the south-east Trade's and the famous South-easter of the
Cape of Good Hope. But though these two sets of currents inter-
mingle, it may be, at the equator, they can scarcely be said to combine;
foi', ascending there in a conjoined m^ss, each portion curves over
almost in its entirety towards the region whence it comes, but with a
tendency from west to east, instead of that from east to west with
which it came. This is accounted for thus : the earth rotates from
west to east, cai-rying with it not only the water of the sea but the
air of the atmosphere ; being a sphere, or spheroid, each spot in the
polar regions is carried through a more limited space in the twenty-
four hours than is any spot nearer to the equator ; its motion per
hour, minute, or second, is less rapid than is that of any spot over
which the air may pass in its course to the equator ; and at this spot
the wind, moving onward, without diminishing its velocity, may be
dragged forward a little ; but at last it will be left behind ; and thus
an apparent current from some easterly point to some westerly point
is given to the current flowing from the pole towards the equator.
And the returning currents from the equator, carrying with them the
velocity from east to west, there acquired when they impinge upon
the surface of the globe, having a greater velocity in that direction

152 EFFECTS OF FORESTS ON RAINFALL,

thau that of the spot on which they strike, they seem to come from
some westerly point nearer to the equator.

Water in contact with air appears to be absorbed by it in a state
of vapour up to a point of saturation, varying with temperatui'e,
beyond which it cannot either absorb or retain more. As the air
advances from the polar regions towards the equator, its temperature
and consequent capacity of absorption are raised, and ere it reaches
the equatorial region it may have absorbed a quantity it ccmld retain
where it is, but could not retain either at a greater height or in the
polar region whence it had come. Accordingly we find that in the
equatorial regions, when it is raised to a great elevation, and is thus
cooled, the air can no longer retain it all dissolved, and the surplns is
deposited in clouds. The moisture thus deposited, attracted by
gravitation, passing through lower strata of a higher tetoiperature,
not saturated, may be again absorbed ; and thus may be explained
the phenomenon of a continuously clouded sky unaccompanied by
rain, which is seen so frequently at sea, within the tropics, as almost
to be the characteristic of the sky in these regions.

The current returning to the polar regions from the equator, in
passing over mountains on the summits of which a polar temperature
prevails, being thus cooled down, and unable to retain more than a
little of the moisture with which they are charged, the surplus is
thei'e deposited in the form of rain, or snow, or sleet, or hail.

To this also is attributable the humidity of the climate of England.
It may be traced to the prevalence of southerly and westerly winds,
which come to us laden, not only with moisture which they may have
absorbed in passing over the Atlantic in their passage thither, but
with moisture previously absorbed in their passage from the polar
towards the equatorial regions.

In England, the southerly and westerly winds are to northerly and
easterly winds in the proportion of 196'4 to 135.

There are waves of wind which come sweeping over the Atlantic
from the north-west, but these are comparatively rare. Those which
come blowing from the south and the west, and more especially those
which c^me blowing from the south-west, have come at a higher
level, with an under current, between them and the ocean, flowing in
an opposite direction ; and these are the most prevalent winds in
England, The following are given by Steinmitz, in his little popular
work, entitled " Sunshines and Showers," as the mean of several
years as the number of days on which the following winds were
observed : —

PRECIPITATION OP MOISTURE. 153

North, days, 40-7. South, days, 34-2.

North-east,... „ 47-6. South-west,... „ 104-0.

East, „ 22-6. West, „ 38-0.

South-east,... „ 19-9. North-west,... „ 24.1.

The east wind, cooling down the atmosphere, may occasion rain ;
but all our deluges come from the south and west.

The air, wh^n it reaches the polar regions, being greatly cooled
down, deposits its moisture in the form of snow ; and of this are
formed the fields of ice which are characteristic of the Arctic and
Antartic regions alike.

By Dr Scoresby, it is reported that in the Arctic regions it snows
nine days out of ten in the months of April, May and June. With
southerly winds near the borders of the ice, where moist air, blowing
from the sea, meets with the cold breeze from the ice, the heaviest
falls of snow occur. In this case a depth of two or three inches falls
in an hour.

In crossing and recrossing the Atlantic, in certain latitudes,
frequently are fogs encountered : the cause and occasion is the same.
Fragments of Arctic glaciers broken off and floated away by oceanic
currents, as icebergs, cool down the ocean and the atmosphere nearer
to the tropics, and that to such an extent as to occasion a deposition
of moisture wherever they go, and it may be for a hundred miles
around them.

As some indication of the immensity of the quantity of moisture
brought back to high latitudes by the return currents in the upper
regions of the atmosphere, I would remind my reader of the immense
body of water composing Lake Superior, Lake Michgan, Lake Erie,
and Lake Ontario, in America, pouring over the Falls of Niagara
unceasingly, and flowing through the Thousand Isles into the St.
Lawrence ; and of the waters poured into the ocean by all the rivers
of the world, great and small alike : these are but the drainage of
the water precipitated by the way on the valleys through which they
flow ; I would remind him of glaciers of the Alps, the product of the
comparatively trifling portion arrested by the higher part of that
mountain range as it was being borne onwards to the north ; and I
would remind him of the immensity of the deposits near to the
pole, not frozen sea, but frozen rain.

In a volume lately published, entitled " Under the Northern
Lights," by Mr MacGraham, — a correspondent of the ** New York

154 EFFECTS OP FORESTS ON RAINFALL.

Herald," sent by the spirited proprietor of that paper on a voyage
of discovery, made by the Pandora, last year to the Arctic regions,
the eipense being shared with him by the late Lady Franklin, and by
Captain Allen Young, who went in command of the vessel, — there is
given the following account of Greenland. Speaking of the interior
of the continent of Greenland as an icy solitude, — a secret unknown
to man, and likely ever to remain such, — he goes on to say : — " Its
surface is 4,000 feet above the sea, and when you ascend to it you
will probably perceive somewhere on the plain which rises before you
in a slight ascent till it touches the sky two or three little sharp
conical hills, a few feet high, that pierce through the ice, and you
will be astonished to learn that these insignificant mole-hills are in
reality the tops of lofty mountains, that have been submei-ged
beneath the mighty inundation of ice. Somebody has said of
Switzerland that if it were ironed out it would be a very large
country. If Switzerland were about ten thousand times larger than
it is, and ice were then poured into it until it should be full up
nearly to a level with the highest mountain peaks, it would present
just the appearance of the interior of Greenland. And yet the
whole of this vast continent was at one period of the earth's history
green and fertile. There have been found here forests of carbonised
trees and plants, and the fossil remains of many animals that could
only have existed in a warm climate. Fossil corals and sponges are
often picked up now in Lancaster Sound and on the shore of Beechy
Island. It is certain that the climate was soft and mild, and that
the country was covered with trees and vei'dure, and it is equally
certain that this terrible inundation of ice came and buried every
vestige of it, as Herculanseum and Pompeii were buried beneath the
ashes of Vesuvius. But, instead of the two poor little villages, and
perhaps a few square miles of the adjacent country, that Vesuvius
covered with its fine ashes as with a soft warm blanket, here is a
continent larger than the whole of Europe, buried beneath a massive
sea of ice. It is as though the watei's of the flood had suddenly
frozen to the very bottom, and had never thawed."

Such are " the treasures of the snow," and " the treasures of the
hail," to be found in the Arctic and Antartic regions of the earth,
borne thither from the equator and the tropics, ever in a state of
flux, but ever renewed by fresh accessions. Of the evaporation by
which this is maintained, the quantity of moisture taken up by the
air in its passage over earth and sea to the equator from the poles,
I cannot hope to convey either an adequate or a definite idea. It i-;

EVAPORATION FROM THE SEA, 155

proportiouate to the area, the temperature, the time, the tension, and
much besides.

Even from the land the evaporation is great. Maury, in his
treatise on the '' Physical Geography of the Sea," (p. 274), estimates
the annual amount of precipitation in the valley of the Mississippi at
620 cubic miles of water, and the discharge of that river into the sea
at 107 cubic miles; and he concludes that "this would leave 513
cubic miles of water to be evaporated from the river basin annually."
This is but one basin — a furrow on the dry land ; and then there is
the sea !

The evaporation from the Mediterranean, the Black Sea, and the
Sea of Azov, is reckoned at 50 inches on the whole extent of their
surface ; this is about 1,500,000 square miles, and a simple calcula-
tion shows that from these seas alone must be evaporated upwards
of 500 (508) cubic miles of fresh water.

A corresponding estimate and calculation shows that the annual
evaporation from the Red Sea must amount to 165 cubic miles of
water.

Such are the quantities with which we have to deal in speaking of
evaporation from inland seas alone.

Of the whole surface of the earth, three-fourths are covered by
sea ; that surface measures in round numbers 196 millions of square
miles, of which nearly 150 millions are covered by water. What
startles me is the consideration of the quantity of water which this im-
plies, and the question arises. What can have been its source 1 But it is
the evaporation from it with which alone we have at present to do.
We should probably err were we to reckon the evaporation, over the
whole area of the ocean, at the ratio of the evaporation which takes
place from the surface of the Red Sea and the Mediterranean. But
it is going on everywhere — in an increasing ratio, probably, towards
the equator, in a decreasing, towards the poles ; and apparently it is
not confined there to what is called the open sea. I have already
had occasion to refer to the statement by M. Hayes, in a work entitled
La mer liber du Pole, published in 1868, that thin wet linen exposed
to the air dries at the lowest temperature, and that a sheet of ice
suspended by a cord evaporates by degrees. He adds, " that evapora-
tion is more restricted near the coast than in the interior districts of
a country, and more restricted under an equatorial wind from the
south-west, than under a polar wind from the north-east, the former
being saturated with moisture, while the latter has been dei>rived of
its humidity."

156 EFFECTS OF FORESTS ON RAINFALL.

Of the moisture thus absorbed by the air from the wide ocean
and the inland sea, and borne onwards to the tropics, no trace is
seen in the atmosphere till the air is cooled below the. temperatare
at which it can keep it so sustained. This happens when it is first
raised aloft, and when, on its return towards the poles, it impinges
on some mountain range or solitary peak.

But while the course detailed may be considered the normal
course of the air in its current to and from the equator, it is liable
to many disturbances.

It is not usual for two currents of water flowing in difl:erent, and
to some extent contrary directions, to glide past each other, each
pursuing its own way ; there is friction, and asaresult of this friction
there are eddies and whirlpools. It is so when they flow side by side ;
it is so when they flow the one over the other ; and it is so with
these aerial currents : the upper current coming completely through
the lower, and producing those westerly winds, of which, otherwise,
we should have none in medium latitudes; and it is reasonable to
conclude by inference that there may be eddies of the lower current
passing into the uppei\ Every one of these disturbances must
aflfect the temperature, and consequent capacity of a great mass of
air to retain the moisture with which it is charged, and that in
different ways : for instance, the eddy of the warm upper current
may be so cooled down that it must deposit a great quantity of the
moisture which it held, or the eddy of the lower current cooling
down a portion of the upper current penetrated by it may render it
incapable of retaining all the moisture with which it was charged ;
and in each of these cases rain or snow, or hail, according to circum-
stances, may be the consequence. The eddy moreover may take a
wide sweep, developing into a whirlwind or cyclone, with a radius of
a hundred miles or more, and advancing onwards thousands of miles,
carrying disturbance of temperature, and of hydrometric conditions
wherever it goes. Similar whirlwinds I have seen produced upon a
smaller scale, with all the indications of capability of being in like
manner developed on a scale as gigantic, simply by the sun beating
on arid ground, or on ground from which water has evaporated.

In the centre of such a whirlwind the air of the district over which
it passes may be raised to such a height as to be cooled so low that
much of its moisture is precipitated, and falls in two parallel lines
of rain, or hail, marking the lateral limits of its course ; and over the
whole area of the ground traversed by it, embracing hundreds of
thousands of square miles, and over all the area of the ground

FORMATION OF CLOUDS. 157

traversed by eddies throwa off by it, rain may be a couseqaence of
disturbances of the hygrocnetric equilibriaoa beyond whit was com-
patible with the retention of the moisture by the air. A current of
cold air so brought into a body of warm air may cool this to a tempera-
ture at which it is saturated with a much less quantity thau it con-
tains, and the excess will be precipitated as rain ; or a current of
warm air brought into a body of cold air may be so cooled down that
its surplus moistux-e is deposited in the form of rain.

Thus are clouds produced ; and a change of wind occasioning^ a
slight rise of temperature may cause the cloud to melt away into
transparent air, by the re-absorption of the vapour of which the cloud
was formed. The phenomena I have seen at the Cape of Good Hope
a hundred times. They are there of constant occurrence,

A correspondent from Sea Point writes : — " On Thursday evening,
during the hard south-east gale, some very remarkable and beautiful
cloud efifeuts were witnessed. Dark masses of cloud came driving
across the Lion's Back at a furious rate, obscuring the brilliant moon-
light. But in a few seconds after passing the zenith, their speed
became checked, and, at the same time, they began rapidly to
dissolve. Some of the cloud masses hung for a few seconds
apparently motionless between the opposing currents of wind.
Others again yielded to the counter current, and rushed back
furiously from the north, meeting the driving masses from the
south, and, almost in the moment of apparent meeting, dissolvino-
utterly away. It was like the unavailable charge of a gallant
body of light cavalry against a masked battery of artillery, — swept
away before the cruel storm. The sudden alternations of clear blue
sky, with black thunderous-looking masses of light fleecy clouds, and
the changing iridescent hues of the vapours as they drifted across
the moon, wei'e very striking, and produced a scenic effect which
those who witnessed it will not soon forget."

By the clouds may be traced the aerial currents, Writin<y on this
subject, in connection with the distribution of rain, it is remarked by
Cezanne that, " From the elevated summit of a mountain above
which shines the sun in a cloudless sky, one may see under his feet
a tide of clouds rising up the slopes on one side of the range. It
impels its mobile billows into all the anfractuosities of the gorges,
lashes and surmounts the buttresses which stop it, in every respect
as does the ocean covered with foam the black head of the reef of
rock. By all the rocks, by all the depressions of the chasm, the
cloudy wave presses on, and pours itself over on the slope on the

158 EFFECTS OF FORESTS ON RAINFALS.

opposite side ; the highest summits aloue emerge above the inunda-
tion ; but down the stream the clouds seem to be falling into an un-
fathomable void ; they are seen to be disappearing, and the slope on
this side, lit up with sunshine, offers a smiling contrast to the other,
which, immersed in the storm, is shrouded in a thick veil. The rain
in such circumstances is invisible to the observer, but he makes its
acquaintance a little later, when in his descent he passes through the
clouds, or, if the storm have then passed away, when he finds all the
streamlets on his road overflowing their banks."

When one is enabled thus to look down upon the clouds he may
see the atmospheric current in obedience to the laws of hydraulics.
It has its rapids, and its eddies, it strikes with fury against jutting
obstacles, and when it is contained between regular sloping hills it
abandons the convex mound, and presses itself out against the
concave bank. Thus is the aerial current made manifest.

Thus far we have had to do with the production of clouds ; the
transition to the consideration of the production of rain is easy.
This is thus detailed by Sir John Herschel* : " When the sun
shines on a cloud which absorbs its beat, the cloud itself is neces-
sarily evaporated, and the vapour by its levity tends to produce an
upward current, and thus to counteract the effects of gravity on
the globules of which it consists. A globule of water jg^jypths of
an inch in diameter, in air of 5-6 ths the density on the surface, or
at the height of about 5000 feet, would have its gravity counter-
acted by resistance, with a velocity of descent of one foot per second
(supposing no friction and no drag) ; and even if the terminal
velocity were reduced to half that quantity by these causes, would
still require some upward action to enable it to maintain its level, —
a circumstance which sufl&ciently accounts for the lower level gene-
rally observed of cloud during the night. It is more probable,
however, that when not actually raining, a cloud is always in process
of generation from below and dissolution from above, and that the
moment this process ceases, rain in the form of ' mizzle ' commences.
In a word, a cloud would seem to be marely the visible form of an
aerial space in which certain processes are at the moment in
equilibrio, and all the particles in a state of upward movement.

In whatever part of a cloud the original ascensional movement of
the vapour ceases, the elementary globules of which it consists,

* " Meteorology : " a volume reprinted from the Encyclopaedia Britannica .

EFFECTS OF FORESTS ON LOCAL RAINFALL. 159

being abandoned to the action of gravity, begin to fall. By the
theory of the resistance of fluids, the velocity of descent in air of a
given density is as the square root of the diameter of the globule.
The larger globules therefore fall fastest, and if (as must happen)
they overtake the slower ones, they incorporate, and the diameter
being thereby increased, the descent grows more rapid and the
encounters more frequent, till at length the globule emerges from the
lower surface of the cloud, at the vapour plane, as a drop of rain ;
the size of the drop depending on the thickness of the cloud-stratum
and its density."

From what has been advanced it appears that rain is simply the
precipitation from the air of moisture which happened to be held by
it in excess of the quantity which it could, at its reduced tempera-
ture, hold in solution. It differs from the cloud or fog only in being
formed of drops produced by the mutual attraction of smaller drops
which are rapidly drawn by gravitation to the ground, instead of
floating long suspended, as the constituent lesser drops had been, in
the air. And this it may be well to bear in mind in proceeding to
the consideration of the local eflPects of forests on the rainfall.

Section II. — The Effects of Forests on the Qnantity of the Local
Rainfall.

I have had occasion in a previous chapter to refer to the existence
of an opinion held by many, and widely-diffused, that forests and
mountains attract rain. I have otherwise explained the phenomena
which have been attributed to some attraction exercised by them
upon clouds, alleging and maintaining that the clouds seen in such
situations must have been pi'oduced there ; and I am disposed to
allege and maintain something similar in regard to rain.

The effects of trees on the humidity of the earth and atmosphere
has received the attention of several men of science and observation
in Britain, some of whom — Sir John Herschel and others — have
spoken out very decidedly on the subject. But in Britain it has
been less of a practical question, demanding attention as a means of
avoiding threatening calamities, than it has been in other lands ; and
while many of those who have given their attention more especially to
this subject speak decidedly, they speak with the caution which science
demands. Boussingault says: "My opinion is that the felling of
trees over a larqe extent of country has always the effect of lessening

160 EFFECTS OF FORESTS ON RAINFALL.

the mean annual quantity of rain." The deliverance of Becquerel is
in accordance with this. He says : " Great clearings diminish the
quantity of spring water in a country." But he says, " It has not
been ascertained whether this effect should be ascribed to a less
quantity of rain which falls annually, or to a greater evaporation
from the soil of rain watei", or to a new distribution of showers of
rain."

The opinions thus expressed are based on observations of facts.
But along with these facts there are other facts which have already
been referred to, and which require to be taken into consideration,
if we would learn the whole truth on the whole of the subject. It
has been stated that in the annual report of the Director of the
Meteorological Observatury in the Central Pa^^k of New York, for
1871, Mr Draper addresses himself to the question — Does the clear-
ing of laud increase or diminsh the fall of rain 1 and in a preceding
chapter I have given his answer.

He gives summaries of observations made in each year, and in
each quarter of the years 1869, 70, 71 ; he states that the indica-
tions given by the instruments of the observations under his direc-
tion may he thoroughly relied on, and he concludes, " so far as these
years are concerned there does not appear any evidence of a decrease,
on the contrary, in the last, there is a very considerable excess on
either of the others."

Citing, then, observations made in England since 1677, and in
unbroken continuance since 1725, in Scotland since 17-31, in Ireland
since 1791, he shows that where a lengthened period and an
extensive area are embraced by the observation, there is a perfect
compensation, the decrease at one place being compensated by the
increase at another, and that even in the same locaUty this principle
of compensation might be seen.

When these facts are taken into consideration along with the
other facts which have been cited, the two classes of facts may at
first appear to the inconsiderate to be inconsistent and incompatible
with each other ; but if all be facts they must be compatible and
consistent, and a little consideration may suffice to show that they
are so.

Harland Coultas, in a work entitled "What may be learned from a
Tree," published in New York in 1860, in a passage cited by Marsh
says, " The ocean, winds, and woods, may be regarded as the several
parts of a great distillatory apparatus. The sea is the boiler, in

VARYING QUANTITIES OP RAIN. 161

which the vapour is raised by the solar heat. The winds are the
guiding tubes, which cany the vapour to the forests, where lower
temperature prevails. This naturally condenses the vapour ; and
showers of rain are thus distilled from the cloud masses, which float
in the atmosphere, by the woods beneath them." All which is true.

By Marsh it is said: — "We cannot positively affirm that the
total annual quantity of rain is even locally diminished or increased
by the destruction of the woo Is, though both theoretical considera-
tions, and the balance of testimony, strongly favour the opinion that
more rain falls in wooded than in open countries. An important
conclusion, at least, upon the meteorological influence of forests, is
certain and undisputed : the proposition namely, that within their
own limits, and near their own borders, they maintain a more
uniform degree of humidity in the atmosphere than is observed in
cleared grounds : scarcely can it be questioned that they tend to
promote the frequency of showers, anl, if they do not augoaeut the
amount of precipitation they probably equalize its distribatioa
through the different seasons."

" The strongest direct evidence which I am able to refer to in
support of the proposition that the woods produce even a local
augmentation of precipitation, is furnished by the observations of
Mathieu, sub-director of the Forest School at Nancy. His pluvio-
metrical measurements, continued for thi-ee yeai-s, 1866-1868, show
that during that period the annual mean of rainfall in the centre of
the wooded district of Cinq-Francheas, at Belle Fontaine on the
borders of the forest, and at Amance, in an open cultivated
territory in the same vicinity, was respectively as the numbers 1000,
957, and 853." In an appendix, Mr Marsh inserted a statement that
•' Fautrat and Sartiaut placed at an elevation of six metres above a
grove of oaks and elms, of twenty years growth and eight or nine
metres height, in the forest doiniin of Hilette, pIuviom&::res and
other meteorological instruments, and like instruments at the same
elevation in the open ground three hundred metres from the forest.
In the months February to July inclusive, the rainfall above the trees
was found to be 192, 50"^'^ and during the same period ITTmm in the
open ground. Comptes-Rendus, t, LXXIX, 409.

The observations made by Mr Mathieu are thus summed up by
himself, in his report to the Director-General of the Forest Adminis-
tration : —

" In 1868 there fell on cleared spaces within the forest region more
rain than beyond the borders of this ; on agricultural land the fall was

q

162

EFFECTS OP FORESTS ON RAINFALL.

least of all. This result agrees entirely with those obtained in pre-
vious years, and tends more and more to present itself as a law.
The following table has been prepared to make this apparent : — ■

9 Last Months of 1866,

11 Do. 1867,

12 Months of 1868,

Depth of Sheet of Water Received by the Ground. |

Cinq-Franchos,

Centre of
Forest Rf^gion.

Belle-Fontaine,

Border of
Forest Region.

Ammence,

Agricultural
Resion.

MU imetres.

691
762
749

Millimetres.

No observation.
716
738

Millimetres.

591
695
631

"If we represent by 1000 the quantity of water which fell each
year at the Cinq-Franch6es, we obtain for the three years during
which the observations were made, the following as the proportions
thus indicated : —

1866, ... 1000 — 855

1867, ... 1000 930 913

1868, ... 1000 985 791
The mean of these gives the proportion noted by M. Marsh.

The difference is probably not greater, but less, than is the popular
belief ; and it is possible it may be represented thus as being greater
than it actually is.

M. Cezanne remarks on this report : — " After what we have seen of
the so-called caprices of rain, and the variations which they present
in one quarter, and in another of the same city, we must
acknowledge that the experiments of M. Mathieu, while furnishing
on the whole an argument in favour of the supposition of an action
of forests on the phenomenon of the rain, are not absolutely
demonstrative. How can we satisfy ourselves that the forests have
not acted simply as an obstacle to the pluvial wind 1 If, for example,
the agricultural region spread itself out on a level plateau, while the
forest region rose on a slope up which crept the pluvial wind, the
pluviomfetres placed in these two regions are in no way comparable
together.

"In order that the experiments might have been conclusive it would
have been necessary that, viewed in regard to a great number of
points, they should have been always accordant. But of this accord-
ance in condition we have no evidence.

" M. Belgrand, comparing the region of the rainfall in the basin of
the Grenetifen, which is wooded, with that of the Bouchat, which is
not wooded, has ascertained and established that the former

EFFECTS OF INCIDENCE. 163

received leas water than the latter, and farther, that in this case the
arrangemeut of the sides of the moautains exercised a prepon-
derating influence, and one which maslsed that of the forests."

M. Cezanne has given attention to the eflfect of the configuration
of the land upon the quantity of the rainfall. He has shown that this
is determined, not only by altitude, but by the incidence with which a
pluvial wind may strike upon any precipice or slope which opposes it,
the rainfall being greater in proportion as the atmospheric current
arrested by an obstacle is compelled to rise more rapidly. Hence
the objection stated by him.

Some, if not all, of the so-called caprices, to which M, Cezanne refers
(while I consider the designation, which originated not with him, not
altogether appropriate), I shall afterwards have occasion to cite, and
also the experiments made by M. Belgrand. Here it is enough to
have established that the popular opinion in regard to the effect of
forests on the rainfall has received support from scientific observa-
tions, but that it may require considerable modification to bring it
into perfect accordance with the matter of fact.

It is with this as it is with many other popular observations on
the weather, which may be said to embody correct observations, but
which have this solid substratum of truth overlaid with much which
is not entitled to be considered such — the confiding trust with which
they are received and propounded may be attributable to the
confident and explicit expi-ession in which they are couched. The
uneducated are often impatient of dubiety, or want of explicitness of
thought ; and they are ready to impose this upon a vague or ambiguous
statement with which they are not satisfied ; and the half-
educated, again, are prone to generalise rashly, and go far beyond
what strict induction would warrant. Education by philosophy may
regulate this tendency and make it productive of good ; and the
study of science may train the educated man to suspend his
judgment in regard to the absolute, while resting with full confidence
on ascertained facts. The generally received opinions in regard to
the eflfect of trees on humidity, to the extent to which they have
been confirmed by observations, are accepted and issued recoined,
with a new impress, by such men of science ; but the impress on the
coin, limits, while it defines its value, and to pass them as equivalent
to more than their determined value ; were to mislead, though there
might be no intention to deceive. The statement made by Mr-
Marsh, and the testimony of M. Mathieu, seem then to confirm and
limit, the popular opinion in regard to the eftect of forests upon the

164 EFFECTS OF FORESTS ON RAINFALL.

rainfall, and what is thus certified is in accordance with all that has
been advanced in preceding chapters.

Rain has been spoken of as the precipitation from the air of
moisture in excess of what could be sustained in solution at the
temperature at the time. The increased moisture passed into the
atmosphere by evaporation through the stomates of the leaves must
render the air surmounting and surrounding a forest more liable to
be affected by any change of wind than air in the open field. This
it will do irrespective of any other means whereby the quantity of
moisture in the air there may be increased; and thus may the increase
of rainfall in question be accounted for.

There may alcso be an increase of rainfall occasioned by the repeated
evaporation and precipitation of the same moisture : it is not the
source of the moisture but the measure of the precipitation occurring
in the locality which is alone in question here.

Besides this, it is alleged, and I believe correctly, that the heated
air passing over a forest becomes cooled, and may thus be led to
deposit the moisture with which it is charged.

While it is thus that trees generally act in maintaining the
humidity of the district in which they grow, it is not impossible that
they may act also in a way much more like what may be called
attracting rain, by their acting as lightning conductors.

If a small pan with a perforated bottom be filled with water, and
suspended from the prime conductor of an electrical machine, on the
cylinder being put in motion, the water, instead of slowly dropping
as it did before, pours in torrents through the perforations in the
bottom of the pan, an electric attraction as well as an atti-action of
gravitation drawing it downwards. And this experiment has been
employed to illustrate the thunder shower. Tapering points are
found to have the effect of drawing off a surcharge of electricity from
a body towards which they are directed ; and thus, it may be, do
trees occasionally act as lightning conductors, attracting the electric
fluid, and thus bringing the water charged with it.

Observations have been reported to me which are in accordance
with this supposition.

The Rev. J. Thomas, of Capetown, writes to me that when occupy-
ing a station of the Wesleyan Missionary Society on the West Coast
of Africa, on one occasion when on a journey from the interior in
1848, he and his fellow-travellers came one evening to a forest where

EFFECT OF FORESTS ON RIVERS. 165

they spent the night under the shelter of some large and lofty trees.
About two A.M. it began to rain, and it rained about three hours,
when it poured in torrents, and continued to do so till they left the
place. On mentioning the circumstance they were informed that
just in that place it frequently rained in the manner they had de-
scribed.

I accept the statement because I have no reason to question the
correctness of the observation. I suspend my judgment, and lie open
to light, as our fathers were wont to say, in regard to the occasion of
the down-pour. My prejudices are in favour of the supposition that
it was a passing thunder-shower, unaffected by the trees one way or
another to a perceptible extent ; but it is in accordance with views such
I have stated, and which I know to be held by others ; and I cite it
as a case which, having been communicated to me, I ought not to
ignore because it is at variance with more general views which I
entertain.

Sect. III. — Effects of Forests and of the Destruction of these on
Rivers, and Streams, and Springs.

It is a somewhat prevalent opinion that as rain proceeds from the
clouds, rivers have their primary source in springs ; and along with
this opinion it is held by many that the primary function of rivers is
to carry moisture to lands which otherwise would be barren, and
there to diflfuse fertility. But, in point of fact, no water springs from
the ground which has not previously been deposited from the atmos-
phere ; and the primary function of streams, brooklets, and rivers is
simply to carry off surplus moisture in excess of what the soil can
retain.

As rain is produced by the gravitation to the earth of surplus
moisture in the atmosphere in excess of what the air can contain
suspended in a state of invisible vapour at the temperature to which
it has been reduced, rivers are produced by the gravitation to a lower
level of the surplus water so precipitated in excess of what is absorbed
by the earth or evaporated again into the atmosphere.

The popular phraseology in regard to many things is far from
being in exact accordance with scientific conceptions. We speak of
catching cold, of the rising sun, and of the new moon. And so we
speak of the little spring of water at the greatest distance or the
highest elevation from the mouth of a river as its source ; but no
one supposes that the whole of the waters of the river come from this.

166 EFFECTS OP FORESTS ON RIVERS.

It may be that there is not an inch of its course, or of the courses
of it3 numerous tributaries aud affluents, which does not pass
many of its sources, chauuels of capillary ditneusioos, through
'which, from time to tims, such excess of rainfall has drained ofif", or
may drain oEf, into its bed, by which the accumulated drainings are
drained oflf into the sea, if they be not absorbed or evaporated by the
way.

It is under this aspect of springs, and streamletss, and rivers, we
should look at them while considering the local etFect upon them of
forests, or of the destruction of these.

At a conference which I attended in Svvartland, at the Cape of
Good Hope, after I had given expression to my views on this subject, one
gentlemaa who was present stated that a neighbour of his had
planted on his place twelve trees twenty years before, or twenty trees
twelve years before, I do not remember which, and that he did not
believe one drop more rain had fallen in the district since these trees
had been planted than usually fell before ! And I think it not im-
possible that this may have been the case ; but there are other ways
besides increasing the quantity of the ramfall in which trees may act
upon the humidity of a country, and even on the rainfall in a way
beneficial to man and beast.

It has frequently been remarked that springs, and streamlets, and
rivers, which have flowed permanently in the vicinity of forests have
ceased to flow when these forests have been destroyed ; nor are cases
awanting of their flow having been resumed when, by plantations or
natural reproductions, the destroyed trees have been replaced by
others ; cases have been cited ; and, while apparently in certain
circumstances even the extensive destruction of forests has not
perceptibly affected the deposit of moisture over a widely extended
region, facts are not awanting illustrative of what has been
referred to occuring on an extended, as well as on a limited, scale.

The observations made by Mr Draper in regard to undiminished
rainfall in America must command acceptance. But along with
these we must attend also to the following.

In the Report of the Commissioners of Agriculture, for 1869, it is
stated : — " From all parts of the State of Maine come up the same
complaint of the diminished volume of water in the streams,
occasioned by clearing off the forests and denuding the hills of trees.
The snows are not so heavy, nor so frequent, as they were twenty or

EFFECTS OF FORESTS ON RIVEKS IN AMERICA. 167

thirty years ago ; and there is less rain in the summer. Many of
the old trout streams of twenty years ago are now completely dry,
aad several parts of the State suffer more than formerly from
droughts. Snow covers and protects the ground with less
regularity."

There is thus brought before us also another of the effects of forests,
or rather of the destruction of forests, but the discussion of this
cannot be prosecuted here without distracting attention from what
more immediately concerns us.

Mr Marsh in his treatise on " The Earth as Modified by Human
Action," in writing of the Influences of the Forest on the flow of
springs, says :^-" It is an almost universal and, I believe, well-founded
opinion, that the protection afforded by the forest against the escape
of moisture from its soil by superficial flow and evaporation insures
the permanence and regularity of natural springs, not only within
the limits of the woods, but at some distance beyond its borders, and
thus contributes to the supply of an element essential to both
vegetable and animal life. As the forests are destroyed, the springs
which flowed from the woods, and, consequently, the greater water-
courses fed by them, diminish both in number and volume. This
fact is so familiar in the American States and the British Provinces,
that there are few old residents of the interior of those districts who
are not able to testify to its truth as a matter of personal observation.
My own recollection suggests to me many instances of this sort, and
I remember one case where a small mountain spring, which dis-
appeared soon after the clearing of the ground where it rose, was
recovered about twenty years ago, by simply allowing the bushes and
young trees to giow up on a rocky knoll, not more than half an acre
in extent, immediately above the spring. The ground was hardly
shaded before the water reappeai-ed, and it has ever since continued
to flow without interruption. The hills in the i^tlantic States
formerly abounded in springs and brooks, but in many parts of these
States which were cleared a generation or two ago, the hill-pastures
now suffer severely from drought, and in dry seasons furnish to
cattle neither grass nor water."

And in regard to the effect of the destruction of forests on the
diminution of springs, he subsequently says there is no want of
positive evidence on the subject.

Marchand cites the following instances : —

" Before the felling of the woods, within the last few years,
in the valley of the Soulce, the Combe-^s-Mounin and the Little

168 BPPE0T8 OP PORE8T8 ON SPRINGS.

Valley, the Some fui-nlshed a regular and sufficient supply of water
for the ironworks of Unterwyl, which was almost unaffected by
drought or by heavy rains. The Some has now became a torrent,
every shower occasions a flood, and after a few days of fine weather
the current falls so low that it has been necessary to change the
water-wheels, because those of the old construction are no longer
able to drive the machinery, and at last to introduce a steam-engine
to prevent the stopage of the works for want of water.

" When the factory of St. Ursanne was established, the river that
furnished its power was abundant, and had, from time immemorial
sufficed for the machinery of a previous factory. Afterwards, the
woods near its sources were cut. The supply of water fell off in con-
sequence, the factory wanted water for half the year, and was at last
obliged to stop altogether.

" The spring of Combefoulat, in the commune of Seleate, was well
known as one of the best in the country ; it was remarkably abuudant,
and si-iffiuient, in the severest draughts, to supply all the fountains of
the town ; but since considerable forests were felled in Combe-de-
pr6 Martin and in the valley of Combefoulat, the famous spring,
which lies below these woods, has become a mere thread of water, and
disappears altogether in times of drought.

" The spring of Varieux, which formerly supplied the castle of
Pruntrut, lost more than half its water after the clearing of Varieux
and Rougeols. These woods have been replanted, the young trees .
are growing well, and, with the woods, the waters of the spring are
increasing.

" The Dog Spring between Pruntrut and Bressancourt has entirely
vanished since the surrounded forest-grounds were brought under
cultivation.

" The Wolf Spring, in the Commune of Soubey, furnishes a remark-
able example of the influence of the woods upon fountains. A. few
years ago this spring did not exist. At the place where it now rises,
a small thread of water wa? observed after very long rains, but the
stream disappeared with the rain. The spot is in the middle of a
very steep pasture inclining to the south. Eighty years ago the
owner of the land, perceiving that young firs were shooting up in the
upper part of it, determined to let them grow, and they soon formed
a flourishing grove. As soon as they were well grown, a fine spring
appeared in place of the occasional rill, and furnished abundant
water in the longest droughts. For forty or fifty years this spring
was considered the best in the Clos du Doubs. A few years since,

EFFECTS OP FORESTS ON SPRINGS. 169

the grove was felled, and the ground tm-ned again to a pasture.
The spring disappeared with the wood, and is now as dry as it was
ninety years ago."

" Siemoni gives the following remarkable facts from his own
personal observation :

"In a rocky nook near the crest of a mountain in the Tuscan
Appennines, there flowed a clear, cool, and perennial fountain,
uniting three distinct springs in a single current. The ancient
beeches around and particularly above the springs were felled.
On the disappearance of the wood, the springs ceased to flow, except
in a thread of water in rainy weather, greatly inferior in quality to
that of the old fountain. The beeches were succeeded by firs, and as
soon as they had grown sufficiently to shade the soil, the springs
began again to flow, and they gradually returned to their former
abundance and quality.

" This and the next preceding case are of great importance both as
to the action of the wood in maintaining springs, and particularly as
tending to prove that evergreens do not exercise the desiccative
influence ascribed to them in France. The latter instance, shows,
too, that the protective influence of the wood extends far below the
surface, for the quality of the water was determined, no doubt, by
the depth from which it was drawn. The slender occasional supply
after the beeches were cut was rain-water which soaked through the
superficial humus and oozed out at the old orifices, carrying the taste
and temperature of the vegetable soil with it ; the more abundant and
grateful water which flowed before the beeches were cut, and after
the firs were well grown, came from a deeper source and had been
purified, and cooled to the mean temperature of the locality, by
filtering through strata of mineral earth."

"The influence of the forest on springs," says Hummel, "is
strikingly shown by an instance at Heilbronn. The woods on the
hills surrounding the town are cut in regular succession every
twentieth year. As the aimual cuttings approach a certain point,
the springs yield less water, some of them none at all ; but as the
young growth shoots up, they flow more freely, and at length bubble
up again in all their original abundance."

" Dr Piper states the following case : ' Within about half a mile of
my residence there is a pond upon which mills have been standing
for a long time, dating back, I believe, to the first settlement of the
town. These have been kept in constant operation until within some
twenty or thirty years, when the supply of water began to fail. The

170 EFFECTS OF FOBESTS ON SPKINGS.

pond owes its existence to a stream that has its source in the hills
which stretch some miles to the south. Within the time mentioned,
these hills, which were clothed with a dense forest, have been almost
entirely stripped of trees ; and to the wonder and loss of the mill-
owners, the water in the pool has failed, except in the season of
freshets ; and, what was never heard of before, the stream itself has
been entirely dry. Within the last ten yeai's a new growth of wood
has sprung up on most of the land formerly occupied by the old
forest ; and now the water runs through the year, notwithstanding
the great droughts of the last few years, going back from 1856.'

" Dr Piper quotes from a letter of William C. Bryant the following
remarks : * It is a common observation that our summers are be-
coming drier and our streams smaller. Take the Cuyahoga as an
illustration. Fifty years ago large barges loaded with goods went up
and down that river, and one of the vessels engaged in the battle of
Lake Erie, in which the gallant Perry was victorious, was built at
Old Portage, six miles north of Albion, and floated down to the lake.
Now, in an ordinary stage of the water, a canoe or skiff can hardly
pass down the stream. Many a boat of fifty tons burden has been
built and loaded in the Tuscarawas, at New Portage, and sailed to
New Orleans without breaking bulk. Now the river hardly affords a
supply of water at New Portage for the canal. The same may be
said of other sti-eams — they are drying up. And from the same cause
— the destruction of our forests — our summers are growing drier and
our winters colder.'

" Becquerel and other European writers adduce numerous other
cases where the destruction of forests has caused the disappearance of
springs, a diminution in the volume of rivers, and a lowering of the
level of lakes, and in fact, the evidence in suppprt of the doctrine I
have been maintaining on this subject seems to be as conclusive as
the nature of the case admits. We cannot, it is true, arrive at the
same certainty and precision of result in these inquiries as in those
branches of physical research where exact quantitative appreciation
is possible, and we must content ourselves with probabilities and
approximations. We cannot possibly affirm that the precipitation in
a given locality is increased by the presence, or lessened by the
destruction, of the forest, and from our ignorance of the subterranean
circulation of the waters, we cannot predict, with certainty, the dry-
ing up of a particular spring as a consequence of the felling of the
wood which shelters it; but the general truth, that the flow of
springJJ and the normal volume of rivers rise and fall with the exten-

EFFECTS OP FORESTS ON SPRINGS. 171

sion and the diminution of the woods where they originate and
through which they run, is as well established as any proposition is
in the science of physical geography.

" Of the converse proposition, namely, that the planting of new
forests gives rise to new springs, and restores the regular flow of
rivers, I find less of positive proof, however probable it may be, that
such effects would follow. A reason for the want of evidence on the
subject may be, that, under ordinary circumstances, the process of
conversion of bare ground to soil with a well-wooded surface is so
gradual and slow, and the time required for a fair experiment is con-
sequently so long, that many changes produced by the action of the
new geographical element escape the notice and the memory of
ordinary observers. The growth of a forest, including the formation
of a thick stratum of vegetable mould beneath it, is the work of a
generation, its destruction may be accomplished in a day ; and hence,
while the results of one process may, for a considerable time, be
doubtful, if not imperceptible, those of the other are immediately
and readily appreciable. Fortunately, the plantation of a wood pro-
duces other beneficial consequences, which are both sooner realised
and more easily estimated ; and though he who drops the seed is
sowing for a future generation as well as for his own, the planter of a
grove may hope himself to reap a fair return for his expenditure and
his labour."

We do not always find all facts in manifest accordance with con-
clusions towards which we may be advancing, or to which we may
previously have come ; and though every fact must necessarily be in
accordance with every other fact we may often find it necessary to
take into account conflicting influences, the efiect of which must be
determined ; and to the preceding statement Mr Marsh has appended
the following note : —

" Some years ago it was popularly believed that the volume of the
Mississippi, like that of the Volga and other rivers of the Eastern
Hemisphere, was diminished by the increased evaporation from its
basin and the drying up of the springs in consequence of the felling of
the forests in the vicinity of the sources of its eastern affluents. The
boatmen of this great river and other intelligent observers now assure
us, however, that the mean and normal level of the Mississippi has
risen within a few years, and that in consequence the river is navi-
gable at low water for boats of greater draught and at higher points
in its course than was the case twenty-five years ago.

" This supposed increase of volume has been attributed by some to

172 EFFECTS OF FORESTS ON SPRINGS.

the recent re-wooding of the prairies, but the plantations thus far made
are not yet sufficiently extensive to pi'oduce an appreciable effect of
this nature ; and besides, while young trees have covered some of the
prairies, the destruction of the forest has been continued perhaps in a
greater pi-oportion in other parts of the basin of the river. A more
plausible opinion is that the substitution of ground that is cultivated,
and consequently spongy and absorbent, for the natural soil of
the prairies, has furnished a reservoir for the rains which are
absorbed by the earth and carried gradually to the river by sub-
terranean flow, instead of running off rapidly from the surface, or, as
is more probable, instead of evaporating or being taken up by the
vigorous herbaceous vegetation which covers the natural prairie.

" A phenomenon so contrary to common experience, as would be a
permanent increase in the waters of a great river, will not be
accepted without the most convincing proofs. The present greater
facility of navigation may be attributed to improvements in the
model of the boats, to the removing of sand-banks and other impedi-
ments to the flow of the waters, or to the confining of these waters in
a narrower channel, by extending the embankments of the river, or
to yet other causes."

A case similar to that occurring on the Wolfspring was reported
to me by Mr S. Van Reenan, of Constantia. The site of the cele-
brated vineyard so long in possession of his family, measuring some
45 acres, or 22| Morgens, was when granted to his forefather a
forest. There was then on it an abundance of water, such abundance
that though there was no spring on the property there was a large
reservoir and large pond in front of the house, supplied and main-
tained by a stream of water, at least four inches in diameter. But
when the forest was felled, and the vineyard planted in its place, the
supply of water gradually diminished till it was reduced to a supply
one inch in diameter, and ultimately to a supply measuring only a
quarter of an inch.

On the same ground he afterwards formed a plantation, to the
destruction of which by fire I have elsewhere had occasion to refer.

In regard to this he informed me that on the abolition of slavery,
probably about 1838, he feared he should not be able to keep so
much vineyard under cultivation as he had previously done, and he
employed several of his slaves in sowing seeds of the Cluster pine and
of the Stone pine {Pinus pinaster, and Pinus pinea). In one night,
specified by him to me as the night on which the " Vulcan" entered

EFFECTS OF FORESTS ON SPRINGS. 173

Table Bay with the German Legion, the wood thus formed was con-
sumed by a fire, occasioned by one of his neighbours burning the
bush on his fai'm, and I understood him to say that the effects were
again the same : a somewhat copious flow of water, which had been
re-established during the growth of the trees, was suddenly stopped
by the denudation of the soil.

In a preceding chapter I have stated that Dr Moffat follows up the
details given by him of the destruction of trees by Bechuanas, which
I have cited, with the remark, " To this system of extermination may
be attributed the long succession of diy seasons." " To the the same
cause," says he, " may be traced the diminution of fountains, and the
entire failure of some which formerly afforded a copious supply, such
as Griqua Town, Campbell, and a great number of others which might
be mentioned. It has been remarked that since the accidental
destruction of whole plains of the Olea similis (wild olive) by fire, near
Griqua Town, as well as the diminishing of large shrubs on the
neighbouring heights a gradual decrease of rain has succeeded in that
region." And Chapman accompanied information which he gave to me
in regard to the destruction of forests in the interior with a similar
observation. Moffat relates that on his settlement at Latakoo " the
natives were wont to tell of the floods of ancient times, the incessant
showers which clothed the very rocks with verdure, and the giant trees
and forests which once studded the brows of the Mamhana hills and
neighbouring plains. They boasted of the Kuruman and other rivers,
with their impassable torrents, in which the hippopotami played, while
the lowing herds walked to their necks in grass, filling their mahckas
(milk sacks) with miik, making eveiy heart to sing for joy."

He speaks of that river as issuing from caverns in lime stone hills,
full formed, like Minerva fully equipped from the head of Jove ; he
writes in 1842 "that it no longer continued to send forth the torrents
it once did :" he speaks of it as " once a large river emptying itself
into the Gariep, or Orange River, at a distance below the water-fall;"
but as then by absorption lost in its bed about ten miles to the north-
west of its source.

In my own tours throughout the Colony I found everywhere in the
superficial aspect of the country indications that, at a period not very
i-emote, it must have been a land well-watered everywhere. I found
that within the memory of the present occupants of the land there
has been a remarkable change in the aridity, both of limited and of
extensive districts. And I found that in not a few places the chauo-e
was observed to follow immediately the destruction of bush. Details

174 EFFECTS OP FORESTS ON SPRINGS.

I have given in a separate volume on the " Hydrology of South
Africa."

By Surell it is mentioned, in a note appended to his Etude sur les
Torrents des Hautes Alpes, " There has been discovered the existence,
in the time of the Romans, of a great corporation of watermen
established on the Durance, which proves that there was then a
considerable flottage, or transport, of timber in rafts, which has been
for a long time given up entirely, and which proves also that this
department was then covered with abounding forests, of which there
exist now only but meagre shreds." But now, that river has
made for itself a bed which in some places exceeds a mile and a
quarter in breadth, while the ordinary flow of the river is confined to
a cm-rent little more than thirty feet in width ; and from Young's
travels in France it appears that so early as 1789 it was computed to
have covered with gravel and pebbles not less than 130,000 acres,
" which, but for its inundations, would have been the forest land in
the province." Thus have we there land undermined and washed
away, — fertile land covered with the debris, and the fertilizing
material carried away to the sea.

The fact in regard to the former state of the Durance is mentioned
also by Ladoucette in his Histoire, i&c , des Hautes Alpes.

In the Avii des Sciences, of December 11, 1873, there is given
the following statement by M. Cantegril, sub-inspector of forests.
In explanation of one of the statements in this I may state that,
with a view to the conservation and improvement of the forests of
France, certain regulations had been laid down for the re-arrangement
of the forests of the States, and liberal arrangements made for the
extension of these regulations, to the management of forests belong-
ing to communes, where this could be done with their consent.

*' Upon the territory of the commune of Labruguifere fTarn) there
is a forest of 1,834 hectares, (4,524 acres,) known as the forest of
Montant, and owned by the commune. It extends northward on the
Montagne-Noire, and the soil is granitic, with a maximum altitude of
1,243 meters, and a slope of from 15 to 60 in 100. A little water-
course, the Caunan brook, rises in this forest and drains the waters
of two-thirds of its surface. At the entrance of the forest, and along
this brook, are located several fulling mills, each requiring eight
horse-power, and moved by water-wheels which work the beaters of
the machines.

"The commune of Labruguiere had long been noted for its

EFFECTS OF FORESTS ON SPRINGS. 175

opposition to the forest regulations; and the cutting of wood, together
with the abuse of pasturage, had converted the forest into an immense
waste, so that this great property would hardly pay the cost ^of
guarding it and afford a meagre supply of wood for its inhabitants.

*' While the forest was thus ruined and the soil denuded, the waters
after each heavy rain swept down through the valley, bringing with
them great quantities of gravel, the debris of which still encumbers
the channel of this stream. The violence of these floods was some-
times so great that they were compelled to stop the machines for
some time. But in the summer time another inconvenience made its
appeai-ance. Little by little the drought extended, the flow of waters
became insignificant, the mills stood idle, or could be run only
occasionally for a short time.

" About 1840 the municipal authorities began to give information to
the population relative to their true interests, and under the protection
of a better supervision the work of replanting has been well managed,
and the forest is to-day in successful growth.

" In proportion as the replanting progressed, the precarious use of
the mills ceased, and the regime of the water-courses was greatly
modified. They now no longer swelled into sudden and violent floods,
compelling the machines to stop, but the rise did not begin until six
or eight hours after the rains began. They rose steadily to their
maximum, and then subsided in the same manner. In short, the mills
were no longer obliged to stop work, and the water was always enough
to run two fulling machines, and sometimes three.

" This example is remarkable in this, that all the other circumstances
had remained the same, and therefore we can only attribute to the
reforesting the changes that occurred, namely, diminution of the flood
at the time of rain, and an increase in its flow during other times."

From a report made by Henry J. Wisner, United States Consul at
Sonneberg, in the Department of State, in November, 1873, the river
Elbe between the years 1787 and 1837, a period of half a century,
diminished at Attenbruecke, in Hanover, ten feet in depth, as a direct
result of the cutting off of forests in the region where the tributaries
have their origin.

In 1873, there appeared in the Zeitschrift des osterr. higenieur
iind Architecteu Vereim, a paper by Herr Gustav Wex, Counsellor
of State, and Director-in-Chief of works undertaken for the regu-
lating of the flow of the Danube, " On the Diminution of Water in
Streams and Rivers, accompanied by Occasional Inundations in

176 EFFECTS OF FORESTS ON SPRINGS.

Agricultural districts." In this the author, after having in an Intro-
duction shown the great importance of the subject, invites his
colleagues as well as other naturalists to examine his book, and
appeals for the support of the Government in favour of his pro-
positions, especially those departments of the Government which ai-e
more specially occupied with the care and defence of the economical
interests of the public ; after which he treats, in the first place, of the
diminution of water in the rivers and streams, and consequently the
diminution in the out-flow. He proceeds upon personal observations
during a period of forty years, made on the Austro-Hungarian great
rivers and streams, with relation to the conditions of their out-flow,
and he comes to the conclusion that the volume of water at present
discharged has decreased considerably during a series of years.

Corresponding facts have been attested also by others, and judging
from these they have given their opinion that the volume of water
discharged by many streams appears to be diminishing. But the
correctness of this conclusion has been disputed, and the author
discusses the obsei-vations which have been adduced against the views
adopted by him, as well as those upon which his conclusions were
based.

The author proceeds on data supplied in the Second Part of the
Allegmeine Lander und Volkerk^mde, by Berghaus, in regard to the
depth of water in the Rhine at Emmerich, of the Elbe at Magdeburg,
and of the Oder at Kiistrain, according to which the average and
lower depths of water have experienced a diminution by no means
inconsiderable, while the floods of greatest depth present, on the
other hand, apparently an increase both in frequency of occurrence
and in magnitude.

Dr Berghaus became convinced through an examination of the
tables of the depth of water in the Elbe and the Oder that on the
main streams of both the flow or delivery have been considerably
diminished ; and he expressed a fear that these two rivers of Germany
were threatening to disappear from the number of navigable rivers,
which would be the case if the reduction in the depth of water should
go on at the same rate at which it had proved to be diminishing since
the year 1781.

Herr Wex, by long-continued observations and studies, had come to
the same conclusion as Berghaus, and he maintains against objections
brought forward on difi^erent sides the opinion that there has been a
progressive diminution in the quantity of water in these rivers, and
not less really so in the Vistula and the Danube.

TREATISE BY HERR WEX. 177

Amongst the objections referred to : — 1. Herr F. Hagen, Royal
Prussian Geheime Oherhaurath, and Oher-Landes-Baii-Director, found
by actual measurement of the Ehine, at Dusseldorf, that the
diminution of the highest and of the medium floods was but incon-
siderable— on an average, the one 2-9 and the other TG lines per
annum, about one-fourth and one-eighth of an inch. And he alleges
that this may be accounted for by the modifications which have
been made in the river's bed, whereby the supplies from the
melting of ice have been retarded, and the flowing away of floods
promoted.

2. Herr Maass, Prussian Royal Hydraulic Inspector, has found by
examination of the observations on the height of the Elbe, made for
143 years in the Pegel at Magdeburg, a considerable diminution
in the greatest, medium, and lowest heights of the river, amounting
to 17, to 35|^, and to 34 zoll, or inches ; but he alleges this reduction
to be the consequence of the modification of the bed of the river
occasioning a deepening of the bed, and an increased rapidity of
flow.

3. A conjecture, which has been expressed, that such considerable
quantities of water may be carried away in the more frequent and
higher floods of later times as to compensate for the diminution in
the medium and lower heights of the flow at other times.

The author shows — 1. By the measurements made by the late Herr
Grebenau, Bavarian Royal Bau-Inspector, at Germersheim, on the
pegel at Sondersheim, throughout a period of twenty-eight years,
which gave not only information in regard to the depth of the river,
as ascertained by the said gauge, but also in regard to the delivery
or quantity of the flow, that the diminution of the average depth
and a diminution in the delivery or flow go together.

2. According to observations made by the Elhe-Stromschcm-Com-
mission, it appears that there has been indeed a deepening of the
bed of the river in its upper part ; but, on the other hand, an eleva-
tion of the river bed by the silting of sand in the middle and the lower
portion of it. So that the diminution in the height of the water at
the gauge at Magdeburg cannot be attributed to a deepening of the
bed of the stream.

3. That the high floods are no compensation for the diminution of
the delivery by the low and medium flow is proved by the author —
first, by the before-mentioned measuremoits by the gauge at Sonders-
heim, according to which difl^erences in the delivery are found to be
nearly proportionate to the depth of the flow; and, further, by

178 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

measurements made for thirty-two years on the Danube gauge at
Alt-Orsova, according to which is established not only a lowering in
the medium and the lowest flows, but also in those of greatest height,
which phenomenon, different from what has been seen in other rivers,
the author attributes to the circumstance that the floods in each of
the large tributaries occur at diff'erent times.

" On the occasion of a Commission to prepare a scheme or project
for the regulation of the flow of the larger streams and rivers of
Austria being entrusted to me by the Government," writes Herr
Wax, " I set about, as a preliminary measure, the study of the
delivery of water by these rivers, and in doing so I have invariably
found that the delivery, measured by such appliances and means of
ascertaining this, has of late years greatly diminished.

" Although a corresponding fact had been previously observed by
scientific students of natural history, and the phenomenon of a
diminution in the delivery of diff'erent rivers had been ascertained,
the correctness of the conclusion arrived at had been called in question
by other scientific men, and more especially by Hydrotechnikern
[hydrologists and students of hydraulic-engineering ?] I shall there-
fore state the views advanced by them, and thereafter meet them by
observations made during protracted periods on some of the principal
rivers of Central Europe.

" Herr F. Hagen, Royal Prussian Geheime Oherhaurath and Oher-
Landes-Bau-Director, has in the last (the third) edition of his Hand-
huches der Wasserbau Kionst, for the year 1871, called in question the
correctness of observations hitherto made on the height of water in
streams and rivers, and of deductions drawn from these in regard to
a diminished flow of water in them, and he bases his opposing views
on observations made with the Rhine pegel at Dusseldorf since the
year 1800, and on the recorded observations on the height of the
level of the river for seventy-one years.

"Herr Hagen has calculated for every separate year the arithmetical
mean yielded by the daily observed height of the water, and also the
average annual height of the water, he has also noted the highest and
lowest heights of the water in each year; and he has represented
these three conditions of the water in a diagram, by which he makes
apparent that no very considerable diminution of the waters has
occurred.

" In consequence of the great importance of the matter, Herr Hagen
has submitted the former selected observations on the state of the
river to a calculation founded on the least common multiple, and

STATEMENTS BY HERR HAGEN, 179

thus found that in the course of the last 71 years, on the Rhone at
Dusseldorf, there has been a reduction of the highest floods to the
extent of 2*9 lines, of the ??iea« to the extent of 1"6 lines, while there
has been a rise in the lowest of 0*2 lines per annum. But on these
calculations Herr Hagen himself does not lay particular stress, as
there may be errors, he says, in the results obtained to the extent
of 2-2'", 0-9'", and 0-7'" respectively.

" Herr Hagen says further : ' It may well be imagined that in the
course of time a diminution in the highest and the mean levels has
taken place ; and that for the reason that in later years, through the
modifications of the water-course which have occurred, the flotation
of ice has been impeded, the flow of water from the higher-lying
districts of the river's basin has been promoted ; whence the small
annual reduction of the calculated mean river-height may have
followed.'

" Subsequently, Herr Hagen having expressed doubts in regard to
the statements of certain Hydrotechnikern, relative to a great
diminution in the level and delivery of the Weser, from a comparison
of the observations made by the pegel at Minden and at Schliissel-
burg, comes to the following conclusion : ' It thence appears that,
in so far as observations made up to this time can show, it is as
impossible to give with certainty a verdict in regard to any general
diminution of its waters in regard to the Weser as in regard to the
Rhone.'

"Although the observations made on three gauges on two rivers
lead Herr Hagen to express himself thus guardedly on the subject of
a lowering of the water-level, yet the greater number of Hydrotechni-
kern— because observations continued through many years, and com-
parison of the water-levels at distant periods of other rivers are not
at their command, and because they consider Herr Hagen an
infallible authority on all that relates to hydraulic engineering — have
come to the conclusion that in general there has not taken place any
great diminution in the flow and delivery of streams and rivers.

" Herr Maass, the Prussian Royal Wasserhau-Inspectm-, has
published, in the Zeitsckrift fur Bauwesen von Erhkani, for the year
1870, observations of the height of the river Elbe for the period of
143 years, extending from 1727 to 1869, with a diagram represen-
tative of these observations ; and from these he has drawn the con-
clusions that within this period the waters of the Elbe have gradually
diminished in the following arithmetical means : a. In the highest
levels reached, 17 inches ; h. In the lowest level observed, 34 inches;

180 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

c. In the meau of the whole of the observations made in the several
years, 35 1 inches.

" According to the views of Herr Maass the lowering of the heights
of the water level is not a consequence of any diminution of the
quantity of water now flowing into the Elbe, but the result of the
rectification of the river bed, an extensive deepening of this as a
consequence of that modification, and an increase of the rapidity of
the flow or delivery of the river. Herr Maass attaches importance to
the efiects of these in lowering the level of the streams, and remarks
that no further lowering of that level is to be expected, because there
are no additional works of modification in contemplation.

" As the observations and views of Herr Hagen and of Herr Maass
are diametrically opposed to observations which I have myself made
on several rivers during the last 40 years, I have brought together the
observations I have made on several rivers and streams, and the con-
clusions I have drawn from them, for publication as measurements of
the water level for many years, upon which reliance may be placed,
as it is only in being in possession of these data that I could have
been so bold as to come forward with any confidence as the opponent
of an authority so distinguished throughout the whole of Germany as
is Herr Hagen in matters pertaining to Hydrotechuics.

" In the course of my observations on the subject in question there
came into my hands the remarkable work, Allgemeine Ldnder-%ind
Volkerlcunde, by Dr Heinrich Bergman, — volume second, Umrises der
HydrogrcqMe, for the year 1837, — and I found in this work, and in
that issued by the same author and by J. Perthes, Hydro-hystorischen
Uehersichten der deutscheii Strome, for the year 1838, collected to-
gether much valuable material relative to the height of the water
and to the floating of the ice in the rivers.

. " From the observations on the river level made with the pegel at
Emmerich, on the frontier of Holland, for the period of 66 years,
from 1770 to 1835, and with these the observations made with the
pegel at Cologne for the period of 54 years, from 1782 to 1835, and
in addition to these the observations made on the Elbe with the
pegel at Magdeburg, for the period of 108 years, from 1728 to 1835,
and on the Oder with the pegel at Kiistrin, for the period of 58 years,
from 1778 to 1835, has the distinguished hydrographer Berghaus
determined the measurements of the highest and of the lowest levels
of these rivers, and from them calculated arithmetically the annual
mean levels. He has represented these by diagrams, and given
diagrams representative of the average height of the rivers in the

STATEMENTS BY DR BERGHAUS. 181

diflferent months of the year, and of the movement of the ice and of
floods ; and finally, he has in addition to these tabulated statements
given others illustrative of the influence of the rainfall on the
quantity of water carried off by the rivers, and has exhibited this in a
way so thorough and efficient as is not equalled in any other work on
Hydrotechnics. By which means Berghaus as a precursor has shown
to Hydrotechnikern in what way observations on the ever-varying
levels of rivers should be brought together and compared, in order to
present a distinct picture of the hydrographic phenomena, or of the
river life of the stream, and from this correctly to draw inferences
and final conclusions.

" Fi-om these extremely detailed and deeply interesting investiga-
tions by Berghaus I make, amongst others, the following leading
deductions : —

" From the ' Hydrographie ' of Dr Berghaus I have prepared a
diagram, which I have appended to this treatise, in which I have
represented what were the highest, and the lowest, and the calculated
mean annual water-levels of the Rhone, observed by the pegel at
Emmerich, from the year 1770 to 1835. From this diagram it
appears at a glance that the water-level of the several years is very
far indeed from being regular, but in successive years they rise and
fall ; and it is consequently difficult to represent by a continuous
line, or to calculate a mean representative of the diminution or
increase of the water-level for a period of some length, as HeiT Hagen
also states to *be the case. I therefore hold to the opinion that the
method adopted by Dr Berghaus, comparing the arithmetical mean of
the water-level during a more lengthened period than two years, is
more easy and supplies data upon which more reliance can be placed ;
and from the data thus procured, inferring or deducing whether there
has been any rise or fall in the river-level. If, then, we divide the
observations made during the period of 66 years into those made in
the first period of 33 years, from 1770 to 1802, and those made in
the second period of 33 years, from 1803 and 1835 ; and if from these
two equal periods of 33 years each we calculate and compare the annual
average levels of the river in each, the result will be, we shall find
that in the second period the average height of that level was 10'" in
excess of the first ; but on the contrary, the annual water-level has
fallen 1' 42" 5'", and the lowest 1' 1* 3"', when compared with the
corresponding earlier period from 1770 to 1802.

"As the arithmetically determined mean of the river-level in the
first period, from 1770 to 1802, was only taken incidentally for com-

182 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

parison, without reference to the fact whether in the course of these
33 years any rise or fall of the water-level had taken place, it is clear
that the above numbei's represent the reduction which had taken
place in the lowest levels and in the annual mean levels of the river
in the second period of 33 years — that is, for the half of the whole
period embraced by the observations made.

"And the same remark will also apply to all subsequent com-
parisons of the water-level in two periods.

" If we consider further the observations made of the pegel on the
Rhone at Cologne, from 1782 to 1835 [which was also appended to
the treatise], and again divide the period embraced of 54 years into
two consecutive periods of 27 years each, and by calculation deter-
mine the mean annual levels, we find that in the second of these
periods, that from 1809 to 1835, the mean height of highest floods
has risen about 0' V 66'" ; while, on the contrary, the mean annual
height has fallen about 4'27", and that of the lowest levels about
7 "21", as compared with those of the first half of the period, that
from 1782 to 1808.

" From the foregoing deductions it is apparent that in the two
principal pegels on the Rhine at Emmerich and Cologne — during
the periods of 66 and of 54 years, embraced by them respectively
from 1770, and from 1782 to 1835 — there has taken place a not
inconsiderable fall both in the lowest levels and in the mean annual
levels ; and that only the mecm of the highest levels is found to be
somewhat higher in the second as compared with the earlier halves
of the periods embraced by the observations.

"As during the period of observation extending from 1770 to 1835,
no such works of modification of the river's course as could have
produced any deepening of the bed of the stream at Cologne and at
Emmerich, or any increase of the rapidity of water-flow, and con-
sequent lowering of the water-level, had been carried on, the fall of
that level in the case of the lowest and the mecai states of the river,
during the later halves of the periods embraced by the observations
in question, can only be attributed to a diminished quantity of water
passing down the Rhine ; while the small rise in the annual mean of
the highest point reached, has to be ascribed to more frequent and
higher floods.

" That the fall in the low and mean annual proves to be less than
it has been in some other rivers is accounted for, by Berghaus, by a
reference to the fact that the Rhine is fed, in a great measure, by the
confluence of numerous currents from the ice and snow on the Alps ;

EXAMINATION OF STATEMENT BY HERR HAGEN. 183

which explanation I would follow up with the remark that by the
Lake of Constance, which receives the waters of the Upper Khine
and afterwards emits them gradually, this river regulates its delivery
at lower-lying points ; and that, as a consequence of this, the reduc-
tion in its delivery at lowest, and in mean annual levels, can show
itself in but very minute measurements.

" The circumstance that the fall, in these levels, shows itself much
more considerable at the pegel at Emmerich than at the pegel at
Cologne, is explained, by Bei'ghaus, by the fact that between Cologne
and Emmerich there flow into the Rhine the Wupper, the Ruhr, the
Emtsche, and the Lippe, which are less uniform in their flow than is
the Rhine which is thus fed.

" Adverting now to the diagram and tabulated statement of the
level of the Rhine, as indicated by the pegel at Dusseldorf, situated
between Cologne and Emmerich, for the period from 1800 to 1871,
published by Herr Hagen, let us examine it with some care.

" Herr Hagen found by his method of investigation that the
annual mean level had fallen upon an average about 1'6 line, which
for a period of 50 years gives a fall of 6'66 inches,

" As according to the observations tabulated by Berghaus the fall
in the mean annual level given above reduced to a like period of 50
years gives at the pegel at Emmerich 24*88 inches, and at the pegel
at Cologne 7*91 inches ; from this it appears that Herr Hagen's
calculation of the fall of the water level at Dusseldorf, amounting to
6"66 inches, although founded on observations embracing a diff'erent
period of time, comes very near to the calculation made of the fall at
the comparatively proximate pegel at Cologne, from which it follows
that the calculated fall must be regarded as an actual fact, and not
an error in calculation, as Herr Hagen had intimated that it not
improbably might be.

" Although according to the older tabulated observations of
Berghaus for the period from 1770 to 1835, there appears a some-
what higher rise in the highest floods of the Rhine, amounting to
from 10 to 18 lines, — still the calculation of Herr Hagen that the
level reached by the high floods had fallen 2-9'" per annum, and
consequently 12" V" in fifty years, may possibly be correct; and are
probably so, since in consequence of the extensive rectification of the
river bed between Basle and Manheim since 1830, the rapid flow of
the high floods must have been accelerated.

"Herr Hagen has found a very slight rise in the level of the
lowest observations at Dusseldorf, about 0"2''' per annum, consequently

184 EFFECTS OF FOREHTS ON SPRINGS AND RIVERS.

only about 10 lines, or five-sixths of an inch, for 50 years. And this
is explicable in that the bed of the stream has been at that place
reduced in breadth within later decades; and also in that the extensive
rectifications of the course of the Rhine, by cuttings above Manheim,
has made it possible that by means of sand and fine silt, transported
to the lower reaches of the river, the bed of the stream at Dusseldorf
may have become somewhat silted up and elevated in a way similar
to what has occurred to a still greater degree in the middle and lower
sections of the Elbe,

" From the foregoing references it is evident that the conclusions
drawn by Herr Hagen, that the observations made up to this time on
the Rhine do not indicate any general lowering of the water level, are
erroneous. And if he had been acquainted with the older observa-
tions at Emmerich and Cologne, published by Berghaus, or if he had
more skilfully compared the observations, extending over a period of
71 years, at Dusseldorf, he would probably have come to a conclu-
sion the very contrary to that to which he has come.

" In order to obtain data on which reliance might be placed in regard
to the flow of the Rhine above Dusseldorf and Cologne, I addressed
myself to the distinguished hydrographer Herr Grebenau, Bavarian
Royal Bcm-Inspectov^i Gemersheim, who was for many years engaged
in the rectification of the new bed of the Rhine, and from him I re-
ceived not only the details of observations on the river-level at the
pegel at Sondersheim for the period of 28 years from 1840 to 1867,
but also the results of investigations on the delivery or quantity of
water passing each year through the cuttings of the Rhine bed at
Gemersheim, which Herr Grebenau had obtained with great care and
precision, partly by means of numerous special measurements of
vertical sections of the current and the rapidity of the flow, and
partly by means of calculations according to the latest formulas of
experimentally-obtained co-efiicients.

" When these tabulated observations on the water level, and the
diagram representative of the quantity of water delivered for the
period of 28 years, are divided into two successive periods of 14 years
each; and when for each of these there is calculated the means both of
the levels and of the delivery, there are obtained from these the
following results : the mean annual water level in the latter period of
14 years is about -432 metres, or 17-63 inches lower, and the delivery
is about 6966 cubic feet per second less, than in the former,

'* Along with this it must be admitted that, to a great extent, the
lowering of the mean annual level of the river is to be ascribed to a

STATEMENT BY HERE WEX. 185

considerable deepening of the bed of the stream, consequent upon
extensive rectifications of the river by cuttings.

"Further, although it must not be concealed that the different
water-levels measured, and deliveries calculated, cannot be relied on
as absolutely correct, and it is unquestionably the case that the
deepening of the bed of the stream had a great effect upon the
lowering of the level and the reduction of the delivery, still it must
be noted that the fall and diminution in the one and the other, which
have been determined, have been brought to light by the same
method, and are in any case approximately correct ; from which it
follows as a consequence, that in the latter period (embracing 28
years), at the pegel at Germersheim, the body of water delivered by
the Rhine has considerably diminished.

*' Along with this must be noted the very remarkable fact, that
the beautifully rectified course of the Rhine from Manheim upwards
toward Basle, converting it almost into a regular canal, has now become
in a great measure unnavigable : in consequence — first, of the
numerous persistent and extending beds of silt in the bed of the
river, and resting in the concave sweep; and next, of the con-
tinually increasing serpentine character of the course of the stream; and
finally, of the low depth of water in the many crossings of the stream
from one concave bay to another, all which can now be accounted
for by the fact that the normal breadth of the river-bed was originally
taken to be greater than it actually is, from which it follows that the
current, in consequence of the diminished water-flow, has not now
the force necessary to remove these masses of silt, and to lodge
them only on the convex or projecting shores of the river-bed.

" The foregoing results of observations made on four gauges on the
Rhine, serve to strengthen my allegations in regard to this river ;
and I proceed to the consideration of the information obtained in
regard to the other rivers of Central Europe."

There are given in an appendix the several tabulated observations
and diagrams referred to. There follow discussions similar to those
which have been quoted in detail : 1. Of observations made on the
Elbe, with a tabulated statement of observations of the highest, mean,
and lowest levels of the river at Magdeburg, with the calculated means,
and a diagram representative of the same, from the year 1728 to 1869,
a division of the former of these being made into periods of 50 years ; a
diagram representative of the calculated delivery of the Elbe in the
several months of the year during the two periods from 1731 to 1780,
and from 1781 to 1830 ; and a diagram representative of the depth in

T

186 EFFECTS OP FORESTS ON SPRINGS AND RIVERS.

metres at twenty-five different stations on the river on several occasions
of very low water,

2. Of observations on the Vistula, with a tabulated statement of the
highest and lowest levels, observed at Weichsel near Kurzebrack in
each year from 1809 to 1871,«with calculated mean annual depth of
the river, and a diagram representative of these. It had been alleged
that a greater quantity of water was being delivered by the Vistula
than previously, and reference is made to these tables as proof that
this was unwarranted, and as supplying evidence that the delivery
was being diminished,

3. In regard to the Danube at Vienna, with a tabulated statement
of the highest and lowest water levels, observed at Vienna in each
year from 1826 to 1871, with the calculated mean level; a tabulated
statement of similar observations at Orsova, for the years from 1840 to
1871 ; and a tabulated statement for comparison of the height of the
Danube at ten other stations on the river ; a diagram representative
of the observations at Vienna, in the period 1849-1871 ; a diagram
representative of the delivery or flow in the several months of the
year in the two periods 1826-1848, 1849-1871 ; and a diagram
representative of the comparative water levels at the several stations
on the Danube mentioned in the tabulated statement.

There is given a similar tabulated statement of observations made
at the pegel on the Oder at Kiistrin, from 1778 to 1835, And in
regard to all of these he writes : " To facilitate the comparison the
fall in the level in the five rivers named, I have reduced the
recorded observations to their equivalents for a period of 50 years,
and I have thus obtained the results embodied in the following-
table. The measurements are given in Rhenish inches : —

TABLE OF OBSERVATIONS.

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188 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

" If we omit from this table the observatious made with the pegel
on the Rhine at Germersheim, — as the loweriug of the water level
there, together with the deepening of the river bed, is mainly attri-
butable to the extensive rectifications of the river by cuttings, and only
in a comparatively small degree to a diminution of the delivery, — we
find that the greatest lowering of the water level is on the Danube at
Orsova, amounting to from 46 to 55 inches ; on the Vistula at Marien-
werder from 26 to 43* 9 inches ; and on the Rhine at Emmerich from
20 to 24*8 inches ; and on the other pegels of the rivers named from
6 to 18 inches.

" In the Elbe the falls of the lowest and of the mean water levels
are 15"76 and 16'28 ; and they might indeed have been considerably
greater had it not been that since 1842, in consequence of the great
silting up of the river bed with sand, the lower water levels have been
elevated from 13 to 22 inches.

" The lowering of the watei* level becomes so much the greater the
larger the river is, and the nearer to the mouth of the river in the sea
that the pegel is situated, and this for the reason that the region
drained by the river is the greater, and that it is the sum of the reduc-
tions in the levels of all the brooks and streams and lesser rivers
which have flowed into the main stream which is there represented
in this greater lowering of the river level.

" In regard to the high floods of the said rivers, we see from the
diagrams submitted that, with the single exception of the station at
Orsova, in all of them floods have latterly occurred more frequently
and reached a greater height than in the earlier years in which the
observations were made, from which it appears clear as day that in
these rivers at present, at times of high flood, a much greater
quantity of water is delivered by them than in the earlier years.

" From the diagrams representative of the high floods, it is further
apparent that in the earlier times of observation the rise of water, in
consecutive years, w^as more uniform ; whereas, in the later decades
of the periods embraced by the observations, in one year there
occurred a very great flood, and in the year before or the year
after only a very insignificant rise of water ; from which it follows
that the alternation of very dry with very wet years occurs more
frequently and to a much more marked degree now than for-
merly.

"This is particularly apparent in the tabulated observatious on
the Elbe and the Vistula.

" The cause of this remarkable pheuomeuou lies evidently in this,

TREATISE BY HERR WEX. l89

that since the clearing away of many forests, more especially in the
mountains, deluges of rain and rain-spouts occur more frequently ;
further, while the rain-water, in lands devoid of trees, sinks less into
the soil, it at the same time more speedily reaches the brooks
and streams and rivers, and fills and overflows these water-courses ;
and finally, the body of water, now tearing along with rapidity, cuts
up the mountain sides cleared of forests, and fills up the beds of the
brooks and streams and rivers with earth and sand and rubbish, and
so raises the bed of the river — whence a higher level is reached by the
water-surface.

" The correctness of this allegation is being attested, in a way
which it is saddening to contemplate, by the ever more frequently
recurring inundations in Italy, in the south of France, in Hungary,
in Bohemia, and in many other lands.

" The aforementioned phenomena of high floods led a disthiguished
meteorologist to express to me the conjecture that the great increase
of the body of water passing along our water-courses, in high floods,
may be about equal to the diminution observable in the low and
mean levels.

" This conjecture, however, is not in accordance with the facts of
the case, because, as I have already shown, in the case of the Rhine
and of the Elbe, the annual delivery is approximately represented by
the mean water-levels, which, even in all these five rivers named, is
on the decrease. But the incorrectness of the conjecture is more
particularly manifested by the tabulated observations by the pegel at
Orsova, in as much as, from the geographical position of the very
extensive basin drained by the Danube, it frequently happens that
the high floods of several of the large afiluents coincide in time with
that of low water level in several other important accessories of the
river, and yet there is not an equivalent compensation for the lesser
supply coming from the one class of affluents, in the greater supply
coming from the other, in as much as, even at Orsova, the average
of the floods of the mean and of the lowest levels have fallen still
more than have these in the four other rivers named.

"But even if, in accordance with this conjecture, in particular years
with repeated extraordinary high floods, some such equalisation of
the increased and the diminished delivery of a river should occur,
this would supply but little consolation for man, as the great evils
consequent on the diminution of the delivery of water at the lowest
and the mean levels are not obviated by the more frequent occurrence
of the greater delivery during high floods, but are being more than

190 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

ever increased in that those high floods now occasion more frequent
and more disastrous inundations."

Hen- Wex goes on to say: — "Having in foregoing statements given
indisputable evidence that in the five principal rivers of Central
Europe, — the Danube, the Rhine, the Elbe, the Vistula, and the
Oder, the basins of which embrace an area of 26,860 [German 1]
square miles,* — the lowest and the mean annual water levels, and
consequently also the quantities of water delivered by these rivers,
during a lengthened period of many years, has been continually
decreasing, we may/rom this draw the following conclusions : —

"1. As the aforesaid rivers are fed mainly by the brooks and
streams which flow into them, there must have been also in these a
continued deci'ease in the quantity of water delivered by them for a
great many years, from which we may further conclude th at if observa-
tions had been made on the levels of the difi'ereut feeders,
similar to those which have been made on the five large rivers named,
and these had been compared, they would have supplied results
similar to those at which we have arrived concerning these.

" The correctness of this allegation receives confirmation from the
fact that many manufactories, &c., which have been built during the
last fifty years, on rivulets and streams, have experienced a marked
diminution in the quantity of water coming through their water-
leadings, and it has been found necessary to employ steam-engines to
meet the deficiency of their water power, which was originally
sufficient for the work they had to do.

"2. As it is possible that the causes which have produced the
eff'ect of the lowering of the water level, and diminution of the
quantity of water delivered in these five river basins, operate
equally in the basins of the other rivers and streams in Europe, and
not only so but in the most populous and cultivated districts of the
other three quarters of the globe — it may be assumed that in most of
the streams and rivers on the surface of the earth a similar lowering
in the lowest and viean levels of the body of water delivered by them
has taken place ; while the high floods in the same, reaching a higher
point, and becoming of more frequency, discharge a greater quantity
of water, and produce more extensive devastating inundations than
previously was the case.

" 3. If the causes which have operated in producing the decrease of
the usual water flow of the streams and rivers, with the rapid over-

* A German mile is equal to 4^ English miles.

TREATISE BY HERE WEX. 191

flowing of them in times of flood, in the course of the last 140 years,
were to continue to operate also in the future, it is evident from what
has taken place that in brooks, and streams, and rivers, the lowest
and the onean levels of these may be expected to be lowered still
further in the future. And the question forces itself upon every one
involuntarily, to what degree may this diminution in the quantity of
water thus delivered by the several streams and rivers be carried %

" In the principal rivers, the Danube, Rhine, Elbe, and Vistula, it
is scarcely to be supposed that the lowering of the lowest level of the
flow will go on till it reach the very ground of the bed of the stream,
occasioning the temporary drying up of the river altogether :
seeing that the two first named rivers are in part fed by the melting
of the masses of ice and snow lying on the Alps ; while, further, it is
to be hoped that the occasion of the lowering of the water level will
not be carried beyond a certain limit ; and finally, because the highest
and the lowest level of the stream occur in many of these streams
and affluents at different times of the year from what they do in
others.

" If, however, we look on the other hand to the very considerable
lowering of the lowest and the 7necm levels of the rivers mentioned in
the foregoing table, which has taken place within the comparatively
short period of 50 years, we are brought to the disturbing conclusion
that these five rivers, in the course of 100 or of 200 years, may have
their lowest and average levels so lowered that they will be no longer
navigable if we do not take measures to counteract the cause which
is continuously operating to effect the diminution of the water flow
in these rivers.

" The brooks and streams, on the contrary, which drain only basins
of limited extent, may, by the continuous lowering of the water level ;
and by the diminution of the delivery in them, be converted into inter-
mittent torrents, which lie dry during many months of the year, and
then, on a fall of rain, suddenly fill and deliver immense bodies of
water.

That the dread of this is not without foundation is proved by
numerous cases in which very large rivers, which in previous cen-
turies, according to historical records, were navigable at all seasons
of the year, have become now only ivildbache and torrents, such as
for example, are most of the torrents which characterise the southern
slopes of the Alps in Italy and in Carinthia. Many other streams
and rivers, which not many decades back were of full water, have
latterly, and within the memory of man, become torrential streams

192 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

which pour down large bodies of water when, and only when, there
have been dashes of rain, and from what has been stated it may be seen
that the prognostication is not without foundation when I allege that
if the causes which have, during the last 140 years, occasioned a
lowering of the water-level and diminution of the above-named five
European rivers shall go on operating in the time immediately before
us, the result will be that the level will be still further lowei-ed and
the delivery diminished, until bye and bye they become so reduced
as to be unnavigable.

" Although, beyond the results which have been published by Dr
Berghaus in his ' Hydrography,' which has been quoted, and which,
unhappily, are but little known, we have hitherto been unable to
obtain reliable compilations and comparisons of observations con-
tinued for many years of the water-level on the larger rivers, there
are men of observation and experience who, in consequence of what
they have noticed on some few rivers, have called attention to the
diminution of the water supply which is going on. An instance of
this we have in the following communication, which is well-deserving
of consideration, found in an article, by F. Perrot, in Deutsche Monat-
schrift fiir Handel, Schif-fahrt und Verkehrswesen (I. Baud, Rostock,
1872).

" A consideration of the three rivers — Weser, Elbe, and Oder —
makes clearly manifest a reduction in the quantity of water delivered
by them, and a silting up of the river-bed with sand. It has been
calculated that if the Elbe continue to diminish in the future at the
same rate at which it has been diminishing up to this time, it will soon
be impossible for heavily laden ships to pass by it. Nor is it otherwise
with the Oder ; in the very dry year 1858, there were only eleveji days
in which the navigation of the Oder in Silesia could be carried on
with full force. The Weser delivers the smallest body of water of
the three. One principal reason for this is the destruction of forests
which has taken place on the heights which are found alongside of
the river and which the Government have latterly taken steps to
prevent ; but still more than what has resulted from the destruction
of forests has been the consequence of the rectifications of the river-bed,
which it has become a general practice to carry out.

" After weighing fully the collected observations on the water
level and consequences deduced from them in the foregoing treatise,
I think no Hydrotechnik will venture to call in question the correct-
ness of the allegations advanced by the distinguished hydrographer
Dr Berghaus, in the year 1835, which allegations have been coufirmed

STATEMENT BY HERR WEX. 193

and established by myself, that in the brooks, streams, and rivers in
central Europe, within the period of observations, extending over
about 140 years, high floods now appear oftener and attain a greater
height; on the contrary, the lowest, and the yiiean levels of the
rivers are falling, and consequently the delivery of the water by these
streams and rivers is being continuously diminished to a very great

There follows an expression of the views of the author on the
great practical importance of the fact brought to light. In the
second chapter he describes the reduction observed in the flow of
springs and in the quantity of water yielded by them, and after
citing numerous facts, illustrative of these points, he thus con-
cludes : —

"In regard to the diminishing of subterranean waters, we can
adduce the following evidence : —

" As we have in the preceding chapter shown, from observations
on the water level continued through long series of years, that there
has been seen in later decades a lowering of the level of the lowest
and of the mean annual flows, while the high floods, consequent on
storms of rain, have become of more frequent occurrence — from which
it comes to pass that a greater quantity of water is thus carried away
at such times than formerly — it follows as a consequence that if the
quantity of the rainfall remains the same, the proportion of this
flowing away on the surface of the earth in such circumstances has
increased. On the other hand the proportion sinking below the
surface must be less ; and from this it comes to pass that the
quantity of the subterranean water supply, the drainage and super-
ficial waters, and with them the springs which are fed by them must
have been reduced ; and the correctness of this conclusion can be
established by the following facts :

" From these long continued observations on river levels we have
further proved that on brooks, streams, and rivers in these later
times, the lowest and the mean levels, and also the quantity of water
delivered, have been being continuously reduced, and that to a marked
degree ; and that in the very months during which the water courses
have been fed almost exclusively from subterranean flows of water
and from springs the diminution of the water delivered has been
greatest. Whence it may with all justice be concluded that in these
later times the water supplies in subterranean reservoirs and in
the water bearing strata have decreased, and also that drainage
waters and the springs in a river basin in their collective contribu-

u

194 EFFECTS OP POBESTS ON SPRINGS AND RIVERS.

tions now furnish smaller water supplies to the feeding of the river
course than was the case at an earlier period.

" Dr H. Berghaus has in his work on * Hydrography' which has
been cited, advanced on this point (p. 30) the following doctrines :

" In some parts of the world it has been remarked, the springs
have suffered a loss in the quantity of their water supplies. Thus it
is in France in what was formerly Poitou, and in the department of
the lower Charente, where there has been remarked a decided reduc-
tion of the springs since 1825.

" The phenomenon is attributable to the desiccation of the land,
the cutting of canals, trenches, &c , while Fleuriau of Bellevue has
-alleged that the cause is to be found in a diminished rainfall.

" It can also be established by manifold evidence that of late years
■many springs have dried up, and that in a great many others the
quantity of water yielded by them has been greatly reduced ; further
it is generally known that several solidly and skilfully constructed
aqueducts which erst while conveyed a rich supply of water have
become completely useless in consequence of a permanent deficiency
of water which has arisen, and that very many old wells known
amongst us as inexhaustible have become, since 1852, in consequence
of the lowering of the water level in the subterranean strata by
which they were fed, in some cases absolutely dry ; and in other
cases so impoverished in water supplies that the wells must be sunk
some fathoms deeper if they would be made permanent sources to
meet the demand.

" From amongst the numerous cases which have become known to
me, I shall adduce but a few specimens :

" It is generally known that the city of Rome, in its pristine glory,
with its public fountains and baths, and its several aqueducts, was
exceedingly richly provided with water ; some of these, from the dry-
ing up of the springs by which they were fed, have now run dry, and
others have lost a large share of their water supply — as, for example
the aqueduct aqua vergine (some 20,000 metres, or between 60 and 70
feet, long), which it is now in contemplation, at extraordinary expense,
to reconstruct.

" The springs and aqueducts which, at one time, provided for the
City of Constantinople a very abundant supply of water for drinking
and for use, have fallen off to a very considerable extent in their pro-
ductiveness, so that it has become necessary to seek out more, and
more remote, springs.

" The world-wide renowned fountains and water-works of Versailles

TREATISE BY HERR WEX. 195

were formerly so abundantly provided with water from the aqueducts
by which they were supplied that they could play almost the whole
day long ; whereas now, from the great diminution which has taken
place in the water coming to them, this must be allowed to accumu-
late for about twenty-three hours to allow the fountains and other
water-works to play a single hour.

" So also with the numerous fountains and artificial cascades in
the Belvidere-Schwarzenberg and Lichtenstein-Gardens at Vienna, and
those in the palace garden at Schtinbrunn, which were abundantly fed
by spring-water led to them, they stand now almost quite dry, as a
saddening monument of the dried up springs.

"The City of Vienna has, besides, about 10,000 sunk wells, and in
addition to these nineteen different aqueducts, with which the springs
and drainage waters in the environs of Vienna are intercepted, col-
lected, and brought into the city. After the water in the sunk wells
had not only diminished, but, in consequence of the filtration from
the canals, had become deteriorated — and also the quantity of water
brought in at one time by the aqueducts had become very much
reduced; there was constructed, in the year 1836, the Emperor
Ferdinand's aqueduct, by means of which were brought into the
City of Vienna, from the Vienna Donaucanale, near Nussdorf, by long
and deep suction pipes, an aggregate of about 100,000 einiers of water
daily ; and now, after this aqueduct also, through a lowering in the
water-level in the Vienna Donaucanale, and partly through the
coincidence with this of a sliming up of the suction pipes, has be-
come insufficient and precarious, the commune of Vienna, after year-
long negociations, has seen itself under the necessity to seek to
obtain the two million eimers per day, required by the city for
drinking and necessary uses, from the high springs of the Schneeberg
(Kaiserbrunnen and Stixensteinerquelle), by means of a canal
about twelve German miles long,* which aqueduct will absorb a
capital of about sixteen miUion of Guldens [or ^1,600,000
sterling],"

Herr Wex goes on to say : — " I consider that I have satisfactorily
proved, by the foregoing observations, deductions, and examples, that
in recent times the supply of water in subterranean reservoirs, and in
the water-bearing strata of the earth, is being diminished ; further,
that many of the drains and springs of to-day have become some
quite dry, and others yield a comparatively small supply of water ;

* A Germaa mile is equal to about 4^ £nglisb miles.

196 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

and finally, that througli these changes the lowest and the mea7i
water-levels in brooks, streams, and rivers are being continuously
lowered, and the quantities of water delivered by them continuously
diminished.

" If this continuous diminution, which has been going on for the
last 140 years, is to go on continuously still, then will these results
and changes on the surface of the earth entail on coming generations
evils, and evils of incalculable extent and magnitude. Through the
lowering of the level, and reduction of the rivers and of the sub-
terranean drainage, and also through the alternation of very wet and
very dry years, — such as is shown, by the diagram referred to, to be
prevailing, — will the fertility and productiveness of the land be
reduced in no inconsiderable degree, and not a few lands now covered
with luxuriant vegetation will become veritable deserts, cheerless and
desolate.

" After the drying up of many brooks and streams, and after the
conversion of streams and rivers into torrents, in consequence of these
changes men would have to go for their water supplies for drinking
and for domestic use, and for other purposes, either to the deeper-
lying water-bearing strata of the earth, or to a greater distance from
their dwelling ; whereby the cost of the water consumed would be
increased, while many industrial establishments and manufactories
would be deprived altogether of the supply of water indispensably
necessary to their operations, and would have either to adopt expen-
sive means of providing a substitute for what has been lost, or remove
to some remote district where brooks and rivers have not as yet been
deprived of their water supplies.

" Finally, by the continuous diminution of water in streams and
rivers, the former would become quite dry through the greater part
of the year, and the latter would become unnavigable.

" As, through the consideration of what has been advanced, it may
thus be seen that, through the continuous diminution and lowering
of the flowing water on the surface of the earth, there is imperilled —
and that to a great extent — not only the prosperity and the health,
but also the existence of future generations, it is desirable that
numerous students of physical science should be incited to further
research into the cause of these intimately connected phenomena, and
then to devise measures to avert the impending calamity, in so far as
it may be within the scope of man's power to do so."

The author adds : — '' I have given myself also to an attempt to
a solution of this difficult problem, and I give the results of my

TREATISE BY HERB WEX, 197

researches in this study in the two following chapters, in the hope
that distinguished collahorateurs in the same calling and men of
scientific attainments may prosecute further the researches I have
been privileged to commence, and that the results of their study
may bring great good to generations yet unborn."
\ The chapter which follows is occupied with a discussion of the
cause or occasion of a diminution having taken place in the quantity
of water flowing in streams and rivers, which he thus concludes : —

" When we fully realise what is implied in the opinions expressed
by jnen of science, and practical men expert in such matters, in
various countries and in very difierent parts of the world, after long
experience, observation, and research, we find that forests affect to a
very great extent the quantities of water coming from springs and
flowing in rivers ; that they affbct the climate ; and that they have a
great effect upon the fertility of the lands in which they exist ; and
that thus : —

" 1. The deposit of rain from the atmosphere is greatly increased
by the amount of woods in a district, in as much as mists and clouds
passing along" the surface, striking upon the forests, have the moisture
of which they are formed condensed and precipitated as rain.
Further, the temperature within the woods is cooler by day, and, on
the contrary, warmer by night than it is in the open fields and
meadows ; and by reason of this, there is a continual cii'culation of
air in the vicinity of forests whereby mists and clouds are precipitated
and led to discharge themselves of their contents. This happens not
through the forests in and for themselves, nor as a consequence of
the forests of themselves, but through the difference between the
forests and the open fields ; and on this depends the abundance of
the rain. It is also very manifest that the forests exercise an
attractive influence upon the clouds, by their attracting from them
electricity with which they are charged, and with this the water of
which they are composed, increasing thereby the rainfall. It is also
an ascertained fact that a great part of the water precipitated as rain
remains on the leaves of the trees, one part of which falls to the
ground, but another portion of which evaporates into the atmosphere,
and is again precipitated as fog, mist, dew, or rain, — whence it comes
to pass that rain water is kept longer within forest lands, and may be
precipitated oftener than once, whereby the rainfall is increased.

" 2. Through the abundance of forests will the copiousness of the
subterranean drainage flow, and springs be increased, while the rain
water retained by the foliage of the forest trees, falling slowly to the

198 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

earth, is kept by the spougy character of the ground in woods from
flowing quickly away, and is in part absorbed, or is left to permeate
the mineral strata, which is considerably facilitated by the numerous
spreading roots of the trees penetrating cracks, fissures, and canals in
the superficial ground, by which means the rain water reaches a
greater depth, and this in a much greater quantity in forest ground
than in the open field. Further, by numerous experiments it has
been established that the evaporation of the humidity in the open
country is at the least from four to five times as great as it is in wood-
lands ; from all which it appears that the moisture absorbed in forests
is not so readily evaporated, but is retained and directed to the feed-
ing of drainages, springs, and brooklets.

" 3. If forests be uprooted, more especially in mountainous regions,
or even in somewhat hilly country, the rain drops, falling upon the
exposed ground with some force, tear it up, and then flowing down the
declivity with considerable rapidity carry with them earth and stones
towards the brooks and streams and rivers, by which these water
courses are suddenly filled up, and experience much higher and more
devastating overflowings, and inundations, than was the case while
the woods stood, as is explicitly testified by the aforementioned
tabulated observations of river levels.

" 4, Through the extensive clearing away of forests the heat of the
summer months and the desiccation of the ground becomes increased,
then, as a consequence of this, the duration of droughts is prolonged,
and from this there follows naturally a diminished productiveness of
the land.

" These most disastrous effects of the clearing away of forest show
themselves in a very marked degree in these countries, once blessed
with a luxuriant vegetation, Palestine, Persia, Greece, Sicily, Spain,
and the Canary Islands."

It is stated also that " a great cause of the diminution of water
aupply from springs and subterranean reservoirs in Europe has been
the draining of lakelets and ponds, and the draining of bogs and
marshes, which has taken place, in various parts, of late years." And
" a third cause of the diminution of water in springs and rivers at
present going on is to be sought for in the greatly extended, and
still from year to year extending, operations to bring under culti-
vation, to cultivate, and to improve the land." Of both of which
statements illustrations are given, with illustrations of the effect of
the latter when carried on on hill sides, to increase the violence and
the maguitude of torrents and devastating inundations.

REPORT BY ACADEMY OF SCIENCE OF VIENNA. 199

There follows a chapter devoted to the consideration of measures
proposed with a view, on the one hand, to prevent continued and ever
extending devastation occasioned by inundations ; and on the other
to arrest and prevent the continuous diminution of water in springs
and in rivers in their lowest state, and in their mean delivery. But
it is the facts of the case established in regard to the effects of forests
on rivers and springs with which alone we have at present to do.

The paper was subsequently published, and it excited much interest.
By several learned Societies Commissioners were appointed to report
upon it. Amongst others this was done by the Royal and Imperial
Academy of Science of Vienna, and the Imperial Academy of Science
of St Petersburg. It was also favourably considered and approved
by the Society of Engineers and Architects of Vienna, the Geogra-
phical Society of Vienna, the Forest Academy of Mariabrun, by
several Polytechnic Schools, and by many men of science.

In regard to the views of Herr Wex relative to the phenomena
observed, the Commission appointed by the Academy of Science of
Vienna reported : —

"In view of the facts brought forward by the author, the Commission
has come to the conclusion that the diminution seen within the last
century, in the medium and lower heights of the rivers made the subject
of observation, is attributable to a diminution in the annual delivery of
these rivers.

" The author finds that the diminution of the quantity of water in
the river is attributable to a diminution in the quantity of water
yielded by springs, of which he finds additional indications in the
diminution of water in streamlets, aqueducts, and wells.

" The Commissioners agree with the author in this view, considering
the low depth of water in the rivers to be justly attributable to the
quantity of water flowing throughout the whole district constituting
the basin of the river having been reduced.

" The causes of this general diminution in the flow of water may be
found — 1. In a diminution of the annual rainfall, connected with the
extension of agriculture occasioned by the cleaving away of forests ;
2. In an increased evaporation from the surface of the soil, consequent
on the change of culture spoken of ; 3, In such a change in the mode
of flow that the rainfall, instead of being, for the most part, retained
for a time and percolating through the gravel, flows away quickly,
producing brief periods of high floods, alternating with protracted
periods of drought."

200 EFFECTS OF FORESTS OX SPRINGS AND RIVERS.

After reporting their opinion in regard to the effects of forests on
the distribution of the rainfall, the Commissioners go on to say : —
" The copious flow of springs, and the abundance of water in rivers,
however, does not naturally depend solely on the quantity of rain
falling in the course of the year ; for, on the one hand, a very con-
siderable quantity of the rainfall is returned by evaporation to the
atmosphere ; on the other hand, the nature of the soil determines, in
a great measure, the quantity of the rainfall which sinks into it,
forming subterranean reservoirs from which springs are fed.

" In regard to both of these phenomena, forests exercise an influence
which can hardly be estimated too highly.

" It is proved by direct observation in France, and in the forest
stations for meteorological observations in Bavaria, that the variations
in the temperature of the air in the forests are less than in the open
country. Especially does this hold good in the hours of the day and
in the seasons of the year in which the greatest heat prevails, the
degree of temperature being at these times considerably lower than
in the open country, and, in accordance with this the temperature of
the soil in the forest, is considerably below that of the land unshaded
by trees.

" In like manner the degree of humidity in the forest differs from
that in the open country ; this being, at all seasons of the year,
greater within the forest than it is outside.*

" In view of these facts, we need not be surprised that the evapora-
tion in the forest is found to be much less than it is in the open
field ;t and all the more so that, besides the relation of evaporation
to temperature, the strength of the wind or movement of the air
constitutes an essential element in the operation, and there is pro-
portionally much less movement of the air in the forest.

" In proportion as it is important to obtain a correct determination
of the quantity of the rainfall which is lost by evaporation so is it
difficult to do so.

" As the means of making observations on the amount of evapora-
tion from the surface of plants and the surface of the ground are
different, — besides which, the comparison between the quantity of
the rainfall and that of the evaporation is prejudiced by difference in

* According to Ebermayer, the difference in the four seasons, from spring onwards,

amounts to 5'7, 93, 5'2, and 5 "2 per cent.

f According to Ebermayer, the evaporation from an exposed suface of water in the

forest was about 64 per cent, less than from one outside the forest.

—Zeitschriftfdr Meteorologie, viii. 253.

riEPORT P.Y Af'APKMY OF SCFKNOE OF VIENNA. 201

the exposure of the mstruments, they being in some places exposed
to the sunshine and the rain, in others protected from these, by
difference in the sizes of the atmometers, and by difference in the
materials of which these are made, — it is not impossible, from these
causes, that an atmometer of small size, made of metal, and set in
the sunshine, may give an annual evaporation which exceeds by far
say two or three times, the amount of the rainfall.

" In consequence of the difl&culty of determining by direct observa-
tion on evaporation the evaporation from the gi'ound, and thereby
determining the quantity of the rainfall available for feeding springs
and streams, some have sought to determine this directly in part
by comparison between the quantity of water delivered by a river
in the course of the year, and the rainfall on the whole valley drained
by it; or, otherwise, between the quantity of water percolating through
a given section and the rainfall over a given range,

" If now there be also in a wood a considerable portion of the
rainfall kept by the twigs and leaves from immediately reaching the
ground, the difference between that rainfall and the evaporation
(amounting, according to Ebermayer, to 72 per cent., Zeit&chrift fxir
Met. viii. 274) will also be retained longer in the forest and get time
to permeate and feed the springs.

" The remainder of what has not been dispersed by evaporation
either penetrates the ground or flows away over the surface.

" In the former case it seems principally to feed the springs; in the
latter case it is carried directly to the water-courses, and after a brief
time produces a more or less considerable flooding of these.

" It is generally acknowledged that the forest, through the vegeta-
tion of lichens, mosses, &c., peculiar to it, is pre-eminently fitted to
absorb the rain, to store up the same, and only gradually — little by
little — to yield it again.

" In view of this, the aforementioned investigations in regard to the
quantity of water which sinks into the ground to certain depths is
very instructive, as they give on the one hand the relative effect of
different kinds of soil on the absorption of the different plants with
which they are covered, and on the other the proportion of the
moisture absorbed by the soil in the course of the year. It appears,
according to the latest of these, that the absorption of the forest is
especially manifested in the warm season of the year.*

" In regard to that portion of the rainfall which does not penetrate

* According to Ebermayer, in the summer the following per centages of the rain-
fall was fovind at the depth of one metre ;—

X

202 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

the ground, but flows away over the smface, and to which popularly
is ascribed the swelling of floods, there exists no difference of opinioa
in regard to the influence of forests. On all hands it is agreed that
with the removal of forests the tributaries to water-courses rush more
rapidly to these ; and that in mountain regions, on steep precipices,
from which woods have been cleared, the fruitful soil is swept away,
and water-courses are converted into torrents.

" In the cutting down of forests which present no longer, as
previously, a hindrance to the flowing off of the rain-water by their
manifold united roots, by lichens and by mosses, may be seen gene-
rally the cause of the more frequent and extensive, and ever more
threatening inundations.

" With the facts before them of the diminution of the water in
the rivers, which diminution is connected with a diminution in
the copiousness of springs, the Commission find the cause of
these phenomena to lie — 1. In the continued extensive destruction
of forests, the beneficial effects of which consist in an increased
humidity of the air, a reduction in the extremes of temperature, a
diminution of evaporation, and the securing a more regular distribu-
tion of the rainfall ; while the injurious effects of the destruction of
them is seen in an alternation of periods of drought at one time, with
wasting floods at another.

" 2. In the drying up of the lakes, marshes, and bogs, which
increased the humidity of the atmosphere, diminished evaporation
elsewhere, kept down excessive heat, and finally escaped through
rents in the ground, increased directly the formation of springs.

"3. In the breaking up and cultivation of extensive tracts of
coimtry, for the watering of which considerable quantities of water
are required.

" 4. In the increase of population and of domestic animals, although
the diminution of the water occasioned by these causes can amount to
what must be relatively a small portion of the whole.

Willi Utter. Without litter on the groiiuJ.

In open ground, 13 — H 11

In the forest 82 72 6* 36

Difference 33 61 51 25

Earlier experiments come to us from Maurice in Geneva, and Gasparin in Orange.
A later one, on a great scale— undertaken by E. Risler at Calfeve, by Nyon (Canton
Wallis), who sowed different experimental fields, of 12-300 square metres, with corn,
clover, etc.,— determined the infiltration at 0-35 metres deep, and showed the
comparative humidity of the soil with that of the superficial soil under different
conditions of culture.— Annuaire Meteorohgique de I' Ohservatoire de Paris, pour 1873,
p. 277,

REPORT BY ACADEMY OP SCIENCE OP ST PETERSBURG. 203

" 5. And, lastly, it appears to this Commission that the view ex-
pressed M. S. Saeman, * according to which, in the interior of the
earth, water is continually required for the formation of minerals in
which it is chemically combined, and from which mineral operation a
diminution of water must follow, deserves consideration."

At the instance of the Academy of Science of Vienna, the paper by
Herr Wex was brought under the attention of the Imperial Academy
of Science in St Petersburg, by which also a Commission was ap-
pointed to consider it, to supply information in regard to similar
phenomena in Russia, and to report. In a report submitted by the
Commission to a meeting of the Academy held on the 27th January
1876, amongst others things it is stated, in reference to what had
been said by the author in regard to the effect of the destruction of
forests on the humidity of different countries : — " To these examples
we may add the districts in Southern Russia, where it is well-known
that large forests existed about 150 or 200 years ago in the very
spots invaded by the steppes, the higher portions of which are
perfectly arid, so that the inhabitants, to prevent their dying of
thirst, are obliged to live on the banks of tiny streamlets in the
lowest valleys. We may also make mention here of the Volga and
Dnieper, where the destruction of the forests, from south to north,
has made and is making such progress that these rivers, so indispen-
sable to the commercial prosperity of Russia in the middle and in the
lower portions of their course, now flow through regions which are
quite cleared of forests. There the floods reach a higher level than
they did formerly. And who has not heard serious complaints,
annually repeated, with regard to the modifications of river-courses
caused by these floods by changing the direction of the navigable
channel and hollowing out new beds for the streams 1 And who does
not know that gorges, deprived of water in winter and dry in summer,
dm-ing spring, in consequence of the rapid melting of the snow on the
naked steppes, become, after heavy rains, impetuous torrents, which
undermine their banks and carry away lai-ge portions of valuable soil 1
Furthermore, all the affluents of these rivers bring down masses of
detritus, which every year contribute to the formation of new river
beds. We may state it as our conviction that the injuiy caused at
present by the Volga, the Don, and the Dnieper, would be much

* Sur V unite des phcmmcties gcologiques dans le systeme du solcil. Bull, de la SociSte
Geologiqw de France. 2 iSerie, t. xoiii. 2>. S22. 1861.

204 ACTION OF FORESTS ON SPRINGS AND RIVERS.

less serious if the land along the banks had been preserved from
deboisement."

Thus do abound observations which go to establish it as a fact
that, whatever may be the effect of trees on the rainfall, there is an
efl'ect produced by them on the humidity and moisture deposited
from the atmosphere which is such as to aff"ect the existence of
springs, and the flow of rivers. It is the fact alone, and not the
way in which it has been brought about, with which we have here to
do, and the fact seems to be established beyond question by the ob-
servations which have been brought forward.

It is not to be expected that the treatise by Herr Wex should at
once command universal unhesitating acceptance of all the observa-
tions cited, and reasonings and deductions founded thereon. Since it
was published (in 1873) Herr Wex has collected a great many new
and interesting observations of facts and experiments in relation to
the diminution of water in lands under culture, and in relation to the
influence of the extensive destruction of forests ; and while these
sheets are passing through the press he is can-ying through the press
a second treatise on the subject, in which he meets all doubts and
conflicting observations known to him to have been advanced against
the statement made by him in regard to the diminution of water
in springs and rivers.

Reference is made by the Commissioners appointed by the Academy
of Science of Vienna to report on the treatise by Herr Wex, to
observations made by Dr Ernst Ebermayer, professor in the Ceiitral-
Forster Lehanstalt, School of Forest Science, Aschaff"enburg. For
some seven or eight years he had been engaged in the study of
observations on the meteorological effects of forests, made by himself,
or under his direction, and corresponding observations made by
others. Results have been published from time to time in scientific
journals. And the more important were embodied in a volume
published under the title of Die jy/ii/sikalischen Eimvirhtngen des
Wcdcles auf Luft und Boden und Seine Uimatologische und hygienische
Bedeutung, hegrimdet durch die Beohachhingeii den forstlich-meteorologi-
schen stationen in K'&nigreich Bayern.

The following is a resicme of facts noted by him, embodied in a
report on the Cultivation of Timber and the Preservation of Forests,
submitted to the Congress of the United States in 1874. It is given
as taken from a report made by H. J. Wiseman, Consul of United
States at Sonneberg, to the Department of State, November 1873.

OBSERVATIONS BY EBERMAYER. 205

" That the forests of a country are not only of great importance
m supplying many necessary productions of ordinary life, but also
serve still higher purposes in the domestic economy of nature — to
the extent that within certain limits the arability, the inhabitability,
and beauty of the land depend upon an appropriate area of woods —
has often been declared. Indeed, this fact is now generally ac-
knowledged, at least by all educated persons, and it forms the basis of
a series of legislative measures, which have for their object the pro-
tection of the forests from destruction and misuse on the part of the
ignorant for selfish purposes. But, hitherto, the exact x-elations
between the woods and the fields have not been fixed by the certainty
of figures. There has always been a lack of scientific accuracy in
connection with a matter of so great importance, simply because no
systematic method has been carried out by which, from actual experi-
ment, these relations could be surely determined, The discussions,
therefore, which for years past have taken place on this subject, the
conflicting opinions which have been advanced in literature and in
scientific bodies, have been only valuable to the extent that they
served to keep alive interest in a vital question. No argument which
has been made has been deemed conclusive, because there has always
been a failure to base theories upon the I'esults of scientific researches.
" To obtain this scientific foundation upon which to prosecute
future investigations, the kingdom of Bavaria has taken the initiative.
Since 1867, under the organization of Dr Ebermayer, professor at the
Forest Academy at Aschafteuburg, a series of meteorological observ-
ations and experiments have been made at several stations within the
kingdom, which were selected as being best adapted for the object in
view ; and most painstaking and minute investigations have been
pursued by competent and experienced observers. These interesting
and very importaut results, which have been obtained by these six
years of close inquiry, have just been made public.

" The observations have been made simultaneously at a station
within the forest, and at a station corresponding thereto in all
respects in the open country. The results which have been reached
are as follows :

" 1. That the average annual temperature of the atmosphere in the
woods is somewhat below that of correspondingly situated areas
which are unwooded. (About 1| to lyj of a degree Fahrenheit.)

" 2. That the average annual temperature at the crowns of the
trees is about 1^° above that which is found in dense woods at a
distance of 5 feet above the surface of the ground ; w hile in the

206 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

former case the average temperature is |^° below that of unwooded
lands at a distance of 5 feet above the surface of the ground,

" 3. That the average temperature of the spring within the forest
was 2-95*^ below that of unwooded land. This difference was less
apparent among shade-trees, than where pines were the growth.

" 4. That the average temperature of summer in the day-time, in
thick woods, is 3*78° below that of unwooded land.

" 5. That the temperature of the atmosphere within the woods, in
the summer season, increased 3 '94° from the ground to the tops of
the trees.

" 6. That the average temperature of autumn within the woods
was scarcely 1^ below that of the open land ; and

" 7. That in winter this difference in temperature almost entirely
disappeared.

" These briefly mentioned differences between the temperatui-e of
the atmosphere within the forests and that of unwooded lands, affect
the constant current of air in the day-time. For instance, the stream
of air flows from the surface of the ground withiu the forests toward
the periphery of the woods, and thence spreads over the open fields.
It afterward passes back again to the crowns of the trees, and by
coniing in contact with the leaves which, during the day, are colder
than the atmosphere, the latter itself grows cooler and heavier, and so
gradually descends from the tops of the trees to the surface of the
ground.

" At night the conditions are entirely different. The thermometer
now is higher in the woods than in the open lands. The Bavarian
observations for the month of July show that, while at midday the
temperature within the forest is 8'01° below that of the unwooded
land, at night it is 4*39 higher, (18 and 29 per cent.); in August,
during the afternoon, 7* 13° lower, and at night 3*71 higher, (16 and
22 per cent.) During the night, therefore, the colder and denser air
of the unwooded land passes into the forest, displaces the warmer air,
which rises and is cooled by contact with the leaves, and then
radiates.

" The maximum and minimum temperature of the open lands is
never reached in the forest. The [mean ?] atmospheric temperature
of the woods always remains several degrees lower.

" From these data, therefore, it is evident that the thermal effects
of woodland are of great moment, and that climatic alterations must
result from deforestation on a large scale ; that these climatic changes
will cousisi, as a general thing, in increasing the annual temperature,

OBSERVATIONS RY ERERMAYER. 207

and in sharpening still more the extremes of heat and cold. But
these thermal effects are not alone confined to the atmosphere, but
have, as well, a particular influence upon the soil. The Bavarian
investigations have clearly demonstrated that the average annual
temperatures at various depths beneath the surface of the ground are
nearly equal ; that the average temperature diminishes downward
quite slowly and by small degrees, (at a depth of 4 feet never more
than ri2°,) but that the average annual temperature of woodland
soil, at all depths, is below that of unwooded land, on an average of
3-37°.

" Further, it has been demonstrated that the temperature of the
soil in the spring and summer is highest at the surface and diminishes
downward. In spring the difference between the warmth of the soil
at the surface and at a depth of 4 feet amounts within the forest to
5*62°. In summer these differences show 7*50° both in the wood and
in the open land. But the soil of the woods in summer is 75.0?
colder than that of the unwooded land, and the greatest diflference
has been found at a depth of 2 feet.

" In contrast to spring and summer, the temperature of the soil
increases in autumn and winter, from the surface to a depth of 4 feet
beneath. In autumn this advance of temperature, according to the
Bavarian observations, amounted to 4'50° outside of the forest and to
3*49° within the forest ; in winter, relatively 4*21'' outside and 4-41'^
inside the woods. Wooded and unwooded lands have, therefore, in
winter, to the depth of 4 feet, very nearly the same temperature ; the
result of which is that the influence of the woods upon the temperature
of the soil is not less than that which they exert upon the tempera-
ture of the atmosphere.*

* It cannot be supposed that trees have any vital process by which a degree of heat
is maintained above the medium in which they grow. Their trunks, branches, and
leaves are heated and cooled in the same manner as inorganic bodies under like condi-
tions of exposure. But wherever evaporation or condensation is taking place, the
same change occurs in them as elsewhere, and the universal law of thermal result ap-
plies. " The trunks of trees," says M. Becquerel, "only acquire their maximum tem-
perature after sunset. In summer it occurs as late as 9 p.m., while in the air the max-
imum temperature occurs from 2 to 3 p. m. Changes of temperature take place very
slowly in the tree, but in the air they are rapid. When the leaves are cooled by noc-
turnal radiation they recover from the trunk by radiation the heat they have lost.
The temperature of the air above the trees which have been heated by solar radiation
acts on the temperature of the air, and prevents it falling as low as it would otherwise
have done." — Comptes Rendus, Seances de VAcad. des Sciences, May 22, 1855, tome ix
p. 1049 ; also Jour, of Scottish Meteorological Soc, (new ser.,) i, 234. [I give the note
as given appended to the text, but I do not homologate what is said in the opening
sentence.— J. C. B.]

208 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

" Far more important, however, than the thermal eflfects upon the
soil and the atmosphere are the influences inherent to the forests of a
country which affect the humidity of the soil and air, the quantity of
the rainfall, and the abundance of the springs. In relation to these
points the investigations of Ebermayer have produced very valuable
results.

" In the fii'st place, it has been discovered that the influence of
forest-lands upon the absolute contents of moisture in the atmosphere
— the evaporation pressure — cannot be proved, in spite of the fact
that the air of the woods is always more humid, relatively, than the
air of the open grounds. This is easily explained by the greater cool-
ness of the former. The higher a place is situated, the more marked
was the relative difference observed in Bavaria between the humidity
of the wooded and imwooded country. Ebermayer assumes that the
augmentation of aqueous descents, caused by a larger area of wood-
land, noticed at many places, is to be attributed merely to the
increase of the relative moisture within the forests.

" In close connection with the relative humidity of the atmosphere
of wooded and unwooded lands stands the quantity of water which
has been discovered to evaporate at given points, during a given
interval of time, at a certain temperature, and at a certain pressui'e
of the atmosphere, from an open surface of water.

" The Bavarian observations have proved that in an average of one
year less than 64 per cent, of water evaporates within the forest than
outside of it. The fact is more remarkable, because the proportion of
evaporation was nearly the same at all seasons of the year, although
the temperature of the atmosphere of the forests and the open lands
is so different in the winter from what it is in summer. This forces
us to the conclusion that the movement of the air, which is very much
less within the woods than outside of them, plays a far more
important part in relation to evaporation than has hitherto been

" But for the abundance of water and the forming of springs in any
country, the evaporation from rivers, ponds, and lakes is not so impor-
tant, by any means, as the evaporation of the water of the soil.

" The amount of evaporation from one square foot (Parisian
measurement) of an open surface show, in Parisian cubic inches, as
follows : —

OBSERVATIONS BY EBERMAYER. 209

In open land. In the woodt.

April, 1869 399 200^

April, 1870 373 226

July, 1869 407 151

July, 1870 394 151

October, 1868 158 73

October, 1869 194 50

" There evaporated, therefore, from the water contained in the soil
of wood-lands, as well as from open water-surfaces, far less than
evaporated from the water of the soil of the open grounds — about 40
to 50 per cent, in April, 60 per cent, in July, and 70 per cent, in
October — and this decrease reaches its maximum in the hottest
season. Still more glaring does this difference of exhalation appear
when wood-soil, covered with leaves and pine-needles, is compared
with wood-soil which is free of litter of this description.

" Under the first-mentioned conditions the evaporation from one
square foot (Parisian measurement) amounted, in Paris cubic inches,
to the following : —

From uncovered From wood-soil

wood-soil. covered with litter,

April, 1869 200J 78

April, 1870 226 102

July, 1869 151 55

July, 1870 151 55

October, 1869 50 25

" In wood-soil covered by litter, when compared with the bare soil
of the fields, the difterence in the amount of evaporation per square
foot (Parisian measurement) is shown, in cubic inches, by the
following figures : —

From bare soil of From litter-covered

the field. forest soil.

April, 1869 399 78

AprU, 1870 373 102

July, 1869 407 55

July, 1870 394 55

October, 1869 194 25

" From these figures, therefore, it is perfectly apparent how impor-
tant are the influences of the woods of a country upon the abundance
of its springs and the mellowness of its soil ; and in this connection
how essential are wood-lands which are covered with the litter of
fallen leaves, the uprooting of which effects a direct injury to
cultivation.

Y

210 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

" But it must also be borne in mind that extensive areas of wood-
land materially increase the quantity of the rain. At Rohrbrunn
(Spessart) 62 per cent, more rain falls than at AschafFenburg, in its
immediate neighbourhood, on an average of the years 1867 to 1871-
Certainly one-quarter of the gross quantity of the rainfall was caught
by the tree-tops and conveyed, by evaporation, again to the atmos-
phere, (average of the years 1868 to 1871 at all the meteorological
stations.) But of the remaining three quarters of the aggregate rain
which fell upon the earth, there evaporated during the same interval
six times less from the soil of the forest than from that of the open
country ; and, therefore, a much greater quantity of water is absorbed
by the forest, where the leaf-litter is retained, penetrating to the
deeper strata of the earth, than is held by the soil of the fields.
This fact is of the utmost importance in its relation to the formation
of springs to the supply of water to the rivers, and to all the
numerous interests of agriculture which stand in so close connection
with it.

" The investigations of Ebermayer have also led to very important
conclusions in regard to the amount of ozone in the atmosphere.

" The air contains most ozone in situations of great altitude,
where there is much humidity. In dense woods, however, the
amount of ozone in the atmosphere is somewhat less than in the
directly adjoining open land. The most healthy dwelling-places,
therefore, are not in the midst of the forests, but at their borders.

" The proportion of ozone, on an average, at the six meteorological
stations in Bavaria, on the borders of the forest, relatively to that
contained in the atmosphere at AschafFenburg and Zwickau, was as
follows :

In spring, as 8-20 : 6-80 : 3-20
In summer, as 7-70 : 3-20 : 3-10
In autumn, as 8-00 : 5-40 : 2-20
In winter, as 8-40 : 6-00 : 1-80

" These few data satisfactorily demonstrate the general importance
to which these forest meteorological stations may lay claim. A con-
siderable increase of the number of these observations may soon be
expected.

" To the six stations now existing in Bavaria will shortly be added
ten in Prussia, one in Mecklenburg-Schwerin, and three in Alsace-
Lorraine. In Bohemia, at PromenhofF, one observatory is already in
operation ; also thi-ee in Switzerland, Canton-Berne. The erection of
a station at Valambrosa, near Florence, in Italy, is also projected."

OBSERVATIONS BY EBERMAYER, 211

About the time that Herr Wex's paper was published in 1873,
there was held in Vienna an International Congress of distinguished
students of forest science. By them was resolved to send to the
different governments of the civilized world the following expression
of their views :

" 1. We recognize the fact that, in order to effectually check the
continually increasing devastation of forests which is being carried on,
international agreements are needed, especially in relation to the
preservation and proper cultivation (for the end in view) of those
forests lying at the sources and along courses of the great rivers,
since it is known that through the reckless destruction of them,
there results a great decrease of the volume of water, causing detri-
ment to trade and commerce, the filling up the river's bed with
sand, caving in of the banks, and inundations of agricultural lands
along the river course.

" 2. We further recognize it to be the mutual duty of all civilized
nations to preserve and to cultivate all such forests as are of vital im-
portance to the well-being — agricultural and otherwise — of the whole
land, such as those on sandy coasts, on the sides and crowns, as well as
on the steep declivities of mountains, and on the sea-coasts and other
exposed places, and that international principles should be laid down,
to which the owners of such protecting or " guardian forests " should
submit in order to preserve the land from damage.

" 3. We recognize further that it is the case that we have not at
present a sufficient knowledge of the evils (disturbances in nature)
which are caused by the devastation of the forests, and therefore
that the efforts of legislators should be directed to causing exact
data to be gathered relating thereto."

It has been noticed as a singular coincidence, that, at nearly the
same time, the American Association for the Advancement of Science
had under discussion measures tending to similar results, although
not expressly designing to extend its recommendations beyond the
limits of the United States, except in the way of correspondence with
other associations having similar objects in view. It is not supposed
that either of these bodies derived their suggestions from the other,
although the proceedings at Portland antedate those at Vienna only
about three weeks in time.

The coincidence, however, shows the wide and general prevalence
of a realizing belief that the time for action has now come, and that it
is the duty of all Uoverumeats to look well to the future, and take

212 EFFECTS OF FORESTS ON SPRINGS AND RIVERS.

early and effectual measures to provide against the injuries that might
soon follow a further neglect of interests in this regard.

Sect. IV. — Immediate Action of Trees in Arresting the Flow and
Uscape of Rainfall.

While it is true that the rainfall is only the precipitation from the
air of a quantity of moisture which it could no longer hold in solution,
it is no less true that thus often a much larger supply of moisture is
brought to a locality than it would have obtained in the same
time, or in a much longer time, either by deposit of dew, or by the
attraction of moisture from the atmosphere by any of the constituents
of the soil ; and we have now to consider the immediate effect of
trees upon it when thus precipitated. Some of these have been
adverted to in documents which have been quoted ; but they require
more detailed consideration.

The testimony which goes to show that the destruction of forests
has occasioned the drying up of springs, and that the replanting of
woods has been followed by their re-appearance, seems to be incon-
trovertible ; but it has been questioned whether the views which
have been advanced and have been generally received in regard to
some of the phenomena connected therewith be correct.

Marshal Vaillant, whose experiments on the emission of moisture
from the leaves of trees have been cited in a preceding chapter,
remarks : — " In the report read by Monsieur Becquerel, at the
Academy of Science, it is asserted that s^sri^^^s^e/icro/^y ^'^^^ their rise
in mountains It is true, and according to nature, that the causes
which formed the mountains have at the same time broken up the
impermeable strata in which are stored the water which creates and
supplies the springs. That forests are more usually formed on
mountain declivities than in the x>lains is generally true, and this is a
simple consequence of the superior fertility of the plains and valleys,
and of the greater trouble which the agriculturist would have in
cultivating such difficult localities where there are often not even
forest tracks ; but to conclude from this that there is a necessary
and intimate relation between the existence of forests and of springs
is perhaps a rather far-fetched conclusion ; and we think it would
be well to examine what the conclusion is really worth.

" The same report states that, ' the roots of the trees by dividing
the soil make it more permeable and facilitate infiltration.'

*' May we be permitted to make some observations on this point.

STATEMENT BY MARSHAL VAILLANT. 213

Usually there is no ground harder or less permeable than that
formed close to the trunks of trees ; if required we can bring forward,
as a proof, the long and deep trenches which have lately been opened
on some of the Boulevards of the capital, the substitution of rich
vegetable mould for the exhausted and, as it were, petrified soil, and
finally, the drainage works intended to convey air and moisture to the
trees on the Boulevards. All these sufficiently prove that these roots
would suffer in the soil in which they are condemned to grow, and they
are powerless as regards the penetration of water or rain, as well as in
imparting theleastmeasureof permeability to the soilwhich stifles them,

" Monsieur Becquerel, in support of the opinion that forests are
favourable to the maintenance of springs, cites two facts the impor-
tance of which we do not deny, but which would require a more
careful study before being considered incontestable. We allude to
the Scamander, which M. de Chouseul-Gouffier found to have dis-
appeared, and the invasion by the lake of Tacariqua of a large tract
of land formerly under cultivation. Is it quite certain that the
source of the Scamander has dried up, simply in consequence of the
destruction of the cedars on Mount Ida 1 May not the reservoir
which supplies this spring have been disturbed by some subterranean
convulsion 1 Have any observations been made regarding the other
springs on Mount Ida 1 And as to the lake of Tacariqua may not the
loose soil of such localities so often disturbed by volcanic eruptions
have first sunk and then risen, so as to cause in the first place the
water to retreat from, and in the second to invade, the shores of the
lake? Does not the entire globe, even in its most stable portions,
continually present such phenomena 1 On the western shore of
Schleswig and Holstein, in the strata of the ground there are found
alternate layers of peat, formed by fresh water, and marine deposits,
which sufficiently indicate alternate rises and falls of the land.

" To resume I agree with my honourable friend, M. Becquerel, in
saying that forests exercise a complex action. I add that this action
has never been studied, specially with regard to the desiccation of
the soil which they cover, and the exhaustion of the springs which
may be the result. On this point there is work to be done, prejudices
to be destroyed, and truth to be revealed."

All that is thus advanced by Marshal Vaillant is entitled to re-
spectful consideration. But along with these theoretic objections may
be taken into consideration facts which have been cited above in
numbers, and at the same time the following ;— -

214 ACTION OF FORESTS ON THE SURFACE-FLOW OF RAIN WATER,

M. Conte-Grauchamps, Ingenieur en Chef des Fonts et Chanssees,
has established by direct experiment, made with precision and with
the greatest care in the forests of conifei'ous trees situated in the
regions of the Loire and the Alps : —

"1. That existing sources have ceased to flow on the desti'uction
of forests.

" 2. That these identical springs have re-appeared along with
vegetation.

" 3. That the discharge from a water-course, the hassin de reception of
which is wooded, varies from one to two ; whilst that of another water-
course, proceeding from a bassin de reception which is devoid of woods,
all things else being equal,, vai'ies from one to six.

" 4. Finally, that the rehoisement of one hectare, or two and a half
acres, will increase the discharge fi'om the spring sixteen cubic
metres daily ; whilst gazonnement, or covering it with herbage, in the
same circumstances increases the discharge by four cubic metres."

And on the other hand, M. d'Arbois de Jubainiville, in reply to an
appeal made to its readers by the Revue des Ecmx et Forets, for
information respecting the influence of forests over the water system,
expresses himself as follows : —

" Several forest clearings have been executed in the canton of
Vaucoul6urs. I have tried to discover what changes have been
produced in the springs. All the springs of this territory have their
rise in the middle strata of the oolitic system. And the forests above
are treated as are usually coppice and timber forests.

" In the territory belonging to the commune of Taillancourt the
spring of Vaux-de-Bure had never dried up so long as the plateau
which supplied it was shaded by the forest of Vaux-de-Bure, but
ever since the half of that forest was cut down every summer the
spring has ceased to flow. The clay bed underlying the spring is at
no great depth ; it lies within a few metres of the surface throughout
the greater part of the basin of supply.

" In the commune of Sauvoy, near the Mayoralty, a perennial
spring became ephemeral when a wood was cut down which covered
the side of a hill, at the foot of which the spring was situated.

" On the contrary, in the commune of Monsigny-les-Vaucouleurs,
the partial clearing of a hill overhanging the spring has not interfered
with the outflow, the fountain of supply seeming to be very deep.

" I have also examined the effects of exploitation where felling
takes place in the basin of the springs, giving thus free access to
to them of sunshine and wind.

TESTIMONY OF M. d'aRBOIS. 215

" In the reserved quarter, in Maxey-sur-Vaise, the summer flow of
the spring of Moymout was much diminished when its basin was
exposed by the exploitations. The impermeable bed on which the
water is collected lies at no great depth, for during the season of
making charcoal the taste of the spring is affected by the smoke.

" The inhabitants of the small town of Void have also noticed a
diminution in the summer discharge of water, on the destruction of
the woods subject to a right of felling which surmount the springs.

" M. Clavery — who, for a long time, and with such enlightened
care, has administered Commercy, — has also made similar observa-
tions on the water system which supplies that town. He writes thus
on the subject : —

" ' Since the exploitation of the woods situated in the basin of the
source called Fontaine Royale, which supplies the town, for two or
three months every year the inhabitants are deprived of water.
Almost all the springs dry up about the month of July. Even
before these woods were cut down this scarcity had begun to appear,
but only slightly, very few springs being entirely dried up during
great heat ; but since the exploitations near the Fontaine Royale the
greater number are exhausted every year.'

" Cutting doft^n woods has a still greater influence on ponds. Thus
the ponds situated in the reserved quarter at Taillaucourt was full of
water during the growth of the neighbouring woods, but ever since
they were cut down it becomes dry during the summer.

" In the same way roads which were muddy and impassable have
been rendered dry and good in summer by cutting down the adjoin-
ing woods.

" In fine," he remarks in conclusion, " forests increase the summer
out-flow of the springs by preventing the ground being dried up, and
this influence is all the greater when the water collects on an
impermeable bed at no great depth."

From these facts, and the many others which have been adduced,
there seems to be no room for doubt, notwithstanding the authority
to be attached to anything proceeding from the pen of a man like
M. le Marshal Vaillant, that forests exercise a great influence on
the water system of a district.

But we can carry our investigations much further, and trace the
operation whereby trees arrest and so regulate the flow of and escape
of the rainfall in many of its details, and so make manifest what the
eftect of trees in this operation is.

216 ACTION OF FORESTS ON THE SURFACE-PLOW OF RAIN WATER.

Herr Wex has expressed his views on this point in a passage I have
quoted, and Marsh in his treatise on the " Earth as Modified by
Human Action," states in regard to a foi'est : —

" By its interposition, as a curtain between the sky and the ground,
it both checks the evaporation from the earth, and mechanically
intercepts a certain portion of the dew and lighter showers, which
would otherwise moisten the surface of the soil, and restores it to the
atmosphere by exhalation. While in heavier rains the large drops
which fall upon the leaves and branches are broken into smaller ones,
and, consequently, strike the ground with less mechanical force, or are,
perhaps, even dispersed into vapour without reaching it.

" The vegetable mould, resulting from the decomposition of leaves
and of wood, seems as a perpetual mulch to forest soil by carpeting
the ground with a spongy covering which obstructs the evaporation
from the mineral earth below, drinks up the rains and melting snows
that would otherwise flow rapidly over the surface, and perhaps be
conveyed to the distant sea, and then slowly give out by evaporation
infiltration, and percolation, the moisture thus imbibed. The roots,
too, penetrate far below the superficial soil, conduct water along
their surface to the lower depths to which they reach, and then by
partially draining the superior strata, remove a certain quantity of
moisture out of the reach of evaporation."

The meteorological eftects produced thus by forests resolve them-
selves into the prolongation and consequent increase of the evapora-
tion of water falling in the forms of rain, snow, and hail, eftected in
two distinct operations, first the absorption and retention of a large
portion of the rainfall, and second the retardation of the flow of the
remainder towards the great reservoir and source of all, in accord-
ance with the observation of the Hebrew preacher, " All the rivers
run into the sea ; yet the sea is not full : for unto the place from
whence the rivers come thither they return again."

Mr Marsh speaks of the ever-renewed and increasing vegetable
mould as a perpetual imdch, and in reference to the humidity of
forest soil he cites the following passage from Etudes su7- V Economic
Forestiere, by Jules Clav6 : — " Why go so far for the proof of a
phenomenon which is repeated every day under our own eyes, and of
which every Parisian may convince himself without venturing beyond
the Bois de Bologne, or the Forest of Meudon 1 Let him after a few
rainy days pass along the Chevreuse road, which is bordered on the
right by the wood, and on the left by cultivated fields. The fall of
water, and the continuance of the rain, have been the same on both

STATEMENT BY M. MARSCHAND, 217

sides ; but the ditch on the side of the forest will remain filled with
water, proceeding from infiltration through the wooded soil long after
the other, contiguous to the open ground, has performed its office of
drainage and become dry. The ditch on the left will have discharged
in a few hours a quantity of water which the ditch on the right requires
several days to receive and carry down to the valley." And but for
this drainage into the ditch the water might have remained there for
an indefinitely longer time. Thus by an operation, distinct from all
that have been mentioned, the humidity of the soil is prolonged and
maintained by forests. By continuous exhalations of moisture
through the stomates of the leaves — the moisture being obtained
in part, and it may be in great part, froni what is stored up in these
superficial and deeper-lying reservoirs, replenished from time to time
by raiu — the humidity of the air in a forest is increased ; bnt it is
the other phase of the operation with which we have at present
more especially to do.

It is this effect of forests which has led to the extensive replanting
of the Alps, the Cevennes, aud the Pyrenees with trees, herbage, and
bush, with a view to arresting and preventing the destructive conse-
quences and effects of torrents. In a separate volume I have given a
copious compilation of records of what has been done, of what led to
this being done, and of the successful results which have followed.
Here I may cite some of the statements made by one of the writers
on the subject, M. L. Marschand. I have already referred to
remarks by him on the hydroscopicity and capillarity of certain
minerals; as a property distinct and different from these which retain
moisture, he speaks of the permeability of soils, by which they give
passage to moisture and allow of its transmission ; aud he gives
cases of minerals which absorb and retain very little moisture in
their structure, but which are very permeable by water.

In general, rocks which are highly hydroscopic are not very
permeable, for the molecules, once moistened, cohere and present the
appearance of a compact mass impermeable to water, as may be seen
in clay.

On a permeable soil or subsoil, trees create and maintain on the
surface a layer of humus of considerable hydroscopic and capillary
properties, retaining water, and modifying the general permeability.
While, on an impermeable rock, the roots break up this and increase
the permeability.

The^principle which he seeks to establish is, that forests have the

"218 ACTION or FORKS^TS ON THE SURFACK-FT.t i\V i.F RAIN WATER.

effect of modulating the properties of rocks, giving to them what they
have not ; and he alleges it is in this way, more especially, that their
action is salutary in the control of waters on the mountains. Of this
view of the subject he gives the following illustration : — " When the
rain falls on a denuded brow of a hill, composed of argillaceous earth
the water moistens the surface — this absorbs a great quantity of it,
through its hydroscopicity and capillarity — but when once this surface
is moistened, the transmission of water goes on only very slowly from
particle to particle, for the permeability is almost nothing, in
consequence of the minute subdivision of the molecules which are
brought into the closest contact ; and that which is absorbed remains
on the surface and dilutes the superficial layer, which is soon thus trans-
formed into a thin clay devoid of cohesion. A layer more or less deep
will then detach itself from the surface of the mass, and will flow to the
bottom as mud more or less fluid, according as the rain may have
been more or less violent. By a very gentle rain, a superficial layer
is moistened ; but the water falling slowly may be able to penetrate
it completely, in virtue of its hydroscopicity and capillarity. In this
cas.^ there will be only a superficial flow, for the greater portion of the
water will penetrate the soil.

" But suppose that this same argillaceous land, or other unstable
ground, were wooded, the trees in spreading the fall of the rain over
an expanded surface, that of their foliage, would moderate the rain-
fall, and would at the same time augment the absorbent power of the
soil, as well as its permeability, and as a consequence augment the
quantity of water retained superficially. The mobility of the surface
thus softened would, undoubtedly, be increased, but the roots im-
prisoning it would retain the softened ground to such a degree that
no amount of water falling upon them from the heavens alone could
cause it to slip away. Wherever landslips occur on wooded grounds
they can be otherwis9 accounted for.

" If, in conclusion," says he, " we examine a forest situated on a
land permeable en masse, as are the plateaux of Jurassic limestone, the
first effect of the forest would be to cover the soil with a thick layer
of humus and of moss, which combine in a very high degree
hydroscopicity and capillarity. The quantity of water retained thus
in the upper layer of the soil will be much greater than it would have
been had there been no forest there, for on the rocks referred to the
destruction of woods is alnaost immediately followed by a denudation
of these rocks of soil.

" It follows from this that on these lands the forest arrests the

r^fATEMKNT BV M. MaKSSCHaND,

219

descent of the waters to the bottom of the valleys, for it is only very
slowly that water retained by hydroscopicity and capillarity quits the
substances which they penetrate. Moreover, as the greatest storms
of rain never do saturate completely the layer of humus on wooded
soils, it is impossible to form torrents on these."

He states that the effect of gazonnement is to augment the
hydroscopicity and capillarity of the surface of the soil, bnt that this
is not sufficient to secure the absorption of all the water that falls
upon it in a storm of rain, and he sites facts in support of the allegation.
The same good effects, he states, are produced to a greater extent by
buissonnement, or the planting of bushes, while a layer of humus of
great hydroscopicity, produced by the decay of their leaves, co-operates
in the production of these good effects ; but he cites evidence that
even gazonnement and buissonnement combined have failed to prevent
erosion and the formation of torrents.

But forests produce in a surpassing degree each and all of the
effects referred to, as produced in a minor degree by meadows and
bush. (I) They form by their detritus a very hydroscopic layer, and
in consequence augment the quantity of water retained ; (2) They
augment the expansion of surface on which the water falls ; and (3)
They augment the capillarity and permeability of the subsoil.

" I have," says he, " in treating of the permeability of the soil,
explained the influence of forests on this. In retaining for some time
the water at the surface they augment considerably the quantity which
is absorbed, particle by particle, by hydroscopicity and capillarity, for
this absorption is slow ; and thus, in a word, the forest tempers the
action of rain dashed downwards in a storm, and leads the water gently
on to the soil, as if it had fallen in a gentle shower ; and further, it
augments, in fine, the permeability of the soil, by keeping the surface
unhardened and in sOme sort always open to receive the water which
comes slowely from the heavens.

" I make no mention of the influence of forests in regard to
evaporation — in regard to the direct absox-ption of water — and in re-
gard to the humidity of the atmosphere, etc. I take up one point of
view alone of the torrential management of waters in the high
mountains, and these relate to this only indirectly.

" If a storm of rain beat upon a forest the whole of the water which
falls is temporarily retained, all penetrates more or less deeply the
soil without flowing on the surface ; and, it may be objected, if the
subsoil is impermeable the result will be the same. But the objection
is without foundation. 1 shall suppose, what is frequently the case,

220 ACTION OF FORESTS ON THE SURFACE-FLOW OF RAIN WATER.

that there is impermeable rock underlying the humus : all the water
should arrive at this bed of rock and flow down, but the hydroscopicity
and capillarity of this humus — of the ground — of the foliage — of the
branches of the trees — in a word, of the material of which the forest
is composeil — will arrest the water to such a degree and measure as
to regulate temporarily the delivery. . .

" I have glanced rapidly at the action of forests, in view simply of
their effect on the water which falls on their surface ; but tlieir
function is by no means limited to this, for they serve also to arrest
the waters which come from the pastures above them. They constitute
in some measure a kind of immense and powerful barrage, or barrier
placed between the summit and the bed of the valleys.

" In support of this allegation, I shall cite personal observations
which seem to me conclusive. Never have I seen, during the most
violent storms of rain, superficial flowings of water in the forests
situated under pastures, though such flowings may have existed in the
meadows at a greater elevation than the forests ; all the waters which
these supplied were literally absorbed aad retained by the forest soil.
I except, intent. onally, well-m irked ravines, which coming from above
traverse forests, for the question here is only of slopes somewhat uniform,
or but slightly undulated ; it is evident that the soil of the forest will
not absorb the water of a stream which traverses it encased in a bed.
" I take, for example, a valley which rises to a summit line some-
what elevated. The end situated at a great height is formed entirely
of pasture lands, which spread out equally on the summits of the
brows of the mountains ; at a lower level beneath these are the
forests. The waters which fall into the cistern formed by the head
of the valley rapidly accumulate, and give birth to a torrent which
traverses the forest. On the contrary, that which falls on the pasture
lands above the brows do not commonly readh the depth of the
ravine ; descending to the forest zone uniformly extended over the
soil, they are there absorbed.

" In a word, the zone of the forest absorbs generally the water
flowing from the zone of pasture lands which correspond to it. In
support of these observations, I appeal to all who, in the Alps, have
observed storms of rain in the forest. I except water accumulated in
ravines or depressions, which are in another condition.

" But the beneficent action of the forests does not limit itself to
this ; the flow in the ravine may also, if it be not completely absorbed,
be by them rendered less injurious if it should come to spread itself
over a cone de ddjection in a forest otherwise covered with wood. I

STATEMENT BY M. LEMOINE. 221

have observed, in connection with this, numerous muddy floods in
ravines which, spreading themselves out in the middle of a forest,
come out thence very limpid, depositing in it their slime, and leaving
in it also almost the whole of the water.

" The great forest of the Ofen, in the Orisons has supplied me
me with many instances of this. The soil, composed of the dolomite
limestone of the triassic period, is somewhat unstable ; in the middle,
of the pasture lands which surmount the forest there are formed every
year numerous torrents, which to an enormous extent carry off the
small pebbles, which are characteristic of the dolomite. All these
torrents arriving in the forest, then expand and diffuse themselves,
and very rarely do they penetrate to the bottom of the valleys. In
the upper portion of the Munster-Thal, I have seen on the right-hand
side an enormous ravine, the muddy torrents of which are arrested by
the forest. And the waters of the Munster, so well enclosed at this
point, are a proof of the beneficial action of the forests. In fine, from
the moment that the forests begin to retain the mud they retain also
temporarily the greater portion of the water in which this was sus-
pended, which are arrested by the enormous absorbent powers they
possess."

At the meeting of the Brititsh Association held at Brighton in
1876, M. G. Lemoine, Ingenieur des Fonts et Chaussees, read a paper
" Sur les Forets dans lew Rapports avec l^ Hydrologie." In which he
stated that in the basin of the Seine it had been established that, com-
pared with soil covered with grass, or even with other permanent culti-
vation forests had no special influence on watercourses. The only
absolutely certain action of forests was their influence in protecting
the soil and preventing it from being carried away ; but from this
single fact it followed that in mountainous countries they would
retard the flow of torrential water. In the Department of the Hautes
Alpes the presence of forest vegetation prevented the formation of
torrents ; re-planting woods led to the drying up of torrents already
formed ; but in most cases turfing, alone, was sufficient to produce
the same effect.

M. Cezanne, in writing of what he calls the Mecanisme de Vlnonda-
tion, remarks that the rain as soon as it has fallen becomes divided
into three portions, the first of which, taken up again by evaporation
returns into the atmosphere to be formed into new showers • the
second, after infiltration into the soil, appears again at a lower level
in the form of springs, when it loses not itself in the deeper

222 ACTION OK FORESTS ON THE SURFAOE-FLOW OF KA^IN WATEK.

reservoirs, whence it is made to project itself by artisian wells ;
finally, the remainder flows away by a thousand streamlets towards
the thalweg, feeding the brooks, and streams, and rivers.

But these portions do not stand to each other in any definite pro-
portion. Their relative importance varies not only, between one
water-course and another, with the nature of the ground, according
as this may be more or less favourable to the flow, or to the infil-
tration, but also in the case of the same water-course according as
the season restrains or promotes evaporation. In summer the drier
soil and warmer air are more greedy ; they drink up or absorb the
waters ; in winter the moist air and damp ground allow the sheet of
rainfall to flow away.

The only general and certain law is that over the area of the river's
basin these are complemental to one another, their sum is equal to
the quantity of rainfall. And if, for example, after evaporation has
taken away its portion, the infiltration be complete, the flow will be
nought.

It is the infiltration which is here brought under consideration.

Following out this division he says that it is by springs that the
permeability of the soil may be said to be revealed to us, and if their
regime be connected with meteorology, their existence depends on
geological conditions. And in illustration he says : —

" Mount Ventoux — separated from the A.lps by deep valleys, and
isolated on all sides, — is a mass of very permeable cleft limestone,
resting on an impermeable base which slopes toward the south-east.
So constructed, the mountain is a veritable filter, through which the
rain disappears at once ; and excepting in the cases of any violent
storms of rain, the superficial ravines are always dry. The sub-
terranean waters protected from evaporation descend slowly by the
internal fissures of the rock, and stopped at last by the impermeable
bed, they are directed towards the south-east, and flow out in springs
and streams sufficiently powerful to give motion to water-mills.

" The fine fountain of Vaucluse owes its origin to analogous
circumstances : it is a veritable rivei-, which is formed as other rivers
are by the means of a great many imperceptible tributaries ; but it
presents this peculiarity, that its basin instead of being open to the
vault of heaven, is subterranean, and covered by a great thickness of
permeable limestone. The area of the basin is nearly 100,000
hectares, * the delivery of the fountain is at low water from 10 to 12

* Bouvi&r, Annates des Fonts et Ohavssees. (1855, p. 367.)

STATEMENT BY M. CEZANNE. 223

cubic metres, 300 to 350 cubic feet, that is almost the sixth part of
the Seine.* The Eure, the basin of which is in extent six times that
of the fountain of Vaucluse, gives no more water than this at low
water.

" What a difference there is between the climate of Px'ovence and
that of Normandy ! In Provence the evaporation might carry off three
or four times as much water as the rain supplies ; the greater part of
the water-courses there are dried up in summer, and the plains of the
Camargue, notwithstanding inundations and irrigation, are covered
with saline inflorescence. If then, under this climate, the source of
the Vaucluse is so constant and so abundant, it is because its basin
being, as is the case with all sources, subterranean, the water which
has once penetrated the ground is there sheltered against evaporation."

Now, turning to the consideration of forest lands, we find that,
besides the desiccating of swampy land by evaporating through the
stomates of the leaves the moisture taken up by the rootlets, another
effect of the growth of trees is to desiccate the superficial soil by
aiding the water which it receives to descend along its roots to a
lower level, whence it is less likely to be carried off quickly by
evaporation.

" The roots of vegetables," says d'Hericourt, in a passage which is
quoted by Marsh, " perform the oflBce of draining in a manner
analogous to that artificially practised in parts of Holland and the
British Islands. The method consists in driving deeply down into
the soil several hundred stakes to the acre ; the water filters down
along the stakes, and in some cases as favourable results have been
obtained by this means as by hoi-izontal drains."

And by Marsh it is remarked : — " It is an important observation
that the desiccation of trees by way of drainage, or external conduc-
tion by the roots, is greater in the artificial than in the natural wood
and hence that the surface of the ground in the former is not char-
acterised by that approach to the state of saturation which it so
generally manifests in the latter. In the spontaneous wood the
leaves, fruits, bark, branches, and dead trunks, by their decayed
material, and by the conversion of rock into loose earth, throuoh the
solvent power of the gases they develope in decomposition, cover the
ground with an easily penetrable matter extremely favourable to the

* On the 12th August, 1858, fhe Seine was lower than had been observed for a
hundred and fifty-six years before. The gauging that day gave a delivery of 48 cubic
metres per second. The ordinary low water of the Seine is from 75 to 80 metres.
Belgrand, Annates des Fonts et Chaussiea. (1858 t. ii p. 222.)

224 ACTION OF FORESTS ON THE SURFACE-FLOW OF RAIN WATER.

growth of trees, and at the same time too retentive of moisture to
part with it readily to the capillary attraction of the roots.

" The trees, finding abundant nutriment near the surface, and so
sheltered against the action of the wind by each other as not to need
the support of deep and firmly fixed stays, send their roots but a
moderate distance downwards, and indeed often spread them out like
a horizontal network almost on the surface of the ground.

" In the artificial wood, on the contrary, the spaces between the
trees are greater ; they are obliged to send their roots deeper, both
for mechanical support and in search of nutriment, and consequently
serve much more effectually as conduits for perpendicular drainage."

If attention be given to the mode of growth in roots and rootlets,
it may be seen how it comes to pass that the fact is as stated by
Mr Marsh.

The root does not bore its way into and through the soil it
enters, but it is prolonged, as is the line of dominoes by the players
with these. The extreme cells, and probably the extreme cells only,
or chiefly, multiply in the spongioles in accordance with the usual
mode of cell genesis by the formation of cells within cells, and that
in proportion as they are supplied with nutriment ; and if this
multiplication of cells occasion a pressure in all directions, it tends
more to the extension of the root than to what may be called the wp
rooting of the tree. The direction of growth appears to be to whence
chiefly come the supplies of nutriment, or material of growth.
Where this is found on the level reached the roots extend. Where it
is found in the soil below them they descend. Where it is found in
tha soil above them they ascend. I have had reported to me a case
of roots extending towards a ditch, descending by the side of this,
changing then their course so as to pass beneath it, ascending then
on the further side till they came near the surface, and then spreading
horizontally as at first.

I have often heard of roots growing towards a quantity of assimilate-
able material as if guided by instinct ; and I am given to understand
that in willows by a stream there is generally a much more copious
growth of roots on the side towards the stream tlian on the other
sides around. Roots of forest trees are often prevented from descend-
ing by plintint^' thsm abjve a flit stone, wiiich cuts off" supplies ; and
roots of fig-trees growing upon rocks follow and penetrate every crack
and crevice where, and where alone, they find nutriment.

Thus may the downward growth of roots of planted trees be ac-

hKCONPARY KFFKCTS OF TREES. L'S;)

counted for, and the horizontal growth of roots of trees in a forest,
when such phenomena are seen; and by this downward growth of the
roots of planted trees may the descent of water to the subsoil be
promoted, there to be reserved against a day of need, converting the
subsoil into a reservoir of water, which, raised by evaporation by heat,
would moisten the superincumbent soil, promote vegetation, and
pass again through the stomates of the leaves into the atmosphere, —
again to be precipitated and absorbed by the soil instead of flowing
off to the sea, to be lost in that abyss which never says it is
enough ! — the springs and fountains and river sources being to us
significant of the greatness of the quantity of water which is thus
retained.

In view of all that has been advanced, it appears that trees
by their growth, the extent of their rootage, and the decay and de-
composition of their foliage and debris, tend to increase the proportion
of the rainfall which is preserved by infiltration, and to utilise for the
promotion of vegetation, a larger portion of what is thus retained
than otherwise would be so utilized.

The depth at which evaporation ceases must vary with the
temperature, humidity of the atmosphere and character of the soil.
Some interesting observatisns on this point are recorded by Johnstrus,
in a work entitled Om Fugtighedens Bevaegelese i den naturlige Jord-
bund, published in Copenhagen in 1866. He found in the neighbour-
hood of Copenhagen that there, at the depth of a mfetre and a half
(59 inches) the effects of rain and evaporation were almost impercep-
tible, and became completely so at a depth of from two to three
metres. (6| to 10 feet.

Sect. V. — Secondary Effects of Trees in Arresting the Flow and

Escape of the Rainfall, and thus equalizing to some extent

the Flow of Rivers.

While rivers in their sources indicate to us that the quantity of
water retained by the earth after a copious fall of rain, by the infil-
tration of a portion of this into the soil, must be very great — even
these being composed of what is only the drainage of the quantity in
excess of what the ground can retain — rivers in their flood indicate
that the portion of the rainfall carried away by ruissdlement, or
by flowing away over the surface of the ground, must also be great.

It may be noted that of what is retained by infiltration a great
deal may be utilized by vegetation ; and that of what is in excess of

2a

220 ACTION OF FORESTS ON THE FLOW OF UIVERS.

this and is carried off, feeding springs and fountains, and streams, the
saddest thing that can be said is that it is lost, thoiigii this can only
be said with a show of truth of that portion of it which is lost in the
sea ; but of what is canned off by ruisseUeni''nt comparatively little is
utilized ; a much greater proportion of it finds its way to the sea, and
this in rushing thither often carries with it devastation and destruc-
tion.

According to the statements I have cited from Surell, evaporation,
infiltration, and ruissellement, are equal in their sum to the quantity
of the rainfall, and if after evaporation has taken up its part the in-
filtration be complete, the ruissellement will be nil.

To the negative good which might thus be done, or damage which
might thus be prevented, and the effect of trees in doing these, by
equalizing to some extent the flow of rivers, would I next di'aw
attention.

In connection with a statement made in the preceding section,
relative to the effect of the destruction of forests upon the Durance,
reference was made to the important circumstance that while the
river is confined to a current little more than thirty feet in width,
the bed in some places exceeds a mile and a quarter in breadth, and
so far back as 1789 it was computed that it had covered an area of
not less than 130,000 acres with gravel and pebbles; and it was
intimated that thus was brought before us another of the effects of
forests, or rather of the desti'uction of forests, which would be -sub-
sequently brought under discussion,

Mr Marsh, writing on this subject, says : " The traveller who visits
the depth of an Alpine ravine, observes the length and width of the
gorge, and the great height and apparent solidity of the precipitous
walls which bound it, and calculates the mass of rock required to fill
the vacancy, can hardly believe that the humble brooklet which
purls at his feet has been the principal agent in accomplishing this
tremendous erosion. Closer observations will often teach him that
the seemipgly unbroken rock which overhangs the valley is full of
cracks and fissures, and really in such a state of disintegration that
every frost must bring down tons of it. If he compute the area of
the basin, which finds here its only discharge, he will perceive that
a sudden thaw of the wintei-'s deposit of snow, or on-e of those terrible
discharges of rain so common in the x\lps, must send forth a deluge
mighty enough to sweep down the hugest masses of gravel and of rock.
The simple measurement of the cubical contents of the semicircular

STATEMENT BY MR MARSH. 227

hillock which he climbed before he entered the gorge, the structure
aud composition of which conclusively show that it must have been
washed out of this latter by torrential action, will often account
satisfactorily for the disposal of most of the matter which once filled
the ravine,

" When a torrent escapes from the latei'al confinement of its moun-
tain walls and pours out of the gorge, it spreads and divides itself
into numerous smaller sti-eams, which shoot out from the mouth of
the ravine as from a centre, in diff"erent directions, like the ribs of a
fan from the pivot, each carrying with it its quota of stones and
gravel. The plain below the point of issue from the mountain is
rapidly raised by newly-formed torrents, the elevation depending on
the inclination of the bed and the form and weight of the matter
transported. Every flood both increases the height of this central
point and extends the entire circumference of the deposit,

" Other things being equal, the transporting power of the water is
greatest where its flow is most rapid. This is usually in the direction
of the axis of the ravine. The stream retaining most nearly this
direction moves with the greatest momentum, and consequently
transports the solid matter with which it is charged to the greatest
distance.

" The untra veiled reader will comprehend this the better when he
is informed that the southern slope of the Alps generally rises suddenly
out of the plain, with no intervening hill to break the abruptness of
the transition, except those consisting of comparatively small heaps
of its own debris brought down by ancient glaciers or i-ecent torrents.
The torrents do not wind down valleys gradually widening to the
rivers or the sea, but leap at once from the flanks of the mountains
upon the plains below. This arrangement of surfaces naturally
facilitates the formation of vast deposits at their points of emergence,
and the centre of the accumulation in the case of very small torrents
is not unfrequently a hundred feet high, and sometimes very much
more.

" The deposits of the torrent which has scooped out the Nautzen
Thai, a couple of miles below Brieg in the Valais, have built up a
semicircular hillock, which most travellers by the Simplon route pass
over without even noticing it, though it is little inferior in dimensions
to the great cones of dejection described by Blanqui. The principal
course of the torrent having been — I know not whether spontaneously
or artificially — directed towards the west, the eastern part of the hill
has been gradually brought under cultivation, and there are many

2-'8 ACTION OF fUltt-STb UN THK iXOW UF KiVEKS.

trees, fields, and houses upon it ; but the larger western part is
furrowed with channels diverging from the summit of the deposit at
the outlet of the Nantzen Thai, which serve as the beds of the water
courses into which the torrent has divided itself. All this portion of
the hillock is subject to inundation after long and heavy rain, and as
I saw it in the great flood of October, 1866, almost its whole surface
seemed covered with an unbroken sheet of rushing water.

" The semi-conical deposit of detritus at the mouth of the Litzner-
thal, a lateral branch of the valley of the Adige, at the point whei'e
the torrent pours out of the gorge, is a thousand feet high and,
measuring along the axis of the principal current, two and a half
miles long. The solid material of this hillock — which it is hardly an
exaggeration to call a mountain, the work of a single insignificant
torrent and its tributaries — includaig what the river which washes its
base has carried otf in a comparatively few years, probably surpasses
the mass of the stupendous pyramid of the Matterhorn.

" In valleys of ancient geological formation, which extend into the
very heart of the mountains, the streams, though rapid, have often
lost the true torrential character, if, indeed, they ever possessed it.
Their beds have become approximately constant, and their walls no
longer crumble and fall into the waters that wash their bases. The
torrent-worn ravines, of which I have spoken, are of later date, and
belong more properly to what may be called the crust of the Alps,
consisting of loose rocks, of gravel, and of eai'th, strewed along the
surface of the great declivities of the central ridge, and accumulated
thickly between the solid buttresses. But it is on this crust that
the mountaineer dwells. Here are his forests, here his pastures, and
the ravages of the torrent both destroy his world, and convert it into
a source of overwhelming desolation to the plains below.

"I do not mean to assert that all the rocky valleys of the Alps
have been produced by the action of torrents resulting from the
destruction of the forests. The greater, and many of the smaller
channels by which that chain is drained owe their origin to higher
^uses. There are primitive fissures, ascribable to disruption in up-
heaval or other geological convulsion, widened and scarped, and
often even polished, so to speak, by the action of glaciers during the
ice period, and but little changed in form by running water in
later eras.

" It has been contended that all rivers which take their rise in
these mountains originated in torrents. These, it is said, have
lowered the aummits by gradual erosion, and with the material thus

sTATliMKNT BY MR MAK.SH.

229

derived have formed shoals in the sea which once beat against the
cliffs ; then, by successive deposits, gradually raised them above the
surface, and finally expanded them into broad plains traversed by
gently flowing streams. If we could go back to earlier geologitial
periods, we should find this theory often verified ; and we cannot fail
to see that the torrents go on, at the present hour, depressing still
lower the ridges of the Alps and the Apennines, raising still higher
the plains of Lombai-dy and Provence, extending the coast still
farther into the Adriatic and the Mediterranean, reducing the
inclination of their own beds and the rapidity of their flow, and thus
tending to become river-like in character.

" We cannot measure the share which human action has had in
augmenting the intensity of causes of mountain degradation, and of
the formation of plains and marshes below, and we know that the
clearing of the woods has, in some cases, produced, within two or
three generations, effects as blasting as those generally ascribed to
geological convulsions, and has laid waste the face of the earth more
hopelessly than if it had been buried by a current of lava or
a shower of volcanic sand. New torrents are forming every year
in the Alps. Tradition, written records, and analogy concur to
establish the belief that the ruin of most of the now desolate valleys
in those mountains is to be ascribed to the same cause, and
authentic descriptions of the irresistible force of the torrent show
that, aided by frost and heat, it is adequate to level Mont Blanc
and Monte Rosa themselves, unless new upheavals shall maintain
their elevation,

" There are cases where torrents cease their ravages of themselves
in consequence of some change in the condition of the basin where
they originate, or of the face of the mountain at a higher level, while
the plain of the sea below remains in substantially the same state as
before. If a torrent rises in a small valley containing no great
amount of earth and of a disintegrated or loose rock, it may, in the
course of a certain period, wash out all the transportable material,
and if the valley is then left with solid walls, it will cease to furnish
debris to be carried down by floods. If, in this state of things, a new
channel be formed at an elevation above the head of the valley, it
may divert a part or even the whole of the rain-water and melted
snow which would otherwise have flowed into it, and the once furious
torrent now sinks to the rank of a humble and harmless brooklet.
* In traversing this department,' says Surell, ' one often sees, at the
outlet of a gorge, a flattened hillock, with a fan-shaped outline and

2 30 ACTION OF FORESTS ON THE FLOW OF RIVERS.

regular slops ; it is the bed of dejectiou of an ancient torrent. It
sometimes requires long and careful study to detect the primitive
form, masked as it is by groves of trees, by cultivated fields, and
often by houses, but, when examined closely, and from different
points of view, its characteristic figure manifestly appears, and its
true history cannot be mistaken. Along the hillock flows a streamlet,
issuing from the ravine, and quietly watering the fields. This was
originally a torrent, and in the back ground may be discovered its
mountain basin. Such extingidshed torrents, if I may use the
expression, are numerous."

The quotation is from Etude sur les Torrents des Haates Alpes, by
Surell (Chap, xxiv.), and Mr Marsh adds in a foot-note: — ''In such
cases, the clearing of the ground, which, in consequence of a temporary
diversion of the waters, or fi'om some other cause, has become re-
wooded, sometimes renews the ravages of the torrent. Thus, on
the left bank of the Durance, a wooded declivity had been formed by
the debris brought down by torrents, which had extinguished them-
selves after having swept off much of the superficial strata of the
mountain of Morgon. ' All this district was covei'ed with woods,
which have now been thinned out and are perishing from day to day ;
consequently, the torrents have recommenced their devastations, and
if the clearings continue, this declivity, now fertile, will be ruined,
like so many others.' "

And resuming, he goes on to say : — " But for the intervention of
man and domestic animals, these latter beneficent revolutions would
occur more frequently, and proceed more rapidly. The now scarped
mountains, the hillocks of debris, the plains elevated by sand and
gravel spread over them, the shores freshly formed by fluviatile
deposits, would clothe themselves with shrubs and trees, the intensity
of the causes of degradation would be diminished, and nature would
thus regain her ancient equilibrium. But these processes, under
ordinary circumstances, demand, not years, or generations, but
centuries ; and man, who even now finds scarce breathing-room on
this vast globe, cannot retire from the Old World to some yet undis-
covered continent, and wait for the slow action of such causes to re-
place, by a new creation, the Eden he has wasted."

In a foot-note he adds : — " Where a torrent has not been long in
operation, and earth still remains mixed with the rocks and gravel it
heaps up at its point of eruption, vegetation soon starts up and
prospers, if protected from encroachment. In Provence, ' several
communes determined, about ten years ago, to i^eserve the soils thus

sTATKMF.NT HY MH M.\f?STI. 'I'M

■wasted, that is, to abandon them for a certain time to spontaneous
vegetation, which was not slow in ranking its appearance.' "

Mr Marsh next treats thus of two subjects intimately connected,
the crushing effects of torrents, and the transporting power of water :
— " I must here notice a mechanical eifect of the rapid flow of the
torrent, which is of much importance in relation to the desolating
action it exercises by covering large tracts of cultivated ground with
infertile material. The torrent, as we have seen, shoots or rolls
forward, with great velocity, masses and fragments of rock, and
sometimes rounded pebbles from more ancient formations. Every
inch of this violent movement is accompanied with crushing con-
cussion, or, at least, with great abrasion of the mineral material, and,
as you follow it along the course of the waters which transport it,
you find the stones gradually rounding off in form, and diminishing in
size, until they pass successively into gravel, and, in the beds of the
rivers to which the torrents convey it, sand, and lastly impalpable
slime.

" There are few operations of nature where the effect seems more
disproportioned to the cause than in this crushing and comminution
of rock in the channel of swift waters. Igneous rocks are generally
so hard as to be wrought with great difficulty, and they bear the
weight of enormous superstructures without yielding to the pressure ;
but to the torrent they are as wheat to the millstone. The streams
which pour down the southern scarp of the Mediterranean Alps along
the Riviera di Ponente, near Genoa, have short courses, and a brisk
walk of a couple of hours, or even less, takes you from the sea-beach
to the headspring of many of them. In their heaviest floods, they
bring rounded masses of serpentine quite down to the sea, but at
ordinary high water their lower course is charged only with finely
divided particles of that rock. Hence, while near their sources their
channels are filled with pebbles and angular fragments, intermixed
with a little gravel, the proportions are reversed near their mouths,
and, just above the points where their outlets are partially choked
by the rolling shingle of the beach, their beds are composed of sand
and gravel to the almost total exclusion of pebbles.

" Guglielmini argued that the gravel and sand of the beds of run-
ning streams were derived fi-om the trituration of rocks by the action
of the currents, and inferred that this action was generally sufficient
to reduce hard rock to sand in its passage from the source to the
outlet of rivers. Frisi controverted this opinion, and maintained

232 ACTION OF FORESTS ON THE FT.O'W OF RIVERS.

that river-sand was of more ancient origin, and he inferred from
experiments in artificallj-grinding stones that the concussion, friction,
and attrition of rock in the channel of rnnning waters were inadequate
to its comminution, though he admitted that these same causes might
reduce silicious sand to a fine powder capable of transportation to the
sea by the currents. Frisi's experiments were tried upon rounded
and polished river-pebbles, and prove nothing with regard to the
action of torrents upon the irregular, more or less weathered, and
often cracked and shattered rocks which lie loose in the ground at
the head of mountain valleys. The fury of tlie waters and of the
wind which accompanies them in the floods of the French Alpine
torrents is such, tliat large blocks of stone are hurled out of the bed
of the stream to the height of twelve or thirteen feet. The impulse
of masses driven with such force overthrows the most solid masonry,
and their concussion cannot fail to be attended with the crushing of
the rocks themselves.

" The greatest length of the basin of the Ardeche is seventy-five
miles, but most of its tributaries have a much shorter course. ' These
affluents,' says Mardigny, ' hurl into the bed of the Ardfeche 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 con-
fluence with the Rhone.'

" Duponchel makes the following remarkable statement : ' The river
Herault rises in a granitic region, but soon reaches calcareous forma-
tions, which it traverses for more than sixty kilometres, rolling
through deep and precipitous ravines, into which the toi'rents are
constantly discharging enormous masses of pebbles belonging to the
hardest rocks of the Jurassian period. These debris, continually
renewed, compose, even below the exit of the gorge where the river
enters into a regular channel cut in a tertiary deposit, broad beaches
prodio'ious accumulations of rolled pebbles, extending several kilome-
tres down the stream, but they diminish in size and weight so rapidly
that above the mouth of the river, which is at a distance of thirty or
thirty-five kilometres from the gorge, every trace of calcareous matter
has disappeared from the sands of the bottom, which are exclusively
silicious.'

•' Similar effects of the rapid flow of water and the concussion of
stones against each other in river-beds may be observed in almost
every Alpine gorge which serves as the channel of a swift stream.
The tremendous cleft through which the well-known Via Mala is
carried receives, every year, from its own crumbling walls and from

STATEMENT BY MR MARSH. 233

the Hinter Rhein and its mild tributaries, enormous quantities of
rock, in blocks and boulders. In fact, the masses hurled into it in a
single flood like those of 1868 would probably fill it up, at its narrow
points, to the level of the road 400 feet above its bottom, were not
the stones crushed and carried off by the force of the current. Yet
below the outlet at Thusis only small rounded boulders, pebbles, and
gravel, not rock, are found in the bed of the river. The Swiss
glaciers bring down thousands of cubic yards of hard rock every
season. Where the glacier ends in a plain or wide valley, the rocks
are accumulated in a terminal moraine, but in numerous instances
the water which pours from the ice-river has force enough to carry
down to larger streams the masses delivered by the glacier, and there
they, with other stones washed out from the earth by the current,
are ground down, so that few of the affluents of the Swiss lakes
deliver into them anything but fine sand and slime.

" Great rivers carry no boulders to the sea, and, in fact, receive
none from their tributaries. Lombardini found, twenty years ago,
that the mineral matter brought down to the Po by its tributaries
was, in general, comminuted to about the same degree of fineness as
the sands of its bed at their points of discharge. In the case of the
Trebbia, which rises high in the Apennines and empties into the Po
at Placenza, it was otherwise, that river rolling pebbles and coarse
gravel mto the channel of the principal stream. The banks of the
other affluents — excepting some of those which discharge their waters
into the great lakes — then either retained their woods, or had been so
long clear of them that the torrents had removed most of the disin-
tegrated and loose rock in their upper basins. The valley of the
Trebbia had been recently cleared, and all the forces which tend to
the degradation and transportation of rock were in full activity." Of
the transporting power of water he writes : " The geographical eflfects
of the action of torrents are not confined to erosion of earth and com-
minution of rock ; for they and the rivers to which they contribute
transport the debris of the mountains to lower levels, and spread them
out over the dry land and the bed of the sea, thus forming alluvial
deposits, sometimes of a beneficial, sometimes of an injurious,
character, and of vast extent.

" A mountain rivulet swollen by rain or melted snow, when it
escapes from its usual channel and floods the adjacent fields, naturally
deposits pebbles and gravel upon them ; but even at low water, if, of
course, it is long enough for its grinding action to have full scope, it
transports the solid material with which it is charged to some larger

234 ACTION OF FORESTS ON THE PLOW OF RIVERS.

stream, and there lets it fall in a state of minute division, and at last
the spoil of the mountain is used to raise the level of the plains, or
is carried down to the sea.

"An instance that fell under my own observation, in 1857, will
serve to show something of the eroding and transporting power of
streams which, in these respects, fall incalculably below the torrents
of the Alps. In a flood of the Ottaquechee, a small river which flows
through Woodstock, Vermont, a mill-dam on that stream burst, and
the sediment with which the pond was filled, estimated after careful
measurement at 1 3,000 cubic yards, was carried down by the current.
Between this dam and the slackwater of another, four miles below,
the bed of the stream, which is composed of pebbles, interspersed m
a few places with larger stones, is about sixty-five feet wide, though,
at low water, the breadth of the current is considerably less. The
sand and fine gravel were smoothly and evenly distributed over the
bed to a width of fifty-five or sixty feet, and, for a distance of about
two miles, except at two or three intervening rapids, filled up all the
interstices between the stones, covering them to the depth of nine or
ten inches, so as to present a regularly formed concave channel, lined
with sand, and reducing the depth of water, in some places, from five
or six feet to fifteen or eighteen inches. Observing this deposit after
the river had subsided and become so clear that the bottom could be
seen, I supposed that the next flood would produce an extraordinary
erosion of the banks and some permanent changes in the channel of
the stream, in consequence of the elevation of the bed and the filling
up of the spaces between the stones through which formerly much
water had flowed ; but no such result followed. The spring freshet
of the next year entirely washed out the sand its predecessor had
left, deposited some of it in ponds and still-water reaches below,
carried the residue beyond the reach of observation, and left the bed
of the river almost precisely in its former condition, though, of
course, with the displacement of the pebbles which every flood
produces in the channels of such streams. The pond, though often
previously discharged by the breakage of the dam, had then been un-
disturbed for about twenty-five years, and its contents consisted
almost entirely of sand, the rapidity of the current in floods being-
such that it would let fall little lighter sediment, even above an
obstruction like a dam. The quantity I have mentioned evidently
bears a very inconsiderable proportion to the total erosion of the
stream during that period, because the wash of the banks consists
chiefly of fine earth rather than of sand, and after the pond was once

STATEMENT BY MR MARSH. 235

filled, or nearly so, even this material could no longer be deposited in
. it. The fact of the complete removal of the deposit I have described
between the two dams in a single freshet, shows that, in spite of con-
siderable obstruction from roughness of bed, large quantities of sand
may be taken up and carried off by streams of no great rapidity of
inclination ; for the whole descent of the bed of the river between
the two dams — a distance of four miles — is but sixty feet, or fifteen
feet to the mile.

" The facts which I have adduced may aid us in forming an idea of
the origin and mode of transportation of the prodigious deposits at
the mouth of great rivers like the Mississippi, the Nile, the Ganges,
and the Hoang-Ho, the delta of which last river, composed entirely of
river sediment, has a superficial extent of not less than 96,500 square
miles. But we shall obtain a clearer conception of the character of
this important geogTaphical process by measuring, more in detail, the
mass of earth and rock which a well-known river and its tributaries
have washed from the mountains and transported to the plains or the
sea, within the historic period."

The whole process of the disintegrating efiects of the Po Mr Marsh
then details with clearness, and concludes : — '•' Upon the whole, we
shall not greatly err if we assume that, for a period of not less than
two thousand years, the walls of the basin of the Po — the Italian
slope of the Alps, and the northern and north-eastern declivities of
the Apennines — have annually sent down into the lakes, the plains,
and the Adriatic, not less than 375,000,000 cubic yards of earth and
disintegrated rock. We have, then, an aggregate of 750,000,000,000
cubic yards of such material, which, allowing to the mountain surface
in question an area of 50,000,000,000 square yards, would cover the
whole to the depth of fifteen yards. There are very large portions
of this area, where, as we know from ancient remains — roads,
bridges, and the like — from other direct testimony, and from geo-
logical considerations, very little degradation has taken place within
twenty centuries, and hence the quantity to be assigned to localities
where the destructive causes have been most active is increased in
proportion.

" If this vast mass of pulverized rock and earth were restored to
the localities from which it was derived, it certainly would not
obliterate valleys and gorges hollowed out by great geological causes,
but it would reduce the length and diminish the depth of ravines of
later formation, modify the inclination of their walls, reclothe with
earth many bare mountain ridges, essentially change the line of

23'6 ACTION OF FORESTS ON THE FLOW OF RIVERS.

junction between plain and mountain, and carry back a long reach
of the Adriatic coast many miles to the west.

" It is, indeed, not to be supposed that all the degradation of the
mountains is due to the destruction of the forests — that the flanks of
every Alpine valley in Central Europe below the snow-line were once
covered with earth and green with woods, but there are not many
particular cases in which we can, with certainty, or even with strong
probability, affirm the contrary."

There is thus brought under consideration a secondary effect of
trees in arresting the flow and escape of the rainfall, and so to some
extent equalizing the flow of rivers. How this is affected next
demands our attention.

As the evaporation, to which attention has been called, may be
considered as only a continuation of evaporation, begun so soon as
the rain-drop was formed in the atmosphere, so may the infiltration
and ruisseUement be considered as only a continuation of the descent
by which, under the influence of gravitation, it fell ; but it is effected
under different conditions, and it presents different phenomena.

So soon as it falls part is absorbed by the hydroscopicity of the
soil, more, it may be, escapes by infiltration through the soil, and the
remainder flows over the surface to a lower level.

It may have been observed that on the footpath, or the rock, it
accumulates in pools, but not on the grass or turf of herbage, or field
of corn ; and on the bare ground, it may be seen flowing off in runnels ;
but on the grassy turf the phenomenon is somewhat different. Even
on the declivity of a knoll, or on the declivity of a mountain side,
the grass arrests, divides and subdivides, and so retains the super-
ficial flow of the superabundant rainfall. In accordance with this is
the action of forests thereon.

The establishment of this fact has followed the study of the natural
history of Alpine torrents. In some of these the whole rainfall in a
mountain basin, rushing off impetuously to the sea, and undermining
the banks of its channel, carried off the detritus, and buried there-
with, it may be, fertile lands, and villages and towns beyond. The
destructive effects thus produced in France called attention to the
subject nearly a century ago, and in 1793 there was published by M.
Fabre, a civil engineer, Essai sur la theorie des Torrents et des Riviers,
in which he alleges that the destruction of forests in the mountains,
and the uprooting of their stumps, had been the primary and the
secbMary causes of the formation of these torrents, and had thus been

STATBMRNT RY M. SURELL. 237

the occasion of all the disasters accompanying or following these
torrents ; and he urged the abandonment or regulation of these pro-
ceedings, and the rehoisement of the mountains, as means of arresting
and counteracting the evil.

The commotions occasioned by the revolution prevented full effect
being given to these views at that time, but some fifty years later a
work was published by M. Alex. Surell, entitled Etude sur les Torrents
des Hautes Alpes, in which similar and more extended views of the
subject were advanced. This work was crowned by the Academy of
Sciences ; and it led to the commencement of extensive works of re-
hoisement on the mountains of France. These have been prosecuted
with energy and success at great expense, but ungrudgingly, — the
result having proved corroborative of the principles upon which they
were undertaken. It is only as illustrative of the soundness of the
views upon which these were founded that they are now referred to ;
and here I can only bring forward statements of these views and prin-
ciples, with a passing notice of results illustrative of their truth.

M. Surell 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 every kind of arborescent vegetation.
On the other hand, when we look at mountain sloj)es 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 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 forest felled on the slope of a
mountain have there seen incontinently a multitude of torrents."

And again, " 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 revers, a number
of small torrents of the third class, which appear as 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 bringing 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

238 ACTION OF FORESTS ON THE PLOW OF RIVERS.

themselves, so to speak, in their very birth, and through the effect
alone of that equilibrium 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 whicfh 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, to its last ridge.

" Amongst the great number of extinct torrents, of which the
basins are wooded, there are some, the forests of which have been
subjected to the commune regime, 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 violence of the torrents, which only
slumbei-ed. 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 dejection 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."

And once more, " This last fact completes all that need be said in
regard to the influence of forests. In seeming 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 became stable, permitted vegetation to develop
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 primitive state, and the torrents 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 devasta-
tions 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
caused them to cease — and the extinction of the torrents is so com-
pletely their work that it begins, continues, and disappears with
them, the eftect ceasing immediately with the cause.

" One sees by this that the action of foi'ests is not confined to pre-
venting the creation of new torrents, but that it is sufficiently

STATEMENT BY M, 8URELL, 239

energetic to destroy torrents already formed. One sees also that the
injurious result of the removal of woods is not only to open every
where 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 on two facts, parallel to those which sum
up their 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."

He proceeds then to explain the modus operandi whereby forests
produce such eff"ects : " When the trees fix themselves in the soil the
roots consolidate this, interlacing it with a thousand fibres ; their
branches protect it, as would a buckler, againet the shock of the
heavy rains ; and their trunks, and at the same time suckers,
brambles, and that multitude of shrubs of all kinds which grow at
their base, oppose additional obstacles to the currents which would
tend to wash it away. The effect 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 meet-
ing there, which would be the case if they flowed freely over the
smooth surface of a denuded ground. Finally, it absorbs a portion
of the water which is 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 them-
selves then modified as they would be if a primitive formation had
been substituted for a formation totally diff'erent. 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 ot
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

240 ACTION OF FORESTS ON THE PLOW OF RIVERS.

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 i-ainfall, and prevent instantaneous con-
centration of the portion which they do not absorb. Consequently
they destroy both the one and the other cause. They prolong the
duration of the flow, and they render the floods at once more pro-
longed, less sudden, and less destructive.

" It may be understood from this how forests, in invading the
bassins de reception, 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, were rendering it more solid, were consequently diminishing
the mass of earth washed away, and above all were opposing them-
selves to the concentration of currents. They were augmenting all
the resisting, all the existing obstacles, and were diminishing all the
motive powers; and they were coming thus to hasten by a double
efl&cacy 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 circumstance 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 eftect.

" 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 Monestier. 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 vegetation. 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 cohesion of limestones, which is

STATEMENT RY M. SURBLL. 241

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 same cause which
multiplies the torrents ought then to multiply also the robust forests,
and to cause productiveness 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 influence, would soon be levelled or cut up
into bits, and they would oflfer to man nothing but a heap of cleft
rocks, uncultivated and uninhabited.

" It 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 [1].
Snows and glaciex's 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 brino-ino-
everything to a state of restored peace."

After dwelling on the thought of self-adjusting provision for the

2c

242 ACTION OP FOEESTS ON THE FLOW OP RIVERS.

natural extinction of torrents, he, in something like a burst of en-
thusiasm, gives expression to his feelings in view of the thorough
and efficient way in which torrents had naturally become extinct, and
of the contrast thus presented 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 VIS 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
natui'e employs when man ceases to oppose her, and when she patiently
prosecutes her work throughout 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.

" I 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 earth-works, 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 ? Wliy 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 V

In 1872 a sequel to this work by M. Surell was published by M.
Cezanne, Ingeneiir des Fonts et Chausees, Representant des Hautes
Alpes a r Assemble Nationcde. Referring to the phenomena of torrents
brought under review in that work by M. Surell, and in the Sequel
supplied by himself, M. Cezanne says : —

" There may be given in a few words a resxmie of the whole series
of these phenomena.

" The mountains are the result of a series of upheavals following

STATEMENT BY M. ofZANNB. 343

one upon another in the same region, A final agitation gave to the
different chains of these the existing elevation; it elevated the
summit and opened up deep fissures or divisions, which have become
the valleys of the present time. From the time this occurred the
waters began to fashion the thalwegs, following the line which best
suited them; wearing down outlets and filling up basins. It is
necessary to admit, or to assume, that the depth or thickness of the
alluvial deposits in the bottom of certain valleys — for instance, those
of the Isere in the Graisivaudau, or of the Rhine in Alsace, — is to be
reckoned by hundreds, and perhaps by thousands, of metres or yards ;
for even yet certain lakes existing in depressions of the Alps have
their bottom below the level of the sea.

" After a long series of ages the mountains assumed the leading
features which they now exhibit, when, the climate changing, great
glaciers carried on actively the work of erosion ; these have planed
away escarpments, and fashioned into something like horizontal lines
the rocky belts of the valleys.

" Dehddes, or inundations, from the escape of the waters of pent-up
lakes, and deluges resulting from the tremendous rains of summers on
the extensive fields of ice, have carried away and deposited in the
principal valleys in certain favourable places, but more especially at
the debouches of lateral gorges, the masses of loess which have
formed cones in the higher plains, and in which the water-courses
have subsequently dug out the secondary valleys,

" At a later period, after the melting away of those glaciers, the
torrents seized upon the bared mountains ; and without restraint
they have dug out their basins, and have again taken up the materials
disintegrated by the glaciers, and deposited these in the gigantic
cones which give to certain regions a physiognomy peculiarly their
own

" But after a time the forests, spreading by degrees, stifled the
waters under a mantle of verdure ; the torrents became extinct, — an
era of peace and of compai'ative quiet supervened in the mountains ;
then the tribes of men, who during the glacial period rambled over
the low-lying plains, in company with the reindeer, the aurochs, and
the bears, began to spread themselves in the high-lying valleys. The
most ancient settlements were made at the gorges of the torrents,
towards the summit of the cone ; in point of fact, there are to be
found in the mountain valleys very few of these gorges in which we
do nut meet either with an existing village or with an ancient ruin.

" Ju this location, which was then one favourable to their pursuits,

344 ACTION OF FORESTS ON THE FLOW OF UIVEUB.

the primary inhabitants could profit by the exceptional fertility of
the cone of deposits ; they had nothing to fear from the principal
river, which flowed through the lower-lying lands, nor from |the
torrent, which was then extinct ; they commanded the plain, and
found themselves at the gate of the mountains ; the adjacent gorge
supplied them with water, the forest supplied them with wood, the
rock supplied them with stone, and their flacks spread themselves
over the verdant ridges around them,

" Little by little, a reckless use of the forests and of the pasturage
disturbed the equilibrium of the natural forces ; and now the old sore
is re-opened, and anew, by man's deed, the mountains are inoculated
with the leprosy of the torrents. The evil has gone on increasing
during prolonged ages of disorder and recklessness ; the position of
the cultivated grounds, and of the villages established at the dehouche
of the torrents, has now become critical in the extreme ; and unless
we go back, as we have done ; to the olden times, we are unable to
account for men having taken up their dwelling in the spots, of all
othei's, which at this day appear to be those which are more
immediately threatened.

" But at last an era of reparation begins ; and, thanks to the eminent
men who have in byegone years given their mind to the work, the
next generation may hope to see the final decline of the modern re-
newed Torrential Era."

In 1874 was published Les Torrents leur lois, leur causes, leur efds:
Moyens de les reprimeur et de les utiliser : leur action geologique
uuiverselle, par Michel Costa de Bastelica, Conservateur des Eaux et
Forks.

This work treats of another aspect or of another department of the
subject than any discussed in the treatises already mentioned, which
the author designates, — Le phenomhie torreiitiel, or la torreiitialiiG ;
and thus is opened up another chapter of the natural history of
torrents.

In speaking of the good done by forests on the face of moun-
tains forming a basin drained by water-courses, he says their bene-
ficial action is manifold ; and though this manifold action it may
be difficult to unfold, the attempt to do this will place beyond all
question that their beneficial action on the water-course is at once
most marked and considerable.

" In the discussions which have taken place on this subject," saya
he, " the point which has engrossed attention to some extent has

STATEMENT BY M. OOSTA DE JSAbTELlOA. 245

been almost exclusively the permeability or impermeability of the
soil, and the proportion borne by the water absorbed to that which
flows off. This is certainly an important question, and no difficulty
is found in showing that forests diminish to an enormous extent the
amount of water which flows away ; but the service which they
render is perhaps greater still in regulating, as they do, the flow, and
in securing the delivery of only water of perfect fluidity,

" The study of torrents has shown that the evil done consists not
so much in the greater or less volume of water discharged as in the
disturbances or perturbations of the flow connected with this. The
principal causes of these are sudden changes or variations in the
delivery and in the degree of fluidity of the flood. And if it be
shown that the forests have, in relation to both of these, a regulating
power superior to that of any other force operating on the torrent,
it will be proved that they are the most potent means of extinguish-
ing torrents.

" If we could expose, by a vertical section, a wooded slope, it would
show in the upper portion a layer of varymg thickness, but most
frequently of from 30 to 40 centimetres (12 or 15 inches) of humus
in which the fibrous rootlets ai-e so developed that the whole has the
appearance of a woolly material. This layer is at once a sponge and
a filter. The large roots of the trees penetrate more or less into the
subjacent rock.

" When the rain falls on ground covered with wood a considerable
portion of the water is restored to the atmosphere by evaporation •
another portion is absorbed by the immense expansion of foliage and
boughs. If the rain be prolonged the water comes at length to the
ground, which again is capable of absorbing an immense quantity.
A flow from this is slow to establish itself; it is necessary, first that
the saturation of the sponge-like layer be complete ; and when this
is effected — when the water has been able to make a passage for it-
self by an infinite number of imperceptible channels — the flow, like
that of a charged syphon, maintains a certain uniformity of flow and
this it continues for a long time after the rain has ceased.

" So much is this the case that opponents have alleged that forests
are more hurtful than beneficial, as they tend to prolong floods. The
flood is prolonged, it is true, but the delivery is regulated — diminished
at the commencement and increased at the close ; the total quantity
of water drained away takes a longer time to flow ; it flows durino- the
whole of that longer time ; and, what is of more importance, it flows
vmiformly and equally, with no sudden variations, and thereby much

246 ACTION OP FORESTS ON THE PLOW OP RIVERS.

evil is avoided ; and, what is of more importauce still, the forest acts
at the same time as a filter, delivers no water but what is of perfect
fluidity, scarcely even discoloured by the washing away of organic
matter, and unable to wash away the earth of the subsoil pi-otected
against erosion by its thick covering of humus.

" When, on the contrary, the rain falls on a soil stript of vegetation,
it tends to cut this up into ravines, and it does so if the tenacity and
resistance of the ground be not sufficient to withstand it ; and the
flood is subject to great variations in its current, carrying oS", here
and there the earth and other debris of the soil.

" Forests have, then, a double action ; on the one hand they
consolidate the soil, on the other hand they reduce and regulate the
flow of the current, — acting at once both on the delivery and on the
perturbation, — in other words, on the primary cause and on the
secondary causes of the overflowing of water-courses.

" It has been tried to subject to experiment and observation the
meteorological and hydrological eftects of forests. And doubtless
studies so interesting are by no means lost to science. They cannot
be too much encouraged ; but it should bs borne in mind that they
can have comparatively little value in this question, seeing that they
cannot take cognisance of this modulating and regulating action.

" In regard to any flood which we may wish to make the subject of
study, it would avail comparatively little to know what quantity of
rain falls annually in the basin drained by it. What is necessary to
be known is — In what way did the flow of the flood operate during
the duration of the flood, taking into account the quantity of water
discharged, and all the causes or sources of perturbation operating —
which is a much more difl&cult problem.

" And in resolving the whole question into the permeability of the
soil, and its capacity of absorption, it appears importance is attached
exclusively to the reduction of the volume of water which flows
away. It seems to be forgotten in this that water-courses, if steadily
supplied, constitute it may be said the principal riches of a country,
and the most potent of all instruments of labour.

" By their modulating power forests act as vast reservoirs, not only
in preventing sudden variations of delivery during a flood, but in
feeding the water-courses and raising their level during the period of
exhaustion. In what relates specially to the torrents of the Alps
it has been demonstrated that the renewed devastating power which
they have exhibited, and which has assumed such portentous magni-
tude iu the course of the last forty years is a consequence of the dis-

STATEMENT BY M. COSTA DE BASTELICA. 247

appearance of the woods. When one goes over these lands — cut into
ravines and despoiled of all vegetation — he meets with numerous
stumps of pine and of larch, which testify that at a period as yet still
recent they were covered by vast foi-ests.

" M. Surell cites, as an example of the action of forests, the torrent
of Savines, now completely extinguished, and the basin of which is
everywhere adorned with a magnificent forest of firs and pines. The
forest has effectively contributed to the extinction of the torrent, but
at this point the following observations may be made :

" This natural extinction of the torrent goes back to ages most
remote. The cone is of a perfect geometric regularity. At its base,
opposite the Durance, it presents a troncature or section, produced by
the erosion of the river, and the escarpment of which is about 30
metres (100 feet) in height at its culminating point. This section
of the ground lays open the interior of the torrential deposit formed
of rolled pebbles.

" The whole surface of the cone is cultivated, and on one portion
has been built the large village of Savines, the chief place of the
canton.

" This enormous heap of deposit is situated at the foot of a high
mountain called Morgon, in the flanks of which are dug out a pro-
found gorge surrounded by a vast basin, the work of the water. All
the upper slopes of the mountain are hung with a beautiful forest,
producing firs more than 30 metres (100 feet) in height, and 3 metres
(10 feet) in girth.

The lower slopes are deeply ravined, but wooded to the very edge
of the thalwegs. A pretty strong stream rises from the principal gorge,
but it swells but little ; it carries down no material, and it flows into
the Durance by a bed deeply enclosed in the left bank of the cone.
Extinction and stability are complete ; but it is certain that if the
forest should be made to disappear, anew would disorder revive, and
this with the same intensity as before.

" In going over the basin with attention, I satisfied myself that
everywhere the bed of the thalwegs of the gorges and the ravines
formed of the hard rock, were absolutely incapable of being under-
mined. From this it may be inferred, that during the activity of the
torrent, when the basin was being deepened more and more, the sur-
face could not have been wooded. But from the time that the waters
had everywhere reached the hard rock, and that they could no more
bo undermined and washed deeper, their thalwegs in the upper slopes
tended to consolidate themselves, taking their natural stable declivity ;

248 ACTION OP FORESTS ON THE PLOW OP RIVERS.

and from that time vegetation could begin to take hold and complete
the extinction.

" This remark is important in this way, that if the disappearance
of a forest always gives birth to torrential disturbances, it does not
always hold true that one can put a stop to them by the planting of
a forest alone,

" Much as an unstable ground is protected by being wooded —
though it maintains itself and behaves, in a hydrological point of
view, as do the most solid lands, if the wood come to disappear, if
the ground be deeply ravined, if the bottom of the ravine continues
to be easily undermined and washed away — it becomes extremely
difficult to establish vegetation on the mountains, which continually
crumble away, and which with this instability no longer retain any
trace of vegetable soil.

" In the Alps there are numerous cases of old mountains which
crumble away when the foot of the slope is undermined by the water.
And one is thus left, if he desire to effect a radical and prompt ex-
tinction of a torrent, to give, artificially, to the bottom of the ravine
a power of resistance to undermining and washing away, by appro-
priate works of consolidation.

" But be this as it may, the potent action of forests is beyond all
question. Whatever be the character of the woods — timber forests,
coppice-wood, or simple shrubbery — all contribute to give firmness to
the soil, to retard and to regulate the flow of the water drained off.

" In comparing the different kinds of woods, it may be said that
lofty timber forests, with their vast apparatus of foliage at a great
elevation above the soil, are of most use with a view to meteorological
and hydrological effects ; and that young trees serve perhaps better
to insure the consolidation of the soil on steep declivities. But as
generally, on poor land, the soil of timber forests covers itself with
branches, &c., it follows that a mixture of the two kinds of woods
accomplishes best the end which it is sought to effect."

He speaks with similar expHcitness in regard to the effect of
gazonnement ; and in reference to artificial structures other than
those which he advocated, he remarks : " MM. Scipion Gras et
Phillipe Breton have also loudly proclaimed, in a way the most
explicit, that the boisement of the valley appeared to them the most
efficacious measure which could be adopted against torrents, and that
it was only in default of proceedings with a view to extinction behig
adopted — the application of which, when they wrote, was still
surrounded with obscurity and uucertaiiity — that they proposed the

STATEMENT BY M. MARCHAND. 249

measures they did, as means of diminishing, at least provisionally,
the danger. The torrents in the Alps which have given occasion for
the study of these phenomena owe their origin to the melting of snow
on higher lying mountains in summer, and to orages, or tremendous
storms of rain, which fall in spring. These torrents occasioned by the
latter are generally the most destructive.

" M. L. Marchand, Garde General des Forets, says on this
subject, — " When the torrential rains of tha Alps are made a subject
of study it is soon seen that they are all of them occasioned by a
particular wind called the foehn. These winds are generally violent,
and present almost always the chiiracter of orages, or storms of rain ;
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 circum-
stauces to bear the most persistent rains.

" The fcehn 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 sirocco, 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 semi-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 Comt6, before reaching which
latitude it has lost much of its force.

" If 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 fcehn comes up 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

2d

250 ACTION OF FOREST.S ON THF, FLOW OF RIVERS,

the Grandes-Communes, taking a deviation to the north of Digne. It
is against this chain that the first great storms of rain dash them-
selves. 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 Grande-Commune, of Enohastrayes, of theCold'Allos, of theLawerq,
of the Bas, and in fine, by the great passage of the mountains of the
Seyne.

' " The foehn 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.

" If now the forest chart of the country spoken of and the chart of
t\iQ foehn be compared, it will be seen that the mountains of Seyne
have been 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 foehn — 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 longei', as is the case above Mentou, a tropical sun to warm
the soil ; the wind has cooled down as it rose higher from the sea,
and it 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 summary is incomplete, but it may suffice to render intelli-
gible 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 foehn is compelled to rise considerably or to change its
direction. The celebrated torrent of Riou-Bordoux, near Barcelonette,
in face of the opening at Alios, is exactly so situated. The portion of
the Alps situated below the department of the Is^re almost completely
relieves the foehn of its humidity, and this is the classic region of the
orages.

^^^he foehn 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 oi debdcle,
or breaking up, and the water arrives in great quantities in the

STATEMENT BY M, MAllCHAND. 251

valleys. If the raiu do not supervene the action of the foehn may
suffice to cause all the snow to melt aLd to produce great consequent
disasters. In 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 mountaiu. In Switzerland the terrible
inundations of 1868 had in general a double origin — with warm con-
tinuous rains were combined 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 moantaius be not covered with
glaciers ; where this is the case the danger is constant,

" The foehrh sometimes produces geueral raius over the whole of
the country over which it blows, but sometimes only local orages, 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."

When the late Emperor Napoleon came to power he took steps to
give effect to the observations and reasonings of MM. Fabre and
Surell, which the pre-occupation of public men with political changes
had previously prevented.

In 1860 the work of reboisement was begun. To the report given
by the Director-General of the Administration of Forests, of what had
been done in 1867-1868, are appended a number of monographs on
works executed in different departments, embracing the departments
of the Isere, the High Alps, the Low Alps, Drome, Gard, H^rault,
Aude, and the High Pyrenees, all telling of success.

Amongst others, of which details are given of what had been
done, and of what results had followed, is mentioned the case of the
torrent of Saint Marthe, on the right bank of the Durance. Of this
M. Costa de Bastelica, in a work already cited, remarks : — " This
torrent supplies amongst many others a remarkable example of what
can be done. In 184:1, when M. Surell wrote his valuable work, this
torrent had a sad celebrity for its violence. It swept away every
bridge thrown across its course. On every occasion of a storm of
rain the inhabitants of the banks of the river were thrown into dis-
quietude, fearing to see it burst their dykes, and spread over the plain.

252 ACTION OF FOKESrtJ ON THE i'hOW OF RIVEBS.

•' The works undertaken with a view to secure its extinction were
only begun in 1864, and in 1869, when M. Cezanne, before the
publication of his work, did me the honour to allow me to show to
him and explain our works, he noted the fact that the work of ex-
tinction was so complete that a simple foot-bridge placed only 50
centimetres, or 20 inches, above the torrent, had become a work
that bade defiance to the greatest floods which now occur. This
foot-bridge still stands, and there have been no want of violent
storms of rain : in the interval there has been no change in the
meteoric conditions. The effect of the extinction of the torrentiality
was then attained and certain, and this so much so that the syndicate,
organised by the proprietors interested, having no longer anything to
do, dissolved itself."

In accordance with this fact are facts innumerable illustrative of
the efficiency of vegetation in extinguishing torrents and preventing
the formation of torrential floods, by which disastrous inundations are
occasioned. Of these, as has been stated, details have been given in
a separate volume,* and with these details copious information in
regard to legislative measures and practical operations by which the
results in question were obtained, together with resumes of the works
which have now been cited, and notices of others which have been
published on the subject.

In the conclusion of the volume there are remarks on the pre-
ventability by reboisement and gazonnemeiU of such sudden and dis-
astrous inundations as that which in 1875 proved so destructive to
Toulouse and the valley of the Garonne.

A similar inundation of the Loire occurred in 1846. In a valuable
work by M. Valles, published in 1875, entitled " Utude sur les in-
ondations leur causes et leurs effets" the author denies the efficacy of
reboiseinent as a means of preventing inundations. But M. A. F.
Hericourt, in writing of this work in the Annales Forestieres for De-
cember 1857, in an article entitled Les inondations et le livre de M.
Valles, combats his views ; and he thus maintains his position that the
reboisement of a portion of the upper basin of the Loire would have
prevented the inundation of 1846 : — " Accepting," says he, " the data
of M. Valles, who has analysed with much care the various phenomena

• Reboisement in Prance ; 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. London : H. S.
King & Co. 1876.

STATEMEM' BV M. HERlt'OUliT. 253

which characterised the flood of October 1846, in the upper basin of
the Loire, I will admit with him that if we could have held back
175,000,000 cubic metres of water, the inundation which proved so
sad a calamity to France would not have proved so painful an
event. The upper basin of the Loire, as far as Roanne, comprises an
area of 640,000 hectares (158,080,000 acres), of which at least a
third, say 213,000 hectares (52,693,000 acres), might be profitably
re-forested. The inundation was caused by a rain which lasted sixty
hours, and poured upon the soil a sheet of water 153 millimetres (about
6 inches) in depth. This portiou of the basin of the Loire, therefore,
received 979,200,000 cubic metres of water. On the hypothesis of
M. Valles, 244,800,000 cubic metres were absorbed. There accord-
ingly remained for superficial flow, 734,400,000 cubic metres.

"But let us suppose that, in 1846, the 213,000 hectares above-
mentioned to have been covered with massive woods, and then let us
calculate what would have happened. These 213,000 metres would
have received, as their share, 290,000,000 cubic metres. The absorbent
qualities of the soil are increased 40 per cent, by reforesting, and this
operation would have withdrawn 130,116,000 cubic metres from the
superficial flow, which would have reduced the amount upon the re-
timbered portions to 195,174,000 cubic metres. But this liquid
mass would have been hindered in its course down the valley, as we
have above explained, by the passive resistances of every kind which
the forest presents, and a half, at least, would not have arrived until
after the other half, which had fallen in other portions of the basin,
had passed otf. We may therefore conclude that the superficial
flow would not have exceeded 500,000,000 cubic metres, and that the
calamities occasioned by the inundation of 1846 would have been
completely prevented by reforesting."

As rain is the precipitation from the air of a quantity of moisture
which it can no longer retain, so rivers are composed of the draining
ofi" of a quantity of the rainfall which the ground upon which it has
fallen can no longer retain ; and — while the flow and escape of the
rainfall is arrested by much of it being absorbed and retained by the
decaying debris of leaves and twigs lying on the surface of the
ground in a forest, and by the humus in the soil, and by being
carried to a great depth along the channels of the roots — a secondary
effect of this is to regulate, and, in doing so, to some extent to
equalise over a considerable time the continuous flow and delivery of
the streams and rivers by which it is drained.

254 ACTION OF FORESTS OX THE FLOW OF RIVERS.

lu not a few of the statements which are given in preceding chap-
ters in regard to the effects of the destruction of forests, mention is
made of what had previously been perennial streams being often dry,
while at other times the water-course was filled from bank to bank
with a rushing torrent. There might be as much water delivered by
these in the course of the year as ever there was — though this might
be questionable, and the observations cited by Herr Wex, and given
above, show that in some of the principal rivers of Europe a greatly
increased irregularity of flow has been accompanied by a diminished
annual delivery — but the flow was irregular, and the correction of
this is a consequence of the absorption referred to. Among the con-
sequences of this may be reckoned the following : —

1. The devastating and destructive effects of floods are mitigated, if
not altogether prevented. 2. The prolonged retention of the rainfall in
an inland situation increases both the moisture of the atmosphere
and of the soil, by prolonging the periods of evaporation and infiltra-
tion. 3. From both of these effects will follow other consequences
tending to perpetuate the results so obtained. 4. Not only will the
promotion of vegetation, desirable as an end, be accomplished, but
one of the meteorological effects of vegetation, the increased or
maintained humidity of the atmosphere, will be secured.

CHAPTER VI.

On the Correspondence between the Distribution of the Rainfall
AND OP Forests.

As the student of Anatomy takes up now a muscle, now a nerve, now
an artery, and now a vein, and tx-aces it by careful dissection from all
integuments and other structures with which it may be united, giving
to it for the time his undivided attention, and leaving for subsequent
consideration the connections and relations in which each stands to
each and each stand to all, so would I pass from the consideration of
one subject to the consideration of another, treating each as for the
time the one subject with which we have to do, and leaving for sub-
sequent consideration the various facts evolved in their combined
connections and relations.

It has been alleged that the distribution of forests corresponds to
some extent with the distribution of the rainfall. And this raises
the questions, Which is cause and which is effect 1 or are they both
consequences of a common cause 1 and in either case to what extent
may they be legitimately regarded as cause and effect 1

In Scottish courts of justice it is customary for the public prose-
cutor to lead evidence and then to state his case as founded on this,
while in English courts he states his case and then leads evidence to
establish it. I do not admit that I have got a case to establish ; but
I shall state what my belief is, adduce observations in illustration of
different particulars, and then state what I consider to have been
proved.

Tt appears to me that observations made show in many cases a
general correspondence between the distribution of the two — that in
many cases the distribution of the rainfall has been determined in a
great measure by the geographical position and by the contour of the
country, and that this distribution of the rainfall may have determined
the distribution of the forests — but that the forests once established
may have exercised an important influence in further modifying the
distribution of the rainfall in time and in space.

256 DISTRIBUTION OF RAINFALL AND OF FORESTS.

Sect. I. — On the Measure of Correspondence between the Distribution
of the Rainfall and of Forests.

I have said it appears to me that observations made show in many
cases a general correspondence in the distribution of the rainfall and
of forests. It may occur to many on the mention of this that while
there are found forests covering extensive plains, their special habitat
appears to be the mountain side — and that the rainfall in the vicinity
of a mountain range is in general greater than it is on the horizontal
area of an extensive plain.

But the correspondence is more marked than this alone would inti-
mate. It happens to be the case that, in some cases, the observations
have been given to the world by observers having decided views in
regard to the connection of cause and effect, and in illustration of
their views ; but at this stage they are adduced only as illustrative
of the measure of correspondence which has been observed.

The first observations I adduce are some brought before the Meet-
ing of the British Association for the Promotion of Science, held
at Brighton in 1867, by Dr Brandis, Superintendant-General of Forests
in India, in a paper On the Geographical Distribution of Forests in
India. Dv Brandis considering India as divided, by observation of
the rainfall, into arid, dry, and wet districts, stated that in the west
corner of India was what might be called the arid tract, extending
from the coast of Cutch and from Scinde in the south to the Salt
range in the north, and from the hills of Beloochistan in the west
to the Aravalli range in the east. The average rainfall in this
district was less than fifteen inches. Throughout this arid part of
India the spontaneous arborescent vegetation was extremely scanty,
although a thin sprinkling of low thorny scrub on the hills offered
ample and interesting employment to the botanist. In this region
the work of the forester was limited to those tracts which stretched
along the Indus and its principal tributaries, watered by the annual
overflow of the river during summei-, or which could be otherwise
irrigated. Thus in Scinde there were on both sides of the Indus
river 352,000 acres of Government forest maintained solely by the
overflow of the river and by percolation. The result of the deflec-
tion of a river from its course was that the forest near the old bed
frequently perished.

Outside this arid tract there were two belts, with an annual
rainfall of between fifteen and thirty inches, which might be called

DISTRIBUTION OF RAINFALL IN INDIA. 257

the dry zones of India. The spontaneous arborescent vegetation was
scanty, save in the moist lauds aloug the great rivers, but it was
better than in the arid tract. In the southeru dry zone, comprising
part of the Deccan, was the country of tlie sandal wood, a small tree
which did not grow gregariously, and did not form continuous forests.
Here, too, were the ancient irrigation works, tanks, and gigantic
stone dams across rivers ; and where water was thus supplied, fields
and gardens were most luxuriant.

" Beyond these dry zones, and in the rest of India generally, the
rainfall exceeded 30 inches; but even in these moister parts of the
country the conditions for forest vegetation weie not everywhere as
favourable in India as in Europe. Eeally thriving forests were only
found where the fall exceeded 45 inches, and luxuriant vegetation
was limited to those belts which had a much higher rainfall. Within
the moist regions, with a rainfall exceeding 60 inches (in one place
rising to 250 inches) and in Eastern lndi;i, tliere was a great variety
of good forest. Of the Deodar forests of the North-West Him;ihiya
a small portion only fell into this belt, the greater pirt lying in laud
where the rainfall was less than 60 inches. Between the dry and
moist regions was a vast tract of country with an annual rainfiU of
more than 30, liut less than 61inches, comprising the greater portion
of the upper Ga:igetic phiiu, the whole of Ceutral India, and the
western side of the peninsula. In this part of India the main
obstacle to a luxuriant forest growth was not so much an in-
suflBcient supply of moisture, as its unequal distribution over the
seasons of the year. Of the moist zones, there were two in which
the annual rain exceed-^d 75 inches, the smaller one along the
western coast of the peuinsula, ami the more extensive one on the
outer Himalaya ranges, the hills of Bengal, and the coasts of Burraah.
" Ou the western coast the rainfall was moderate as far down
as Surat, 47 inches, and Bombay had 72 inches ; but Janna, only
a few miles inland, had 102. Further down the coast the rain-
fall was heavier. Rutnaghem had 115, and Canara had 123 inches.
Approaching the soutaeru extremity of the peniusula, the rainfall
gradually diminished to 28 inches at C.ipe Comoriu. In this narrow
moist belt were found some of the finest forests in India. The teak
forests of Noi'tli Canara, protected by the difficult nature of the
country, the teak aud blackwood forests of Wynaad and the
Anamallays and the forests of Travancore were reputable forests,
which might stand comparison with the oak and beech forests of the
Spessart, and the oak forests of Central France. The teak planta-

28

258 HBLATION OF FORESTS TO

tions of Nellumboor, in Malabar, which were commenced in 1844,
and now covered upwards of 2,400 acres, were a splendid instance of
luxuriant forest growth on a good soil, in a foreign climate, and
under good management. The moist region of the Himalaya and
the eastern part of India had a much larger extent. The Kangra
valley, in the Punjab, had a rainfall of 100 inches, and from here
the moist narrow belt, but widening gradually, ran in a south-westerly
direction as far as Sikkim. Near Simla, the width of this belt, with
a rainfall of 75 inches, was not more than 30 miles. Near Darjeel-
inz, it extended into and comprised the whole of Assam, Eastern
Bengal, as far as Dacca and British Burmah. A second belt of
between 60 and 75 miles, ran outside the foot of the Himalaya,
comprising the estuary of the Ganges and part of Orissa. Within
these moist regions of northern and eastern India, were a great
variety of good f )rests. Only a small portion of the deodar forests
of the north-west Himalaya fell within this belt, the greater part
lying inland, where the rainfall was less than sixty inches. The
india-rubber forests of Assam and Cachar were within the range of
the heavy rainfall as well as the ironwood forests of Arracan and the
teak forests of British Burmah.

" Between the dry and moist belts there lay, as has been intimated
above, a vast tract of country with an annual rainfall varying
from thirty to sixty inches. In this part of India the main obstacle
to a luxuriant forest growth was not so much an insufficient supply
of moisture as its unequal distributions over the seasons of the year.
In the grenter portion there was a long dry season and a short rainy
season. During the dry season the leaves and grass get excessively
dry and inflammable, and the smallest spark was then sufficient to
create a conflagration, which did not stop until it had reached the
limits of the forest. These jungle-fires destroyed millions of seed-
lings, and those which escaped were scarred and had in them the
germs of early decay. The jangle-fires were sufficient to explain the
remarkable fact that, in a large proportion of the forests of Southern
and Central India, and in some of those of the north, the mature trees
were unsound or hollow."

I could scarcely desire a better illustration of what I mean by a
general correspondence between the distribution of rainfall and of
forests, leaving out of view all that may be said bearing upon the
question of cause and effect, than is afforded by this statement.

A view similar to that advanced in regard to the geographical

distribution of forests in India is advanced in regard to the distriba-
tion of forests in America, by Mr Ciiarles M lulareu, in an article on
America in the " EncyclopoeJia Britannica."

In this the writer says, — " We are induced to think that in all
countries having a summer heat exceeding 70°, the presence or
absence of natural woods, and their greater or less luxuriance, may
be taken as a measure of the amount of humidity and of the fertility
of the soil. Short and heavy rains in a warm country will produce
grass, which, having its roots near the surface, springs up in a few
days, and withers when the moisture is exhausted; but transitory
rains, however heavy, will not nourish trees, because after the sur-
face is saturated with water the rest runs off, and the moisture
lodged in the soil neither sinks deep enough nor is in sufficient
quantity to furnish the giants of the forest with the necessary
sustenance. It may be assumed that twenty inches of rain falling
moderately, or at intervals, will leave a greater permanent supply in
the soil than forty inches falling, as it sometimes does in the torrid
zone, in as many hours. It is only necessary to qualify this con-
clusion by stating that something depends on the subsoil. If that is
gravel or a rock full of fissures, the water imbedded will soon drain
off; if it is clay or a compact rock, the water will remain in the soil.
It must be remembered also that both heat and moisture diminish as
we ascend in the atmosphere, while evaporation increases ; and hence
that trees will not grow on very high ground, though its position in
reference to the sea and the prevailing winds should be favourable in
other respects."

Assuming as unquestionable that the trade winds are the agents
which transport the moisture exhaled from its surface to the interior
of great continents, where it is precipitated as rain, or dew, or snow ;
and that mountains, by obstructing aerial currents and presenting
great inequalities of temperature, cause precipitation, this writer says,
— " Let us consider then what will be the effect of a mural rid^e like
the Andes in the situation which it occupies. In the re '■ioa within
the 30th parallel the moisture swept up by the trade wind from the
Atlantic will be precipitated, part upon the mountaius of Brazil,
which are but low, and so distributed as to extend far iato the
interior; the portion which remains will be borne westward, and,
losing a little as it proceeds, will be arrested by the Andes, and fall
down in showers on their summits. The aerial current will now be
deprived of all the humidity which it can part with, and arrive in a
state of complete exsiccation at Peru, where no rain will consequently

260 RELATION OF FORESTS TO

fiill. That even a much lower riflge t.lian the Andes may intercept
the whole muisture of the atiaoi[)'aerj is proved by a weU ktiowa
phenomenon in India, whea the G^Miits, a cliain only SuOO or 4030
feet high, d.vide samner frotu winter, aa it is called: that is, they
have copious ruins on their windward side, while on the other the
weather remains clear and dry ; and the rains regularly change froai
the west side to the east wiih the monsoons.

" In the region heyoud the 30th parallel this effect will be reversed.
The Andes will in this case serve as a screen to intercept the moisture
brought by the prevailing west winds from the Pacific Ocean ; rains
will be copious on tlieir summits, and in Chili on the their western
declivities, but mme will fall on the plains to the eastward, except
occasionally when the winds blow from the Atlantic."

And he adds, — " The views on the sal)jeut of climate we have been
unfolding will enable us to throw some light on an interesting point,
the distribution of ft) ests."

Thtre is a[>pended a small map of America, in which by long
hatched lines are shown the positious of the chains of mountains ;
white spaces rL-presout land* o.i wliich little or no wooi grows ;
shading represent the regiou-s of fjrjsts, dease forests bjing repre-
sented by double sl»a ling, au I thiuuar o les by open Hues; while
arrows i.idic ate the direction of prevailing winds. And in explanation
it is stated, — " In speaking of the rejim of forests, we neither restrict
tie term to those districts where the n itural wojds present au un-
brukjn continuity, nor extend it to every place where a few trees
grow in open plains. It is not easy to give a de.l;iiti<m that will be
always appropriate ; but in using the ex[>ression we vvisli to be under-
stood as applying i: to groan 1 where the natural wools cover more
than one-fourth of the surface." An 1 there is given the following
statement in regard to the distribution of the forests, — " In North
America, to the west of the Rocky mountains, is thus represented a
woody region, extending from lat. 35' to about 58°, of unknown
breadth, densely wooded from the coast, more thinly wooded towards
the mountain range ; to the east of the mountains, an extensive
region stretching E.NE. to the ocean, partly a bare desert, partly
covered with grass and clothed with trees. On the east coast and
more to the south is the Allegany range, with dense forests on the
east and the south and thin on the west, the forest region thus
indicated being bounded by a curved line passing from the mouth of
the St. Lawrence, in lat. 50", through Lake Huron to St. Luis in
Mexico ; and an arrow points out the direction of the wind turned

DISTRIBUTION OF RAINFALL. 261

from its course, ascending the valley of the Mississippi, and nourish-
ing the western parts of these forests. To the south of lat. 30° the
equatorial winds blowing from the east prevail ; and from 35° south-
ward from the forest lands of the Rocky Mountains, is the table land
of Me.xico, graduating in the north-west into the dry plains of Sonora
and California, all bare or nearly bare of wood. From this region,
down through the Isthmus of Panama, there are dense forests.
These dense forests fork and stretch to some extent along the
western coast of South America to Amotape, whence stretches a long
strip of dry bare sand ; on the west side of the Andes, which
constitute Lower Peru and the north part of Chili, a little to the
north of the equator, about midway from both coasts, is the Llanos,
(a bare plain of caraccas, nearly fenced round with mountains) ;
passing this to eastward, the dense forests follow the coast line,
stretching far into the interior, somewhat diminished in densit}', and
forming the great region of forest which constitute the basin of the
Amazon and occupies all the rest of Brazil.

" Near the equator the moisture is so excessive that after 150 or
200 inches of rain have fallen on the east coast there is still sufficient
humidity in the atmosphere to afford copious showers to all the
country up to the Andes. Here, therefore, the woods reach from side to
side of the continent. But as we recede from the equator the
humidity diminishes rapidly, and though the continent becomes
narrower towards the south the supply of rain falls off in a still
greater proportion, and the forests extend over a much smaller space.
At the foot of the Andes the forests extend to 16° or 18° south lat. ;
on the east coast, to 25°, probably 30°. Thence, on the east coast
are the Pampas, or open lands of Buenos Ayi'es, extending, on the
east side of the Andes, from the latitudes mentioned to Cape Horn.
^ " But on the western side of the Andes, extending through the
same latitude, are the forests of Chili, where the prevailing winds
•which are from the west, coming loaded with the moisture of the
Pacific Ocean, produce copious raiuSjto nourish the hei-bage and
forests. This applies chiefly to the country south of the 35° parallel.
From that to Coquimbo, lat. 30°, the wood is scanty."

In this, as in the account given by Dr Brandis of the Geographical
distribution of forests in India, we find, apart from the facts
embodied in the statement, an illustration of a general correspon-
dence between the distribution of the rainfall and of forests.

Independent testimony on the distribution of the rftinfall in

262 RELATION OF FORESTS TO

America is supplied by the Smithsonian Institution, unencumbered
by any theory. The arrangements made by this Institution for col-
lecting, collating, reducing, and utilizing meteorological observations
are on the most ample scale.

Towards the close of 1873 I received from Professor Henry a series
of rainfall tables, comprising all the observations that have been made
in regard to the rainMl in the United States since the settlement of
Europeans in the country, and an intimation that they had com-
menced a new epoch, and had subsequently to the publication of
these tables distributed several hundred rain-gauges in addition to
those previously used, and to those which had been been provided by
the Gjverumeut in connection with the signal source ; aud three rain
charts are given showing, from the material collected in the general
table of results, the geographical distribution of rain over the area of
the United States, with the average amount fallen during the year, and
during the seasons of summer and winter. The first chart exhibits
the results from 750 stations, and the others the result obtained from
nearly the same number.

In regard to the general character of the distributions of rain on
the average throughout the year, it is stated, — " The most striking
features of the phenomenon of rain, as delineated on the chart, are
the apparent precision and continuity in the law of its distribution,
and the great variation or range in its amount. Thus the curve,
passing over places where the annual fall amounts to 40 inches, can
be followed from New Brunswick, on the Bay of Fandy, to Texas ;
the isohyetal line of 36 inches, similarly, runs without interruption
from the St. Lawrence River to the mouth of the Rio Grande. The
regularity of the curves is sufficiently disti-nct to mark out everywhere
the progression in the deposition of the aqueous vapour. The annual
amount varies from four inches in the Yuma aud Gila Deserts, at the
head of the Gulf of California, to 80 inches and more on the Pacific
Coast in Washington Territory ; on the Gulf Coast 6i inches appears
to be the maximum amount, and 48 on the Atlantic Coast.

" The principal supply of rain over the United States comes from the
Gulf of Mexico ; its diffused vapour can be traced from the eastern
slope of the Rocky Mountains to the Great Lakes ; while the supply of
vapour from the Atlantic Ocean is distinctly traceable over that area
lying north and east of Virginia. All States and Territories west of
the Rocky Mountains receive their supply of rain from the condensed
vapours of the Pacific Ocean.

" There are distinct localities of entry of maximum rain from each

DISTRIBUTION OF RAINFALIi. 263

of these basins of supply ; the vapours from the Pacific are deposited
■within a remarkably well-defined coast region between latitude 41°
and our boundary at the Straits of Juan de Fuca ; the rain pours
down with great intensity on the coast between the mouth of Columba
River and Cape Flattery. It is surprising how little rain falls on the
Pacific coast between San Diego and Cape Mendocino, and how
quickly the atmosphere becomes drained of its vapour as we leave
the coast and proceed inland in latitudes north of 41°. The coast
range of mountains here act powerfully as condensers by forcing the
air up their western slopes.

" The densest part of the Gulf vapour is thrown over the delta of
the Mississippi River, and as far east as longitude 8Q^ its axis of
dlffasio7i can be traced distinctly to the west end of the Lake Erie :
it is inclined towards the northeast for two reasons — the effect of the
earth's rotation on a fl^w from the south, and the influence generally
of the prevailing westerly winds. A second sweep over the country
occurs in southern Florida, most likely due to the immediate proximity
of the Gulf Stream ; and there is a thinl, as yet undefined, influx,
passing through Georgia and South Carolina.

" The condensation of vapor from the Atlantic is most apparent a
short distance inland at the following localities : Along the coast of
Maine near Eastport and near Portland, in central Connecticut,
western Massachusetts, and extending to southern Vermont, and
near the entrance of Chesapeake Bay. Upon the whole, hills and
mountain ranges appear to have a comparatively small directive
influence upon the distribution of the rain. Florida, which may be
considered as almost perfectly flat, exhibits well-defined bounding
lines of rain distribution. River courses also seem to influence the
amount of rain, as along the Rio Grande. At the mouth of the Hudson
River, the curves become suddenly contracted ; and some similar
feature can perhaps be traced out on the Mississippi delta near New
Orleans. Beyond furnishing by their evaporation a supply to the
general fund of moisture, the Great Lakes do not appear to exercise
any direct influence ; on the yearly average the rains along their
borders are not increased. There is even a remarkably small amount
of rain-fall in northern New York, close to Lake Ontario. The effect
of equalizing the temperature produced by all large bodies of water
has no doubt a direct influence upon the distribution of rain; the
greater and more sudden the variations in temperature, the greater,
comparatively, the rain-fall.

" The laws of the distribution of the rain-fall, as far as they depend

264 RELATION OF FORESTS T(^

upon the changes of teraperatui'e and direction of wind, can be studied
to better advantage by means of the two charts showing the dis-
tribution in summer and in winter, tliau by that for the yeai*, since
the l*^tter necessarily brings out the resultant phenomena, and should
consequently be of greater complexity than either of those for the
extreme seasons. "With a few exceptions, presently to be noticed, the
distribution of rain in the extreme seasons is not very dissimilar from
that of the year as a whole."

It is stated in the report that the tables show that mountains and
hills have apparently a comparative trifling divertive influence on the
distributions of rain. Fur this conclusion some of my readers may
not have been prepared. To what extent, if any, the distribution of
forests may correspond with the distribution of rain is not referred
to ; but in a work on the aspects presented by forests in different
parts of the world, by M. F. S. Marny, we have notices of the forests
in the United States, of which we may avail ourselves to see how far
these independent records — the one of the rainfall, and the other of
the forests — correspond.

After a graphic description of the forests of South America, M.
Marny says: — "On re-ascending into upper Mexico and reaching
California, arborescent vegetation resumes, with regard to kinds, the
character of our tempemte climates, but it still preserves its gigantic
character which belongs to the trees of the New World. In Oregon,
the pines that fill the forests spread along the sea shore seem to be
the kings of all the pines in the universe. Their diameter is often 5
mfetrcs, their height surpasses sometimes 100, and their cones are 15
inches long. The pine lamhertina gives to the coast of California an
imposing but melancholy aspect. The lines of pines run alnng the
shore as far as Russian America, where they are associated with oaks
and birches. Their less lofty species prevail in the forests of New
Hanover, of New Georgia, where they adorn, with sycamores and
maples, the slopes which inpline towards the ocean "

Along the coast, from lat. 50° to 41", we have according to the
rain-chart a rainfall of from 60 to 40 inches, diminishing as we pro-
ceed inland to .52, 44, 32, 30 ; and in the longitudes of Nevada,
extending thence to Minnesota, Nebraska, and Kansas, 16 and 20,
with no mention of forests, but in the State last-named it rises to 20,
24, and 28.

M. Marny proceeds : — " Crossing the Appalachian and the Rocky

DISTRIBUTION OF RAINFALL. 265

Mountains, we encounter new lines of forest-trees. One of the first
is traced by the bald cypress, which seems to be surrounded by
natural boundaries. These are protuberances formed upon the roots
of this conifera, and they often rise to a metre in height : which
barriers defend the trunk against the attacks of large animals.
These cypresses compose gigantic thickets, which cover the swamps
of the lower Mississippi, of the Arkansas, of the Red River, and of
Florida, and extend as far as the mouth of the Ohio. It was under
the vast shade of one of these trees that Cortez and all his army
found a refuge in Mexico. Their wide stems, of conical form, are
crowned with a multitude of horizontal branches, which are entangled
with each othei", and confounded with those of the neighbouring
cypresses. These vaults of foliage, which are frequently superimposed,
give to the forests of this cypress an aspect quite peculiar. The short
leaves of a sombre green, represent on drawing near a kind of crape,
which impresses on these shades a funereal appearance. And under
these gloomy domes, which are here and there enlightened by a few
openings made by the winds, or due to the age of the branches, all
the scourges of man, whether animate or inanimate, seem to have
given each other the rendezvous. Death soars over these shady
solitudes, which incessantly evoke the idea of it. Fevers, alligators,
serpents, mosquitoes contend with each other for the woodman
who goes with his axe to strike their trunks — the growth of ages.
But no danger arrests the avidity of man, nothing terrifies the enter-
prising descendant of the Anglo-Saxon race. The lumberers venture
through these pestilential swamps, and precipitate into the waters of
the Mississippi the trunks they have uprooted.

" The Mississippi, that ancient father of waters, is indeed the great
agent of destruction to these forests of North America ; its waters,
especially at the period of inundation, are continually charged with
enormous masses of wood, with gigantic rafts which encumber its
bed, and are self-constracted with moi-e solidity than any raft made
by the hand of man. These trains of trees are especially remarkable
upon the Atachafalaya, one of the arms of the Mississippi. They are
equally met with upon the Red River. One of the affluents of this
river, the Nashita, is interrupted for a space of seventeen leagues by
an almost uninterrupted succession of these rafts. M. de Humboldt
has made known the same fact in the Orinoco, whose bed is unceas-
ingly encumbered by a mass of trunks, which seem as if driven into
the mud.
"These swampy forests, by the destructive action of humidity,

2f

266 RELATION OP FORESTS TO THE

finish by transforming themselves into vast bogs, which present the
appearance of great inundated plains, whose surface might be covered
with trees brought along by the waters. These immense stagnant
pools, these seas of mud, still fui-nish a soil sufficiently firm for a
species of cypress, and of broom which grow there ; they offer the
only ground of support for the foot of the animals that wander in
these aquatic solitudes, — bears, wild cats, wolves. The most cele-
brated of these swamps is the Great Dismal, which Mr Lyell has
described in his interesting journey in the United States, and which
extends between the towns of Norfolk, Virginia, and Weldon, North
Carolina."

In the Lower Mississippi we have, according to the rain-charts, a
rainfall of 56, 60, and 64 inches per annum ; in Arkansas, a rainfall
of 42, 44, and 50 ; in Norfolk, Virginia, 44 ; in North Carolina, 44,
48, and 52.

M. Marny continues, — " Upon the lower levels of the Alleghany
Mountains, the rhododendron and the kalmia display their elegant
flowers. From stage to stage the vegetation is modified ; and to
forests of oak ssucceed the resinous pines, with which are associated
magnolias, poplars, and different species of nyssa.

" The forests of the Alleghanies belong to one of four forest zones
which embrace North America; they extend over the south-west
coast as far as to the south of the bay of Chesapeake. They chiefly
contain pines, firs, cedars, and cypresses."

In this district we have a rainfall of 36, 40, and 44 inches.

"The second zone, which corresponds with the region of magnolias,
catalpas, tulip-trees, stretches over the Floridas and Louisiana ; it is
characterised in several parts by forests of cedars, known under the
name of cedar-swamps. In Louisiana the rather stunted stems of the
wax-myrtle are found among the rhododendrons.

" In Florida and Carolina are forests called pine-harrens composed
of gigantic pines, reaching a height of more than 50 metres, and
rivalling those which clothe the opposite coast of the American
continent. These pine-harrens comprise a broad band several hundred
miles in length. Behind these forests of coniferse, which form the
second forest line, one encounters on disembarking upon these shores
— the first being composed of graceful palms — come other forests not
less dense, but composed of a thousand kinds of wood. 'There,*
writes M. F. de Castelnau, * the magnolia exhibits with profusion its

DISTRIBUTION OP RAINFALL. 267

leaves like immense spatulas, while the air is embalmed by itsbeautiful
and enormous flowers so dazzlingly white. It is intermingled with a
hundred species of sassafras, catalpas, laurels, cedars, gum-trees, in
the midst of which the magnificent evergreen-oak distinguishes itself.
Everywhere the cornel-tree dazzles the eyes by its silvery splendour ;
the azalea is lavish of its corolla, like an elegant butterfly ; and the
sumach displays with pride the magnificent splendour of its scarlet
bouquets. All these various trees are closely matted together by
lianes without number — veritable alliances with these brides of
nature.' "

In Florida we have a rain-fall of 60, 52, 48, 44, 40, and 36 inches,
and in South Carolina the same.

" The third forest zone invests the hills and low mountains
of the Carolinas, of Pennsylvania, and comprehends the slopes
of the Alleghanies which we have just described. The oak, the
birch, the mulberry, the sycamore, the maple, occupy these
woods. The willow-leaved oak, the elm, and the chestnut, principally
form forests in Pennsylvania and in New Jt-rsey ; in the environs
of Habochene venerable forests run parallel to the coast. The two
parts of this state form a striking contrast to the rest; whilst a
vigorous vegetation adorns the northern divisions, those that lie to the
south offer only an arid sandy soil, which has its own species and its
especial forests. The upper Ohio flows under a bower of tulip-trees
and planes, whose elegant foliage is reflected in its waters.

" But it is iu the state of Indiana, above all in the environs of New
Harmony, upon the banks of the Wabach, that the forests of North
America show themselves in all their magnificence. They present,
among the forests of the New world, a distinct character, and one of
their peculiarities is the want of evergreen plants, with the exception of
the mistletoe, a species of bignonia, Dutch rushes, which are a kind of
equisetum, and the Miegia microsperma. When the woods are stripped
of their foliage, the eye is attracted only by the equisetum just named
which reaches a height of eight or ten feet In these collections of trees
the traveller is struck by the gigantic planes, ramifying themselves
into a certain number of hollow trunks, which serve him as a shelter
in time of need. To these planes are united maples of proportions
almost as great, several oaks, and notably that which bears the name
Mossy over-cup oak, whose enormous acorns are strewn over the ground
and which grow in close ranks. A multitude of climbing-plants em-
brace the trunks of the large kinds, the quinate-leaved ivy, the poison

268 RELATION OF FORESTS TO THE

ivy, the bignonia, which attach themselves to the trunks like a thick
net-work formed of aerial roots, to which are attached at right angles
the branches that bear the leaves. Among these mighty trees there
are lofty thickets of 15, 20, and 30 feet in height, composed of the
papaw-tree, the spice-wood or fever-bush, and the red-bud tree. Be-
low these smaller kind of trees the ground is still covered with shrubs,
and in the openings grow the RJms typhina and the Rhus glabra,
Magnificent catalpas appear at every step in a wild state ; but the
botanist seeks in vain for trees with aciculate leaves, the pine, the
cypress, or for the rhododendrons, the azaleas, the magnolias, the
chestnuts, which are met with in other parts of America.

" These woods are rapidly thinning. Legions of backwoodsmen
take up their abode in them ; and they are speedily cleared. Already
wood is becoming singularly dear at New Harmony ; and the hickory,
which gives out so powerful a heat, has been cut down with a pro-
fusion and ignorance usual with the first colonists of forest countries."

In Indiana we have a rainfall of 44, and 40.

" The fourth zone loses the physiognomy of the subtropical vegeta-
tion, to resume that of the vegetation of our northern countries. It
comprehends the greater part of New York, New England, Vermont,
New Brunswick, Canada, the region of the lakes ; to this region New-
foundland belongs.

" In the state of New York, forest vegetation is of a heavy and
dense character; which is owing to the predominance of certain
kinds of hemlock, spruce, fir. The black-spruce constitutes the
characteristic tree of this cold region ; it forms a third of the forests
in all the districts comprised between 44« and 53" north latitude.

" A great part of Long Island is covered with forests, of which
one-half is formed, according to Dr Timothy Dwight, of yellow-pines.

" The borders of Lake Huron are covered with gigantic forests of
planes, between the close ranks of which are seen groups of tamarask
or of American larch, of pendulous larch, that frail tree which seems to
be an arborescent reed. All the vegetation of the borders of this lake
is of a more decidedly grand character than that of the other lakes.
The forests of Lake Erie are enriched with the sassafras-laurel, the
magnolia-, the Cormis Florida, whose branches, adorned in autumn
with bunches of scarlet, agreeably diversify the sombre verdure of the
rest of the forest. The vegetation of Lake Ontario resembles that of
Lower Canada ; yet we find there some characteristic species — Canada
poplars, the robinia, the lime, the resinous pine, and the red pine.

DISTRIBUTION OF RAINFALL, 269

Upon the borders of Lake Champlain, the sugar-maple, the balsam-fir,
the Virginian poplar, are equally remarkable.

" In the environs of the Falls of Niagara the t ulip-tree, the red
cedar, and the Canadian yew grow in great abundance ; whilst near
to Kingston, which is only seven miles from the cataracts, an immense
forest, composed of horse-chestnut trees, has taken possession of the
soil to the exclusion of every other kind,

" Around Bloomfield, not far from Lake Canandagua, magnificent
forests of oak furnish the colonists with a valuable wood, and embel-
lish the slopes of the hills.

Throughout the district specified we have a rain-fall of 44, 40, 36,
32, and on one very limited spot so little as 28.

" When we advance into Canada, forest vegetation gradually
dwindles, and at length becomes quite stunted. We no longer meet
with any thing but little firs, dwarf birches, and lank poplars. This
is observed to the north of Quebec, and of the parallel of the Isle of
Manitoulin."

Within the line indicated we have a rainfall of from 32 to 44, the
latter being the rainfall at St. Johns, New Brunswick ; falling to 40
and 36 as we come nearer to the St. Laurence.

Thus does it appear that every observation made in North America
seems to tend to show a general accordance between the distribution
of the rainfall and of forests.

Something similar may be observed in the distribution of forests in
South Africa, In the Colony of the Cape of Gooa Hope all the existing
forests are found on mountain slopes following the convex curve of
the sea coast from the mouth of the Orange River on the west to
Port Natal on the east. The trees are comparatively few in number
on the Cedar-Bergen range, in Clanwilliam, but so numerous were
they formerly as to have suggested the name given to the mountains ;
they are more numerous on the Table Mountain range near Capetown ;
they appear in greatest abundance in the districts of the Knysna and
George ; but they abound also in Kafi'raria and in the Trans-Kei
territory. This curve encloses an extensive inland district almost
destitute of trees, bounded on the north by a district crossing the
continent beyond the colonies, in which trees are more numerous,
connecting the forest lands of the east with forests on the west coast
further to the north.

Co- extensive with these forests, there is what may be called com-

270 RELATION OP FORESTS TO THE

paratively a copious humidity of soil and climate ; while in the
districts in which there are none, the soil and the climate are com.
paratively dry. There have been described by Livingstone three
distinct meteorological zones in South Africa : the eastern, compre-
hending Zulu-land, Natal, Independent and British Kaffraria ; the
central, comprising a portion of the elevated Central Basin of the
continent, and divided from the eastern by the Drakenberg, Malutis,
and other ranges ; and the western, including the KaUhdri Proper,
the wastes of Namaqualand, and^^the wilds of Bushmanland — the
latter, situated to the south of the Orange Eiver.

The first of these is comparatively well watered, and there we find
extensive districts covered with ever-green succulent arborescent
herbs, and most of the extensive forests. In the second we find
comparatively little water, and forests disappearing. The third is
arid and sterile and barren in the extreme.

I have had occasion to cite the statement that " the prevalent
winds of most of the countiy thus divided are from the northeast.
Heavily laden with vapour from the Indian Ocean, the clouds, under
the influence of these easterly currents, are driven over the Zulu
territory. Natal, and Kafikland, watering those lands luxuriantly; but
when the moisture-bearing nimbi arrive at the peaks of the mountain
ranges, not only have they parted with a large proportion of their
water, but they are then on the edge of the more arid central basin,
and begin to meet with the influences of the heated and naked plains,
under the radiation from the surface of which, and in an increasing
degree as the Bechuana tribes are past and the K41dhdz'i is reached,
the clouds rise higher above the earth, the moisture evaporates in a
thinner vapour, and as a consequence fewer showers fall upon the hot
thirsty soil beneath.

"The further we journey from the Drakensberg eastwards, the
greater becomes the diminution of water.

" Leaving the mountains, the Lesuto or Basuto land, as it is called,
is without doubt the best watered portion of the central meteoro-
logical district, mainly, it is presumed, on account its being intersected
by the Malutis range. Towards this important section of country,
from November to April, the northeast winds blow from the shores
of Mozambique and the delta of the Zambesi immense masses of
cloud, which sweep heavily over the earth, darkening the sky, and
preceded in their course by dreadful peals of thunder. On reaching
the high land, the aerial lake is shut in by the huge table-headed
mountains ; as a consequence, a rapid condensation takes place, and

DISTRIBUTION OP RAINFALL. 271

then a veritable deluge ensues. In a few moments cataracts rush
from the mountain heights, the smallest and most thread-like rivulets
are transformed into torrents, and the rivers overflowing their banks
cover the plains : this sometimes lasts for days together (Casalis).
It is from the accumulation of these waters that the Lekoa, the
Caledon, and many other tributaries of the great Orange River, which
with slow and majestic course flows to the westward across the vast
plains of the centre of South Africa, take their rise. As the moun-
tains, however, merge into the plains, and these again into the
Kdldhdri, we are reminded by the gradual diminishing rivers of the
continual aridity of the soil, till we reach Great Namaqualand, where
the occurrences of periodically filled water-courses again testifies to
the descent of rain.

" In this latter district, however, as well as in the desert, rain falls
only from thunder-clouds. These rise from the northeast, and are
always hailed with delight by the inhabitants of those parched and
burning regions ; but they are partial in the distribution of their
precious treasure, the storms frequently passing over with tremendous
violence, striking both European and native with awe at their terrific
grandeur, while not a particle of rain descends to cool and fructify
the barren waste."

Thus do we find in Asia, in America, and in Africa alike, a general
accordance between the distribution of the rainfall and of trees.

Sect. II. — On the Distribution of the Rainfall dependent on Geogra-
phical Position, being determined by the contour of a country.

Of two existing phenomena it is sometimes difiicult to determine
what is the order of sequence in which they have appeared — which
is cause and which is eff'ect — or whether both be not consequences
of the same cause ; and this we may experience in view of the cor-
respondence between the distribution of the rainfall and that of
forests.

Whatever may be the effect of a copious rainfall on a mountain
side in promoting a growth of forest trees — and whatever may be the
effect of a forest there, in producing and maintaining an abundant
rainfall — it is the case that the configuration of a country, irrespective
of forests, exercises a considerable influence on the territorial distri-
bution of the rainfall.

The effect which may be produced by altitude alone on the dis-
tribution of the rainfall receives an interesting illustration from

272 RELATION OF FORESTS TO THE

observations collected and publisbed by M. Belgrand* in regard to
a wind-wave which passed over Europe towards the end of September,
1866.

This wave originated in America, on a line which extends from
Buenos- Ayres to the North Pole ; it traversed the Atlantic, and reached
England on the 20th September, and France, Belgium, and Holland
on the 21st. On the 22nd, it reigned at the same time over Nancy,
and over Paris. On the 23rd, it raged over the sources of the Seine,
and of the Loire, and extended to the Garonne. On the 24:th, it
passed over Lyons ; its fury broke upon the St Bernard, from the
24th to the 26th; and from the 23rd to the 24th, upon the
Simplon.

On all the elevated places it poured out a quantity of rain equal to
about a fifth of the average annual rainfall. On the contrary the
low-lying plains were almost everywhere spared ; England and Nor-
mandy did not receive a twentieth of the annual rainfall. Shielded
by the mountainous backbone of France, which stretches obliquely
from the Vosges to the Pyrenees, and as a watershed divides the
water between the ocean and the Mediterranean, Carcassonne, Mont-
pelier, Grenoble, Lyons, Bourg, and Bezangon did not receive any
extraordinary rainfall ; it did not rain at all at Strasburg, at Dresden,
at Munich, at Breslau — nor did it in Austria or in Italy. In Swit-
zerland, and even in Savoy the rain was not great, while Mont Blanc,
the Simplon, and the St Bernard received only 17 per cent, of the
annual rainfall.

There is much that is interesting in the study of the atmospheric
wave, sweeping along 1700 feet above the level of the sea, with a
stretch of wing, extending some 1200 miles and more, skimming the
high lying plateaux of France, and by a flight of 200 leagues a day
dashing itself against the summits of the Alps ; but it is to the dis-
tribution of the rainfall occasioned by it with which alone we have to
do here.

At the meeting of the British Association for the advancement of
science, held this year (1876) in Glasgow, Sir William Thomson
made a communication in regard to the production of the phenomenon
known as a " mackerel sky," which suggests an illustration of the
phenomenon under consideration.

Schoolboys amuse themselves sometimes with skimming flat stones

* Belgrand' Anuales des Fonts et Chausees. Sept. 1866.

DISTRIBUTION OP RAINFALL. 2f7'^'

along the surface of smooth water. The same phenomenon is pro-
duced upon a greater scale when a cannon ball, aimed at a floating
target, strikes the water and rebounds into the air again and again
ere it disappears. I have often, at the Cape of Good Hope, seen
indications of the southeast wind advancing in waves, raising dust
where it seemed to descend and strike the ground, but leaving un-
disturbed alternate stripes over which it seemed to bound or rebound
at a higher level. Thus may it be with all currents, whether of
water or of air, descending and striking upon other matter, solid,
liquid, or gaseous, at an acute angle of inclination — as is indicated by
the undulations or waves raised by the breath on a cup of tea,
by the wind on a pond or placid stream, and by a storm upon
the sea. And, according to the supposition of Sir William Thomson,
a current of air striking upon^a lower current, advancing in the same
direction but with less velocity, or advancing in another direction, or
upon a stratum of air in a state of quiescence,may rebound as does the
skimming stone or the rebounding cannon ball on striking the water.
And if the temperature of this current of air were near to that of the
dew-point, or point of saturation, when it rebounded to a higher
elevation, the temperature being thereby reduced, a condensation of
moisture would ensue ; but when the rebounding force was exhausted,
and it again descended to a lower level, it would acquire a higher
temperature, and the condensed vapour would be again dissolved in
the air, producing the phenomenon of alternating stripes of cloud
and of sky.

It is to this difference in the power of air to sustain vapour in
solution at the different temperatures through which it passes at
different elevations that I refer as illustrative of the rainfall occa-
sioned by the wind-wave which has been spoken of. I have had
occasion to refer to an illustration of the same kind afforded by
the passage of the southeast wind over Table Mountain, producing
dense clouds and even drizzling rain on the mountain top, but the
clouds disappearing as the current pouring over the front of the
mountain reached a lower level but a higher temperature ; so is it
with the wind-wave deluging the mountains with rain but passing
over the lower-lying plains without any such effect.

Such wind waves, varying in their sweep and in their dimensions,
but essentially the same, are not of un frequent occurrence. Most of
those, of which the phenomena have been studied, have swept along
the surface of the earth and the ocean, and even they may have

2a

274 RELATION OF PORESTa TO T HE

produced or yielded a greater rainfall on mountains than on plains ;
as in passing over mountain elevations the temperature of the air
would experience a great reduction, and a precipitation of the
moisture they contained would follow.

And it may be the case that the presence or the absence of forests
on the mountain summits might affect within a limited range the
degree to which the temperature of the wave in passing over the
ridge would be reduced. So would a fire in a hunter's cabin ! So
would the huntsman's breath, and even the huntsman's presence, and
every discharge of the huntsman's rifle ! But in the presence of
such meteorological phenomena as are under consideration all of
these are as nothing.

And as is the case in such occasional disturbances, so may it be,
and most probably it is, with the regular current of the atmosphere
passing over a mountain range in its coui'se to the equator from the
pole, or striking upon a mountain top in its return to the arctic or
antarctic zone. The great change of temperature occurring in the
case cited made manifest in such a way as to arrest attention the
consequence of such a change in so far as it afi'ected the rainfall ;
but any reduction of temperature below the dew-point would, in pro-
portion to its extent, produce corresponding effects. Such a reduction
of temperature frequently follows the passage of an atmospheric
current over a mountain range ; and to the altitude of the mountain,
so completely as almost to warrant the use of the term exclusively, ia
the greater rainfall on the mountain attributable.

I have hesitated about using the term exclusively, not on account
of the influence which the circumstance of the^ mountain summit
beinc clothed or being bare of forests might have in somewhat, but
probably to an imperceptible degree, modifying the result ; but I
have done so on account of the influence on the rainfall exercised by
the contour of the mountain range.

This subject, the influence on the rainfall exercised by the super-
ficial configuration of a country, has engaged the attention of M.
Cezanne. From his sequel to Etude sur les torrents des Hautes-Alpes,
I translate the following statement : —

" When a rain-producing wind strikes against an eminence which
forces it to rise in the atmosphere, a double efl'ect is produced : the
ascent of the air itself tends to a reduction of temperature, and con-
sequent condensation of vapour j but besides this, the atmospheric cur-
rent turned from its course is subjected to friction against the cooled

DISTRIBUTION OF RAINFALL. 275

surface of the earth, and the rain is, as one may say, mechanically
pressed out of the clouds. For these reasons, it rains more on the
headlands than on the exposed slopes ; but in the deep fiords of
Norway, a pluvial rain, sharply arrested by a wall of rock, deposits
immediately a maximum of rain,

" There falls annually at Bergen, 2 metres (80 inches) of rain ; at
Bourdeaux, only 719 millimetres (29 inches) ; at Nantes, 1 m^tre (40
inches); at Cherbourg, 830 millimetres (33 inches).

" On the coast-land of the Mediterranean, the rain-producing wind
blows from the east, or the south-east, in a vertical direction to the
wall of the Cevennes, upon which descend violent showers. There
falls annually at Marseilles, 512 millimetres (20| inches); at Tou-
lon, 505 (20 inches) ; at Nismes, 640 (26 inches) ; at Montpelier,
770 (31 inches) ; at Viviers, at the foot of the mountains, 900 (36
inches); at Joyeuse, at the bottom of a valley, 1-300 millimetres
(52 inches).

" The region of the Jui'a gives as characteristic of the rainfall the
following figures: Lyons, 776 millimetres; Magon, 876; Bourg,
l"* 172; Syam, in the gorge, l"* 630.

" Some writers have erred in thinking that they may conclude,
from such and similar facts, that the quantity of the rainfall in a
place increases with the altitude of the place. Formulated thus, the
law is not correct ; and the phenomenon cannot be explained satis-
factorily. The phenomenon is mechanical as well as physical, and is
more intelligible when formulated thus: The pluvial ralnfallis greater
in proportiot), as the atmospheric current arrested hy an obstacle is com-
pelled to rise more rapidly. It is not then the altitude of a place
which is of most importance, it is the incidence with which the rain-
yielding wind strikes the slope which opposes it ; but the law regu-
lating this incidence it is not easy to determine.

" From what has been stated it comes to pass that in order satis-
torily to compare two rain-gauges it is necessary to take into account
their absolute elevation, and along with this the slope and configura-
tion of the mountain sides which support them. The following table,
in which are brought together several localities situated in the gorges
of the Jura, show that the altitude is not the dominating element —
for the maximum of rainfall is far from corresponding with the
maximum of elevation : — *

* L'Eveille: Eecherclies sur les inondation {annates de la Societe d^ agriculture
de Lyon, 1858).

Altitude,

Eainfall.

MHres.

Millimetres.

161

1260

233

1111-8

310

1592

365

1741

444

1457-7

840

970

1001

1176-7

1045

1560

276 RELATION OF FORESTS TO THE

Locality.

Pierrechatel,

Varambon,

Saint Bambert,

Syam,

Saint-Claude,

Pontarlier,

Fortde-Joux,

Saint- Cerques,

" At the convent of the great Saint Bernard (altitude, 2620
mfetres, = 8733 feet) there is collected annually 1500 millimetres (60
inches) of water. If the most elevated pluviometre in Europe be at
the same time one of those giving the high measurements, the cause
of this is perhaps less its altitude than its topographical position.
The instrument is placed in a narrow embrasure, dominated by
glaciers, in which the winds, come from what direction they may,
must pass on violently, and be rapidly cooled.

" The obstacle once passed, the rain diminishes — the current
descends and becomes heated again ; desirous of repairing its loss,
it drinks up the clouds with avidity, and dries up the mountain
slope on the opposite side."

Giving then a graphic account of the appearance presented by a
sea of clouds rising up a mountain side and pouring over into the
valley beyond, when this is contemplated from a surmounting height,
which has been already quoted (ante p. 157), he goes on to say, —
" That the superficial aspect of a country has an important influence
on the phenomena of the rain may be illustrated by many well-
known cases.

" On the two sides of the Scandinavian Alps, the west wind and
the east wind give inversely fine weather and rain, the one to Sweden
and the other to Norway.

" When it rains at Narbonne the sun shines at Montauban.

" The rain comes from the west in Switzerland, and from the east
in Lombardy. It is in consequence of its being sheltered from the
south and southeast winds, which drench the basin of the Rhone,
that the valley of the Durance presents that exceptionally dry climate
which M. Surell points out to be favourable to the development of
torrents.* It rains upon an average, at Marseilles, 57 days in the
year; at Aries, 45 days; at Aix, 40; but in the region of the Durance
it rains only 38 days in the year.t

• Sorrel, chap. xxi. t Arago : Melanges, p. 430.

DISTRIBUTION OF RAINFALL, 277

" Under the tropics, where prevail the trade-winds blowing from
the east, the lands which incline towards the east are inundated with
torrential rains : thus is it on the coast of Mozambique, and in the
basin of the Amazon. On the contrary, it almost never rains on the
western slope of the Andes. It is said that thunder has not been
heard at Lima three times in as many centuries.*

" In the Indian peninsula the eastern coast, or that of Coromandel,
is watered by the North-east Monsoon ; and the west coast, or that of
Malabar, by the South-west Monsoon.t

" When, after having climbed the slope of a mountain, the atmos-
pheric current, greatly relieved of its load, comes upon a plateau, it
freely expands ; but its lowest layer, being in contact with the earth,
is alone reduced to a lower temperature. From which it comes to
pass that, from the same wind, a plateau, though more elevated,
receives less rain than the ascending slope, but receives more than
does the descending slope beyond.

" The summit of the elevation which separates the Ocean from the
Mediterranean supplies the following table : — |

Region.

Altitude— Metres.

Kainfall-MillimStres.

West Slope (Toulouse), ...

148-50

632-7

Summit (Castelnaudary), ...

170-00

630-0

East Slope (Carcassonne), ...

113-00

757-3

" From this table it may be seen that the slopes receive a little
more rain than do the summits, and if it be borne in mind that the
summit gets rain — now from the east wind, now from the west
wind, — while Carcassonne, for example, does not receive it except
by the east wind, it is beyond a doubt that the summit receives
less rain from the same wind than is received by the two slopes
which are ascended by the pluvial current.

" On a very interesting hy^tographic chart, prepared by M. Delesse,
Ingenieur en chef des mines\\ it is seen that the plateaux of La Beauce
and of La Brie, subject to the influence of the west wind alone, present
a very manifest minimum. There falls at Chartres 540 millimetres, at
Meaux 400 millimetres of rain annuaUy.

" La Burgogne forms, as is known, a basin which stretches itself

* Eevieu : Theorie de la pluU [Annuaire de la SocUti m^teorologique de

France, (1866) tome XIV.)

■f Lamairesse (annales despont et Chaussees, October 1869).

X Raulin : Ohseroations Pluviometriques.

D Deleste : Distribution de la Pluie en France (Bulletin de la 8oci6t6 de

geographie dm, 1868.)

278 RELATION OP FORESTS TO THE

from North to South, between the walls of the Forez and of the
Jura. This basin is crossed by the west wind, which distributes its
rain in such a way as to give clear testimony to the influence of
mountain elevations. *

Regions, Mean of observations. Places of

Slope of the Forez passed over by the
pluvial wind descending,

Bottom of (Eight bank of the Saone,
Valley. (Left bank of the Saone,

Adjacent region et the base of the Jura
passed over by the pluvial wind re-
ascending, .. ... 301 1087-8

Gorges of the Jura where the pluvial

current is compressed, ... ... ... 549 1358 '0

Altitude-

Rainfall -

Observation.

Metres.

Millimetres.

440

704-3

3 stations.

252

695-7

5 „

234

730-1

6 „

" From this table it is seen that the pluvial wind produces very
different effects indeed according as it descends an incline, or re-
mounts an acclivity. When it is descending it gives quantities of
rain almost equal at the very different altitudes of 440 and 252.
While, when it re-ascends, it sufl&ces to pass on the opposite bank, from
the level of 234 to the height of 301, for the quantity of rainfall to
increase 50 per cent. During the descent there is precipitated less
rain at the level of 252, than is precipitated in the re-ascent at the
lower level of 234 ; there falls twice as much rain on the re-
ascending acclivity, at the level of 549 metres, than falls on the
descending incline by which it came, at the level of 440 metres,
although the difference between the two altitudes scarcely exceeds
100 metres."

From what has been advanced it may be seen that in rainfall
determined by geographical position, the distribution of this is
greatly modified by the contour of the country. Bat this is not
done only in the way which has been referred to. M. Cezanne goes
on to say : — " The elevation of the ground acts in yet another way
on the distribution of the rain : altitude modifies the proportion of
rain falling in the different seasons of the year ; in this way elevation
above the level of the sea has the same influence as distance from the
coast. During summer the maximum of rain falls in places of con-
siderable elevation or distance from the sea, but during winter in

* L'Eveille : BecJierches, <&c.

DISTRIBUTION OF RAINFALL. 279

low-lying lands or places near the coast. And when one observes the
distribution of the rainfall over the ramifications of the same valley,
the phenomena become still more interesting. The basin of the
Seine is particularly suited for this study, since it is regular in form,
lai'gely open to pluvial winds, and more especially since M. Belgrand,
who has explored it in its every part, has made us acquainted with
his scientific investigations.*

" Near the sea, at the lighthouse of Fatonville, there falls annually
799 millimetres of rain. From this point to the valley of the Oise
the plateau maintains perceptibly its level ; in consequence of this
the quantity of the rainfall diminishes in proportion as the pluvial
current advances from the sea. The average sinks to 580 milli-
metres in the valley D'Oise, and to 575 '6 millimetres at Paris ; but
it re-increases from that point as the land itself rises : it amounts to
656 millimetres at Hirson ; towards the Ardennes, at the altitude of
196 metres ; and to 1570 millimfeti-es at the Settons, on the height of
the Morvan, where the altitude is 596 metres.

" It is remarked that it rains more in valleys than on elevated
plains, because the atmospheric current follows by preference the
deep depressions which cut up the plateaux, in the same way as on
the flat bottom of a valley levelled by an inundation, the current by
its tumultuous waves still marks out distinctly the line of the old

" But M. Belgrand, however, has established as a fact that the
pluvial current does not go up iudifierently every valley ; it passes
bye the valley D'Oise, and ascends by preference the valley of the
Seine, and by that of the Yonne, which in going up from Montereau
is a direct continuation of the first.

" Even at Paris the hill of Montmartre divides this current, which
bifurcates as does a river around a pier of a bridge ; the pluvial
wind passes by preference behind the hill, and La Villette receives
more rain than does Paris. Thus each valley receives more rain in
proportion as it is set towards the atmospheric current which brings
the rain."

Other observations not less interesting -are adduced by M. Cezanne,
illustrative of an influence on the distribution of the rainfall being
exercised by the contour of a country. '

In illustration of the same thing, M. Eaulin, Frofesseur <X la

* Belgrani ; Regime dc la pluie dans le basin de la Seine [annales des Fonts
et Chaui6es. 1865).

280 RELATION OF FORESTS TO THE

Faeulte de Bourdemix, has given the following note as a contribu-
tion to the researches of M. C6zanne : —

"In 1868 and in 1869 I established as a fact that in Northern
and Central Europe, and in Siberia, on to Kamschatka, there had
been a predominance of rain during three months of summer, the
more marked as we advanced farther to the east, while in the region
of the Mediterranean there had been a sparsity of rain during the
same season.

" It is interesting to investigate what is in France the pluvial regime
of the lofty chain which separates the two great orographic or
mountain-bound basins of northern and of southern Europe; and this
I shall now attempt to do by means more especially of observations
made by the Service des Fonts, et Chaussees, which the Tngenieurs en
Chef of the Alpine Departments have had the kindness to communi-
cate to me.

" It might naturally be supposed, a priori, the northern regime
having summer rains so copious and predominant on one hand in all the
plains of Switzerland, and on to Lyons ; and ou the other hand in the
Lombardo- Venetian plain of the Adriatic, on to that of Milan, — that
this regime would be continued in the equally cold high mountains of
the western branches of the Alps, which stretch from Mont Blanc in
the south to Nice and Draguigan ; but it is not so.

" In the high southern summits at the Great St Bernard, even there
the Mediterranean regime is deplored, and it is matter of complaint
that the rains of summer are scarcely two-thirds of those of spring,
which exceed somewhat those of autumn ; and this poverty of atmos-
pheric moisture in summer goes on progressingly increasing in pro-
portion as advancing from that northern station one approaches to
the Mediterranean.

" In the High Alps, at Briangon, the rains of spring prevail still
more, being more than double those of the summer ; on the other
stations of the department. Gap and Serres, and also at Die on the
Drome, the rains of autumn reach on an average double the measure
of those of summer.

" In the Lower Alps, at Barcelonnette, Digne, Castellane and
Manosque, the difference between the quantities of the rainfall in
summer and in autumn is still greater : it is the same on the
plateaus from Var to R^gusse.

" At Valences, at Yiviers, at Orange, at Avignon, the spring rains
still predominate, but they are greatly exceeded by those of autumn.

" On the coast from Marseilles to Toulon, Hy^ns and G6nes, the

DISTRIBUTION OP THE RAINFALL. 281

rains of spring are frequently less than those of winter, the quantity
of which is greatly exceeded by that of the autumn rains.

" The Mediterranean rec/wwe, thus characterised, clears the Appennines
and extends itself into the southern portion of the plain, from the Po
to Parma and to Guastalla ; but already at Bologne, and in the
northern part at Padua and Milan, and in Piedmont at Turin and
Yvr^e, the northern regime is again found characterised there as at
Geneva by a constant augmentation of the quantity of rain in winter
and in autumn,

"On the circumference of the western branch of the Alps, the pluvial
region presents a great difference, such as has already been referred to.
On the plain of Switzerland, and on its prolongation to the south-west,
from Zurich to the confluence of the Rhone and the Is6re, it is the
northern regime which most prevails, with a preponderance of summer
rain at Zurich, exceeded by that of autumn rains at Geneva, at
Chamberg, at Lyons, and even at Annonay and Tournon (Ardfeche).
But it is seen suddenly to change and to pass completely into the
Mediterranean regime in the valley of the Rhone, from the point at
which it passes the confluence of the Isere."

There is given a tabulated statement of observations made on the
coast of the Mediterranean throughout the year from 1851 to 1866;
on the basin of the Rhone from 1853 to 1860 ; and on the basin of
the Durance from 1856 to 1866 ; with the names and the altitudes
of the stations at which they were made, which gives evidence of the
facts stated. The stations included in the table, with the respective
altitudes are the following : — On the sea-border of the Mediterranean,
Marseilles, Toulon, Hyeres, Genes and Regusse ; in the basin of the
Rhone, altitude 40 metres. Valence 113, Lyons 295, Chamberg 305,
Geneva 387, Die 413, and Great St. Bernard 2491 ; in the basin of
the Durance, Manosque, altitude 370 metres, Digne 639, Serres 662,
Gap 740, Castelane 786, Embrun 870, Barcelonne 1173, and Brian-
9on 1305.

And M. Raulin goes on to say : — " As regards the quantity of rain
which, upon an average, annually falls on the ground in the Western
Alps, there are great diff'erences between difi"erent stations. That
of the Great St. Bernard, the most elevated, receives the greatest
quantity of water.

" In the High Alps, and in the Lower Alps, the quantity much
less considerable goes on, in general, increasing in proportion as the
stations are less elevated, as is also the case from Briangon to Die
(Dr6me) and from Bai'celonnette to Regusse (Var).

2h

RELATION OP FORESTS TO THE

iltitude in Metres.

Bainfall in

2491

Gt. St Bernard, ...

1239-1

1305

Brian^on,

684-6

1173

Barcelonette,

439-7

870

Embrun,

603-6

™3{ \%

Gap,

796-9

Castellane,

873-4

«»«{ '^

Serres,

706-4

Digne,

705-5

575

Regusse. " ...

993-3

332 { '^l

Die,

732-9

Manosque,

632-0

835-1
706

682-5

" Thus whilst in the Pyrenees the rainfall goes on increasing with
the altitude, it is rather (with the exception of the Great St. Bernard)
the reverse which is the case in the French Alps, which are more-
over much less rainy.

" The quantities of water which fall in the circumference of the
Alpine region to a similar extent show great diversities : almost the
same at Zurich and Geneva ; they increase at Chamberg, to diminish
at Lyons, Annonay and Tournon. Descending the Isere they are
greatest from Valence to Orauge ; and diminish greatly at Avignon.
On the sea board they are remarkably great from Mai-seilles to G^nes.
In Piedmont they are as great at Turin as in the valley of the Rhone ;
in descending the Isfere ; at Yvr^e they reach a figure much higher
than at the Great St. Bernard."

To this statement by M. Raulin there is appended a valuable note
of considerable length on the extent of what has yet to be learned in
connection with the theory of rain. The observations which have
beeu cited are advanced in proof of its not being the altitude of
localities irrespective of the contour of the country which determines
the quantity of rain falling there ; and they have been adduced here
solely in illustration of the fact that the contour of a country has
much to do with the disti'ibution of the rainfall.

There are countries in which rain rarely or never falls. In the Great
Sahara of Africa, says Sir John Herschel, rain is unknown ; as also in
Arabia and part of Persia, in the great desert of Geb ; in the table
land of Thibet, &c. ; while at Coitnbra, on the coast of Portugal,
there falls 118'8 inches of rain per annum; at Mahabalchwar, near
Bombay, there falls upwards of 254 inches ; at Uttray-Mallay, there
falls upwards of 267 inches; and at Cherra-Ponjee, 592 inches.

DISTRIBUTION OP THE RAINFALL. 283

Such a distribution of the rainfall is evidently attributable
primarily to geographical situation, and thus may it be with the
rainfall generally. But the observations of M. Cezanne and of M.
Raulin seem to show that irrespective of forests the distribution of
rainfall dependent on geographical position may be determined by
the contour of a country. And when, in view of this, we look to the
correspondence between the distribution of the rainfall which has
been adverted to, we see no necessity for concluding that it has been
the existence of the forests which has determined the corresponding
distribution of the rainfall in the places cited, as that seems to
exercise a much more powerful influence than this can.

Sect. III. — On the Distribution of Forests Affected hy the Distribution
of the Rainfall.

The general accordance between the distribution of forests and the
distribution of the rainfall on the earth's surface, detailed in the first
section of this chapter, naturally suggests, as has been stated, the
enquiry. Can they be consequences of some common cause? or is
this general accordance only an incidental coincidence 1 or are they
connected together as being one of them the effect of the other as
the cause or the occasion of its appearance? And if so which of them,
the distribution of the rainfall or the distribution of the forests, which
is the cause and which is the effect ] To what extent is the one the
cause or occasion of the appearance of the other ? and may not that
which may appear to be the effect have a reflex influence upon that
which appears to be the cause or occasion of the other ?

Such is the question raised, and I have adduced evidence to show
that the distribution of the rainfall dependent on geographical
position may be determined in a great measure by the contour of a
country, the elevation and the configurations of its mountains, its
valleys and its plains, irrespective of whether it be clothed with
woods or altogether devoid of these ; and in a preceding section
I have stated my opinion to be that the distribution of the rainfall
may primarily have determined the distribution of the forests, but
that the forests once established may have exercised an important
influence on the distribution of the rainfall.

It is stated by Mr Marsh : " There is good reason to believe that
the surface of the habitable earth, in all the climates and regions
which have been the abodes of dense and civilized populations, was,

284 RELATION OF FORESTS TO THE

with few exceptions, already covered with a forest growth when it
first became the home of man. This we infer from the extensive
vegetable remains — trunks, branches, roots, fruits, seeds, and leaves
of trees — so often found in conjunction with works of primitive ai't,
in the boggy soil of districts where no forests appear to have existed
within the eras through which written annals reach ; from ancient
historical records, which prove that large provinces, where the earth
has long been wholly bare of trees, were clothed with vast and almost
unbroken woods when first made known to Greek and Roman civiliza-
tion ; and from the state of much of North and of South America, as
well as of many islands, when they were discovered and colonized by
the European race.

" Whenever a tract of country, once inhabited and cultivated by
man, is abandoned by him and by domestic animals, and surrendered
to the undisturbed influences of spontaneous nature, its soil sooner or
later clothes itself with herbaceous and arborescent plants, and, at
no long interval, with a dense forest growth. Indeed, upon surfaces
of a certain stability and not absolutely precipitous inclination, the
special conditions required for the spontaneous propagation of trees
may all be negatively expressed and reduced to these three : ex-
emption from defect or excess of moisture, from perpetual frost, and
from the depredations of man and browsing quadrupeds. Where
these requisites are secured, the hardest rook is as certain to be over-
grown with wood as the most fertile plain, though, for obvious reasons,
the process is slower in the former than in the latter case. Lichens
and mosses first prepare the way for a more highly organized vegeta-
tion. They retain the moisture of rains and dews, and bring it to
act, in combination with the gases evolved Tjy their organic processes,
in decomposing the surface of the rocks they cover ; they arrest and
confine the dust which the wind scatters over them, and their final
decay adds new material to the soil already half formed beneath and
upon them. A very thin stratum of mould is sufficient for the ger-
mination of seeds of the hardy evergreens and birches, the roots of
which are often found in immediate contact with the rock, supplying
their trees with nourishment from a soil deepened and enriched by
the decomposition of their own foliage, or sending out long rootlets
into the surrounding earth in search of juices to feed them,

" The eruptive matter of volcanoes, forbidding as is its aspect, does
not refuse nutriment to the woods. The refractory lava of Etna, it is
true, remains long barren, and that of the great eruption of 1669 is
still almost whoUy devoid of vegetation. Bat the cactus is making

DISTRIBUTION OF THE RAINFALL. 285

inroads even here, while the volcanic sand and molten rock thrown
out by Vesuvius soon become productive. Before tlie great eruption
of 1631 even the interior of the ci-ater was covered with vegetation.
George Sandys, who visited Vesuvius in 1611, after it had reposed
for several centuries, found the throat of the volcano at the bottom of
the crater ' almost cholied witli broken rocks and trees that had falne
therein.' ' Next to this,' he continues, ' the matter thrown up is
ruddy, light, and soft : more removed, blacke and ponderous : the
uttermost brow, that declineth like the seates in a theater, flourish-
ing with trees and excellent pastui'age. The midst of the hill is
shaded with chesnut trees, and others bearing sundry fruits.' "

A.nd Mr Marsh adds in a foot-note : — " Even the volcanic dust of
Etna remains very long unproductive. Near Nicolosi is a great extent
of coarse black sand, thrown out in 1669, which, for almost two
centuries, lay entirely bare, and can be made to grow plants only by
artificial mixtures and much labour.

" The increase in the price of wines, in consequence of the diminu-
tion of the product from the grape disease, however, has brought
even these ashes under cultivation. ' I found,' says Waltershausen,
referring to the years 1861-62, ' plains of volcanic sand and half-
subdued lava streams, which twenty years ago lay utterly waste, now
covered with fine vineyards. The ashfield of ten square miles above
Nicolosi, created by the eruption of 1669, which was entirely barren
in 1835, is now planted with vines almost to the summits of Monte
Rosso, at a height of three thousand feet.' — Ueber den Sicilianischen
Ackerhati, p. 19."

I accept as probable the statements which have been cited in re-
gard to the tendency of trees and arborescent shrubs, in common with
other vegetables, to diffuse themselves extensively, and in the struggle
for life to retain possession of the soil ; but there are conditions
essential to their success in doing so, and one of these is an adequate
supply of water, not in excess, and varying with varying require-
ments. An excess of water may prevent vegetation, — it may pre-
vent germination, prevent vigorous growth, prevent the formation
of flowers and the maturation of fruit ; and a deficiency of water at
any corresponding critical period may have the same effects. There
are general laws in accordance with which is governed the distribution
of all vegetables, and the consideration of some of these laws may
make this manifest.

We may study the phenomena in the growth of mould as well as
in the growth of a forest, and find some advantage in doing so.

286 RELATION OF FORESTS TO THE

If a little decaying cheese, a decaying orange, and a decaying pear
be exposed to the air they may be found after a time covered with
mould ; and microscopic examination will show the three moulds to
be different each from the others. How may this be accounted for 1
Observation fails us ; we are thrown upon reason. Nobly have several
students of natural history endeavoured to extort from Nature an
answer to the question — How do germs first originate ? and Nature,
ever truthful, has truthfully replied to her questioners, but the reply
has always shown that the question was not so expressed as to elicit
by an explicit answer to it the information svhich was desired. It is
thus that I look at the experiments which have been made in con-
nection with what has conventionally but unscientifically been called
spontaneous genei'ation. And whilst awaiting patiently, and with
deep interest, the devising and application of a testing experiment—
which shall finally close all controversy — I take up the question I
have stated : How has the mould been produced, and that in three
difi'erent forms 1

There are three solutions of the problem which at once offer them-
selves ; and these are not necessarily antagonistic to each other : it
may be the case that each and all of them may be correct. It may
have been the case, for aught we know to the contraiy, that by
chemical action, or this in some one or other of its correlated forms,
the decomposed organic matters which were the subjects of experi-
ment have been resolved into the germs of these moulds ; it may, for
aught we know to the contrary, have been the case that there were
germs of mould floating in the atmosphere, which alighted on the
decaying cheese, orange, and pear, and there germinated, the difi'erent
forms they took being determined by differences in the conditions in
which they were placed on these difi'erent substances ; or it may have
been the case, for aught we know to the contrary, that germs of all
the three species of mould, and many germs of other genera of organic
structures were floating in the atmosphere, but of these only those
which found in the decaying masses an appropriate soil and con-
dition of growth germinated there, and grew and brought forth fruit.

These several suppositions are not necessarily antagonistic ; but
the last is the only one in entire harmony, — or, if that form of ex-
pression be deemed too sweeping, the one most in accordance, —
with what has been observed in regard to the difi'usion of more
highly organised vegetable forms.

It is of these I have to speak, and I employ what has been said not
as an argument but as an illustration.

DISTRIBUTION OF THE RAINFALL. 287

To allay suspicions and fears which may arise in some minds, but
which I consider groundless and unnecessary, I may state that the
underlying question does not relate to the existence of what may be
called a personal Creator, though that question may legitimately be
engrafted upon it ; but it relates solely to the mode of creation — the
wonderful workings of the Creator in clothing the earth with diversi-
fied forms of vegetation ; and further, that it takes not up the
question of evolution and development, which has disturbed many
of the Christians of our day — as did the discovery of the earth's
motion, by Galileo, disturb many of the Christians of his day, — but
it takes up only the question of the distribution of existing species of
plants, in whatsoever way these have been produced.

We do not find the pear mould growing on the cheese, nor the
cheese mould on the orange, nor the orange mould on either. Each is
confined to it own habitat. Neither do we anywhere find all kinds of
plants growing intermixed on the same bank. In diff"erent places we
may find many different kinds of plants growing intermixed, but the
plants so intermixed in their growth are different in different places.

There are some plants which are widely distributed. With others
it is otherwise, they are confined each to some one locality. Of the
former, we have examples in the silver weed (Potentilla anserina),
in the goosegrass or cleavers (Galium aperine), in the square-stalked
willow herb ( Eiyilohiiiin tetragonum), in the water starwart (Calitriche
verna), and in the daisy (BelUs perennis); of the latter, we have
examples in the Scottish primrose (Primula Scottica), which is found
only in the north of Scotland and the Orkneys, in the Pride of
Table Mountain (Disa grandiflora), which is found only on the
mountain at the Cape of Good Hope, whose name it bears, and in the
Kerguelens-land cabbage (Pringlea antiscorhiitica), which is found
growing on an island most remote from any continent, and which,
besides this esculent, yields only seventeen other flowering plants.

Again there are some plants which you never find excepting near
the sea ; others which you never find excepting on marshy ground ;
others which you never find but in Alpine regions. There are some
plants which are never found growing wild excepting in the tropics,
and others which cannot be reared there even hy artificial culture.
There appear to be, at least, three determining conditions of the
distribution of plants : heat, moisture, and soil. I say, at least three,
for I think there are others, such as atmospheric pressure, &c. ; and
the modifications of these three, and the combinations of these

288 BELATION OF FORESTS TO THE

supply an indefinite variety of conditions only some of which will
secure the germination, fructification, and continued reproduction of
any one or more kinds of plants.

Seeds are dispersed widely by the wind and rivers and ocean
currents, by man and bird and beast ; but in order to germination
there is required for each, within a definite range, heat and moisture
and shade ; in order to growth there is required, it may be, some
other measure not less definite of moisture and heat and sunshine,
and along with these a soil containing certain constituents for each,
in a definite state of disintegration, and in definite states of combina-
tion ; in order to the flowering, and again in order to the fruiting, and
yet again in order to the conservation of the seed in the soil, on until the
period of germination, there are required a succession of definite
varying measures of heat and sunshine and moisture : the range of
each may be more or less considerable, but still it is limited by ex-
tremes beyond which it cannot pass without fatal effects to the re-
production of the plant.

If the seed have decayed before reaching the spot where it finally
rests, if there it be eaten by bird or beast, or if the germ be destroyed
or be consumed by some insect, it will never germinate. If through-
out the various stages of growth and reproduction which I have
referred to, and the intermediate stages connecting these, there be at
any time too much moisture, or too little, too much heat or too
little, too much sunshine — for the effect of this is not confined to
the production of heat alone — or too little, the plant — be it herb, or
grass, or bush, or tree — will not be reproduced ; and be it noted the
definite measure of heat and moisture and sunshine are not the same
throughout but vary in a definite order of pi-ogression ; and should
these fail at any subsequent period, at any point of the progression,
this will be fatal to the continued reproduction of the plant, be it
grass, or herb, or bush, or tree.

Did occasion serve I could produce illustrative cases in point.

And it begins to appear that if, when the seed of a tree was borne
to any spot by the winds, or by the waves of the sea, or by the cur-
rent of a stream, or by bird or by beast, there was on that spot
either excess or deficiency of moisture the seed would not germinate.
Other pre-requisites there are, but with these others these. To many
seeds the stagnant pool and the arid sand would be equally fatal, but
the rainfall evaporating and draining off by infiltration and ruisselle-
ment all in excess of what the soil could retain by its hydroscopicity
and capillary attraction, would supply the very amount of humidity

DISTRIBUTION OP THE RAINFALL. 289

required. But fresh supplies varying in quantity with the requisites
of the seedling, the sapling and the tree, and with the requisites of
the tree at the period of flowering, of the setting of the fruit, of the
maturing of the fruit, and of the casting of the seed, are needed. These
the parched land could not supply, neither could the snow covering
the mountain summit, nor the marsh in the valley below, though the
rain falling on the mountain side, with its excess drained off before
it could damage, and its supply from time to time renewed, might to
some extent determine the primary distribution of forests clothing
the mountain side ; and while other kinds of trees perished there,
they might find the conditions of their growth in the moister land
below, kept moist by the rainfall, and the drainage of the rainfall,
from a higher level, or on the banks of streamlets and rivers fed by
this rainfall and dependent thereon for their continuous flow.

We need not to take up, in connection with this subject, the
question, Whence come the seeds ? But there is another question,
nearly akin to this, which suggests itself, and which finds in con-
nection with the subject under consideration a ready answer : Might
not other seeds besides those producing the forests also find their way
thither 1 They might and so might seeds of trees ; find their way to
plains where grow only herbs and grass ; and where now grow the
trees there may grass and herbage, as well as moss and fern have
formerly flourished ; and on the arid plains seedling trees may have
appeared again and again but only to perish in all the leaves of their
spring. And to the rainfall may be attributed the limitation as well
as the determination of the distribution of each.

It has been intimated by a writer, quoted in the preceding section,
that much depends on the distribution of rain in time as well as in
space.

From what has been advanced we may infer that of the seeds of
grasses, of herbs, and of trees alike, falling anywhere, like the mould
germs alighting on the cheese, the orange, and the pear, those only
which found there all the appropriate conditions of germination, growth
and reproduction would there flourish and be reproduced, and any
failure of the requisite conditions, occurring at any time, would
prove fatal to them. An appropriate supply of moisture is one of
those conditions. Under artificial culture we may see a plant damp
ofi", turnips braird but never come to maturity, and a seeding tree
perish from drought : thus may seedling trees have perished on the
plain, a consequence of the distribution of the rainfall, and in the

2i

290 RELATION OP FORESTS TO THE

account which has been given of the geographical distribution of
forests in India, mention is made of forests near the bed of a river
frequently perishing, through that river changing its course ; all of
these are occurrences indirectly connected with the distribution of
the rainfiill. But while the trees perished, the herbage and the grass
flourished ; and it is the converse of this which we see in the growth
of the forest, where, it may be, lichen and moss, and fern and sedge,
and grass and herbage, had successively, alone or conjointly, held
for a time exclusive possession of the field.

In further elucidation of this subject it may be mentioned that by
many it is held that, apart from all that has been alleged in regard
to evolution and development, there is a natural succession of plants
following each other in the occupation of the same ground, the homo-
logue of the natural succession of animals which have inhabited the
world, specified in Genesis as water animals and winged fowls, cattle
and creeping thing, and beast of the field and man, — and a struggle
for the possession of it between plants and possession by immigrants :
the homologue of man's replenishing the earth and colonising with
immigrant families lands previously peopled by other races And
both in connection with the natural succession and with the succes-
sion by immigration the distribution of rainfall has its function.

It is frequently alleged that the order of natural succession is some-
thing like this : the germ of a lichen, falling upon a rock or stone, it
may be, being moistened by rain, or dew, or a little water lying there,
germinated, produced other germs, and died. Some generations did,
it may be, the same, produced other germs, and died ; subsequently,
it may be ages later, the germ of a moss, or of some other more
highy organised vegetable structure, fell there, and found in the
remains of decayed lichens a soil and the conditions favourable to its
germination and growth and reproductiun, and more favourable to its
continued reproduction than to that of the lichen, and ultimately it
obtained and maintained exclusive possession, it may have been for
ages, until some other germ or seed of some vegetable holding a still
hio-her position in the gradation of organic structures — a fern, it may
have been, a grass, a daisy, or some other herb, or all of these in
succession fell there, until at length on the accumulating soil there
appeared in succession, or in contemporaneous growth, a mass of
mixed and tangled vegetation, requiring only to be subdued by man
to make the soil composed of mineral constituents and decomposed
organic matter bring forth " fruits of increase" and " herbs meet for
them by whom it is dressed."

DISTRIBUTION OP THE RAINFALL. 291

I do not like the expression " struggle for possession " being applied
to vegetation ; I prefer making use of the corresponding expression,
" survival of the fittest ;" bnt the expression " struggle for possession "
has come into more general use.

In illustration of what has been likened to a struggle for possession
between immigrants and earlier settlers, let me refer to what may
sometimes be seen, in our own day, on a flowery bank of one of our
hedge-rows, or by the side of a country walk. Let it be supposed
that the case is one in which the flowers consist mainly of dog violets
and of pausies in equal proportion. Any other plants would equally
serve for illustration ; these are selected of design. If such a bank
were revisited, after some years of absence, it might be found as
flowery as ever ; but the flowers would not be all of the same kinds,
in the same proportion, as bsfore. Amongst other changes, it may be
that either the pansies or dog-violets would have disappeared, and
the species remaining would be more numerous than either were.
By transmutation or development 1 Oh, no ! not at all ; but thus :
the soil exposure, heat, and moisture could scarcely fail to be more
adapted to the requirements of the one than to those of the other :
in an infinitely minute degree it might be, but still the difference
was there ; and even if the quantity of seed cast by each plant
should have been precisely equal, this infinitely minute diS'erence of
adaptation would sufl&ce to bring about the change.

I shall magnify the effect to make it more apparent. If there
were a hundred plants of each when first observed, in the year
following there might be 105 of the one and only 95 of the other;
in the year after there would be the progeny of 105 plants of the one
and the progeny of 95 of the other less favourably situated species,
and this might present us, not with 110 of the one and 90 of the
other, but perhaps 112 of the one and 88 of the other; and the dis-
proportion in years following would go on increasing in a corre-
sponding accelerating ratio. And indications of something like this
having occurred in forests have been observed : a forest of mixed
trees giving place to one of uniform production. And thus may the
successions have occurred, while the seeds of trees which had not
germinated lay dormant, awaiting their time to germinate whenever,
in the changes accompanying progressive desiccation, the dominating
trees should succumb, and they be able with greater success to take
their place.

From a work by Vaupell we learn that the earlier forests of Den-
mark were composed of birches, oaks, firs, aspens, willows, hazel and

292 RELATION OF FORESTS TO THE

maple, the first three being the leading species, but these have now
been succeeded by the beech, which at present is the tree which
greatly predominates. It is a tree more inclined to be exclusive
than any other broad-leaved tree, but it is being encroached upon
again by the fir. And is there not a cause 1 There is ; and Vaupell
seems to consider that man is unconsciously — and to his own dis-
advantage— helping forward the encroachment of the Goths and
Vandals on the nobler races at present in possession. And the views
advanced by them may subserve our present aim.

In regard to the removal of fallen leaves he remarks : — " The
removal of the leaves is injurious to the forest, not only because it
retards the growth of trees, but still more because it disqualifies the
soil for the production of particular species. When the beech
languishes and the development of its leaves is less vigorous, and its
crown less spreading, it becomes unable to resist the encroachments
of the fir. The latter tree thrives in an inferior soil, and being no
longer stifled by the thick foliage of the beech, it spreads gradually
through the wood, while the beech retreats before it aaid finally
perishes." And in connection with this he adverts to the fact that
" The leaves belong to the soil. Without them it cannot preserve its
fertility, and cannot furnish nutriment to the beech. The trees
languish, produce seed incapable of germination, and the spontaneous
self-sowing, which is an indispensable element in the best systems
of sylviculture, fails altogether in the bared and impoverished soil."

Thus may the succession of firs to beeches, if it should ultimately
occur, be satisfactorily accounted for. And in a corresponding way
may some of the previous successions of difierent kinds of trees be
accounted for : I say not in the same way but in some corresponding
way ; and in some corresponding way may much of the grass and
herbage which previously covered the forest ground have given way
to the forest trees, not because the conditions were absolutely un-
favourable to them, but because being also favourable to the growth
of trees, and perhaps comparatively more so, or otherwise simply in
virtue of their more sturdy constitution, these having gained a footing
maintained it, and the others were overpowered. Now one of the
conditions determining this was a particular distribution of the
rainfall both as to time and space, which was essential to the
growth of the trees which then existed, and but for whch the grass
and herbage would have been left in undisturbed possession.

Such is in part the eSect of the distribution of the rainfall on the
distribution of forests.

DISTRIBUTION OP THE RAINFALL. 293

Sect. IV. — On the Local Effects of Forests on the DistriUition of the
Rainfall ivithin the Forest District.

While the primary distribution of forests appears to have been
determined by the general distribution of the rainfall, forests appear
to influence the subordinate distribution of the rainfall, both in time
and space, over the forest district ; and irrespective of this, though
connected therewith, they exercise an important influence on the
disposal or distribution of the rainfall within the district in which
they exist.

The most manifest of the eff'ects of forests on the rainfall is that
which they exercise upon the distribution of it after it has fallen.
Of the water which falls as rain a portion is evaporated, a portion is
absorbed by the ground, and a portion immediately flows back again
toward the sea ; each of these is the complement of the others, and
their proportions vary under varying conditions; previous to the
growth of forests the rush was impetuous ; subsequent to the growth
of forests it is restrained. What was then allowed to run to waste,
like the extravagant expenditure of the prodigal, is now husbanded,
as is the income of the typical pater-familias.

C6zanne, speaking of the whole series of phenomena brought under
review by him in treating of this eff'ect of forests in connection with
geological changes, says in a passage I have cited in a volume on
" Keboisement in France " : — .

" There may be given in a few words a resume of the whole series
of these phenomena.

" The mountains are the result of a series of upheavals following
one upon another in the same region. A final agitation gave to the
different chains of these the existing elevation ; it elevated the
summit and opened up deep fissures or divisions, which have become
the valleys of the present time. From the time this occurred the
waters began to fashion the thalwegs, following the line which best
suited them ; wearing down outlets and filling up basins. It is
necessary to admit, or to assume, that the depth or thickness of
the alluvial deposits in the bottom of certain valleys — for instance,
those of the Isfere in the Graisivaudan, or of the Rhine in Alsace, — is
to be reckoned by hundreds, and perhaps by thousands, of metres or
yards ; for even yet certain lakes existing in depressions of the Alps
have their bottom below the level of the sea.

" After a long series of ages the mountains assumed the leading

294 LOCAL EFFECTS OF FORESTS

features which they now exhibit, when, the climate changing, great
glaciers carried on actively the work of erosion ; these have planed
away escarpments, and fashioned into something like horizontal lines
the rocky belts of the valleys.

" Debdcles, or inundations, from the escape of the waters of pent-
up lakes, and deluges resulting from the tremendous rains of summers
on the extensive fields of ice, have carried away and deposited in the
principal valleys in certain favourable places, but more especially at
the debouches of lateral gorges, the masses of loess which have
formed cones in the higher plains, and in which the water-courses
have subsequently dug out the secondary valleys.

" At a later period, after the melting away of those glaciers, the
torrents seized upon the bared mountains ; and without restraint they
have dug out their basins, and have again taken up the materials
disintegrated by the glaciers, and deposited these in the gigantic
cones which give to certain regions a physiognomy peculiarly their
own.

" But after a time the forests, spreading by degrees, stifled the waters
under a mantle of verdure ; the torrents became extinct, — an ei-a of
peace and of comparative quiet supervened in the mountains ; then
the tribes of men, who during the glacial period rambled over the
low-lying plains, in company with the reindeer, the aurochs, and the
bears, began to spread themselves in the high-lying valleys. The
most ancient settlements were made at the gorges of the torrents,
towards the summit of the cone ; in point of fact, there are to be
found in the mountain valleys very few of these gorges in which we
do not meet either with an existing village or with an ancient ruin.

" In this location, which was then one favourable to their pursuits,
the primary inhabitants could profit by the exceptional fertility of the
cone of deposits ; they had nothing to fear from the principal river,
which flowed through the lower-lying lands, nor from the torrent,
which was then extinct; they commanded the plain, and found
themselves at the gate of the mountains ; the adjacent gorge
supplied them with water, the forest supplied them with wood, the
rock supplied them with stone, and their flocks spread themselves
over the verdant ridges around them.

" Little by little, a reckless use of the forests and of the pasturage
disturbed the equilibrium of the natural forces; and now the old
sore is re-opened, and anew, by man's deed, the mountains are
inoculated with the leprosy of the torrents. The evil has gone on
increasing during prolonged ages of disorder and recklessness; the

ON DISTRIBUTION OP THE RAINFALL. 295

position of the cultivated grounds, and of the villages established at
the debouches of the torrents, has now become critical in the extreme ;
and unless we go back, as we have done, to the olden times, we are
unable to account for men having taken up their dwelling in the
spots, of all others, which at this day appear to be those which are
more immediately threatened.

" But at last an era of reparation begins ; and, thanks to the
eminent men who have in bygone years given their mind to the
work, the next generation may hope to see the final decline of the
modern renewed Torrential Era."

Views similar to the views thus advanced by Cezanne are advanced
by Costa de Bastelica, with this difference that he considers even the
mounds of detritus attributed to glaciers have been also the products
of torrents, which have become extinct under the effects of the
forests.

In illustration of how the forests may have opei-ated, in those pre-
historic times, in arresting the flow of the rainfall, I adduce the
following, the type of many others which I have brought forward in
the volume referred to. It is from a paper which appeared in Revue
des JEaux et Forks, for April 1866.

" The State possesses, in the department of Vancluse (says the
Forest Conservator, Labuissi^re), a forest of more than 3000 hectares,
situated on a portion of the mountain Luberon nearest to the valley
of the Durance. This region is very much cut up, and traversed in
all directions by very narrow and deeply embanked ravines in the
midst of masses, more or less dense, of Aleppo pines and green oaks.

" These ravines are almost the only outlets for the transport of
woods, in consequence of the difficulties which would be encountered
and the expense which would be incurred in making more practicable
ones on the rapid declivities, strewn with enormous masses of rock.
There exists one so situated, called the Ravine de Saint-Phalez.
The direction is from north to south, in the midst of a mass of Aleppo
pines in a state of growth more or less compact.

" Its length, and for four kilometres, or from the road from
Cavaillon to Pertuis, to the domain of Saint-Phalez, of an area of
about 50 hectares, forms the hassin de reception of the torrent.

" This land is well cultivated ; there are no declivities too steep for
cultivation ; it comprises vineyards, meadows, and arable land ; the
soil is argillaceons

"The ravine of Saint-Phalez receives many affluents, the most

296 LOCAL EFFECTS OF FORESTS

important of which is that of the Combe d'Yeuse, which joins it near
the summit, where are some hundred metres of the cultivated grounds
of which I have spoken.

" The Ravine de la Combe-d'Yeuse is of much less considerable
length than that of Saint-Phalez ; it is scarcely two kilometres. It is
strongly embanked, surmounted by steep declines, covered with green
oaks of eight or ten years growth and with Aleppo pines of different
ages. Its bassin de reception, of about 250 hectares (or 113 acres),
comprises the whole slope, pi-ecipitately inclined, with a general
southwest aspect ; it is closed at the top by a deep bed of rock cut
into peaks of the most imposing aspect.

" The geological formation is absolutely the same, as are all the
other conditions, at all the points which I have examined. In no
part is to be seen either spring or appearance of humidity ; no water
is seen excepting at the time of storms or great rains, and this water
soon passes away, with the differences which will afterwards be men-
tioned. At all other times these ravines are of a desolating aridity.

" In the night of the 2d or 3d of September, 1864, there fell a
rather abundant rain over all this portion of the mountain. In the
morning the argillaceous grounds of Saint-Phalez were saturated, of
which evidence was found by anyone attempting to cross them. The
ravine of Saint-Phalez, the receptacle of the surplus water, had flowed
but slightly ; that of the Combe-d'Yeuse remained dry.

" The day of the 4th September was very warm ; a water-spout
borne along by a southwest wind struck on the Lnberon. Its passage
did not last more than forty minutes ; but scarcely had it come when
the torrent of Saint Phalez became awful. Its maximum delivery
was about two cubic metres. It did not flow more than fifty minutes,
but with an average delivery of half a cubic mfetre ; it had then
passed in all 15,000 cubic metres of water; its height had been
0*04"*. Each square metre had received 40 litres, and the 50 hectares
of Saiut-Phalez 20,000 cubic metres. The ground had only retained
5000, which is sufficiently explained by their argillaceous character
and their state of saturation the night before. But while the torrent of
Saint-Phalez flowed, filled from bank to bank, seizing and carrying off
rocks which had been employed to form a road which was believed to
be safe against all contingencies, that of the Combe-d'Yeuse and all
those traversing wooded lands remained dry, or gave only an insignifi-
cant quantity of water.

" On the slope opposite to that of which I have been speaking, in
the valley of the Peyne, a carriage-road newly formed did not ex-

ON DISTRIBUTION OF THE RAINFALL. 297

perience the least injury throughout the whole of the portion of it
passing through tne forest of the domain ; but at its issue, on the
lands of the Libaude and of the Roquette, it had been, so to say,
destroyed. A cart loaded with faggots was upset and smas hed by
the waters, which flowed from all the cultivated slopes, and tore
along, with the noise of thunder, at the bottom of the ravine.

" My good fortune secured to me another subject of study on the
same ground.

" On the 25th October following I went to the sale of the fellings
of the Tarascon, where there fell an abundant rain. The next day
(the 26th) the weather was clouded. I set off for the Luberon in the
hope of arriving there at the same time as would a storm of rain
which I saw approaching. I arrived first ; the ravine of Saint-Phalez
was still moist, from the passage in small quantity of the waters of
the night before ; they had served, as appeared, to saturate the
lands of the domain, as had previously happened on the 7th [3rd 1]
September.

" I had scarcely gone over two kilometres in the ravine when the
water began to rush with great violence ; ten minutes later it pre-
cipitated itself in its ordinary canal d'ecoiilement, completing the
work of destruction begun in the month of September. The lands of
Saint-Phalez had then absorbed but little or none of the water that
day.

"The storm was not of long duration — an hour at most. The
time was unfavourable for collecting on the ground exact measure-
ments, but I reckon that the torrent delivered, at its maximum,
somewhat less water, perhaps, than on the 4th of September. The
flood, however, was more frightful ; it swept away rocks with so
much the greater ease that nothing had been repaired since the first
storm, which had left the stones dag out, and without bond of co-
hesion among themselves.

" To gain the forester's house, which was on the slope of the left
bank, it was necessary to mike a long circuit — to go round the
domain of Saint-Phalez, and to cross the grounds belonging to it, in
which one sank to the depth of 0 30 metres, or twelve inches. Before
arriving at my home I had still before me the ravine of the Comba-
d'Yeuse, and I feared I should be stopped there by a new obstacle.
I was agreeably surprised to find it dry. An hour after the storm
the ravine of Saint-Phalez had ceased to flow.

" It rained throughout the whole of the 2Sth without there bein»
anything to remark similar to what had happened on the preceding

2k

298 LOCAL EFFECTS OF FORESTS

davs. The only effect of this was that, on the evening of the 30th,
near the forester's house, and at 200 or 300 metres from the ravine
of Saint-Phalez, there was seen coming down, in that of Yeuse, a
small fillet of clear water ; its volume increased perceptibly during
three days, to diminish in like manner during the two which followed;
its passage broke down a little of the foot-path which goes along the
valley, but caused only a damage easily repaired. This foot-path did
not present the same solidity of structure as that of the Combe de
Saint-Phalez, built on enormous blocks of rock which had stood for
several years, and which had allowed of passage with a waggon some
days before its destruction by the storm in September. If the
Combe-d' Yeuse had yielded as much water as that of Phalez, and if
these two masses of water had come at the same time, the damage
caused in the plain would have been considerable, and the Durance,
which received these waters, would have been so much the larger.

" Thus we have two torrents very near and under the same condi-
tions— except that the basin drained by the one comprises 50 hectares
of cultivated lands, that of the other 250 hectares of woodlands. The
first receives, and allows to flow away, the waters of the greater part
of a storm in a few hours at most, causing thereby considerable
damage ; the second, which had received a greater quantity of rain,
stores it — keeps it for two days — evidently retaining a portion of it,
and takes three or four days to yield up the surplus, which it does in
the form of a limpid and inoflfensive stream."

A question in connection with this subject, which excites much
general interest, is — Do woods and forests increase the quantity of
the rainfall] "We have had testimony to the affect that in certain
conditions they increase the quantity of the local rainfall ; there is
no evidence that in consequence of this there is a diminished rainfall
elsewhere, and if there be not it follows as a consequence that they
do increase the rainfall, though it should be found that they do so
only by causing the same material to fall again and again in the form
of rain ; but the increase, whether tested by local observations care-
fully couducted as were those of Mathieu, and of which have been
cited, [ante p. 64] or by more general observations carefully collected
as were those discussed by Mr Draper, [ante p. 100] appears to be very
trifling ; and when there are brought under consideration such features
of physical geography as are referred to by Cezanne and by Costa de
Bastelica, and attributed to torrents occasioned by the rainfall previous
to the regime of forests in the locality, it may well be doubted whether

ON THE RAINFALL. 299

the amount of rainfall all the world over has not been diminished rather
than increased since was issued the fiat : Let the earth bring forth
grass upon the earth — the herb yielding seed, and the fruit tree
yielding fruit after its kind whose seed is in itself.

I have quoted the statements of Herr Wex in regard to the local
effects of forests on the rainfall, given in his treatise on the " Diminu-
tion of Water in Streams and Rivers, with the increase at the same
time of occasional inundations in low-lying agricultural districts. "

The Commission appointed by the Academy of Science at Vienna,
appointed to consider that treatise and to report, reported in regard
to the effect of forests on the rainfall as follows : — " The influence of
forests on the quantity of the rainfall is a subject which has engaged
the attention of many naturalists. From many different points of
view has this influence been discussed, the discussion being founded
partly on theoretical considerations, partly on the altered climatal
conditions of country in which forests have been destroyed.

"In connection with theoretical considerations it has been ex-
tensively maintained that forests arrest the floating clouds, as do
mountain ranges opposed to a current of clouds, and like these occa-
sion a condensation of moisture ; and further that by the relatively
lower temperature prevailing in a forest than in the open country, thus
occasion a precipitation of that moisture in the form of rain ; and in
reference to this point more especially has Dr Berger in Frankfort
devoted attention to the difference in favour of rainfall in the
temperature and condition of moisture in the forest, in comparison
with these in the open country.

" It is on the whole probable that some such influence is produced
by forests ; but perhaps on the one hand the importance of this in-
fluence has been over-estimated ; and on the other hand there is a lack
of direct and decisive proof as to the effect ; as the pluviometrical
observations made for this purpose in stations within and outside the
forests extend over too short periods, and to some extent have been
made in conditions or circumstances which do not admit of strict
comparison, such as the difference in condition at different eleva-
tions, inclinations, and exposures in difierent directions, &c.

" From the great importance, in the interest of agi-icultui-e, of the
alleged diminution in the rainfall, the Scottish Meteorological Society
decided, in 1859, at the request of their president, the Marquis of
Tweeddale, to offer a prize for an essay on the question, Whether any
change had occurred in the quantity of rainfall in the west of Europe.

300 EFFECTS OF FORESTS

The successful essayist, Mr F. H. Jamieson, found in the observations
of the rainfall over extended periods, to which he had access, no
reason to conclude that there had been any progressive diminution in
the rainfall ; local oscillations alone were apparent, and the causes of
these it would be difficult to determine.

" This essay gave occasion for the institution of other similar in-
vestigations ; and also for the establishment, through the British
Association for the Advancement of Science, of a number of stations
for the observation of the rainfall in different parts of Great Britain
and Ireland. And a committee was appointed by the Association to
give attention to the subject.

" Mr G. J. Symons, in London, undertook the inspection of the
stations and the collating of the observations reported.

" Observations made at several stations in England and Scotland?
of which Mr Symons was enabled to avail himself in the investigation,
extended back to 172G.*

" Thanks to the observatory at Paris, we have still earlier observa-
tions, carrying us back to the year 1688.t

" According to observations made in England and in France there
is no evidence of a diminution in the annual rainfall ; but on averages
of ten years there are seen differences in the quantity of the rainfall,
the causes of which have not yet been determined.

* He gives iu tbe Report of the British Association for 1866, by means of registers
received from seventeen stations, the following data iu regard to the rainfall in England
in proportional measurements :—

Period. Proportional measurement.

1726-1735 9^"^ l 86-7

1736—1745 78-7 >

1746-1755 'S'^ I 83-5

1756—1765 88-2)'

1766—1775 103-6 \ gg.^

1776-1785 93-2 >
1786-1795

Period.

Proportional mea^surement.

1806—1815

9^H99-3
103-9 J

1816-1825

1826-1835
1836-1845

lO^-HlOO-8
100-2 J

1846-1855
1856—1865

26-3 i

"^■6 I 93-2
1796—1805 89 7 i

f In the Annuaire meteorologiquc de V Ohservatoire physique central pour 1873, Marie
Davy gives the following calculation of the annnal ramfall at Paris :—
Period. Average in millimeires.

1688—1700 517

1701—1710 481

1711—1720 465

1721—1730 378

1731—1740 411

1741—1750 420

1773—1780 540

1781—1790 507

Period.

Average mm.

1791-1798

413

1804—1810

518

1811-1820

496

1821—1830

514

1831-1840

507

1841—1850

529

1851—1860

520

1861—1870

493

ON THE RAINFALL. 301

" It would be rash to conclude, from the fact that no permanent
change in the direction spoken of has been proved to have occurred
in the west of Europe, that no alteration of the kind has taken place
in the interior of the continent ; and there are certain pluviometrical
records made at continental stations which do not indeed go so far
back, bat which also, so far as they go, ai*e not unfavourable to the sup-
position of some such diminution having occurred.*

" Blodget arrived at a similar conclusion from an examination of
pluviometrical observations in North America ; although the destruc-
tion of forests had been carried out there to such an extent that a
change in the rainfall might have been expected.

" In reference to the older observations of the rainfall we must
observe that their value is very much diminished by the circumstance
that the observations were not made every day, but sometimes at long
intervals ; besides which, the rain-gauges were often placed in unsuit-
able localities, as on roofs and on towers, &c. Both of these circum-
stances would produce an effect in the same direction, giving returns
of less than the actual rainfall at the time at which ^they were
made.-

" In view of all the facts of the case, although the actual measure-
ments of the rainfall, extending back for 200 years, cannot be adduced
as evidence of any progressive diminution in the quantity of the rain-
fall, it would not be right to attach no weight to the facts brought
forward by the author, more especially from Milne Home's paper in
the Journal of the Scottish Meteorological Society, (vol. III. p. 35)
from Becquerel, (Atlas meteor ologiq^iie de V Observatoire de Paris, pour
1867) and from a great many other sources, which tend to prove a
deterioration in climate to have taken place in consequence of the
extensive destruction of forests.

" The Commission agrees with him in considering thai it is pro-
bable, forests have an i?ijluence on the quantity of the rainfall, and
especially on the distribution of the rainfall over the year, although
the direct observations in our possession do not as yet seem sufficient
to determine the extent of that influence."

I am quite aware that there are facts recorded which appear to

* In the Imperial Central- Amtalt fiir meteorologie have the obervations in abou*
120 stations in Europe and North America, been examined on this point.

*0n the effect of altitude on the returns of the rain-gauge there are numerous state
ments. In Mijllendorfs works (p. 102) it is shown that at different stations the lower
rain-gauge received from 13 to 60 per can',, mora rain than on a higher place one did,

302 DISPUTED EFFECTS OF FORESTS

point to a different conclusion from that which is thus announced.
But I have to say in reference to this, that it was implied in or covered
by the instructions given to the Commission to consider this matter
and to report ; and further, that I find no difficulty in accounting
for any of the apparently conflicting facts referred to, without com-
promising the conclusion arrived at by the Commission, and I know
of numerous facts in accordance with that conclusion.

M. E. Renou, in a paper entitled Theorie de la pluie, which ap-
peared in the Annuaire de la Societe MeUorologique de France (t. xiv.
p. 89, 1866), writes : — "When it is seen that the rain depends as its
condition on great atmospheric movements, and is only modified by
the principal accidents of soil, mountains, and seas, what influence
can the cultivation by man, and more especially the forests, have
upon this phenomenon ? A generally-existing opinion attributes to
them an important influence on the distribution of the moisture pre-
cipitated from the atmosphere ; but this opinion, which is purely
theoretic, has absolutely no foundation : there never has been cited
in support of it a single indisputable observation, and if in certain
lands, as Algeria, it rains more on forests than on the lands devoid
of these, in attributing to them an influence on the rain this is only
to confound the effect with the cause. The rainfall follows in a striking
manner the relief oi the soil, and forests appear nowhere spontaneously
excepting where there is a sufficiency of rain. This observation is
applicable to the analogous cases cited by M. Boussingault in America,
It is precisely at the line of contact of the bare regions and the
wooded regions near the limits of the natural growth of woods that
this can be remarked ; these forests do not generally receive sufficient
rain for them to grow everywhere, and they are found only there
where the position and arrangement of the mountains permit the soil
to receive the greatest quantity of water.

" Charts representing courses followed by storms of rain and storms
of hail do not indicate the least deviation from their course in the
vicinity of forests. The celebrated hail-storm of the 13th June 1788
has long ago shown this to be the case ; it followed a line almost
straight, absolutely independent of what was seen on the soil
beneath it.

" The opinion in regard to the influence of forests on rain is just
like all prejudices : it has been repeated for a considerable length of
time without having the least proof. In my opinion, man has not
the least influence on natural phenonena. Formerly, it was sought
to connect meteorological phenomena with dominant local influences ;

ON THE RAINFALL. 303

but, ia proportion as the study of them extended, the magnitude,
grandeur, and general character of atmospheric phenomena came to
be recognised,"

In citing these views of M. Renou I am citing what has been cited
in France with approval ; and there is much in them with which I
agree, but this so combined with much with which I do not agree
that I am almost glad to have the opportunity to • state wherein we
differ.

I have given evidence of my belief that the primary distribution of
forests is attributable to the previous geographical distribution of the
rainfall; but I consider that this is not incompatible with their
exercising an influence on the subordinate subsequent distribution of
the rainfall within the district in which they have grown : in
other words, that while the primary distribution of forests appears to
have been determined by the rainfall, once established, they may, and
they do, exercise a manifold influence on the rainfall. Sinbad's
adventures with the Old Man of the sea, and ^sop's fable of the
horse being saddled and bridled by man, have made us acquainted —
many of us while yet young, acquainted — with the principle that con-
sequences may flow from an action which were not anticipated when
that action was performed. The Spaniards have a proverb to the
effect that Whoever gets a wife gets a master. The Scotch have
another version of the same proverb which is not less pat : their
version of it is — Whoever gets a man gets a master. And in many
lands it is seen that a family often produces on both of the parents a
very marked change of habit. So is it here, the mountains once
clothed with forests, all is changed. And it is to what takes place in
this altered condition that the report cited refers.

M. Renou seems to attach importance to storms of rain and storms
of hail advancing in a direct line, deviating from this in passing near
by a forest. On this subject M. Cezanne writes : — " On charts
which have been published by the Academy M. Becquerel has re-
presented the course of certain [thunder] storms. Some people have
thought that they could conclude from these charts that storms avoid
forests. But it should be remarked that these charts having been
prepared from testimony supplied by populations and Assurance
Companies, the abundance of documents establishing the devasta-
tions caused by the hail is not necessarily in exact relative propor-
tion of the frequency and violence of these storms : it depends more
especially on the density of the populations and the richness of the
crops. If the wooded regions do not supply documents towards

304 DISPUTED EFFECTS OP FORESTS

establishing the statistics of storms, it is because iu the forests there
are neither notable devastations committed by them nor inhabi-
tants to report them.

" The department of the Gironde furnishes a striking case in
support of this explanation. According to the storm chart of this
department (Atlas meteor ologique, 1868) the hail would seem to fall
by preference on the banks of the Garonne, or in the rich canton
which extends between that river and the Dordogne, but particularly
on the inhabited places; and, on the contrary, that the desert landes
were entirely spared by the hail.

"But it is well known that the landes are traversed by violent
storms ; but the shepherds of the landes do not send bulletins to the
Observatory !"

So much in regard to storm-charts such as are cited by M. Renou.
In regard to the kind of storms referred to by him, they are such as
were not likely to deviate from the cause in consequence of any such
difference on the surface of the earth as a forest might present.

Of the hailstorm cited by M. Renou, Sir John Herschel writes ; —
"In the hail-storm of July 13th, 1788, which passed across France
from south to north, two such tracks were marked, of 175 and 200
leagues in length respectively, parallel to each other, the one four
leao-ues broad, the other two, and separated by a track five leagues
in breadth, in which only rain fell. A similar character is very com-
mon though not to such an extent. Such linear hail-storms are
always attended with violent wind, sudden depression of the baro-
meter, indicating a great commotion in the air, and probable mingling
of saturated masses of very different temperature.

And in writing on the Hydrology of South Africa, I had occasion to
state : " According to views advanced by Espy, a distinguished
American meteorologist, the two parallel lines along which the hail-
storm advanced in the case mentioned by Sir John Herschel can be
satisfactorily accounted for. According to one of the laws regulating
storms, many of these advance, as does a wheel, rotating and pro-
crressino- horizontally — as a wheel does vertically in advancing along

a road as is made visible in a small advancing whirlwind of dust, or

leaves, or straw, or chaff. The cyclone, a whirlwind of such extent
as to create a storm, is fed with air as it advances; this, raised to a
gi-eat height, expands, cools, precipitates the moisture it contained,
and throws this off in a frozen state — as does a twirled wet mop
throw off drops of water, — and by gravitation it falls. As the rotaiing
■whirlwind advances, the motion of the air forming the forefront will

ON THE RAINFALL. 305

cross the breadth of the circle from left to right, or from right to left,
as the case may be ; the air forming the rear will cross the breadth
of the circle in the opposite direction, and scatter the hailstones or rain
over the whole breadth traversed in two showers, minutes, hours, or
days apart ; but at the sides the wind blows in but one direction
on the right of the circle, and in one direction, the opposite of this,^
on the other, and along the lines followed by these the hail or rain
falls continuously in greater abundance."

M. Cezanne writes in reference to what he had stated relative to
the fall of rain being determined in a great measure by the contour
of a country, and which I have already quoted : —

" It may be said — if the rain acted as if it had caprices and the
protuburances of the soil caused a change in the pluvial current —
will a mass of forests which raises itself on the plain remain without
any influence 1 Stating the question thus, it must be admitted as un-
questionable that forests may exercise an influence on the rainfall. It
may so happen, for example, that a forest of trees coming to bar up a
valley of little depth may interrupt the pluvial current, and notably
diminish the quantity of water collected in a pluviometer which would
be placed behind it. The town of Erfurt, for example, sheltered
against the west wind by the Thuringian forest, receives less rain than
do adjacent regions.* It is not necessary to speak of a high forest of
timber trees ; a simple wall, suitably disposed, suffices. It is well
known that the face of such a wall, exposed to the pluvial wind, re-
ceives more rain than does the sheltered side, — what is kept on the
one side falling there leaving so much the less to fall on the
other ; and observations show that it is enough to raise up buildings
or other erections in the neighbourhood of a pluviometer to produce
a change in its receipts."

But the hail-storm cited by Renou was not a fall of rain produced
by a pluvial wind blowing along the surface. The hail was produced
at an elevation far above the loftiest forest, where the forest could
not pi'oduce such a deviation as he states did not occur.

And with regard to his belief that it is beyond the power of man
to exercise the least influence over physical phenomena, the expression
given of it would require some qualification in order to exempt at least
such physical phenomena as are mentioned by M. Cezanne in the state-
ment by him which I have just cited, and who holds the same opinions
as does M. Renou on the point to which I understand him to refer.

* Kaemiti.

2l

306 EFFECTS OF FORESTS ON RAINFALL.

So far as my own observations have gone it is in accordance with
what has now been advanced. My observations have been made
incidentally and not of purpose, and they are general rather than
precise. They have been made, one class of them in Scotland, the
other in Africa, or countries which are in very different climatal condi-
tions, and for this it may be considered by some that some allowance
should be made; but such as they are they are these : While the genial
shower or the drizzling mist appears to be a characteristic of wood-
land rain, deluges of rain like thunder plumps are the forms which I
have found most characteristic of rain in the arid regions of South
Africa ; frequent showers and constant damp in spring and autumn
and winter alike are characteristic of woodlands in Britain with which
I am familiar, a cloudless sky, and a persistent drought broken only
by an occasional deluge, brief in its duration and local in its range,
are the characteristics of the other. In the one we have the rainfall
distributed over eight or ten months of the year, with occasional
showers in the course of the intervening summer ; in the other a
drought continued for months, or it may be for years, and a rainfall
of two days or three, or of some hours, or it may be of half an hour at
most. In the one we may have the rainfall distributed over the whole
of the area of a hundred or a thousand square miles, falling not over
the whole simultaneously or continuously, but so distributed in time
as well as in space that no part suffers lack ; in the other we may
have a deluge of rain over twenty square miles at one time within an
area of a thousand, and a deluge over other twenty square miles
at another time, weeks or months, or it may be years thereafter.

The geographical distribution of rain may be attributable to geo-
graphical position and contour of the country. Such deluges of rain
as have now been referred to may be attributable in some cases to
eddies in one or other of the aerial currents flowing continuously be-
tween the equator and the poles ; in other cases to the passage of
a minor cyclone or whirlwind above the place ; but the frequent
drizzling genial showers prevailing in a wooded country may be con-
sidered a form given to the rainfall in some measure by an influence
of the woods ; and the absence of these in arid woodless regions, in
which the mean annual rainfall is the same and the conditions similar,
may be considered in a corresponding manner attributable to the
absence of forests.

CONCLUSION.

We are told in the book of Proverbs : " He that is first in his own
cause seemeth just • but his neighbour cometh and searcheth him."
I have stated in preceding chapters, with such precision as I could
attain unto, what I consider to be the effect of forests on the humidity
of the soil and character of the districts in which they exist ; but I
am aware that a compilation might be prepared of observations made
by men of science which might seem to support a widely-diflFerent
conclusion. I have given attentive consideration to all such to which
I have had access, and prepai'ed a statement on their apparent bear-
ing on what I have advanced ; but I refrain from inserting this,
not because I consider them unimportant, for I consider them equally
valid and equally important with many — I may say with any — which
I had advanced. I refrain from inserting this first, and mainly, because
I am unwilling to add to the expense and the bulk of the volume; 2ndly,
and the reason weighs with me almost as much as the first, I wish to
present the subject to my readers in as simple a form as I can, and
without complications which I do not consider necessary for my pur-
pose ; and I know of nothing which has been advanced as observations
made, or conclusions deduced by reasoning, or phenomena observed,
which are incompatible with what I have advanced.

From what has been advanced it appears to be established as a fact
that there are cases in which an extensive destruction of forests has
been followed by a marked desiccation of soil and aridity of climate,
and some cases in which the replanting of trees has been followed
by a more or less complete restoration of humidity, — or the planting
of trees where there were none has been followed by a degree of
humidity greatly in excess of what had previously been observed;
that there are cases in which the rainfall within forests, or in their
immediate vicinity, has been perceptibly greater than in the open
country beyond ; but that there are also cases in which it is alleged
that the desiccation of some lands once clothed with forests and

308 CONCLUSION.

fertile, now treeless and barren and dry, may be attributable in part,
if not in whole, to other causes besides the destruction of the forests,
and cases in which the extensive destruction of forests does not
appear to have extensively aifected the quantity of the rainfall over
a wide expanse of country.

These facts may, by a little latitude in the use of language, be
characterised as antagonistic or conflicting ; but they may neverthe-
less be accepted as facts, and that with the admission that if facts
they must be perfectly compatible with each other, and not only
compatible but consistent with each other in the actually existing
system of things, and necessary to be known in order to a correct con-
ception of this system as a whole.

s it is with these apparently conflicting facts which I have cited
so does it appear to me to be with those apparently conflicting facts,
connected with details, which I have refrained from bringing forward
here : they do not appear to me to invalidate in any way those which
have been founded on in the conclusions I have advanced.

When I was a boy I was told of one of my townsmen, that, being on
trial before one of the magistrates for the theft of a hen, when a
witness testified that he had seen him take it, he broke forth with a
vehement appeal " Your honour ! I can bring forward twenty men who
did not see me." And to such testimony might be likened testimonies
to facts which are not in question cited as sufficient to invalidate
explicit testimony to other facts observed. I am prepared to admit
unhesitatingly all that can reasonally be said in regard to my accept-
ance as facts of what I have accepted as such ; the conclusions I
have drawn from them I commend to the consideration of my readers ;
and I leave to their judgment to determine to what extent these should
influence deliberations on the adoption of practical measures to avert
the evil and to secure the good which appear to be at our command.

The effects of forests in retarding the flow of the rainfall after its
precipitation has been established, I consider, beyond all question ;
and not less so their eff'ect in maintaining a general humidity of
atmosphere and of soil.

PINE PLANTATIONS

ON THE

SAND-WASTES OF FRANCE.

COMPILED BY

JOHN CROUMBIE BROWN, LL.D.,

Formerly Government Botanist at the Cape of Good Hope, and Prof essor
of Botany in the South African College, Capetow7i, Fellow of the
Royal Geographical Society, Felloiv of the Linnean Society, arid
Honorary Vice-President of the African Institute of Paris, etc.

EDINBURGH:

OLIVER & BOYD, TWEEDDALE COURT.

LONDON : SIMPKIN, MARSHALL, AND CO.

1878.

Kirkcaldy : Cra\\tord & Walker, Peinte::s

[All rights of Translation and Reproduction are reserved.]

CONTENTS AND ARGUMENT.

PAGE.

Index to Authorities Cited, . . . . y

Preface, ----... vii
States circumstances in which the vohime is published.

Chapter I. — Apjjearances Presented hy Plantations on Drift-
Sand, ------- 1

Cites the appearance presented by plantations seen from the bell
tower of the Cathedral at Antwerp (p. 1) ; and by vineyards in
M6doc and the vicinity of Bourdeaux (p. 2) ; by Landes adjacent
(p. 3) J by Arcachon (p. 4), and the pignadas in the vicinity (p. 5).

Chapter II. — Appearances Presented hy Landes adjacent to the

Pine Plantations on Gascony, - - - - 9

There are given Mangin's description of the Landes (p. 9), and of
the Dunes (p. 13), of Dartmoor (p. 17), as corresponding to scenes
in Brittany (p. 18) ; of the swampy land of Montoir resembling
the Fen country of England (p. 21) ; and there follow notices
of what has been done to reclaim the adjacent sand-wastes (p. 24).

Chapter III. — Legislation in Regard to the Planting of the

Landes with Trees, - - - - - 27

There are given excerpts from the laws issued on 13th Messidor an
IX (2ud Jidy, 1801) ; on 3rd Jour compldinentaire, an IX (p. 27);
12th July, 1808, 14th December, 1810 (p; 28) ; 5th February,
1817 (p. 29) ; and 29th April, 1862 (p. 30).

Chapter IV. — Literattcre Relative to the Arrest and Cidtivation

of Drift-Sands in France, - - - - 32

Works in French are specified (p. 32) ; works in German (p. 33) ;
and works published in Hungary, America, and England are
referred to (j). 34).

Chapter V. — Culture of the Maritime Pine on the Landes of

Gascony, - - - - - - 36

The preparation of the ground is described (p. 36) ; the zone ad-
jacent to the sea is described (p. 37) ; dayonnages (p. 39) ; sowing
and planting (p. 40) ; account given by M. Bagneris (p. 42) ; and
by M. Boitel (p. 45) ; thinning (p. 46) ; pruning (p. 48).

Chapter VI. — Exploitation of the Five Plantations of Gascony, 51
Account of the exploitation of resin, by Bagneris (p. 51) ; of the
manufacture of charcoal, by Boitel (p. 57), and that of charcoal
dust (p. 63) ; products exhibited in English museums (p. 66).

Chapter VII, — Sylviculture on the Landes of La Sologne, - 69

Account of the Landes of La Sologne (p. 70) ; of their soil (p. 72) ;
woods (p. 74) ; culture of pine woods (p. 75) ; reclaiming land by
plantation (p. 80).

Chapter VIII. — Inlaiid Sand-Wastes, and Sand-Wastes on the

Coast, ----.-- 81
Differences seen in sand-wastes (p. 81) ; Wessely's account of sand-
wastes on the coast (p. 82) ; account of the impermeable alios by
M. Faye (p. 84) ; capillary attraction of sand (p. 86) ; absorption
and retention of moisture (p. 88) ; absorption of vegetable nutri-
ment (p. 90) ; peat lands in sand-wastes (p. 92) ; composition of
sand (p. 92) ; sand-wastes of the tertiary formation (p. 96) ;
woods on such sands (p. 97).

Chapter IX. — Natural History and General Cidture of the

Scotch Fir in France, - - - - - 100

Description of the Scotch fir by MM. Lorentz and Parade (p. 100) ;
account of arboretum at Barres by the founder, M. Vilmorin
(p. 103) ; his observation on the Scotch fir (pinus sijlvestris)
(p. 107) ; the Riga pine (p. 115) ; pine of Smolensk (p. 117) ;
Wilna pine (p. 117) ; pine of Tschernigoff (p. 118) ; pine of
Volhynia (p. 118) ; varieties of the Riga pine (p. 119) ; Scotch
fir (p. 122) ; intermediate varieties (p. 123) ; instructions given
in School of Forestry at Nancy in regard to the exploitation of
the Scotch fir (p. 131) ; in regard to its economic uses (p. 137) ;
and the collecting and preservation of its seed (p. 138), and
sowing (p. 141).

Chapter X. — Natural History and General Culture of the

Maritime Pine in France, - - - - 143

Section I. — Commendations bestowed on the Maritime Pine, - 143
Commendation by M. Boitel (p. 143) ; by M. Samanos (p. 145) ;
and by MM, Delamarre, Crinon, and others (p. 147).

Section II. — General Culture and Exploitation of the Maritime

Pine, ------- 148

Instructions given at the School of Forestry at Nancy relative to
its natural history (p. 149) ; its economic uses and mode of
gemmage (p. 151) ; sowing (p. 152) ; exploitation (p. 154).

Chapter XL — Diseases and Injurioiis Influences to tvhich the

Maritime Pine is subject, - - - - 157

Section I. — Choking by an Over-growth of Local Vegetation, - 157

Section II. — Destructive Ravages by Birds, and Sqtdrrels, and

Insects, ...... 157

Mode of destruction (p. 157) ; accounts of lignivorous insects by
M. Perris (p. 159) ; destruction of the chenille processioiiaire
(p. 161).

Section III. — Destructive Conseqxiences folloiuing the Effects of

Charcoal Burning, - - - - -163

Evils pointed out by Professor Bagnei'is (p. 163), and accounted for
by M. Boitel (p. 163).

Section IV. — Destructive Ravages occasioned by the Mole, - 167
Natural history of the mole by M. Boitel (p. 167) ; destruction of
moles (p. 169).

Section V. — Destructive Ravages by Forest Fires, - - 170

Prevention of forest lires mentioned by M. Samanos (p. 170) ; by
M. Bartro (p. 171) ; by M. Boitel (p. 171).

INDEX TO AUTHORITIES CITED.

Andresen, 86. Bagneris, 42, 51, 163. Bartro, 171. Baude, 1. Boitel, 37,
41, 45, 46, 51, 57, 63, 71, 74-79, 143, 157, 163, 167, 171. Chambray (Marquis),
159. Clavt5, 91, 98, 99. Cotta, 100. Courreges, 39, 40. Crinon, 148. Dela-
marre, 147. Edinburgh Eeview, 34. Faye, 84. Forchhammer, 86, Grouven,
90. Haddington (Earl), 109. Hartig, 100, 138. Hauer, 93. Heyer, 88.
Janin, 20. Javil, 66, 84. Kedzie, 34. Kerner, 89, 95. Laurent, 87,
Lorentz, 100, 132. Mangin, 9, 13, 16, 21, 24, 70, 98. Marchand, 88, Marsh, 34,
86, 96. Mayer, 89. Nanquette, 135. Parade, 100, 139, 149. Perris, 159.
Samanos, 51, 145, 170. Schuebler, 88, 89, 93, 94. Thurmann, 87. Vilmorin,
103-130, 157. Weld, 1, 2, 3, 5. Wessely, 82, 88, 92, 99.

PREFACE.

The preparation of this volume for the press was undertaken in con-
sequence of a statement in the Standard and Mail, a Capetown
paper, of the 22nd July, 1876, to the effect that in the estimates
submitted to Parliament £1,000 had been put down for the Cape
Flats, it was supposed with a view to its being employed in carrying
out planting operations as a means of reclaiming the sandy tracts
beyond Salt River.

In view of the success which has followed the planting of the Landes
of Gascony and the Gironde with the maritime pine, it might seem
that nothing now can be required in order to arrest and utilise drift-
sands, but to plant them judiciously with that tree. But, happily, I
may say, the failure of such plantations on the Landes of La Sologne
comes to warn us against any such rash generalisation. And the
observation of sand downs in Britain, and sand plains elsewhere, show
that herbs, carices, reeds, and grasses have operated extensively in
arresting effectually, and, according to their measures, in utilising
what otherwise would have been barren and destructive sand-
wastes.

Looking at the subject generally, all that I consider established by
the pine plantations on the sand-wastes of France is the practicability
of arresting and utilising sand-drifts by means of plantations of trees.
What has been accomplished there we may legitimately infer may be
effected elsewhere, not necessarily by the same means, but by means
as appropriate, if they can be discovered. But while this may be all
that is established there is much more suggested.

And still more might be found to be suggested by a study of the
whole of the sand-wastes of Europe, and of the natural history of
sand, its composition, its formation, and its aggregation on the shore,
in dunes, in drifts, in sand-wastes, and in sand plains, and of the
various genera and species of plants growing upon it, and of planta-

tions of broad-leaved trees which have succeeded in other conditions —
the poplar, the willow, and the aspen, the elm, the elder, the ash,
the acacia, the oak, the hazel, and the dogwood, the birch, and the
wild pear. There has been prepared a twin volume, in which these
subjects have been discussed.

This volume was originally compiled in view of what seemed to be
required at the Cape of Good Hope. It has been revised, and printed
now, only as a contribution towards a renewed enterprise, to arrest and
utilise sand-wastes which stretch from Table Mountain to the
Hottentot Holland Mountains ; and additional information is forth-
coming if it should be desired.

Appended to reports of the Colonial Botanist for 1864 is a letter
on grasses adapted to arrest drifting sand (pp. 99-102), and appended
to report of the Colonial Botanist for 1865 is a letter on the arrest of
drifting sand, and planting the same with trees (pp. 83-93).

Haddington, 10th A2)ril, 1878.

PINE PLANTATIONS ON THE SAND-
WASTES OF FRANCE.

CHAPTER I.

Appearances Pebsbnted by Plantations on Drift Sands.

Within the last eighty years much has been accomplished in the
arresting of Drift Sand, and in utilising Sand Wastes by a judicious
combination of sylviculture and agriculture.

" A spectator placed on the famous bell tower of the cathedral of
Antwerp," says Baude in an article in the Hevue des Deux Mondes,
January, 1859, one of an interesting series of articles entitled Les
Cotes de la Manche, " saw not long since on the opposite side of the
Schelde only a vast desert plain ; now he sees a forest, the limits of
which are confounded with the horizon. Let him enter within its
shades. The supposed forest is but a system of regular rows of trees,
the oldest of which is not yet forty years of age. These plantations
have ameliorated the climate, which had doomed to sterility the soil
where they are planted ; while the tempest is violently agitating their
tops, the air a little below is still, and sands far more barren than
the plateau of La Hague have been formed under their protection
into fertile fields."

A similar description of landscape eflfects, produced by the planting
of the Landes of the Gironde in Gascony with pines occurs in Weld's
tour through the Pyrenees.

Writing of this district he says : — " Opposite to Blaye, and extend-
ing for a considerable distance up and down the Gironde, is the
M6doc district, unlovely in appearance, being a vast plain composed
of stones and sand, the deposit probably of the river in long past
ages. But no smiling valley,

' Deep meadowed, hajspy, fair with orchard lawns,
And bowery hollows crown'd with summer sea,'

is so fruitful as is this seeming waste : for it is the nursing mother
of those vines, which, stunted though they be, produce the far.

2 APPEARANCE PRESENTED BY PLANTATIONS.

famed claret grape. Who, ignorant of these facts, would suppose
that an acre of Medoc land is a fortune !"

Writing of Bourdeaux, the capital port of the district, he says : —
" Grand indeed is the water avenue to the great city of Bourdeaux.
Flowing beneath the softly wooded heights of Floirac, the tawny
Garonne, here upwards of 2,000 feet wide, sweeps in a semi-circle
past handsome quays three miles long, bearing all kinds of crafts,
from the jaunty felucca from the Mediterranean, to the stately India-
man ; for the tide at Bourdeaux, though the city is seventy miles
from the sea, rises twenty feet. Looking at all this beauty and com-
mercial grandeur, I thought of our Thames, and what it might be if
properly embanked and provided with capacious quays.

" Long to be remembered is an afternoon which I spent at Floirac,
where one of the great wine merchants resides. After an early
dinner, consisting of many delicacies, we adjourned, ladies as well as
gentlemen, to an arbour in the pleasure ground, situated at the edge
of the wooded heights. Within the arbour a large table was covered
with an endless variety of delicious fruits, all grown on the estate ;
and while we sat round these abundant products of the rich south,
the distant views, which are of the most exquisite nature, were illumed
by a sunset of great glory.

" On a day remarkable for an exti'a allowance of caloric — Bourdeaux
is exceedingly hot in summer — I visited the fai'-famed claret vaults
of Messrs Barton & Guestiei-. 0h, how delicious was the wine I
tasted in these deliciously cool regions — tasted ! no, drank ; for it
would have been nothing short of an insult to that rare old nestar to
have acted according to the advice given when you enter the London
Dock wine vaults — taste but do not swallow. Here, within the cool
precincts of the cellars, if you have the good fortune to be favoured
by being allowed to taste famous vintages, you will be made aware
how little, how very little, the middle classes really know what good
claret is. The stuff which, impudently assuming that name, is generally
our potion at a dinner party, is no more like the prime first growth
clarets of Medoc than sloe juice and brandy is genuine port ; but
when we remember that a hogshead of good claret, the produce of a
first-rate vintage, frequently fetches a thousand francs on the spot,
we at least I, who am of the middle classes, can understand that
the chance of making acquaintance with prime claret is very small.
The more then, if you are a middle man, will you enjoy a tasting visit
to the Bourdeaux claret vaults, and especially if you enter them after
a lionising tour through streets baked with a temperature of about 90°

WELD S DESCRIPTION OF THE LANDBS. 6

. . . Lighted by huge wax candles, I walked long and wonderingly
through alleys lined by hogsheads, or barriques, as they are called.
The value of these, as I was informed, was £120,000. There
are generally 10,000 harriqiies in store, for the most part cob-
webbed and venerable vessels emitting a peculiar aroma, something
like that of new hay ', for your first-class claret reqviires to be kept
many years before it is ripe for post-prandial honours."

But sterile as seem the lands of the M6doc, where such treasures
are produced, they come short in this respect of the appearance
presented by the Landes of the Gironde, which have no such
tales to tell of fruit and wine.

" A few miles from Bourdeaux," he writes, " you enter the Landes,
across which the line is carried to Bayonne. Nothing can be more
dreary than these apparently interminable wastes. Your passage
across them suggests ideas of the ocean, with this great difference
however, that whereas the latter is rarely at rest, the vast tract of
the Landes, comprising 600,000 hectares, equal to 1,482,600 acres,
except when swept by hurricanes, presents a still and monotonous
surface. The soil is sand — endless sand — vertically as well as
superficially. Artesian wells have been sunk to nearly the depth of
1,000 feet, and then a scanty supply of wretched yellow water has
been the only result. As may be supposed, the lives of the inhabitants
of this unpromising region are short, feverish, and sickly. The
Landais have a proverb —

* Tant que Landes sera Landes
Lapellajri te demande.^

The said pellagri, being a fatal disease occasioned by malaria
and bad water. Amidst these wastes, lying to the east of the pine
forests which fringe the sea coast, the Landais, who are with few
exceptions shepherds, spend the long summer days with their flocks
of sheep, each animal being as well known to them as their dogs.
The Landais shepherd is a primitive being, fond of solitude, rarely
venturing near the railway ; when he does, he gazes wonderingly at
the passing train — so to see him, you must penetrate into his wilder-
ness. There, amidst the great wastes, clothed in sheeps' skins, and
wearing the Navarre cap, you will find him mounted on tall stilts,
become, from long habit, like a second pair of legs, for he has been
accustomed to them from childhood ; pi'obably knitting while his
flock cross the scanty herbage. There he stands, resting against his
pole, a strange tripod-looking figure — stranger still when he strides

4 APPEARANCE PRESENTED BY PLANTATIONS.

across the Landes in hot haste after a wandering sheep. He has
a small hut, sometimes a wife who aids him in cultivating a small
patch of ground, from which he obtains a little corn and a few
vegetables. A miserable existence is this, but the dawn of brighter
days has, we may hope, appeai-ed for the poor Landais."

Some two hours journeying by rail takes the traveller from
Bourdeaux through clouds of dust and forests of pine to Arcachon.
*' Here," writes an English tourist, " houses, like Indian bungalows,
with broad verandahs, and often of only one storey, run for more
than a mile along the water's edge, each surrouuded by its own
* compound,' to keep up the Indian phraseology, and each with its
bathing-house and steps leading down to the beach. From these the
lightly-clad inmates emerge at all hours, and pass the greater part of
their time either paddling barefoot on the shore when the tide is out,
or dancing in groups in the sea, which has the merit, in the eyes of
the nervous part of the population, of always being as smooth as a
mill-pond. I never saw a place so absolutely and completely given
over to bathing. , . But the real charm of Arcachon lies in its pine
forests, covering sand-dunes sometimes three or four hundred feet high,
and stretching back over the landes, where fresh-water lakes glimmer
in the blue distance. Picturesquely grouped within these resinous
groves are perched the villas and cottages of the winter town, to
which consumptive patients resort in the colder months to breathe
turpentine mixed with the soft sea breeze. The extraordinary
advantages of this hygienic compound seem to be getting more and
more recognised, and each year the number of visitors increases.
The high dunes completely shelter the winter town from the violence
of the gales, while there is a life and purity in the atmosphere which
have worked marvellous results. With a compass one may explore
the recesses of these forests for miles on horseback, for there is
scarcely any underwood, and one can therefore steer through them
in any direction ; though in fact there is not much danger of being
very seriously lost, for the forest abounds with the wooden shanties
of the collectors of turpentine, who are perpetually at work gashing
the trees and emptying the little pots tied on to them, and which
contain the sap, into the small tanks prepared to receive it. In the
centre of the basin are a couple of sand-banks, one of them partially
dry at low water, and on which any number of rabbits may be shot ;
and on the other an oyster-park, with an old hulk stranded upon it.
Large parties of merry-makers sail to this moist and oozy spot, and,

DESCRIPTION OP THE PIGNADAS. 0

taking off their shoes and stockings, catch their own shrimps, gather
their own cockles, and knock the oysters off the tiles upon which
they are growing, for themselves ; and then retiiing to the hulk,
where sundry articles of diet may be purchased, make their cannibal
pic-nic with the addition of these living creatures, . . . Another
pleasing entertainment, much resorted to by both sexes, is spearing
fish by torchlight. On a dark night the bay is sometimes brightly
illuminated with the glare of the pine-splinters flaming from the
prows of boats in iron cradles, and the shouts of laughter tell of un-
successful prods with many-pronged spears at the eels and mullet
which wriggle or dart round the bright reflection on the water. It
requires considerable skill and practice to bring home a large basket-
ful, but some ladies become tolerably expert at this sport."

And here, amidst all the gaiety of a fashionable watering-place, the
residenter or the forester may find a solitude, for which he might
seek in vain elsewhere, in the forest of pines. " This, indeed," writes
Weld, " is the characteristic feature of Arcachon. The great pine
forest of the Landes, locally called pignadas, extends from the Adour
to the Gironde, and is an extraordinary monument of man's skill and
perseverance.

" Prior to 1789 this vast forest area was —

' A bare strand
Of hillocks heaped from ever-shifting sand,
Matted with thistles and amphibious weeds,
Such as from earth's embrace the salt ooze breeds. '

The sand was so fine as to be wafted by the faintest breeze ; while
the great sea storms raised huge sand waves, which overwhelmed
vegetation, and, rolling inland, frequently carried desolation and
destruction among far distant villages and fields. Such was the
state of this part of the countr-y when M. Bremontier, an officer in
the Government department of the administration of forests of
France, conceived the idea of erecting wattle hurdles and boards
near the sea, so as to break the storms ; and of sowing in narrow
zones, leeward and at right angles to the prevailing wind, seeds of
the Pinus Pinaster and common broom, in the proportion of five
pounds of the former to two of the latter per acre. The area sown
was then covered or thatched with pine branches, care being taken
to prevent these being blown away, by pinning them to the ground.
In about six weeks the broom seeds produced plants sis inches high,
which attained the height of two feet at the close of the year. These

6 APPEARANCE PRESENTED BY PLANTATIONS.

now afforded excellent shelter to the pine plants, which were but
4:-inch striplings, and under their fostering protection the pines grew
and flourished.^ until at length, with an ingratitude not unhappily
confined to the vegetable world, they suffocated their infantine
pi'otectors, and rose high, defiant of the raging sand-storms.

" So effective was M. Bremontier's process that, in 1871, a com-
mission, appointed by Government to examine the Landes, reported
that 12,500 acres were covered with thriving and profitable pines;
and the Landais, who had lived to see their howling wastes clothed
with far-stretching forests, were enabled to gain a livelihood, less
precarious and perilous than that obtained by fishing in the stormy
waters of the Biscay Bay.

" Twenty-five years passed, and then the hand of man was busy
among the pines. Good as the pinaster is for domestic purposes. La
Fontaine says :

' Sera-t-il Dieu, table, ou cuvette ?
it is far more valuable for the great quantity of resin, tar, and lamp-
black which it produces. As you ride thi'ough the pines you will
meet the resin-gatherers, resiniers, as they are called, who during the
summer months live in the forest ; for the most part a rude set of
men, speaking a strange j^cttois, from which, however, you may glean
some information. When the resin-harvest is at hand, the resinier
goes forth provided with a short ladder and a curved axe. His
manner of testing the fitness of a tree to be tapped is by throwing
his arms around it. If the trunk be so thick that he cannot see his
finger ends, the pine is ripe for the operation. This is performed
with great quickness and dexterity. A longitudinal cut or groove is
made in the trunk, down which the resin flows, and is caught at the
bottom of the stem, in a little trough fashioned in a few moments
from the bark removed by the cut. Weekly the wound is re-opened
but not widened, and the operation is renewed yearly, until the
entire trunk is scored in such a manner as to make you wonder how
the maimed bole can support the superincumbent weight. But,
stranger still, the pine is not injured by this scoring process ; for, if
the operation be judiciously performed, by the time that the resinier
has gone round the tree, the first wound has healed, and the trunk is
ready to be bled again. Wonderful too is the quantity of resin which
exudes from these bountiful trees. You may know where the
resiniers have lately been, by the palsamic odour proceeding from
the wounded pine. A resin-gatherer told me that after a season's
practice — from the first of May to the end of September — a good

COLLEOTING OP EESIN. 7

hand could score 2,400 trees, scrape the resine molle, which encrusts
the trunks, into the troughs with small iron rakes, and carry the
resin to the pits where it is boiled. I saw a resinier frequently score
a tree to the height of 15 feet, and make a ik'ough in two minutes
and a quarter. Such a proficient earns 25 francs weekly, a high
wage in this part of France. Indeed, the resinier is far better off
now than the small vineyard proprietor, who generally, destitute of
capital, is ruined by a failure of his crop. . . .

'•' When the pines have been scored and re-scored, those destined
to make tar — called pins perdus — are cut down. The tar, com-
mercially known as goudron des Landes, not so good, however, as
that derived from the Scotch pine, is made by burning the roots and
thick portion of the trunk very slowly in cavities made in sloping
ground, and the tar is caught in cast-iron pans and run into barrels.
An inferior kind of lamp-black is deposited from the smoke of the
wood, but a better description is obtained by burning the straw used
in straining the resin.

" Besides these products, the resin of the Finns Pinaster yields
common turpentine, and is used extensively for pills. Glaring
placards and advertisements at Arcachon further inform the visitor
that ' Sdve de Fin Maritime est recommandee contre les affections de
poitrine, cafarrhes, bronchitis,' &c., by the French Faculty, — a revival
by the way, in another form, of tar-water, whose varieties were
extolled by Bishop Berkeley long ago, in his curious book, entitled
* Sevis'. . .

" And even now the economical uses of resin are not exhausted ;
so the Frenchman did not exaggerate when he asserted that, resine
est I'or en barriques.

" Many and delightful were the hours that I spent in the Pignadas,
generally on horseback, for the country around Arcachon is very
favourable for riding, and the small Landais horses are excellent.
Arab blood runs in their veins.

*' As all the ayrhnens of Arcachon are not yet chronicled in guide
books, I may mention that by far the most enjoyable excursion is
that to the Fointe du Slid, about six miles south of the town. Start
early, when the tide is ebbing, so that you may enjoy the fine, broad,
hard sand. At the Fointe du Sud you have the mighty Atlantic before
you, the great Biscayan waves breaking at your feet ; while behind
dark pines fringe the coast. Return through the forest ; avenues,
called Gardes-feii cut through the pines to prevent the spread of fire,
extend to Arcachoa ; and when you are on the right track, you will

8 APPEARANCE PRESENTED BY PLANTATIONS.

do well not to stray from it, as it is quite possible to realise in these
pignadas the unpleasant feeling of losing your way, particularly when
-the sun has set.

"Few places are more. impressive than dark pine forests, now scream-
ing when the wind sweeps through to the trees, and now filling the
solitude with murmering voices, when stirred by gentle breezes, and
yet not a solitude ; for as you pass through them in the noontide the
air trembles with ceaseless hum. Pines are always a favourite home
for insects ; and here, in the warm south, they exist in countless
multitudes, making even silence vocal ; for, flashing through the air,
or sluggishly basking in the summer sun, they are endowed with the
power of making the forest resonant with strange sounds. By far the
most remarkable of these noisy animals is the Cicada, which attains
a great size in the pine forests in Southern France, and emits a loud
sound, according to my observation, always increasing in intensity as
the temperature rises."

Agriculture, as from the first was intended, has followed in the
wake of sylviculture.

" After innumerable futile attempts to reclaim and fertilise portions
of this desert, two joint stock companies (Gompagnie des Landes, and
Gompagnie d'Arcachon), have succeeded in reclaiming a considerable
portion of the Plaine de Gazaux.

"Sheltered from the prevalent west winds, by the great maritime
pine forest, the Plaine de Gazaux, situated to the east or leeward,
as may be said, of that forest, is not so liable to the destructive effects
of the great sand storms as other parts of the Landes. Rice, tobacco,
and the topinamhour or Jerusalem artechoke, for which the soil is
admirably adapted, are the chief crops. The improvements are in a
great measure due to a M. Pierre."

From these pen and ink sketches some idea may be formed of the
appearances presented by the pine plantations on the Landes of the
Gironde. The forest-like character of these will bear comparison
with that of the plantations seen from the tower of the cathedral of
Antwerp. And a knowledge of the general appearance presented by
the district may lead to the conclusion that the transformation
cannot have been less complete.

CHAPTER II.

Appearances Presented by Lands Adjacent to the Pine
Plantations in Gascony.

To appreciate ai-ight the effect produced by the planting of the drift
sands of the Landes with pine trees, it is necessary to know some-
thing of the appearance presented by the land thus utilised, and of
the land around which has thus been transformed into what in com-
parison therewith is a paradise — a garden of delight. A description
of the district, which may be reckoned one of the most dreary and
dismal in the land, one altogether at variance with the ideas called
up by the designation La Belle France, is given in a work by Arthur
Mangin, entitled " The Desert World," from an English translation,
of which I cite the following description :

" The department which borrows its name from the Landes of
Gascony is divided by the Adour into two wholly dissimilar parts.
To the south of the river lies a rich, undulating, vine-bearing country,
rich in pasturage and harvest, sown with pleasant villages and smiling
country houses, and watered by full streams and little rivers. To
the north the appearance of the country changes abruptly. When
the traveller has crossed the alluvial zone of the Adour he sees before
him a thin, dry, sandy level of a comparatively recent marine for-
mation. Its only products are rye, millet, and maize ; its only vege-
tation, forests of pines and scattered coppices of oaks ; beyond these,
and they do not extend far, all cultivation ceases, and the soil is
stripped of verdure ; you enter upon the Landes — seemingly vast as
a sea — occupied by permanent or periodical swamps ; and where,
over a space of several square leagues, in an horizon apparently
boundless, you perceive nothing but heaths, sheepfolds or steadings
for the flocks of sheep that traverse these deserts, and shepherds
keeping mute watch over their animals, living wholly among them,
and having no intercourse with the rest of humanity, except when
once a week they seek their masters' houses to procure their supply
of provisions. It is these shepherds only (Landescots and Aouillys),
and not, as is generally supposed, all the peasants of the Landes, who
are perched upon stilts, so as to survey from afar their wandering
flocks, and to traverse more safely the marshes which frequently lie
across their path. b

10 APPBARANOB OP THE LANDBS,

" Wild and uncouth are the figures which these stilt-walkers
present, as they move rapidly over the country, often at the rate of
six or seven miles an hour ; occasionally indulging in an interval of
rest, by the aid of a third wooden support at the back (curved at the
top, so as to fit the hollow of the body), while they pursue their
favourite pastime of knitting. The dress of the Landescot is singu-
larly rude. His coat or paletot is a fleece; cuisses and greaves of the
same material protect his legs and thighs ; his feet are thrust into
sabots and coarse woollen socks, which cover only the heels and instep.
Over his shoulder hangs the gourd which contains his week's store of
provisions : some mouldy rye-bread, a few sardines, some onions and
cloves of garlic, and a flask of thin sour wine. From sunrise to sun-
set he lives upon the stilts, never touching the ground. Sometimes
he drives his flock home at eventide ; sometimes he bivouacs stcb Jove
frigido, under the cold heaven of night. Unbuckling his stilts, and
producing his flint and steel, he soon kindles a cheery fire of fir-
branches, and gathering his sheepskins round him, composes himself
to sleep ; his only annoyances being the musquitoes, and his fears of
the evil tricks of wizard or witch, who may peradventure catch a
glimpse of him in the moonlight, as they ride past on their besom to
some unholy gathering or demon-dance.

" An English traveller has sketched in vivid colours the landscape
of the Landes. Over all its gloom and barrenness, he remarks, over
all its * blasted heaths,' its monotonous pine-woods, its sudden
morasses, its glaring sand-heaps, prevails a strong sense of loneliness,
a grandeur and intensity of desolation, which invests the scene with
a sad, solemn poetry peculiar to itself. Emerging from the black
shadows of the forest, the pilgrim treads a plain, ' flat as a billiard-
table,' apparently boundless as the ocean, clad in one unvaried un-
broken garb of dusky heath. Sometimes stripes and ridges, or great
ragged patches of sand, glisten in the fervid sunshine ; sometimes
belts of scraggy young fir trees appear rising from the horizon on the
right, and sinking into it again on the left. Occasionally a brighter
shade of green, with jungles of willows and water weeds, giant rushes,
and 'clustered marish mosses,' will tell of the 'blackened waters'
beneath —

' Hard by a poplar shook alway,

All silver-green with gnarled bark ;
For leagues no other tree doth mark
The level waste, the rounding gray.'

" The dwellings which stud this dreary, yet not wholly unpoetic

DESCRIPTI0N OP THE LANDES. 11

landscape, are generally mere isolated huts, separated oftentimes by
many miles. Bound them spreads a miserable field or two, planted
with such crops as might be expected on a poor soil and from
deficient cultivation. The cottages are mouldering heaps of sod and
unhewn and unmortared stones, clustered round with ragged sheds
composed of masses of tangled bushes, pine-stakes and broad-leaved
reeds, beneath which the meagrest looking cattle conceivable find a
precarious shelter.

" The Landes are divided into the Little Landes, near Mont-de-
Marsan ; and the Great Landes, stretching to the north and west of
the department of which that town is the capital, and uniting unin-
terruptedly with those that occupy the vast country situated south of
the Gironde. The total superficial area of these plains is estimated
at upwards of 2,400,000 acres, of which two-thirds belong to the de-
partment of the Landes, and the remainder to that of the Gironde."

Again — '* In shape, the Great Landes may be compared to an
immense rectangular triangle, having for its base the coast, which,
from the mouth of the Gironde to Bayonne, or for a length of more
than sixty leagues, is almost rectilineal. But they are separated
from the sea by a long parallel chain of lakes and water-courses —
a waste of shallow pools — a labyrinth of gulfs and morasses, and then
by the continuous chain of the Dunes.

" That which is commonly called the Great Lande is bounded on the
north by the etang, or lake, of Cazau. It is a sandy, treeless plain, and
upon which, for a traject of several leagues from east to west, not
one habitation worthy of the name is perceptible until the traveller
arrives at Mimizan, near the southern point of the lake of Aureilhan.
This lake on the south-west pours its waters into the sea. To the
north it communicates, through the canal of St. Eulalie, with the
lake of Biscarosse, which is itself connected with that of Cazau.
East of this chain of lakes lies the Lande ; west of it stretches the
range of Dunes, or sand hills.

** The lake or pool of Cazau is a small sea of fresh water, perfectly
clear, profoundly deep, and fourteen to fifteen thousand acres in
extent. It has its whirlwinds and its tempests, so that in certain
seasons it is perilous to embark on its surface. And were its banks
clothed with rich woods, or raised aloft in irregular or precipitous
cliffs, it would surely attract as great a throng of tourists as the
mountain-tarns and lochs of Scotland or Cumberland, or the Arcadian
waters of Northern Italy. The lake of Biscarosse, in form a triangle,
with one side formed by the Dunes, covers about twelve" thousand

12 APPEARANCE OF THE LANDES,

acres. It derives its name from a village situated at its northern
angle, on the bank of the canal which connects it with the lake of
Cazau. The lake of Aureilhan is the smallest of the three ; the St.
Eulalie canal, which links it to the preceding, traverses a series of
peat-bogs bounded eastward by gloomy pine-forests, and westward
by the interminable Dunes, which, by arresting the flow of the rain-
waters, have really created these so-called lakes and extensive
swamps. Enormous quantities of rain fall every year in the Landes,
— which district the Eomans would certainly have dedicated to Jupiter
Pluvius, — and find beneath the thin superficial stratum or crust of
sand and earth, a sub-soil of tii^a and allios — in other words, of com-
pact chalk and sand agglutinated by a ferruginous sediment. Fre-
quently this tufa possesses all the hardness of stone, and its
imperviousness is its fundamental property. Hence it follows, that
a portion of the heavy annual rainfall remains in the receptacles
provided by the hollows and depressions of the soil, and in due time
accumulates into marshes and lagoons, until gradually evaporated by
the heat of spring.

" When of old the scared peasants beheld the irresistible advance
of these strange ministers of destruction, they had no other resource
than to fell their woods, abandon their dwellings, and surrender their
* little all' to the pitiless sand and devouring sea. What could avail
against such a scourge? Efibrts were made to repel it. It is
said that Charlemagne, during a brief residence in the Landes, on
his return from his expedition against the Saracens, employed his
veterans, and expended large sums of money in preserving the cities
of the coast from imminent ruin ; but whether the means employed
were insufficient, or whether the imperial resources failed, and other
urgent needs diverted the population and their leaders from this
struggle against nature, the works were wholly abandoned."

But in more propitious circumstances the work has been resumed
with better success.

" The reader," says the writer I have quoted, " must not believe
this country to be a desert in the popular acceptation of the word ;
it has its forests of pines, where the extraction and pi-eparation of
resinous matter are carried on with considerable activity. It has its
small towns, its pretty villages, its factories, and even its handsome
villas. Finally, modern industry has cut the Landes in two by the
Bordeaux railway, which traverses them from north to south, and
bifurcates at Morans to throw ofi" a line to Bayoune, and another to
Tarbes."

DESCRIPTION OF DUNES. 13

Of the Dunes which have been so transformed M. Mangin gives
the following description : — " The Dunes form the extreme line of
the Brittany coast for nearly two hundred miles, from the Adour to
the Garonne. They are hills of white sand, as fine and soft as if it
had been sifted through an hour-glass. Their outline, therefore,
changes every hour. When the wind blows from the land, millions
of tons of sand are hourly driven into the sea, to be washed up again
on the beach and blown inland by the first Biscay gale. A water
hurricane from the west will fill up with sand square miles of shallow
lake, driving the displaced waters into the interior, dispersing them
in shining pools among the ' murmurous pines,' flooding and fre-
quently destroying the scattered hamlets of the people, and inun-
dating their fields of rye and millet.

" Their origin is due to the prevalence of the sea-winds on those
points of the coast which are not protected by rock and cliff, and
whose slopes of sand descend very gradually to the margin of the
waves. Their formation is easily explained. The sand of which
they are composed is a silicious material, reduced to minute grains,
generally rounded, by trituration. These grains, nevertheless, are
often too big and too heavy for the wind to take them up and scatter
them afar, like the dust of the highways or the ashes of volcanoes.
But at low tide the sand, dried by the sun's rays and the action of
the wind, ofi'ers to the latter a sufficient holdfast to be dragged up
the slopes which descend seaward, and deposited at a certain distance.
This process being constantly repeated, the heaps are daily increasing
in dimensions.

" It will easily be understood that this accumulation along the
shore cannot have taken place where the force and direction of the
sands experience periodical or capricious changes ; for then the sands
cast upon the beach by the winds of the north and west would be
driven back into the sea by the winds of the south and east. This is
noticeable in many places where the nature of the coast is favourable
for the production of such a phenomenon. But on other shores — as
on the Atlantic littoral of France — the winds which blow most
frequently and most violently are from the west and south-west. And
it is there we encounter the Dunes. Those of Gascony are by far the
most remarkable. Northward, they extend as far as the Point de
Grave, which shuts in the mouth of the Gironde ; southward, to the
bank of the Adour, and even further, to the olifis of Beam. Here
the basin of Arcachon constitutes one vast hollow ; and some open-
ings exist, moreover, in the department of Landes, between that basin

14 APPEARANCE OF THE LANDES.

and the Adour, for the overflow of the waters which descend from the
interior. To the north and south of the Teste de Buch the chain of
sand hills measures from 4,400 to 6,600 feet in width. At other
points it is still wider ; but it narrows towards its extremities, and
both at the Point de Grave and near Bayoune does not exceed 450
yards.

" Owing to their extreme shiftiness of soil, the Dunes can attain no
considerable elevation. The sand deposited by the wind on the sum-
mit of the hill is always in a state of precarious equilibrium. It has
a constant tendency to be precipitated down the other side, and the
higher the summit the greater is this tendency, so that there comes
at last a moment when no further accumulation in height is possible.
The Dune may then extend its basis, may even increase twofold in
dimensions, but it no longer rises.

" Let us note, moreover, that owing to its density the sand cannot
be carried even by the most violent winds into the higher regions of
the atmosphere ; and that the Dunes, when they have reached a cer-
tain elevation, oppose to them an insuperable obstacle. This circum-
stance would consequently have a salutary effect, and the accumulation
of sand would be determined by a law of its own, if the Dunes, once
formed, had time to cohere. But this is not the case. Incessantly
does the wind undo or modify its work ; and the loftiest hills being
the most exposed to its violence, are quickly reduced to the common
level. In general, the greatest elevation of the Dunes corresponds to
their greatest breadth. Thus the culminating point of those of Gas-
couy is found in the belt situated between the lakes of Cazau and
Biscarosse, where the chain is from 7,500 to 9,000 yards across.
Their average height is 180 feet to 200 feet above the sea-level ; but
some of the hills in the forest of Biscarosse attain an altitude of 320
feet. In the neighbourhood of the mouths of the Gironde and the
Adour, where the chain is considerably narrowed, the height of the
Dunes is only thirty to forty-five feet.

" The reader must not suppose that the Danes consist of a single
series of sand hills ranged along the shore. He will, however, have
conjectured, from our statements respecting their width, that they
really compose a chain of several more or less regular ridges. The
hills are separated from one another by valleys, locally named laites
or lettes. These valleys, where the pluvial waters flow and accumu-
late, exhibit a striking contrast, in their freshly-blooming verdure, to
the naked, barren Dunes. The general aspect of the landscape may,
therefore, be compared to that of the ocean. There is the same

DISORIPTION OP DUNES. 16

broken surface, the same extent of undulation, the billows of sand
being upheaved by the wind like the billows of the sea, and sharing
in their mobility. You must see, says a writer, in order to form an
idea of those colossal masses of fine sand, which the wind incessantly
skims, and which travel in this way towards the inland country ; you
must see their contours so softened that they look like mountains of
plaster of Paris polished by the workman's hand, and their surface so
mobile that a little insect leaves upon it a conspicuous track ; their
slopes, at every degree of inclination ; their everlasting sterility —
not a blade of grass, not an atom of vegetation ; their solitude, less
imposing than that of the mountains, but still of a truly savage
character. You must see, from the summit of one of these ridges, the
ocean on your right hand, and on your left the extensive lakes which
border the littoral ; and, in the midst of this tumultuous sea of tawny
sand, green grassy valleys, rich and fertile pastures, smiling oases of
verdure, where herds of horses graze, and cows, half-wild, guarded by
shepherds scarcely less wild than they.

" The marked characteristic of the Dunes, as we have already said,
is their mobility, which renders them a constant menace for the
neighbouring populations. To the wind which creates them they
owe their frequent changes and their inland movement. While the
sea eats into the coast, assisted by the breezes which gradually sweep
clear the ground before it, the Dunes extend, and drive before them
the shallow lakes : these in their turn encroach upon the Laudes, and
until now man has been constrained to recoil, step by step, before his
threefold enemy. It is in this phenomenon, rather than in the un-
grateful soil of the Landes, that we must seek the cause of the curse
which has seemed so long to rest upon this country-side. You must
go back some twenty centuries to trace the origin of the Dunes of
Gascony. Fourteen or fifteen hundred years ago the coast north of
the Adour was inhabited, and comparatively flourishing. Mimizan
was then a town and a sea-port, from which were exported the resinous
products of the neighbouring forests. The Normans disembarked
there on several occasions. Under its walls, in 506, was fought a
great battle between the allied Goths and Ostrogoths on the one side,
and the Bearnais, commanded by a bishop of Lescar, on the other.
Both town and port to-day are buried under the sands. ' Full fathom
five ' lie church and convent, and the busy street, the noisy mart, and
the once peaceful home. The present village has nearly perished :
the Dune was not three yards from the church when its progress was
recently arrester). Other cities, laid down in old charts of the country,

16 APPBARANOB OF THE LANDEB.

but of which not a trace remains, have in this manner disappeared,
and entire forests have been ingulfed, now under the sands of the
Dunes, now under the sands and waves of the sea.

" Some parts of the chain have been rendered to a great extent
immovable by the vegetation which has gradually covered them, and
these have opposed a formidable obstacle to the encroachments of the
sands. Yet here and there the barrier has been defied. For example,
in the forest of Biscai'osse the movable Dunes, actually sweeping over
the ancient hills, have not only filled up the valleys, but ingulfed a
great number of pines, and raised themselves several yards above the
crest of the oldest trees, planted on the summit of the highest hills."

The name Dunes is traced etymologically to Bun, a hill, and in the
designation we may trace the origin of the designation downs given to
extensive districts in England. The designation lande is given to
waste lands and moors ; and thus may the landes of the Gironde be
associated in thought with Dartmoor and Exmooi', and with Howns-
low Heath and other places bearing similar designations in England.

But if associated in thought differences in their character must not
be lost sight of. Of Dartmoor, the extensive and romantic table land
of granite, which occupies the south-western part of the country of
Devon, it is stated in the work ft-om which I have quoted — " In its
recesses still linger the eagle, the bustard, and the crane; its solitudes
are broken by the hoarse cries of the sparrow-hawk, the hobby, and
the goshawk ; and the Cyclopean memorials of Druidism which cover
its surface — cromlechs and kistvaens, tolmens and stone-avenues —
invest it with a peculiar air of mysterious awe. It extends in length
about twenty-two miles (from north to south), and in breadth twenty
miles (from east to west). Its total area exceeds 130,000 acres. It
rises above the surrounding country like ' the long, rolling waves of
a tempestuous ocean, fixed into solidity by some instantaneous and
powerful impulse.' A natural rampart is cast around it. Deep
ravines, watered by murmuring streams, diversify its aspect, and
lofty hills of granite, locally called tors, of which the principal. Yes
Tor, has an elevation of 2,050 feet above the sea. Its soil is composed
of peat, in some places twenty-five feet deep, underneath which lies
a solid mass of granite, occasionally relieved by trap (a volcanic rock),
and traversed by veins of tin, copper, and manganese.

" Nearly in the centre of this dismal wilderness lies an immense
morass, whose surface is in many places incapable of supporting the
lightest animal, and whose inexhaustible reservoirs supply the foun

DESCRIPTION OF DARTMOOR. 17

taias of many a river aud stream — the Darfc, the Teign, the Taw, the
Tavy — all clear as crystal iu the summer months, but, after heavy
rains, running redly through the ' stony vales.' The roaring of these
torrents, when angry and swollen, is sublime to a degree inconceiv-
able by those who have never heard the wild impressive music of
untamed Nature.

" The tors are remarkable for their quaint fantastic outlines, which,
like the clouds, suggest all manner of strange similitudes — to dragons,
and grilfins, and hoary ruins, and even to human forms of gigantic
size, apparently confronting the traveller as the lords and natural
denizens of the rugged waste. The principal summits are Yes Tor,
Cawsand Beacon, Fur Tor, Lynx Tor, Rough Tor, Holne Ridge, Brent
Tor, Rippen Tor, Hound Toi', Sheep's Tor, Crockern Tor, aud Great
Mis Tor. Not only must their variety of form delight the artist, but
his eye rests well pleased on their manifold changes of colour — purple,
and green, and gray, and blue — now softened by a delicate vaporous
shadow, now glowing with intense fulness in the sun's unclouded
light.

" Dartmoor is traditionally reputed to have been anciently clothed
with forest. The sole relic now existing is the lonely Wistman't
Wood, which occupies a sombre valley, bounded on the one side by
Crockern Tor, on the other by Little and Great Bairdown ; the slopes
being strewn with gray blocks of granite in ' admired disorder,' as
if the Titans had been at their cumbrous play. Starting from this
chaos of rocks, appears a wood or grove of dwarf weird-looking oaks,
interspersed with the mountain-ash, and everywhere festooned about
aud garlanded with ferns and parasitical plants. None of these trees
exceed twelve feet in height, but at the top they spread far and wide,
and ' branch and twist in so fantastic and tortuous a manner as to
remind one of those strange things called mandrakes.' Their branches
are literally covered with ivy and creeping plants, and their trunks
so thickly embedded in a coating of moss that at first sight, says
Mrs. Bray, ' you would imagine them to be of enormous thickness in
proportion to their height. Their whole appearance conveys to you
the idea of hoary age in the vegetable world of creation; and on
visiting Wistman's Wood it is impossible to do other than think of
those " groves in stony places " so often mentioned in Scripture as
being dedicated to Baal and Astaroth.'

" That heathen rites were celebrated here in the pre-historic era
seems very probable, the best etymologists agreeing that the name is
a corruption of Wise-man, or Wish-man ; that is, of the old Norse god

C

18 APPEARANCE OP THE LANDE8.

Woden, who is still supposed to drive his spectral hounds across the
silent wastes of Dartmoor. Celtic or Cymric memorials, as we have
previously hinted, are very abundant and very various. There are
cromlechs, where the Britons buried their dead ; stone pillars, with
which they commemorated their priests and heroes ; avenues of
upright stones leading up to the circles, where, perhaps, their priests
celebrated their religious rites ; kistvaens, or stone-chests, containing
the body unburned ; tolmens, or holed stones, whose meaning cannot
be determined, but which may probably have had some astronomical
uses; bridges, huts, and walled villages, all bearing traces of the
handiwork of our ' rude forefathers.' "

For the counterpart of this we must go considerably to the north
of the Landes ; but we find it in Brittany, which, geologically speak-
ing, may be regarded as a prolongation of our English mountains, to
which, with all the north-west coast of France, they were formerly
united. " Brittany," writes Mangin, " belongs to what geologists call
the primitive and intermediary formations. It is divided into three
belts or longitudinal trenches : those of the north and south consist
of primitive rocks, granite, and porphyry ; the central appertains to
a more recent formation, to the group of intermediary or secondary
rocks, composed in the main of schists and mica-schists, quartz, and
gneiss. Schist prevails over a considerable area, and is prolonged to
the very extremity of the peninsula. These hard, compact, imper-
vious rocks, are entirely bare in many places ; elsewhere, and over a
great extent, they are covered but by a thin layer of clayey and
sandy earth, where the sudden slopes of the soil do not allow the
rains to settle.

" Here are the plains, often of considerable dimensions, which,
bristling with rocks, and broken up by ravines, water-courses, and
marshes, constitute the Landes of Brittany. True deserts these,
relieved at distant points by an isolated hut, or by a wandering herd
of swine, lean cows, and meagre-looking horses, which obtain a scanty
subsistence from the heathery soil, sown here and there with tufts of
furze, broom, and fern.

" Under a sky of almost continual sombreness, like that which
impends over the pottery districts of England, these landes present a
sufl&ciently sinister and uninviting aspect. The traveller, as he crosses
their sepulchral wastes, will hardly marvel that they were anciently
a chosen seat of Druidical worship. Like Dartmoor, they would
seem to have offered a peculiarly fitting arena for the rites and
ceremonies of a creed which we know to have been mysterious in

DESCRIPTION OP BRITTANY. 19

character and sanguinaiy ia spirit. They are covered with its gray
memorials : the masses of granite of different shapes known as Maen-
hirs, or 'long stones,' and i-)eidvens, which appear to have been
employed as sepulchral monuments ; dolmens, or ' table-stones ;' and
cromlechs (crom, bowed or bending, and lech, a stone), which anti-
quaries are now agreed to regard as the remains of the ancient
cemeteries or burial places. At Camae, near Quiberon Bay, may be
seen a truly remarkable example of the Parallelitha, or avenues of
upright stones, forming five parallel rows, which extend for milea
over the dreary moorland. What were their uses it is impossible to
determine, for there seems little ground to believe, as some writers
would have us believe, that they were * serpent temples,' where the
old Ophite worship was celebrated. We can only gaze at them in
wonder : mile upon mile of gray lichen stained stones, some twenty
feet high, laboriously fashioned, and raised in their present places by
the hand of man some twenty centuries agone.

" On these very dolmens, where the priests of the Tentates were
wont to immolate their human victims to their unknown god, the
mediaeval sorcerers and sorceresses celebrated the Black Mass, or
Mass of Satin, in terrible burlesque of the Eoman Catholic sacrament,
concocted their abominable philtres, and performed their dreary
incantations. Alas for human nature ! In every age it is a prey to
the wildest credulity. Even in the present day more than one
superstition hovers around the monuments of the Celtic epoch.
The Bretons believe them haunted by demons called potdjnquets, who
love to make sport of the passing stranger, but will sometimes give
both counsel and encouragement to those who know how to address
them in the prescribed formulas ; who, like the Ladye in the * Lay of
the Last Minstrel,' at their bidding can bow

' The viewless forms of air.'

For, in the Breton mind, the superstitions of Druidism have not been
wholly uprooted by the teachings of Christianity, still less by those
of science and reason. Many a dark and dismal legend flourishes in
the lonely recesses of the landes.

" Brittany, like England, has its Cornoiiaille, or Cornwall, and it
is here, particularly in North Cornwall, that we see it under its most
desolate aspect, with its chains of black treeless hills covered with
heath and furze ; with its deserts of broom and fern, its ruins scat-
tered along the winding roads, its attenuated herds wandering at their
will across the moors, and its savage, ignorant, and scanty population.

20 APPBARANOB OP THE LANDES.

The Bretons of Cornwall, according to a French writer, are elevated
but a little above the true savage life. Those who dwell upon the
coast live on the products of their fishing, except when the fortunate
occurrence of a wreck provides them with temporary abundance.
At bottom, they possess the qualities and defects of characters
strongly tempered, but absolutely uncultivated. They are as hard
and bare as their own granite rocks. Persevering, courageous,
resolute, they make excellent sailors, the best which France can
find ; the sea is for them a second country. Progress, which they
do not understand, inspires them with a sort of terror, a gloomy mis-
trust. When the railway surveyors first intruded upon their solitudes,
these rigid conservatives assailed them with volleys of stones, and,
when the railroads were laid down, flung beams across the lines to
overthrow the hissing, whirring trains which threatened to disturb
their prescriptive barbarism. They asked but to be left alone — to
be suffered to live as their forefathers lived — to be spared the
ingenuities, successes, vices^ and virtues of the New World. But
modern civilization, like Thor's hammer, or Siegfried's magic sword
Balmung, will break down the last barriers raised by ignorance and
superstition. It will shed its light upon the wilds and wastes of
Brittany, and compel their inhabitants in the course of years to
acknowledge its value and accept its benefits."

There is not a little in the ethnological remarks made which I am
not prepared to homologate. I consider the Parallelitha and similar
erections had no connection with Druidism, that they were more
probably connected with the worship of Baal in some of its forms,
having their counterpart in the high places spoken of in the Jewish
Scriptures, while the Druids represented the worshippers of the
" groves." But referring thus to this in passing I gladly, and with
gratitude, avail myself of the topographical desci'iption.

Ere we reach that stony region in travelling northwards from the
Landes of Gascony, we must pass across the peat bogs of Montoir
and the Grand Briere, near Savenay, in the department of the Loire
Inf^rieure. They occupy a considerable area of a vast desolate plain,
where a few lean sheep crop an insufl&cient food from the scanty
herbage, and whose sole product is turf. " This country," says
Jules Janin, " has no other harvest, no other wealth than its peat ;
neither fruit, nor flowers, nor corn, nor pastures, nor rtpose, nor
well-being ; the earth is wild, the sky one of iron. It is a region of
stagnant waters, pestiferous exhalations, deci-epit men, famished
animals."

THE SWAMPS OP MONTOIR 21

" The swampy levels of Montoir form the natural vestibule to the
Armorican Peninsula, which of all the French provinces has the
longest and the most vigorously withstood the advance of civiliza-
tion, its ideas, and its modern institutions, and has the most rigidly
preserved its primitive character. There are many nooks and cor-
ners in Brittany scarcely changed in outward aspect or inner life
since the remote days when it was a valued appanage of the English
crown. They seem to have been plunged in a sleep of centuries,
from which the shrill whistle of the steam-engine is only just awaken-
ing them. The country is undulating and broken ; in the central
districts it assumes quite a mountainous character. It is true that
its heights are only of moderate elevation, the loftiest not exceeding
2,000 feet ; but they are barren, rude, and sombre in appearance.
The coast is picturesque enough to delight the most zealous artist,
bordered with high and abrupt cliffs, and lined, as it were, with a
beach where the waters of the Channel ever break in floods of spray
and foam, and where masses of rock lie scattered of immense size
and the most fantastic forms."

The counterpart to this we find in the English fen country,
which extends inland, around an arm of the North Sea called the
Wash, into the six counties of Cambridge, Huntingdon, Lincoln,
Norfolk, Northampton, and Sufiblk, with an area of upwards of
420,000 acres. Inland it is bounded by an amphitheatral barrier of
high lands, and touches the towns of Bolingbroke, Brandon, Earith,
Milton, and Peterborough. Into this great basin flow the waters of
the greater part of the drainage of nine counties, which gather into
the rivers Cam, Glen, Lark, Nene, Great and Little Ouse, Stoke, and
Welland, these being linked together by a network of natural and
artificial canals.

" Anciently, the Fens were pleasant to the eye of the lover of the
picturesque ; for they contained shining meres and golden reed-beds,
haunted by countless watei'-fowl, and strange, gaudy insects. ' Dark-
green alders,' says Kingsley, ' and pale-green reeds stretched for miles
round the broad lagoon, where the coot clanked and the bittern
boomed, and the sedge-bird, not content with its own sweet song,
mocked the notes of all the birds around ; while high overhead hung
hawk beyond hawk, buzzard beyond buzzai'd, kite beyond kite, as far
as eye could see.' What strange transformations must this wild
region have undergone 1 There was a time, in all probability, when
a great part of the German Ocean was dry land, through which, into
a vast estuary between North Britain and Norway, flowed together

22 APPBARANOB OF THE LANDES.

all the rivers of North-eastern Europe — Elbe, Weser, Rhine, Scheldt,
Seine, Thames, and all the rivers of east England, as far north as the
Humber, Meanwhile, the valleys of the Cam, the Ouse, the Nene,
the Welland, the Glen, and the Witham, were slowly ' sawing them-
selves out' by the quiet action of rain and x'ivers. Then came an age
when the lowland was swept away by the biting, corroding sea-wash
still so powerfully destructive on the east coast of England, as far as
Flamborough Head. ' Wave and tide by sea, rain and river by land ;
these are God's mighty mills in which he makes the old world new.
And as Longfellow says of moral things, so may we of physical, —

" Though the mills of God grind slowly, yet they grind exceeding small ;
Though he sit and wait with patience, with exactness grinds he all." '

These ever-active causes have converted the dry land into the fens.
The mud brought down by the rivers cannot get away to sea ; and,
with the debris of the coast, it is constantly swept southward by tide
and current, and deposited within the great curving basin of the
"Wash, between Lincolnshire and Norfolk. There it is kept by the
strong barrier of shifting sands coming inwards from the sea ; a
barrier which also confines the very water of the fens, and spreads it
inland into a labyrinth of streams, shallow meres, and bogs. The
rainfall, over the whole vast area of dull level, has found no adequate
channels of escape for centui'ies; and hence we may understand how
peat — the certain product of standing water — has slowly overwhelmed
the rich alluvium, and swallowed up gradually the stately forests of
fir and oak, ash and poplar, hazel and yew, which once spread far
and wide over the blooming country.

' Many a green isle needs must be
In the deep wide sea of misery,'

sings Shelley ; and this dreary outcome of mudbank and bog and
mere had its wooded isles, very fair and lovely to behold, redeeming
the desolation of the landscape. Such were Ramsey, Lindsey,
Whittlesea, whose names remind us of their whilome characteristics
[ea, ey, an island). In these green places the old monks loved to
build their quiet abbeys, rearing their herds in rich pastures, feeding
fat fish in their tranquil streams, and dreaming in the shadow of
green alder and stately ash.

" But these Eden-isles were few, and the surrounding marsh was
black and dismal enough to scare the boldest spirit, and pestilential
enough to sap and undermine the strongest frame. The Romans had
attempted to drain and embank it, and their vallum may still be

DESCRIPTION OF THE FENS. 23

tracked along the surface of the marsh-lands, marked to this day by
the names of Walsoken, Walton, and Walpoole. In the Middle Ages,
however, it returned to its primeval desolateness — a waste and
■wilderness, haunted by the foul legends of an unwholesome super-
stition. In the immediate neighbourhood of the great monasteries
of Crowland and Ely, and of the thriving towns, the good work of
drainage went on slowly ; but elsewhere the land was given up to
the bittern and the heron."

By Dukes of Bedford much was accomplished in the earlier half of
the seventeenth century, and by Rennie, the great engineer, some
hundred and fifty years later, to fit these fens for agricultural opera-
tions. " Works are now in progress," says the writer from whom, in
furtherance of my work, I have quoted so largely, " for rescuing a
further portion of the basin of the Wash, to be formed into a new
county, and named after the Queen, So that now, in tracts once
covered by the sea, or knee-deep in reedy, slushy, pestilential slime,
the grass grows luxuriantly, the crops wave in golden abundance, or
the breeze takes up and carries afar —

' The livelong bleat
Of the thick-fleecfed sheep from wattled folds.'

" But the dominion of labour has not yet been established over the
the whole Fen-districts. There are still dreary nooks, and gloomy
corners, and unproductive wastes ; wild scenes there are, which few
Englishmen have any conception of as contained within the boun-
daries of their own ' inviolable isle.' Romantic scenery, remarks Mr.
Walter White, must not be looked for on the Lincolnshire coast. In
all the journey from the Wash till you see the land of Yorkshire,
beyond the Humber, not an inch of cliff will your eyes discover.
Monotonous is the prospect of —

' A level waste, a roitnding gray'

of sand-hills, which vary but slightly in height, and bristle with
marum. ' But tame though it be,' continues our authority, ' the
scene derives interest from its peculiarity. Strange perspective
effects appear in those irregular hills : yonder they run out and form
a low dark, purple headland, against which the pale green and yellow
of a nearer tongue look bright by contrast. Here for a few furlongs
the range rises gray, cold, and monotonous ; there it has a warmth
of colour relieved by deep shadows, that change their tint during
the hours ihat accompany the sun while he begins and ends his day.
Sitting ou the summit of those dry hills, you will remark the con-

24 APPEARANCE OP THE LANDES.

trasted landscape : on the one side, the level pasture land, league
after league of grassy gi-eeu, sprinkled with villages, farms, churches,
and schools, where work and worship will find exercise through ages
yet to come ; on the other, league after league of tawny sand, sloping
gently outwards to meet the great sea that ever foams or ripples
thereupon. On the one hand, a living scene bounded by the distant
wolds ; on the other, a desert, sea and shore alike solitary, bounded
only by the overarching sky. More thoughts come crowding into
the mind in presence of such a scene than are easy to express.' "

Such as are these English Dunes and Moors and Fens are the
Landes, with which the sand dunes which have been reclaimed to
man are associated, and of which they form a part. The special
characteristic of them is the sand of which they are composed ; the
second characteristic of them is the superficial aspect which the hill-
like accumulation of the sand gives to the contour of the country ;
a thii'd characteristic is the constant onward movement of the sand
landward, covering up valuable fertile land with sterile sand and
stagnant waters ; and the last, but not least remarkable characteristic
is the forests which now wave over extensive areas thus recovered.

Of these the writer I have quoted, — I am unable to say whether M.
Mangin or his translator, — for the latter states that he has made
copious additions to the original work, with the view of rendering its
scope more comprehensive and complete, and of adapting it specially
to the requirements of the English reader — says : — " The works of
Charlemagne, on which he employed his veterans to preserve imperilled
cities, have been resumed, and with greater success, by a skilful
agriculturist, M. Desbiey, of Bordeaux, and an able engineer, M.
Bremontier, who have called in nature herself to assist man in his
war against nature. Their system consists of sowing in the driest
sand the seeds of the sea-pine, mixed with those of the broom
(genista scoparia), and the psamma arenaria. The spaces thus sown
are then closely covered with branches to protect them from the
action of the winds. These seeds germinate spontaneously. The
brooms, which spring up rapidly, restrain the sand, while sheltering
the young pines, and thenceforth the Dune ceases to move, because
the wind can no longer unsettle its substance, and the grains are
held together by the roots of the young plants. The work is always
begun on the inland side, in order to protect the farmer and the
peasant, and to withdraw the infant forest from the unwholesome
influence of the ocean-winds. And, in order that the sown spaces

THE PEATUKB OP THE LANDE8. 25

shall not themselves be buried under the sands blown up from the
shore, a palisade of wicker-work is raised at a suitable distance,
which, reinforced by young plants of sandwort (losamma arenaria),
check the moving sands for a sufficiently long time to favour the
development of the seeds. Finally, the work is completed by the
construction of a substantial wall, or rather an artificial cliflf, which
efiectually prevents the further progress of the flood, or directs it
seaward, to be arrested on its course by the barrier of the sand-hills.
Unable to force a passage thi'ough these natural ramparts, they have
excavated certain basins, more or less extensive, and more or less
deep, which have formed inland seas, communicating with the Atlantic
by one narrow issue.

" It is a noteworthy fact that, owing to the encroachment of the
Dunes, these lakes have been constantly forced back upon the inland
country. Fortunately, this menacing invasion of the sands has been
checked by the great engineering works executed a few years ago ;
which, on the one hand, have fixed, and, as it were, solidified the
Dunes, and, on the other, have provided for the regular outflow of
the waters. The Landes have thus been opened to the persevering
labours of the cultivator. The culture of the pine, and the manu-
facture of resinous substances, have largely extended, and the time,
perhaps, is not far distant when these deserts will almost completely
disappear; when these desolate and unproductive plains will pleasantly
bloom, transformed into shadowy woods or verdurous meadows.

" To so fortunate a result nothing will more powerfully contribute
than the embankment of the Dunes. These have been, in reality, the
true scourge of this country ; these were the moving desert, the con-
stantly ascending sea, which had already engulfed forests, villages,
even towns, under its billows of sand, and driven before it the ter-
rified inhabitants of the coast."

The expressions employed in this intimation of what is expected
remind a Scotsman of his Scottish paraphrase of the predictions of
Isaiah —

" With joy and peace shall then be led
the glad converted lands ;
The lofty mountains then shall sing,

the forests clap their hands.
Where briers grew 'midst barren wilds,

shall firs and myrtles spring ;
And nature, through its utmost bounds,
eternal praises sing."

26 APPEARANCE OP THE LANDE8.

I have not seen these plantations, but I have in France had much
conversation in regard to them with others of similar tastes who have
resided in the midst of them. The accounts given to me were vague,
but not more so than conversational statements in general are. They
left on my mind the impression that on the sea margin there is a pretty
broad beach, and some 100 yards or more from this — 200 it may be,
or 300 — the trees have been planted in a belt following, to some ex-
tent, the line of the coast, and extending in breadth irregularly from
half a mile to a mile, it may be, or more, beyond which the planta-
tions are continued in strips of some breadth, crossing each other at
right angles, and thus enclosing quadrangular patches or fields, which
have been brought under cultivation. Upwards of 100,000 acres of
land were reported to me as having been reclaimed, and to a con-
siderable extent covered with trees.

CHAPTER III.

Legislation in Regard to the Planting op the Landes
WITH Trees.

The planting of the Landes with trees was begun in 1789, under the
direction of the Minister, M. Necker, (father of Madame de Stael).

On the 13th Messidor an /X(2nd July, 1801), there was issued the
following Arret6, or Order, relative to the plantation with wood of
the Dunes on the coast of Gascony.

" The Consuls of the Republic on the report of the Minister of the
Interior, the Council of State having been heard, order :

" Art. 1. Measures shall be taken to continue to fix and to plant in
wood the Dunes of the coasts of Gascony — beginning with those of
La Teste — according to the plans presented by the citizen Bremon-
tier, engineer, and the Prefect of the department of the Gironde.

" 2. To this effect there shall be established a commission, composed
of the chief engineer of the department, who shall preside, a forest
administrator, and three members taken from the agricultural section
of La Societe des sciences, arts et belles-lettres de Bourdeaux, who shall
be appointed by the Prefect on presentation by the society.

" The said commission shall direct and superintend the execution of
the works, together with the employment of the funds which shall be
appropriated thereto. The whole under the authority, and with the
approval of, the Prefect." . . .

By another order, issued under date of the 3rd Jour complementaire,
an IX, it was ordered :

" Art. I. The measures prescribed under Order of the IStk Messidor,
an IX, for the fixation and plantation of the Dunes on the coasts of
Gascony shall, in what relates to wicker hurdles and other artificial
works which they shall require, be discussed on the plans of the
citizen Bremontier, Engineer-in-chief, and approved by the Prefect of
the department of the Gironde ; and in what relates to sowings and
plantations these must be arranged with the Administration of Forests.

" 2. The expenses for hurdles and other artificial works shall be
made from the funds of the department of the Interior, and those for
the plantations and the salaries of forest agents from the funds
appropriated to forests."

28 LEGISLATION RELATIVE TO

By decree of 12th July, 1808, it was declared : "Art. 22. There
shall be established in the departmeut of the Landes a commission
for the plantation of the Dunes.

" This commission shall be organised in the same manner as that
established at Bordeaux in execution of the decree of the 18th
Ifcssidor, an IX."

On the 14th December, 1810, the following decree was passed by
Napoleon :

"Napoleon, &c. — On the report of our Minister of the Interior,
our Council of State having been heard, we have decreed and do
decree as follows :

" Art, 1. In the maritime departments there shall be taken measures
for the sowing, the plantation, and the culture of vegetables known
to be the most suitable for the fixation of Dunes.

" 2. To this effect the Prefects of all the departments in which are
Dunes shaU cause to be prepared in their respective departments by
the Ingenieurs des Fonts et Chaussees, a chart of the Dunes which are
susceptible of being fixed by plantations appropriate to their nature ;
they shall cause to be distinguished on their charts the Dunes which
belong to the domains, those which belong to communes, and those
which are the property of private persons.

" 3. Each Prefect shall draw out, or cause to be drawn out, in
support of these charts, a memoir on the most advantageous manner
of proceeding, according to localities, in the sowing and planting of
the Dunes ; they shall annex to this report a draft of regulations,
which shall contain the measures of administration the most
appropriate to his department, which can be usefully employed to
effect the end desired.

" 4. The charts, memoirs, and drafts of regulations, got up and
drawn out in execution of the foregoing articles, shall be sent by the
Prefects to our Minister of the Interior, who can, on the report of our
Director-General des Fonts et Chcmssees, order the plantation if the
Dunes do not include any private property ; and, in the contrary case,
he shall make his report to us, to be by us decided in Council of State
in the form adopted for regulations of public administration.

" 6. In the cases in which the Dunes shall be the property of private
persons, or of communes, the charts shall be published, and posted
up in the forms prescribed by the law of 8th March, 1810 ; and if
the said private persons or communes find themselves incapable of
executing the works commanded, or refuse to do so, the public

PLANTATIONS ON THE DUNES. 29.

administration shall be authorised to see to the plantation at their
expense ; they shall retain possession of the Dunes, and collect the
proceeds of the fellings which may then be made, until complete
recovery shall have been made of the expenses which have been
incurred in the case, and of interest thereon ; after this the Dunes
shall return to the proprietors, under burden of maintaining satis-
factorily the plantations thereon.

" 6. In time coming no felling de plants d'oT/ats, of mat grass epines
maritimes, pine trees, silver firs, larches, and other arenaceous plants,
ministering to the conservation of the Dunes, shall be made without
the special authorisation of the Director-General des Fonts et
Chaussees, and on the advice of the Prefects.

" 7. There shall be established Guards for the conservation of the
plantations actually existing on the Dunes, or which shall be made
there in time to come ; their appointment, their number, their duties,
their salary, their uniform, shall be regulated after the mode in use,
for the guards of communal woods.

" Offences shall be prosecuted before the tribunal, and punished
conformally to the provisions of the Penal Code.

" 8. We do not design, by the present decree, to innovate aught on
what is practised for the plantations which are being executed in the
Dunes of the departments of the Landes, and of the department of
the Gironde.

" 9. Our Ministers of the Interior, and of Finances, are charged
each in what concerns him, with the execution of this decree."

After the restoration there was decreed the following Ordinance :

" Ordinance of 5th February, 1817, relative to the fixation and the
sowing of the Dunes on the departments of the Gironde and the
Landes.

" Louis, &c. — On the reports of our Ministers, Secretaries of State
in the departments of the Interior and of Finance, our Council of
State being heard, we have ordained, and do ordain as follows :

"Art. 1. The works of fixation and of sowing the Dunes in the
departments of the Gironde and of the Landes shall be resumed in
1817.

" These works shall, in regard to execution, be directed by our
Director-General des Fonts et Chaussees, under the authority of our
Minister of the Interior.

2. The necessary funds for this operation shall be charged in the
budget des Fonts et Chaussees, the yearly credit must not exceed
9 0 ,000 francs for the two departments.

30 LEGISLATION RELATIVE_TO

3. The works shall be executed, the expenditure made, and the
accounts rendered, according to the mode adopted for the service
des Fonts et Chaussees.

" 4. In succession as the sowings reach an age which shall be
afterwards determined, they shall cease to be entrusted to the
Director des Fonts et Chaussees ; but he shall transfer them to the
General Administration of Forests.

*' 5. The General Administration of Forests shall furnish, free of
charge, to the Direction des Fonts et Chaussees, the seeds, young trees,
and boughs, yielded by the forests which they administer, which
shall be necessary for the fixation and sowing of the Dunes.

" 6. The Ingenieurs des Fonts et Chaussees are authorised to require
assistance of the forest agents and guards in the tours of inspection
which they shall have to make over the whole extent of the Danes.

" 7. It shall subsequently be decided what special measures shall
be taken to prevent and to repress the offences which tend to destroy
or to injure the works of sowing the Dunes.

" 8. A regulation of our Director-General des Fonts et Chaussees,
approved by our Minister, Secretary of State for the Interior, shall
determine the advance of the works, their range and their surveillance.
(This was done by a regulation dated 7th October, 1817.)

"9. The orders of 2nd July, and 20th September, 1807, are
abrogated, together with all other provisions contrary to the present
ordinance.

'* 10. Our Minister, Secretary of State for the Interior, is charged
with the execution of the present ordinance."

On 29th April, 1862, was issued a decree, which places the
superintendauce of the Dunes within the duties of the Minister of
Finance. * The provisions of this are as follows :

" Art. 2. The works of fixation, of maintenance, of conservation, and
of exploitation of the Dunes in the maritime coast are placed within
the range of duties of the Minister, Secretary of State of Finance,
and they are entrusted to the Forest Administration.

" 8. These provisions shall come into operation on 1st July, 1862.

" 4. Our Ministers of State, of Finance, of Agriculture, of Commerce,
and of Public Works, are charged each in what relates to his de-

* A law appears to have been issued in 1857, enjoining the draining and
planting of all lands belonging to communities within the district of the
Landes, but this I have not seen.

PLANTATIONS ON THE DUNES. 31

partment with the execution of the present decree, which shall be
inserted in the Bulletin des Lois.

These enactments tell this much of the history of the work :
that the views of M. Bremontier commended themselves to the
execution of the Kepublic, and that he was entrusted with the
execution of the work at the public expense, under legitimate
restriction ; that the work was ordered to be begun at the Dunes
of La Teste in Gascony, in the first year of the present century, and
seven years later they were begun on the Landes ; that the work was
carried out with if possible greater energy under Napoleon the 1st,
and subsequently under Louis XIV ; and that, carried out previously
under the Minister of the Interior, they were in 1862 transferred to
the control of the Minister of Finance, and entrusted to the Forest
Administration.

CHAPTER IV.

Literature Relative to the Arrest and Cultivation op
Drift-Sands in France.

The work of planting the Landes of Gascony, as has been stated, was
begun in 1789.

In 1790 was published a Memoire sur les Dunes, c&c, by" M.
Bremontier, by whom the work was projected and begun under the
direction of M. Necker. In this memoir M. Bremontier describes the
formation of the sand-dunes, and of the measures which had been
adopted to arrest the drifting of the sand.

In 1806 appeared a Rapport sur les diff events Memoirs de M.
Bremontier, by M. M. Laumont, et autres.

In 1827 was published Historique de la creation d^une Eichesse
Millionaire, par la culture des Pins, by M. Delamarre ;

In 1831, a Notice stir les travaux de la fixation des Dunes, by M.
Lefert, Ingenieur des Fonts et des Chaussees, in Annales des Fonts et
Chaussees, 1831, 2nd Semestre.

In 1833, in Annales des Fonts, &c., 1st Semestre, were reprinted
the Memoire by Bremontier, and the Ra2}port, by Laumont and others,
mentioned above.

1842, a Notice sur le pin Maritime, by M. Lorentz, appeared in
Annales forestiere.

1847, a Memoire sur les Dunes de Golf de Gascoyne, par M. Laval,
Ingenieur en chef, Directeur des Fonts et Chaussees, appeared in
Annales des Fonts, &c., 2nd Semestre.

This is spoken of as a very remarkable Memoir, which, though
less extensive and comprehensive in subject than that of the dis-
tinguished Bremontier, fully and perfectly explains the formation of
Dunes, and the latest and most approved methods employed to fix
them.

In 1857 was published a second edition of Mise en valeur des terres
pauvres par le Fin Maritime, by Am6d6e Boitel, Inspecteur de
r agriculture.

In 1862 appeared an interesting article entitled, Le littoral de la
France, by Missee Reclus, in the Revue des Deux Mondes, for
December, 1862.

FRENCH AND GERMAN LITERATURE. 33

In 1864 was published Traite de la Culture du Pin Maritime dans
les Landes, by Eloi Samanos, Paris. 8vo,

About this time, I presume, was published " The Desert World,"
by Arthur Mangiu, from a translation of which, published by Nelson
and Sons, I have quoted so largely ; and Weld's " Tour through the
Pyrenees," to which I am also so greatly indebted.

In 1870 an interesting report on the Landes of Gascony was made
to the academy, by M. Faye.

These works I cite as bearing chiefly upon the planting of the
Landes of Gascony and the Gironde.

The literature thus cited relates only to one aspect or department
of a wider subject : The natural history of drift sands, and means
of arresting and utilising them.

The literature on this subject is voluminous. It is chiefly in con-
nection with sylviculture in Gascony that the students of the natural
history of Dunes in France have published the results of their obser-
vations. It may be, and probably it was the case, that the planting
of the Landes with trees called then for the study of the subject, and
supplied, at the same time, the opportunity of careful observation.
But much as we may owe to French writers on the subject, it is not
to them alone that we are indebted for information on the subject ;
and none will be more ready than they, with the courtesy of their
nation, and the honourable feeling of men of science, to admit that it
is not to them or to their countrymen, but to others, we are indebted
for information on many points surpassing in importance in their
relation to physical geography what they have communicated,
relating as this did chiefly, though not exclusively, to the cultivation
of these Dunes when formed, and the practicability of doing so
advantageously to all concerned.

While they were thus employed, in other nations the subject in
other aspects of it was commanding and receiving attention. In
1832 appeared Anleitung zum A^tban der Sandficichen ; and in 1838
was published a work entitled Over den Oorsprong en die Geschiedenis
der HoUandsche Duiueii, by Hull. The latter relating to the origin
of the Dunes, the former to the planting of them.

In 1841 appeared a paper, by G. Forchhammer, entitled Geognostische
Studien am Meeres Ufer, in Leonhard und Broun's JVeues Jahrbuch
fur Mineralogie, Geognosie, Geologie, o&c. Jahrgang, 1841.

In 1846, was published Die Inseln und Marschen der Herzogtkiimer
Schleswig und Holstein. Dresden and Leipsig. 3 vols. 8vo.

E

34 LITERATURE OF THE SUBJECT

In 1850, Ber DUnenhau auf Ostsee, Kusten Wesf-Preussens, by G.
C. A, Krause, 1850, appeared; and subsequently there was published.

In 1854, Ansichteii uher die Bewaldiing der Stepioen des Europdischen
Russlands, by J. von den Brincken. Braunschwieg. 8vo.

In 1856 was published at Haarlem De Boden von Nederlanden, by
W. C. H. Staring.

In 1861 was published at Copenhagen Om Klit formationen og
Klittens BeJiandlhig, og Bestyvelse, by C. C. Andreson.

And in 1873 was published at Vienna Der Euroixiische Flug sand
und seine Kidtv^r, by Josef Wessely, in which is given a list of upwards
of 100 books and papers on subjects pertaining to this department of
forest science in Hungarian, Latin, and German, published in
Hungary alone.

In our own language valuable information in regard to the natural
history of sand, and of sand dunes, is given by the Honourable Mr
G. P. Marsh in his volume on " The Earth as Modified by Human
Action ;" and by Professor R. C. Kedzie of the Agricultural College
of the State of Michigan, in a lecture delivered at the College, in
September, 1870 ; which will be printed in the appendix.

It does not come within the scope of my purpose in this volume
to enter upon the consideration of the more comprehensive views of
the subject thus opened up. The discussion of these is for the pre-
sent postponed.

In accordance with what has been advanced in a previous chapter,
is a narrative of the operations given in an article on pine trees,
which appeared in the Edinburgh Review in October, 1864.

From this it appears the Landes, in Gascony in 1789, covered 300
square miles, ever shifting, and ever encroaching on the productive
land beyond this sand. M. Bremontier, in the administration of forests,
set himself to fix, and, if practicable, so to utilise this as to make it
productive.

" In his report of proceedings, he compared this sandy tract to a
billowy sea. It ofi'ered nothing to the eye but a monotonous
repetition of white wavy hillocks perfectly destitute of vegetation.
When violent storms of wind occurred, the surface of these downs was
entirely changed — what were hills had become valleys, and valleys,
hills. The sand on these occasions was often blown into the interior
of the country, actually covering cultivated fields, villages, and
even entire forests. This was done so gradually by a shower of
particles as fine as the sand used for hour glasses that nothing was

IN THE " EDINBURGH REVIEW." 35

destroyed. The sand gradually rose amongst the crops as if they
were inundated with water ; and the herbage and the tops of trees
appeared quite green, and healthy even at the moment of their being
submerged. On this moving and shifting sea, M. Bremontier sowed
seeds of the common broom mixed with those of the pinaster, com-
mencing on the side next the sea — or on that from which the wind
generally prevailed, and sowing in narrow zones in directions at right
angles to that of the wind. The first zone was protected by a line
of hurdles, and after it was established, it protected the second, as
the second did the third, and so on.

" To prevent the seed being blown away before it had germinated
and become firmly rooted, he protected it by various ingenious modes,
such as hurdles and thatching, and he had at last the gratification,
after conquering many difficulties, of seeing his first zones firmly
established. The rest was then comparatively easy ; and by degrees
the trees covered the whole of these sandy downs, not only providing
the interior country with a barrier against the incursion of the sands,
but turning the downs themselves from a desolate waste into a source
of productive industry. Although the timber is of little value, the
manufacture of tar, turpentine, and other resinous products furnishes
sufficient occupation for the inhabitants, who are thinly scattered
over large spaces. Among the effisrts of man to control the elements
and the powers of nature the conquests of the Landes from the desola-
tion of the desert is entitled to a place beside the recovery of Holland
from the empire of the sea.

"An agricultural genius, who, having studied agriculture, and
particularly drainage, under scientific teachers, devised a system of
reclaiming and husbandry, which has been very successful.

" Prosperity is rapidly following these improvements, and, what is
better, malaria no longer poisons the reclaimed district. The
peasantry enjoy better health, and M. Pierre firmly believes that the
terrible pellagri will soon be unknown in the Landes."

CHAPTER V.

Culture op the Maritime Pine on the Landes op Gascony.

M. BoiTBL, in his volume entitled Mise en valeur des Terres pauvres
par le pin maritime, supplies much of the information which is
naturally desired in proceeding to enquire what steps should be taken
in carrying out similar measures elsewhere.

The following is a resum6 of the details of operations followed in
Gascony, as reported by him. Having referred to the circumstance
that these two distinct forms of sand-lands, the one situated more in
the interior of the land, immobile, or at least settled, and ranked by
geologists amongst the formations of the tertiary period ; the other
found in the neighbourhood of the sea, and belonging to the dune
formations still going on, mobile, and affected by the winds ; he
describes, first, the formation of pineries, or plantations of pine on
the fixed sands.

Operations are carried on generally thus on lands covered with
heather, or heather brooms, and whins : If the land be capable of
tillage they begin by enclosing it, so as to exclude cattle, which, but
for this precaution, would over-run the plantation, and do great
damage to the seedlings or plants. This is effected by the formation
of what is locally called a harradeau, composed of an exterior ditch,
the inner bank of which is furnished with a wall of earth covered
with sods about a metre, or- 40 inches, in height. It is constructed
entirely of earth dug in the formation of the ditch, and is almost
vertical on the outside ; on its inner side it is formed of the sand
furnished by the same ditch, leaning against the wall to a height of
45 m.m., or 18 inches.

This done, advantage is taken of the weather to set fire to the
bush, taking necessary precautions against the extension of this
beyond the enclosure to the bush, or pineries adjacent. If the ditch
be not deemed sufficient, a band of 1 or 2 metres in breadth is cut
with a scythe along the outside of the harradeau, and the bush and
brushwood thus obtained is thrown into the interior of the enclosure.

When the growth of bush is strong and near a tile-work, it is often
advantageous, instead of burning it on the ground, to sell it for use
in the kiln.

boitbl's account of operation. 37

Some careless proprietors sow the pine seed on the land amongst
the bush, without any preparatory work. In such cases the seedlings
push their way with difficulty, and the young pines remain long in a
miserable and languishing state, if they do not altogether succumb in
the struggle. In the district of Orleans a careful preparation of the
soil is necessary, but in Gascony it is enough that the heath be
mown or burned.

It is found advantageous to sow in September, but it may be sown
on till May, and in favourable spots till the end of that month.

When the ground is free, five or sis seeds are deposited in holes
made with a small wooden trowel, 60 m.m., or 2 feet apart, and 10 or
12 inches deep. Where the ground is hard or covered with sod,
the holes are dug with a pick-axe or a hoe. Brooms are sown at the
same time to give shade and shelter to the seedlings, which are very
sensitive, both to sunshine and to cold,

By Bremontier, first hurdles or wicker work, and afterwards trees
were employed in his successful undertakings to arrest the drift-sands
of the Landes, and the two appliances are used conjointly; while not
a little is accomplished by the natural, or aided, spread of the
indigenous vegetation, the different kinds of which, in accordance with
the laws regulating the distribution of plants, grow well in their own
domains.

"On the very margin of the sea," says Boitel, "that is at the limit
reached by the waves on the slope of the coast directly opposed to all
the marine inflaences, we admire the robust vegetation of the
calamagrostis arenaria, (a species of small reed), called there gourhet ;
of the triticum junceum, (a species of Couch grass) ; and of the
Festuca sabulicola (a species of Fescue grass). These are the three
species of plants which, by their vivacious condition, their long, wide-
stretching and resisting roots, their numerous and persistent leaves,
and the length of their stipes, or stalks, contribute most powerfully to
arrest the sands. Some other herbaceous plants also are feeble
auxiliaries to them in doing so — such are the convolvulus soklanella
(the sea convolvulus), the arenaria jyej^loides (ovate leaved Honckenya),
the caTcile maritima (sea rocket), the galum arenaria (a species of
lady's obedstraw), the eryngiimi maritimum (sea holly), and the
euphorbia paralis (sea spurge).

" Leaving this little slope battered by the sea, and mounting the
terrace which dominates the sea there for a breadth of from 400 to
500 metres — ligneous vegetables are as yet unable to maintain them-

38 CULTURE OF THE MARITIME PINE.

selves against the sea-breeze, — we find only a herbaceous vegetation,
which comprehends the species which have been mentioned, and with
them the following : — Elychrysum stoechas (a species of everlasting),
carex aremiria (sand carex), Unaria serpyllifolia (thyme-leaved toad
flax), thymus serpylliom (wild thyme), hoeleria cristata (crested koeleria),
aira canescens (gray hair grass), lotus corlatus (nicurd's foot trefoil),
jasione montana (common sheep's bit), silene hicolor (a species of
campion, or catchfly), cdyssicm arenarium (sand alyssum), hieraceum
prostatum (a species of hawliwood), anthyllis vulneraria (lady's fingers),
astragalus hayonensis (a species of milk vetch), medicago maritima
(seaside medick), dianthus gallicus (French pink), ononis spinosa
(prickly rest-harrow), sedum acre (biting stoncrop), diotis candidissiam
(white cotton weed), thrincia hirta (hairy thrincia), Grithmum mariti-
mum (sea camphire), artemisia crinthmifolium (camphire leaved worm-
wood)."

It is the zone which succeeds this last, extending from Bayonne to
Cape Breton, which has, by the care of the Government, been devoted
to the culture of the maritime pine.

In regard to outlying portions of the zone of plantations, he says :
— "It is interesting to visit the maritime pines, which look like
advanced posts, planted there to withstand the sea, and arrest the
winds and the sand. Although they are under the shelter of an en-
ormous screen of sand accumulated by the waves, they are all mutil-
ated and deformed ; no one has kept his head ; they have the trunk
laid against the ground, the branches are covered up with sand, and
having assumed the appearance of young pine layers. The sea winds
have levelled up the sand on them to a depth of 1.50 meters, or 5 feet.
The grains of sand driven by the tempest give to the leaves violent
and multiplied strokes, which make them become yellow and dry.

" In proportion as the distance between them and the sea is in-
creased, being numerous and varied, they give mutual support ;
they also increase in size, and resume by degrees their natural form.

"Beyond this zone of deformed and stunted pines we find at about a
kilometre, (two thirds of a mile) from the sea, beautiful pineries
which furnish in abundance wood and resin. But it must always be
born in mind that these pines never acquire the dimensions, the
regularity, and the vertical growth of the pineries farther inland ;
the influence of the sea makes itself be felt over a radius of from 2
to 3 kilometres (or two miles)."

Sometimes a spontaneous and vigorous vegetation fixes and oonsoli-

ACCOUNT GIVEN BY OOURREQES. 39

dates the sand on level spots which present little hold to the violence
of the wind ; but it is the maritime pine which plays the most im-
portant part in eflfecting this.

Two principal things have to be attended to by the forester to
whom it is entrusted to sow the pines in these mobile lands. He
must seek first to prevent the adjacent sand from invading and
annihilating the sowing ; and, second, to prevent the wind cai'rying
away or otherwise modifying the surface of the ground sown: that is,
in other words, he must fix down the adjoining sand, and protect the
ground sown. The first must be done by plantation of Gourbet,
calamagrostis arenaria (sand small reed), or by clayonnages, lines of
wickerwork. We are indebted to Courreges, a careful observer,
early lost to forest science, for the following notes preserved in the
Annates forestiere for 1847, which relate to the employment of these
wickerwork fences and the subsequent sowing of the seed.

" The clayonnage is the best means to employ to consolidate the
drift-sands and prevent their displacement on parts exposed to the
wind ; and this is the first thing to do before proceeding to sow the
seed,

" Clayonnage may be eff"ected in three ways — first, with planks or
beams j second, with stakes dressed with branches ; third, with
heather or other bushes.

" It is carried out in such a way as to receive at an angle of 45°,
the winds coming from the north-west or from the south-west, which
are the most violent winds, and those most to be feared for the
sowings. It takes the form of a triangle of which the base is parallel
to the shore, and the two sides form, with this base, an angle of 45°,
the exact direction of the aforesaid winds."

The employment of planks and beams, in the structure of these, is
almost abandoned. It is the most expensive of the three modes
of clayonnage, and it does not appear to me that it would be of any
use to describe it.

" The Clayonnage of stakes, is composed of poles, about 2 metres
(or nearly 7 feet) long, planted in lines some 20 inches apart. They
are united by branches of heather, or other bushes placed as closely
together as possible

" The Clayonnage of heather is formed of four parallel ranges of
bundles of Erica Scoparia (small green-flowered heath), or of other
bushes growing on the land, such as whins, brooms, &c. These
bundles may be 9 or 10 inches in girth ; they are planted — quincunx,
fashion 6 inches apart — in lines 10 inches distant.

40 CULTURE OF THE MARITIME PINE.

"The moving sand striking against this is stopped, and it gradually
fills up all the intervals, and forms thus a slope with two sides. In
proportion as the dune rises, care is taken to raise, from time to time,
all the bundles of the four ranks until it is judged that the dune is
sufiiciently elevated to protect the sowings on the adjacent zone.

" The costs of the two are about the same ; but the latter lasts
longer, and is more easily maintained. Nevertheless, the former is
perferred for points on which the wind acts with more force and
violence."

Of the sowing, M. Courreges reports —

" They sow by hand broad cast 16 kilogrammes (about 351bs.) of
pine seed, and 7 kilogrammes (15| lbs.) of broom seed to the acre,
sowing the one after the other, because, being of different weights,
they would be ill sown if they were mixed.

"They immediately cover up the surface sown with brushwood,
composed of heather, whins, and other bushes, laid with the root to
the wind, that they may be less easily raised by the action of the
wind, and fixity is given to the covering by loading it with some
shovelfuls of sand.

" Branches of the pine are little esteemed as a covering, because
they very soon become despoiled of the leaves with which they are
clothed.

" When the covering up of the ground is completed, it is well to
cast over it 4 or 5 kilogrammes (9 or 10 lbs.) of pine seed, which
falling between the branches, may come to replace seeds buried to
too great a depth by the treading of the workmen.

" The broom and the maritime pine appear above the sand about
the same time, but the broom developes more rapidly, and soon covers,
with its shade, the young pines, the vegetation of which shows itself
pretty promptly and pretty vigorously under the protecting shelter."

In the Landes they value the cork oak, and not without reason,
because of its product, and it is often grown along with the maritime
pine, under the shade and shelter of which it grows up erect, yielding
its bark in good condition for sale, whereas otherwise it is apt to be-
come bushy. It is sown in a similar way two years after the sowing
of the pine.

In some cases, but not generally, pines produced by natural sowing
on marshy land, are cut out with a sod of such size as to contain all
the rootlets, and planted in holes dug for them of the same size, with

ARREST OF THE SAND. 4l

the same exposure, arranged in lines, and from 6 to 7 metres, (20 to
24 feet) apart. This cannot be done with seedlings in sandy soil,
as the soil would not cohere to the roots. When done quickly it
often succeeds well; bat with sundry disadvantages.

The trees yield resin as well as the others, but they do not grow so
regularly as to yield equally useful wood.

By Boitel it is intimated that it is well that the young pines which
grow in the vicinity of the sea should be numerous and closely grown,
as they can then resist with greater efficacy the shock of the winds
and storms, and, through the mutual support which they give, they are
less likely to bead and break under the load of snow cast upon them
in winter.

The expense being greatly increased by the covering of branches,
to avoid this in many cases after the preliminary step of securing
shelter by an artificial dune, raised by clayonnage, they wait till the
sand is fixed by a spontaneous vegetation, or a plantation of gourhet
(calamagrostis arenaria), in spots a mfetre, or 40 inches apart ; and
when this has been done the grain is sown or planted in accordance
with the method adopted on old inland sands. This is found to
do pretty well.

When none of the measures described are practicable, the seed is
sown on the bare and mobile sand, and covered with branches of
pine obtained from the thinnings and prunings of the nearest pineries.

In this case, the branches are disposed north and south ; along-
side of the first branch is laid a second ; along-side of the second a
third, and so on till the summit of the dune is reached. The
branches are cut of equal length, somewhere between 3 metres, or
3-50— or 10 and 12 feet.

The first line of branches being formed, a second is laid down, and
a third, the one to the right, and the other to the left, in such a way
that the branches intercross.

And to fix the whole, there is laid on the ends of the branches
a pine pole of about 8 centimetres, 3 or 4 inches in circumference,
which is fixed in the ground at the end with small hooks of wood.

If any part of the dune be firm, then this covering is dispensed
with.

The expense of covering is great, but this need not be grudged, as
the drift sands, once covered with pines, produce vigorous forests,
which in a few years furnish wood and resins in abundance. And
thus have these drift sands been arrested, and kept from carrying
destruction to fields, and forests, and villages more remote, as may

F

42 CULTURE OF THE MARITIME PINE.

be seen to have happened near the little lake of L6ou, and at Vielle, a
village of the Landes, where even the church disappeared under the
sand borne thither by the wind.

In accordance with this account is the following given by M.
Bagneris, hispecteur des Forks, et Professeur a VEcole foresti^re
de Nancy, who visited the plantations in 1873 : — " In the month of
January last," says he in a supplement to a volume published by him,
entitled, Manuel de Sylvicdture, " I made an excursion through the
district of the Dunes, from Bayonne to Tremblade, accompanied by
M. Nanquette, Director of the School of Forest Science, and my
colleague, M. Broilliard. I can thus give an account of the means
used for their fixation and reboisement. I also studied the treatment
of the maritime pine as regards the collection of resinous products.

" On the low and sandy shores which skirt the sea between the
mouths of the Adour and the Gironde, every tide bears along a very
fine sand. At low water this sand is conveyed inland by the wind,
making constant encroachments and it is always succeeded by more,
whence result moving heaps, sometimes 70 metres high (upwards of
230 feet), sloping gently on the side next the sea, and steep on that
next the land. Sometimes these heaps take the form of continuous
hills lying in straight lines with valleys between, sometimes they
appear without any order. This depends on the coast line. The
former arrangement is met with between the Adour and the Gironde,
whilst at the Point de la Coubre the second form I found to prevail.

"These moving sand hills are called Dunes. It is ascertained that
their progress landward is at the average rate of 4*30 m. a year
(15 feet), and that the quantity of sand thus transported is about 75
cubic metres to the running metre of the length of the Dune, (In-
formation given by M. Dutemps du Gric, Conservateur at Bourdeaux).
The valleys there called lettes are of variable size, the bottom is flat
and usually marshy where the Dunes are bare, or dunes blanches as
they are called in that country.

" It may easily be imagined what an interest is taken in reclaiming
and fixing these Dunes whose advance threatens to swallow up all,
even menacing human habitations, which more than once it has been
necessary to move inland from before them. In the first place the
sand is temporarily arrested by means of clagonnages and stone,
rooted plants, such as the goicrbet, the spurge, the fesgue grass. The
maritime pine follows to fix it and make it valuable. This last is
admirably suited for such local conditions as there prevail. It grows
uaturaUj in mild climates, and its tap root is furnished with strong

REPORT BY BAGNERI8. 43

lateral branches, which throw off throughout their length numerous
secondary tap-roots. Along with these valuable properties it possesses
the advantage of supplying valuable and abundant resinous products.

" The maritime pine has long been used in the Dunes. The forest
of Teste must be several centuries old. But it will only thrive quite
close to the sea. After the works carried on by Bremontier, which
were begun in 1787, it was planted quite up to the brink of the
beach. I shall state how this is done.

" Before putting in the seed a protecting barrier must be erected
to prevent the sand from burying the seed and young trees. This
barrier is nothing but an artificial Dune, called the dune littorale ;
it is formed by erecting a palisade parallel to the shore, at about
100 metres from the high water mark. For this purpose planks are
employed of about 1*60 metres in length, 3 centimetres in thickness,
and from 12 to 15 centimetres broad ; a furrow, 40 centimetres deep,
is dug in the sand, in which the planks are sunk to a depth
of 20 centimetres, the lower ends being cut in a tapering form.
In this way, when the furrow is filled up, the planks are buried
to a depth of 60 centimetres, 1 metre being above ground. They
do not touch each other, a space of 2 centimetres being left
between.

"The sand arrested by the palisade arranges itself in heaps
sloping gently towards the sea; the interstices allow a certain
quantity of sand to pass through, which increases the base, and
consequently the solidity of the Dunes. When the palisades are
almost covered, the planks are extracted by the help of a lever with
claws, and the Dune goes on increasing. It should not increase too
rapidly, because, if so, it might be destroyed by a wave.

" The better to secure its base behind the palisade a barrier is
formed of stakes, of 2*50 metres, between which flexible branches are
interlaced. The stakes are driven in to a depth of 50 centimetres,
and the clayonnages at first are only one metre high ; the height is
increased as the Dune rises, and when it reaches the top of the
stakes a new barrier is erected as the stakes cannot be removed as was
done with the palisade.

" The whole is then consolidated by plantations of gourhet, which is
arranged in tufts of from 5 to 6 stems, with 50 centimetres between
each. The gourhet has this advantage, that as the sand increases in
depth, the stalks rise, and produce roots which form a perfect net-
work; 300 bundles of gourhet of 10 kilogrammes each, besides 6
kilogrammes of seed are required per hectare. The seed is sown

44 CULTURE OF THE MARITIME PINE.

broad cast ; the operation of planting, and the feet of the workmen
assist in covering it.

'* The palisade costs from 2*50 francs to 3 francs per mfetre, it lasts
five years when made of pine which has not been injected. Its
keeping up and removal cost about 50 centimes a year. The
barrier costs about 30 centimes per running mfetre, and it should be
renewed nearly every year.

" If there be any danger of the littoral Dune being injured by the
wind, other palisades should be erected, at a certain angle with the
first, on the sand which has been dislodged. At present there is a
well kept up dune littorale, more than 200 kilometres long, from the
bar of the Adour to the mouth of the Gironde.

" When once a shelter from the wind is provided rehoisement should
be begun. This is done by scattering a mixture of the maritime
pine, broom, whins, and gourhet. For example, in the operations
carried on by the State, 10 kilogrammes of the seed of the maritime
pine, 9 kilogrammes of broom, and 4 kilogrammes of gourhet seed are
used per hectare. It is then covered by faggots of brushwood, broom,
and whins. One man unties the bundles, two others spread them
out, and a third places a spadeful of soil at every 50 centimetres to
secure the covering which is absolutely necessary to prevent the seed
being carried away, and especially to keep the sand in its place. For
this purpose rushes are better than broom, because they furnish a
better manure when decomposed.

" The seed should be sown, and the covering put on, simultaneously.
At the close of each day additional earth should be laid on the last
laid brushwood to protect it from the wind. Care should also be
taken to arrange it equally and close to the ground, so as to leave no
air holes, for in a single night the labour of several days may be lost.

" Pines, broom, and whins will grow together, and it is remarked
that pines thrive best where the two last abound. When these are
sparse much care must be taken in watching over the covering, as
protection is necessary for four years. It should even be renewed,
and this is one of the chief things to be done in maintaining the work.

" After some years the rehoisement of the dune littorale may be pro-
ceeded with, by erecting a wide palisade nearer the sea, but whether
this be done or not, the dune littorcde must always be kept in good
order, otherwise the works would be inevitably buried by the con-
tinual advance of the sand.

"Such is, in short, the kind of work to be done. It is often
tedious, and, in certain circumstances, difficult. To consolidate and

ACCOUNT GIVEN BY BOITEL, 45

plant with trees the Dune, will cost, at least, 500 francs per hectare.
This outlay ceases, however, to appear exorbitant when we consider
the protection which it provides. Almost the whole is laid out on
the erection and keeping up of palisades, and chiefly in the ti'ansport
from long distances, across moving sands of great depth, of the
required planks and faggots of brushwood."

And it is stated by him that one effect of the reboisement — or, as
that word is scarcely applicable though the word employed, the
growth of the pineries — has the effect of drying up the stagnant
water in the lettes, " either," says Boitel, " by the evaporation con-
nected with vegetation, or more likely by the formation of mould, by
which the moisture is absorbed and retained, or by some unknown
operation."

Such artificial sowing as has been described may be necessary in
taking in new ground, and it is practised elsewhere; but in the
Landes natural reproduction is sufi&cient to maintain the pignadas.

" The pine," says Boitel," produces cones with impricated scales.
These scales, compactly arranged, varnished, and of bone-like consis-
tence, form a covering for the seed which may seem to be indestruc-
tible ; but by an organisation which calls forth manifested admira-
tion of the Providence, the scales which man could scarcely break by
artificial means open as if by enchantment when they attain a
certain temperature.

" The heat in dilating them, causing them to bend backward,
separates them one from another, and in the new position thus taken
they oflfer an easy exit to the winged seed which they had previously
held imprisoned.

"Let it be borne in mind that the cones remain attached to the tree
beyond the period of their maturity, that they are persistent and
pendent on their peduncle, or stalk, and it will be seen that they are in
a position admirably adapted for favouring the escape of the seed, and
this, yielding to its weight, detaches itself freely from the opened
out scale, and immediately by its wings it comes under the disseminat-
ing influence of the winds.

" The seeds thus sown germinate under the shade of the old trees,
and form a young repeuplement, or new generation of trees, to take
the place of the old when they shall pass away ; and destined to be
productive when the time shall come for the final and complete
exploitation of the older trees reserved for this purpose.

" These natural sowings are, so to speak, the only means of produo

46 CULTURE OF THE MARITIME PINE.

ing the repeuplement of the pineries of Gascony required. The
maritime pine finds in that land conditions so favourable to its
development that it goes on reproducing itself indefinitely on the
same ground, without any necessity for man to trouble himself about
the sowing of fresh seeds. Often, in order that a sandy surface may
cover itself spontaneously with young pines, it is enough to surround
it with an enclosure, which shall keep out from the pasturage which
it supplies cattle left without surveillance in the pineries."

An illustration of the importance of this occurs in one of the earlier
works by Darwin. It is stated, if my memory serves me right, that on
a piece of waste land or heath a common having been enclosed, forth-
with, to the surprise of many, there began to grow up vigorously
seedling pines, though pines had never been grown there before.
And, on examination, it was found that all around, growing amongst
the grass, were decapitated seedling trees, which had sprung up from
self-sown seed, but been broken over by cattle grazing there ; and
apparently nothing more was required in order to the whole becoming
a forest of pines than that this destructive operation should be
prevented by a fence to exclude the cattle.

When the pineries become fairly established on the Dunes in
Gascony, or on fixed sands more inland, which belong to the tertiary
formation, they require, as the trees increase in size, to be subjected
to periodical thinnings, and in some cases to moderate pruning
judiciously executed.

" In thinning, attention is given to removing the worst of the
trees, and to leave to the better trees the air, light, and space
required for their perfect development. Pineries which are not
thinned at the proper times suffer from this, as do crops overgrown
by weec^ ' from neglect of hoeing suffer from these injurious plants.
The be. sowings are those which are neither too sparse nor too
dense; L ues which have much space for growth develope more in
breadth inan in height; they present a dwarfed trunk, irregular and
full of knots, and they are loaded with strong and vigorous crowns,
conditions which are as unfavourable to the operation of tapping for
resin as to the production of useful timber. If the plants remain
too numerous and too close they famish one another, shoot up
beyond what is desirable, and fall into an emaciated condition, in
which they succumb to every injurious influence. The stems are
slender ; and the crowns, weak and few in number, fall ofif of them-
selves, leaving stumps, which disappear. But they recover them-

ACCOUNT GIVEN BY BOITEL. 47

selves easily, and protect one another in the pineries which have been
moderately thinned during the first twenty years of their growth.
Beyond this general observation it is difficult to lay down precise
rules in regard to the best means of executing thinnings. If germina-
tion have produced many more seedlings than was expected, it will
do good to remove, by hand, a certain number of these at the age of
3 or 4 years, or as soon as they ai'e seen to be injuring and starving
one another ; on the contrary, in a sowing which has come up badly,
and which does not sufficiently cover the ground, the first thinning
should be deferred till they have attained the age of 15 or 16 years.
In ordinary circumstances pines require to be thinned when they
have reached the age of 7 or 8 years. At this age the expense of the
operation may be covered by the produce in faggots and charcoal
wood. But in every case it is less the value of the produce than the
future of the pines which should determine the time at which this
first operation is to take place. That man would ill understand his
own interests, and would imperil the continued existence of, and the
revenue to be derived from, a young crop of seedling pine, who did
not clear it of diseased and dying plants, on the ground that the
expense of the work would not be entirely covered by the sale of the
produce of the first thinning.

" The subsequent thinnings, eclaircies, as they are technically called
in France, are determined by the kind of products which it is desired
to obtain, regard being had to the nature of the soil and the state of
the markets. In Sologne, for example, where the maritime pine does
not grow well above 25 years, but where it furnishes faggots, for
which there is a ready sale in Paris and Orleans, it is subjected to
periodical moderate thinnings, carried out much as are the fellings
of the coppice wood of deciduous trees. On a deep and firm sand where
the maritime pine may form a timber forest fit for tapping, for resin,
and for the production of workable timber, the earlier thinnings ought
to be somewhat more energetic, in order that they may favour more
especially the trees destined to form the standing wood.

" In any case there is a risk of disappointment if there be a lack of
prudence and moderation in the management of these successive
thinnings. The maritime pine is a tree which, especially in youth,
is very sensitive to cold winds, to hail, and to coups de soleil ; it
suffers greatly when, by excessive clearing or thinning, it is exposed
suddenly and extensively to the air and the heat of which it has been
deprived.

" Growu up piuea of a slender trunk, terminating in a heavy and

48 ACCOUNT GIVEN BY BOITEL.

bulky head, succumb easily to the action of strong winds, if there
be removed, all at once, neighbouring trees which had served to
shelter and protect them.

" The space which should be allotted to pines depends on their age,
the vigour of their vegetation, and the nature of the products which
it is desired they should yield.

" Delamarre, in Normandy, allows the following spaces round the
trees :

1st eclaircie at the age of 7 years, ... 0'33 metres.

2nd „ „ 8 „ ... -66 to 1 metre.

3rd „ „ 12 „ ... 1-33 metres.

4th „ „ 16 „ ... 1-66 „

5th „ „ 20 „ ... 2-

6th „ „ 24 „ ... 2-33 „

7th „ „ 28 „ ... 2-66 „

A mfetre is equal to nearly 40 inches.
" In Gascony pines destined for tapping for resin are allowed a space
all round them.

At 20 years of age, ... ... 3 mfetres.

„ 25 „ ... ... 4 „

„ 40 „ 5-50 „

„ 35 to 60 years of age, ... ... 7 „

" Timber woods of pines submitted to a definitive tapping contain
about 200 trees to the hectare of nearly 2| acres."

Magageov pruning, in its application to the maritime pine, consists
in removing one or more couronnes or tiers of branches, beginning
with the lowest. Although the maritime pine appears to support
amputation better than do most other resin yielding trees, " I have
always observed," says Boitel, " that the removal of a certain number
of couronnes was hurtful to the vigour and the health of the trees.
The leaves play an important part among the nutritive organs ; and
if pruning do more harm to resinous trees than to broad leaved trees,
which put forth new buds on the old wood, this must without doubt
be attributable in a great measure to this — that the growing trees do
not produce in place of the amputated branches young shoots, the
leaves of which might discharge the functions of those which have
disappeared by the operation of pruning. Pruning has, moveover,
the inconvenience of leaving in the trunks running sores, which are
healed with difficulty, and are the occasion of a pretty considerable
loss of sap.

ACCOUNT GIVEN BY BOITEL. 49

" It is remarked that the pines most loaded with branches and with
leaves are those which give the greatest bulk of wood and the most
abundant crops of resin. Notwithstanding this, pruning, objection-
able in theory, becomes useful in certain peculiar cases. If there be
seedlings with too much space around them, shooting out more in
circumference than in height, and loading themselves with heavy and
vigorous lateral couronnes, which absorb the greater part of the sap,
then there is removed gradually the lower branches in order to
concentrate the sap upon the stem, which is the part of the tree
which it is of most importance to cause to increase in size and in
length. As for sowings which are sufficiently stocked, instead of
employing pruning to force the trees to shoot upwards, it is now ad-
vantageous to get the same result by moderating the thinning, and
leaving on the ground as many trees as may be necessary to induce
development in height, and one knows not how sufficiently to
blame proprietors who, giving no attention to their seedlings for
eight or ten years, all at once subject the reserved trees to a
vigorous thiiming, accompanied by an excessive Uaqage or prun-
ing. This great mutilation, joined to a too immediate action of
air and light, occasions a state of disease, from the injurious effects
of which the pinery suffers throughout the whole period of its
growth.

'' Elagage is also proper on grown up pines, the lower couronnes of
which, enfeebled by age, finally die and fall, leaving long stumps,
which, in decaying, produce in the wood perforations which diminish
much its value. This serious inconvenience is avoided by prunino-
away at a proper time languishing and dying boughs ; and, in place
of cutting them off close to the stem, leaving a stump 5 to 6 centi-
mHres, or 2 and 2^ inches long.

" Such spikes, hardened by the action of resin which accumulates
in them, embody themselves without difficulty in the trunks, and
produce no other inconvenience than that of obstructing the tools in
the working up of the wood. Spikes in parts of the trunk destined
to be tapped for resin should not be above half-an-inch in length ;
otherwise, they arrest and blunt the hatchet of the resinier when he
comes to make gashes where they are. The good of attending to this
is experienced in the pineries of Gascony.

" At Belle-Isle M. Trochu prefers, on the contrary, pruning close to
the trunk, and leaving no spike, executed in the beginning of winter
as being the method most favourable to the production of planks
without knots and without holes,

o

50 CULTURE OF THE MARITIME PINE.

" Both Eclaircies, or thinnings, and Elagages, or prunings, are deli-
cate operations, which should only be entrusted to conscientious
and skilled workmen. The woodman who is engaged on piece work
works without other consideration than how he can increase the
number of his faggots and of his carts of charcoal, and it is to be
feared that in his precipitation he might sacrifice trees which in
every respect deserve to be preserved."

CHAPTER VI.

Exploitation op the Pine Plantations op Gascony.

In the exploitation of forests there are two methods of procedure which
have come down to us from times preceding these, in which the
practical application of science to the management of forests has led
to a more complicated, but more advantageous n^ethod, being adopted.
In the one, single trees are cut down here and there, as required,
leaving the others standing; in the other, extended areas are
successively brought under the axe, and completely cleared. To the
former method of procedure in France the designation Jardinage is
given.

" Exploitation by Jardinage," says Boitel, " appears to me to be that
most used by the inhabitants of the Landes. In the tapping for
resin, and in the felling of trees, they give less attention to the tout
ensemble of the pinery than to the special <;ondition of the individual
tree ; on the same ground are seen very often numerous distinct
generations of trees : some young, and good for removal in thinning
the wood ; others full grown, and regularly tapped ; and others, in
pine, more aged, and disappearing in proportion as they become less
fit for yielding resin, and better adapted to yield workable timber or
fire-wood. In these pineries it is by the natural spreading of the
woods that the ground finds itself constantly clothed with trees, and
it is the same in the pineries of Corsica and Spain."

But a more important feature of the pineries than the felling of
the trees, is the collecting and manufacture of the resinous sap
which they yield.

Full details of the various operations connected with this are
given by M. Eloi Samanos, Alemhre de la Societe d'agriculture des
Landes, in his volume entitled " Traiti de la culture du Fin
Maritime." The following more succinct account of these is given
by M. Bagneris in his account of these plantations already cited.

"It seems to be well-known," writes M. Bagneris, " that resinage is
not remunerative except where the maritime pine is indigenous, which
is only in mild and warm climates. This tree is found in abundance
on the ocean seaboard between the mouths of the Adour and the
Gironde. To the north of the latter, between Royan and Rochefort

52

EXPLOITATJON IN GASCONY.

it is less vigorous, produces less resin, and is of a smaller size ; and
the woods are not so thickly planted. Farther north, and especially
in the basin of the Loire, where, as I think, foolishly it has been
extensively introduced, it is not in its element. It does not
reproduce itself naturally, it is short lived, its wood loses all its good
qualities, and it is not possible to tap it with advantage.

"Resin never abounds unless the trees have plenty of room, are
vigorous, and have thick foliage ; it is thus a good plan to thin
plantations at the age of from six to eight years. Till the age of
twenty, the thinnings should be repeated every five or six years, so as
to leave at that period no more than 600 or 700 trees per hectare.
Those intended for felling should now be tapped. This is why
200 or 250 trees to be felled are now marked beforehand. When the
plantation is thirty yearsold, only 250 or 300 should be left per hectare.
This number is further reduced to 200 or even 150, which remain till
nearly seventy or eighty years of age, when the pinery should be
renewed, that is to say, if resinous products are not the chief object.

" This renewal may be effected either by means of the self-sown
plants which have sprung up in later years, or by artificial planting.
According to M. Eloi Samanos, this is usually done by seed in the
Landes. A.s to the mode, he advises lines from 4 to 6 metres distant
from each other to be marked out, according as the trees are to be
placed ; this should be deeply trenched, either by the mattock or
plough, for a breadth of 60 centimetres ; 6 kilogrammes of seed should
be allowed per hectare, which should be covered in by a slight
harrowing.

"While the early thinnings are going on, before beginning the
gemmage or tapping, the lower branches are lopped, so as to leave a
bare trunk of at least 5 metres high ; this is to hinder the formation
of dead branches which interfere with the flow of the resin. The
incisions can be made more easily and regularly in the layers of
wood covering these old wounds. Experience has proved the benefit
of this, but, on lopping branches close to the stem, care should be
taken not to enlarge the wound unnecessarily. It should always be
remembered that a tree never has too many leaves, and therefore too
many branches should never be lopped at once.

" It may easily be supposed that in thinning the young plantations
and in lopping the lower branches, the soil is left without sufficient
shelter. The sparse foliage of the pine adds to the evil. But there
immediately appears a thick vegetation of grass, whins, heath, broom,
thorns, &c. ; this is a very valuable source of litter and manure. But

COLLECTION OF RESIN, 53

the forest does not profit thereby. Under the name of ioutrage, this
brushwood vegetation is collected and sold at 50 centimes per cart-
load, containing about two cubic metres. One hectare may produce
from 5 to 12 cart-loads.

" It is evidently a loss to the forest that the vegetable mould
should not be allowed to accumulate, but it clears paths for the
resiniers, and diminishes the danger from the fires, which desolate the
country in the summer months. This danger is so great that at
certain distances large trenches are dug from 10 to 20 metres broad,
which are kept open for five years. In new plantations, and
especially in the Dunes, these are made at every 1,000 metres distant,
so as to enclose squares containing 100 hectares.

" There are two methods of tapping, le gemmage d, vie and le
gemmage ct, mort. In both the qxiarres are opened thus : after having
cut away part of the bark, it is pierced as far as the wood ; at about
ten centimetres from the foot of the tree an incision is made with a
habchat, a kind of hatchet, the head of which is slightly hollowed out,
and the handle is bent to the right. Once or twice a week the
workman scarifies the wound, and increases its height by one
centimetre. In the forests under the forest regime, the height of
4 metres, 14 centimetres, should never be exceeded. The regulations
also stipulate that thQ-quarres should never exceed 12 centimetres in
size, or one centimetre in depth.

" Trees to be gemme ct vie, should have only one incision made at a
time, and it will tend to prolong the life of the tree that that should
be only 8 centimetres in size. The same incision is kept open for
five years, and is raised vertically, the first year 55 centimetres,
the three following, 64, the fifth, 67 centimetres. When the five
years are expired, another incision is made in the same way, and so
on, till the time when the tree is gemme h mort, previous to being
felled. The gemmage a vie begins when the tree is one metre in cir-
cumference. According to M. Lamarque it is good, especially at the
beginning, to tap for four years and then to allow the tree to repose
for one. The old incisions soon heal up, and after a certain time
others may be opened above them, on the protuberances of bark
which have formed, and which are called ourles.

" Here and there old pines may be found with a great number of
qnarres. It frequently happens that the old incisions are exposed
owing to a want of adherence in the ourles. The latter shrink and
causes swelling, so that the foot of the tree resembles a spindle.

54 EXPLOITATION IN GASOONT.

One would think it was going to give way under the weight of its
branches.

" In private woods the incisions are sometimes 4 or 5 metres long,
and 2 or 3 are opened at once on the old trees. This is a mistake,
because, if more resin is obtained for the moment, the longevity of
the tree is materially diminished.

'' As has been said, gemmage ci mort is practised on old trees which
are to be felled, and upon those which are to be removed, so as to give
more room to the others. With the latter, it is done so soon as they
can bear a qtmrre, which is when they measure from 50 to 60
centimetres round, this they usually do at about twenty years of age.
The quarres are opened as in the gemmage d, vie, only they are en-
larged more rapidly, and several are made on the tree at once. It
usually takes three or four years to gemmer d, mort, or to bleed them
to death.

" When a quarre is opened or scarified the sap is seen in the form
of drops on the exposed wood ; some runs down the wound, the rest
solidifies and forms a crust, this is the Galipot. In former times the
gemme was allowed to run down to the foot of the tree, where it was
collected in a little trough cut in a root or hollowed in the ground. A
great deal was lost, especially during the first year, as much of it
was absorbed by the sand. Now small earthen pots are hung on the
tree, and are gradually raised so as to be on a level with the incision.
To direct the gemme into the pot there is a little zinc spout slightly
attached to the tree ; the pot is kept in its place between this spout
and a nail fixed below it on which it rests. To prevent any loss the
pot may be covered by a piece of wood. The resinier or resin collector
examines the pots when he scarifies the wound, and he empties them
when full. The Galipot is scraped off" once or twice in the course of
the year.

" The use of pots and spouts is known as the system of M. Hughes.
The outlay at first is greater, but the gemme is purer and in larger
quantities, the diff'erence being as four to three, so says M. Samanos.
It is much employed in the Dunes, at Cape Breton, at Mimizan, at
Biscarosse, at La Teste. It is less usual in Dax, and still less so at
Mont de Marsan. The gemmage is there inferior, because, to prevent
loss by absorption in the ground, the workmen lead the gemme from
several quarres into the same trough. Now to do this they ai'e obliged
to cut spouts in the foot of the tree which pierce the wood almost
completely round the tree, and this causes a rapid decay. Gemmage

COLLECTION OP RESIN. 55

is only performed between the 1st March and 15th October, but the
bark may be begun to be removed from the 10th January. A pine
gemme d, vie yields about three litres, or quarts of gemme when at its
best, that is to say when its diameter is a least forty centimetres.
It may also be alleged that taking into account the decreasing num-
ber of trees a hectare yields nearly a cask of 340 litres of resin
yearly, whatever the age of the trees may be. It is more difficult to
reckon the yield of the gemmage ct mort. But it may be admitted
that 200 to 250 trees of 20 centimetres in diameter yield about a
harrique or hogshead yearly, and that for three years. At Biscarosse
I have seen in a wood belonging to M. Marcellus, a pine 4 metres in
circumference, and with a bare trunk 11 metres high, on which
were 4 active quarres, which produced yearly from 7 to 8 litres
of resin.

" The price of resin varies considerably. It is sometimes as low
as 40 francs per harrique or hogshead, which is very little. During the
American war it rose to 290 francs.

"At present (1873) raw resin brings 120 francs per barrique sA
Mont de Marsan, where it is manufactured. The resinier is paid at
so much per harrique. His wages vary from 30 to 35 francs, which
represents an average day's wage of from 4 to 5 francs.

" I have visited several manufactories at Mont de Marsan, in one
of which essence of turpentine is distilled. It is done thus : the raw
resin is put into a large reservoir ; but as it always contains much
foreign matter, according to the greater or less care taken in collecting
it, earth, chips, bits of bark, leaves, &c. To separate these the raw
resin is heated in coppers, taking care that the temperature does not
rise so high as to disengage the essence. It is then filtered through
rye straw and received in a trough in a state in which it is called
terebenthine. From this trough it passes into an alembic by a valve
which opens when necessary. During the distillation a thread of
water is introduced by means of a pipe, and this becoming vaporised,
it conveys the essence of turpentine along with it through the room,
where both are received, in a liquid state, in a bucket, and separation
is eflPected by decantation.

" What remains in the Alembic is made into resin, dry pitch, and
yellow resin. It runs off through an opening below it to a pipe which
leads it to a trough. The resin is obtained by filtering it through a
very fine brass sieve placed ever a box. Dry pitch is nothing but
the residuum, which is at once run into moulds made in fine sand.
It is formed into bricks of from 45 to 90 kilogrammes in weight. To

56 EXPLOITATION IN GASCONY,

obtain yellow resin the residue is washed up warm with a tenth of
water, and is also run into sand moulds.

" All these products are useful. The essence is used in maiiing
varnish, in painting, in polishing, and in cleaning furniture, &c. It is
also used in medicine. Solid resin is used in making paper, soap,
stearine candles, torches, and sealing wax, and it is also used in
caulking vessels.

" The residue of the first filtration of the raw resin is burned in
furnaces constructed for the purpose, the products being pitch and
tar.

"One harrique of resin will produce 100 kilogrammes of essence of
turpentine which at present is worth 125 fi'ancs. The other products
cover the expense of manufacture, and yield a small profit. Dry pitch
sells at 18 francs the 100 kilogrammes. The same weight of yellow
resin fetches 20 francs. In another manufactory in the same town,
by exposing the dry pitch to intense heat, a double decomposition is
effected, and by different processes there are produced ethereal oils
for making vai'nish ; fixed oils, which are used for lamps, for greasing
the iron-work of carriages, and for injecting wood, and in making
printers' ink.

" All these products conjointly constitute the principal value of the
maritime pine. But where there are means for removing it, the
product of timber becomes important. There are different opinions
as to the respective qualities of timber which has been gemnie or
tapped, and not genime. In pines which have been gemme the
current of resin, owing to the evaporation of the essence, always
leaves a good deal of concrete resin in the tissues, which increases
their durability. The annual growth decreases in thickness; but
data are awanting for making comparisons, as pines are rarely found
which have not been tapped, and these have generally been left to
serve as boundary lines between properties. They grow to a great
size, but they are seldom felled till they begin to decay.

" One thing is certain, that the portion of the trunk which
contains the incisions is too much broken up to be useful for the
saw pit, but it furnishes very valuable and desirable vine poles ; it
is quite gorged with resin, which ensures their preservation. It
will also make staves for casks to hold solid resinous matter.
But the upper part of the tree is always free from breaks in the
continuity. At Cape Breton I have seen planks seven feet long by
seven inches broad, and five lines in thickness. In reducing these
measurements to the metrical system it will be seen that 100 of

MANUFACTURE OF CHARCOAL. 57

these planks are equivalent to 2 cubic mfetres. They are sold at
70 francs per hundred.

"Railway sleepers can also be made. When injected they are
worth 2 francs 10 cents each, delivered at the railway station.
One may judge of the importance of this when we remember that
the Southern French Railway and those of the north of Spain are
laid on pine sleepers.

" To conclude, charcoal for forges is also made from the maritime
pine. The cubic mfetre of this charcoal weighs from 200 to 220
kilogrammes, and in the forest it brings from 18 to 20 francs."

In regard to the manufacture of charcoal, which occupies an
important place in the exploitation of pine forests, M. Boitel reports:
" Branches and very young trees are not saleable as fire-wood, but
may be profitably converted into charcoal. In certain localities, where
the roads are bad, and the centres of population are at a distance,
the manufacture of charcoal is the only way of profitably employing
wood, which, if in the form of cotrets or faggots, would cost a great
deal for transport.

" Usually pieces of wood of from 4 to 5 centimetres in diameter
are made into charcoal. Smaller ones are made into bourrees, small
faggots ; larger, into cotrets or bois de service.

"The first fellings, which are from six to ten years old, furnish wood
for charcoal and bourrees. When the pines are older, charcoal is only
made from the branches and upper parts of the stem.

" The best pieces f n- making charcoal are straight, not very thick,
and sufiiciently dry. They should not be more than from 075
metres to 0-80 metres in length. The crooked branches are cut
into two or three pieces, the lateral twigs are cut off close, and the
ends are round and smoothly cut. Twigs hinder the wood being
properly arranged, and when the ends are ragged there is a good deal
of charcoal lost. Green and dead wood are avoided. The first yields
very little charcoal, the second only ashes, which may ignite the
furnace after the workman believes it to have been completely
extinguished — a great inconvenience, which spoils a great deal of
charcoal and occasions conflagrations. The maritime pine is fit for
the furnace six months after being felled.

" Spring and autumn are the best seasons for making charcoal.
In summer it is dangerous to make it when there is no water. When
possible, the charcoal maker should always have plenty of this at
hand.

H

58 EXPLOiTATIOiS OF THE MARITIME PINE.

" In choosing a site for a furnace, the position of the timber to be
used should be considered. A central position is best, so as to
diminish the expense of land carriage. The ground is first levelled,
and all heath and shrubs removed to prevent the chance of fire.
The maritime pine is easily injured by the heat and smoke of a
furnace, and it is best to place the kiln either outside the forest or
else in the centre of a considerable clearing, as dead trees become a
nursery of insects destructive to trees.

" Where old sites are conveniently situated, it is a good plan to
make choice of these.

'' When a new furnace is made the first bed should be laid on a
layer of horizontal branches. This is called a plancher, a platform or
floor.

" The size of the furnace varies according as the charcoal is for
domestic or for other uses.

"For kitchen use, experts recommend that 15 or 18 steres or
cubic meters of wood should be burned at a time, and 30 or 35
when it is to be used in forges. Small furnaces occasion less waste,
but sometimes they are apt to fail.

" The site of the furnace being prepai'ed, a large post is placed
vertically in the centre, the wood to be carbonised is placed round it
after its being surrounded by twigs and dry wood which will ignite
easily ; the faggota are placed on end, but inclining gently ; the first
layer being made, a second, third, and fourth are added. In doing
this the largest and greenest pieces are used for the lowest and most
central part of the furnace, because there the fire burns most fiercely.
The small dry pieces are placed on the outside and top of the mass.
The faggots should be pressed closely together, and the interstices
filled with twigs. If several kinds of wood are used at once, the
hardest should be placed in the centre.

"The cone completed, the central post is withdrawn, and this
leaves a chimney in the centre, the whole is then covered with leaves,
twigs, earth, and moss, more or less mixed with sand. This layer of
earth should be 5 or 6 centimetres thick. Fire is then set to the
lower part of the chimney, which remains open a certain time so that
the mass may be ignited. The chief fire is thus in the middle of the
chimney, and the workman takes care to feed it with wood when a
vacancy is produced. Whenever the mass is sufiiciently ignited, the
opening is stopped, the moment for doing this is regulated by the
colour of the smoke, which, white at first, becomes blue and
transparent when the flames acquire strength. The entrance and

MANUFACTURE OF CHARCOAL. 59

exit of air must be regulated so that the heat may not be too great
or too low. When too low, the charcoal is of inferior quality ; when
too high, there is great waste, and the yield of charcoal is small.

" The skill of a chai-coal maker is now seen in ascertaining what
progress the fire makes in the interior, in such a way that it can be
moderated in some places and increased in others. It is by the
smoke and cracks on the surface that this can be judged of. The
fire is moderated by stopping the openings, or increased by making
others.

" The bad eSect of currents of wind is prevented by pallisades, or
bourrees, arranged like a wall, or by a simple clayonnage of branches.

" The best constituted charcoal furnace is the one which, remaining
uniform and homogeneous throughout the operation, sinks and
breaks in regularly, allowing the smoke to escape in the same
quantities from all the openings disposed round the furnace.

" The fire extends from above to below, and from the centre to the
circumference. At the end of 36 hours, in furnaces of the usual size,
the whole covering becomes incandescent. This is the time of the
' grand feu.'' When this point is reached, M. Thomais says, that
a good charcoal burner will make it blaze furiously, and then put it
out dexterously. This, when done at the right time, produces a
great deal of charcoal. But to prevent failure, the furnaces should
be sheltered from currents of air, otherwise there is a chance of
considerable loss.

" After the violent blaze, the charcoal making may be considered
finished. The fire is moderated by degrees by making openings
which allow the air to pass, and by replacing the warm dry earth of
the covering by earth which is cold and damp. The fire is
extinguished in five or six hours ; but another day is required
before the charcoal becomes cool and is fit to be carried away.

*' To obtain a good yield of charcoal one must guard against
raising the temperature too much at the beginning of the operation.
The first part of the time is spent not in carbonising the wood, but
in getting rid of the moisture. If the faggots are strongly heated
before the water is dispelled, the latter being decomposed, two sorts
of gas are created, which, combining with the charcoal, issue from
the furnace in the form of carbonic acid, and carbonic oxide, and
carburetted hydrogen. From thence results a real loss of carbon,
which in this case is consumed in the same way as in our kitchen
stoves. The water decomposed by the fire acts on the incandescent
charcoal with more force than would the atmospheric air.

60 EXPLOITATION OF THE MARITIME PINE.

" Well burned charcoal may be known by its hardness, and the
sound it emits when struck. If nothing is lost in the furnace, 42
kilogrammes of charcoal are yielded by 100 kilogrammes of wood, but
even in the most favourable cases this is never done. The most perfect
operation does not yield more than 25 per 100. By the usual
methods, only 15 or 20 per 100 are obtained.

" In Sologne the usual cord of charcoal is of the following dimen-
sions : —

Height, ... ... 30 inches, or 0*82 metres.

Breadth, ... ... 30 „ or 0-82 „

Length, ... ... 16 feet, or 5-33 „

Cubic measurement of a cord of charcoal, 3 sUres, 58, or 3'58 cub. „

" According to the success of the operation, a cord of charcoal pro-
duces from 4 or 4^, to 5 bags, containing 230 litres each.

The stere of dry pine weighs, 250 kilogrammes.

The cord of the same, ... 895 „

The hectolitre of dry pine charcoal, 19 „

The bag, ... ... 43 „

** The yield of 4 bags per cord is equivalent to 18 per 100 metres
weight. The yield of 6 bags per cord is equivalent to that of 24 per
100.

"Pine charcoal sells in the market at from 5 to 6 francs, oak
charcoal from 10 to 12 francs. To give the charcoal burner an
interest in the operation, his wages are regulated by the supply of
charcoal he gets — 45 cents per bag. Some proprietors who have
confidence in their workmen, in place of paying by the bag, give
them 2 francs for every cord of wood which is carbonised. Pine
charcoal is lighter and of less value than that of the oak ; the last
weighs a quarter more, about 25 kilogrammes per hectolitre.

" The difi'erent kinds of charcoal are distinguished with difficulty.
Merchants often fraudulently mix them.

" In Sologne, when pine charcoal is worth from 1*75 to 2"25 francs
per bag, that of the oak is worth from 3 to 4 francs.

" Some years ago there was established at Sologne a manufactory
where the pine was carbonised in air-tight vases. The volatile
products were condensed, and produced by distillation tar and
pyroligneous acid. Besides these articles, which are usually lost,
the yield of charcoal was much greater. The death of the proprietor
put an end to this interesting manufacture.

" There is in Sologne an encumbering kind of forest produce
which it is difficult to get rid of. I refer to the bourree, a so^^ o

MANUFACTURE OP CHARCOAL. 61

faggot bound by a single cord, exclusively composed of fragments
from the saw-mill, or the clearings of the woods. In the Landes
there are bourrees of a peculiar kind, formed of heath, broom, and
whins. Whatever it is made of the hourree is from 1 metre to 1'33
metres in length, and from O'SO to 0-85 metres in circumference.
Sologne furnishes a great quantity of these bourrees, which are not
needed for fuel, except when within reach of the great centres of
population. They rarely pay the cost of being carried farther than
12 or 16 kilometres.

" When they are not sold to the poorer classes for fire-wood it is
necessary to get rid of them in such a way as to reimburse the
proprietor for their collection. Rather than make an article which
costs from 1 franc to 2 francs per hundred, and which it is diflScult
to sell, he would prefer to leave the twigs to rot on the spot so as to
produce a sort of compost for the trees. In this case he should copy
the Gascoyne farmer, who litters his cattle with the smaller twigs,
which act as absorbents.

" In Sologne this is not the custom, and the bourrees are used in the
manufacture of bricks, tiles, and lime. The manufacturers buy
them at from 2 francs to 2 francs 50 cents the hundred, which leaves
the proprietor a clear gain of 50 cents. The making of bourrees is a
good employment for the idle season.

" Unfortunately, brick kilns are not able to use all the bourrees
supplied by making cotrets, or faggots, of pine, and it would be im-
possible to sell all if they could not be converted into other articles
made use of in various manufactories.

" For several years the botirrees have been burned in air-tight vases ;
petite braise, or charcoal cinders, is produced, and a more powdery
sort of charcoal called charcoal dust. The experiment leaves nothing
to be desired, for the bourrees are carbonised so perfectly that with
care they may be withdrawn from the furnace in the same shape in
which they were put in. Pine needles, leaves of heath, are perfectly
carbonised, undergoing no physical change except in the colour,
which changes from grey to black. Twigs of a certain size furnish
braise, which is used in the same way as ordinary charcoal, but this
article is of secondary importance beside the charcoal dust, which is
the chief product. This is used in many manufactories. M. Popelin-
Ducart uses it for the preparation of the cylindrical charcoal, known
as Charbon de Paris.

" Such is the power of science. Bourrees, which would not repay
the cost of transport to warm the inhabitants of Sologne, are,

62 EXPLOITATION OF THE MARITIME PINE.

after a chemical change, able to rival the ordinary charcoal in the
furnaces and kitchens of Paris. This new article has to make its way
against the prejudices of servants, but it may be hoped that at length
it will be justly appreciated.

" Charcoal dust is used largely in the manufacture of artificial
manures. It is known that carbon disinfects and solidifies the
material. It is used for this purpose in several important towns.
It is to be wished that this process of disinfection of drainage were
more general. If it were so, what great services would be rendered
to agriculture and the public health ! In the first place, it opens a
market for charcoal dust, which it is difficult to dispose of at present ;
and it preserves, for the benefit of agriculture, a great quantity of
useful substances, which in towns are wasted, while at the sametime
the air is vitiated and the public health endangered.

" Of two almost worthless articles, the botcrrees of Sologne and the
drainage of large towns, is thus composed a powerful manure, each
hectolitre of which represents at least a hectolitre of wheat. When
viewing the numerous advantages of such a manufacture, one is
surprised that there has not been established long ago an interchange
betweeu Sologne and Paris of charcoal and disinfected and solidified
sewage. What could be better than the carbonised heath being
saturated in Paris with fertilising nature, and again restoring in
Sologne fertility to the sterile soil which had produced it !

" If Sologne exchanged charcoal dust for disinfected drainage, the
Landes which only require manure to be productive, would be cleared
as if by enchantment, and would soon be covered with rich harvests.

" The improvement in the healthiness of the country which follows
the progress of agriculture and this marvellous result, would both be
attained by the use of fertilising substances which would otherwise
be a powerful cause of disease.

" It would be a bold thing to say that such an end can be attained
without difiiculty. In the first place, there must first be invented a
simple and easy way of making charcoal dust.

" When the dust is made, negotiations must be entered into with
municipalities. Finally, to extend the sale, the resistance and
prejudices of farmers must be subdued ; but these men have been
so often deceived by pretended artificial manures, that they stand
aloof from any new substance,"

There are given, by M. Boitel, the following details of the manu-
facture of charcoal dust :

MANUFACTURE OP CHARCOAL DUST. 63

"At the Imperial Castle of La Motte-Beuvron, Sologne, the
carbonisation of hourrees is carried on in a brick oven placed in a
central position in relation to the Forests or the Landes which are to
yield the material, and special regard is had to the roads as it is
desirable the oven should be near the best roads. Water also is
required to extinguish the charcoal when drawn from the oven. It
should therefore be of easy access.

" In such ovens or kilns the upper aperture of the oven, into
which the hourrees are thrown, should be easily reached, and also
the lower opening, from which the carbon is withdrawn. This double
condition is attained by placing them where there are two surfaces
with unequal levels. The upper opening on a level with the
higher surface, while the lower is also on a level with the ground.
This ai-rangement is to be seen in many lime kilns. The earliest
kilns were not made in this way. The upper opening was above the
ground by the whole height of the kiln. The workman could not
throw in the howTees at once, but was obliged to carry them up a
scaffolding. This additional labour increased the expense.

" This inconvenience is prevented by erecting kilns of the kind
described : In default of a suitable slope, the kiln may be placed on
the ground, piling up earth to the half of its height and forming two
inclined planes, one leading to the upper opening, the other leading
down to the inferior one. Care should be taken to prevent rain from
collecting in the oven.

" The hourrees are collected in isolated heaps in the neighbourhood
of the oven. It is considered that these should not be massed
together for fear of their taking fire ; and that they should as much
as possible be sheltered from rain. Wet hoitrrSes are difficult to
carbonise, and yield less powder, especially if they have been exposed
to damp for any length of time.

" The workman throws in the hourrees either by hand or with a
wooden fork. Thirty hourrees are enough to fill a kiln. It is lighted
by the lateral opening ; immediately it ignites this opening is carefully
stopped with clay so as to exclude the air. The upper opening is
left half open, from which issues a thick white smoke chiefly formed
of vapour. So long as the smoke continues white, the workman
throws no more hourrees, but whenever it loses a blueish tinge he
hastens to feed it up, as this is a certain indication of an advanced
degree of carbonisation.

•' He continues to work all day without withdrawing the charcoal,
and before leaving at night he puts in a fresh supply of boxmxes.

64 EXPLOITATION OF THE MARITIME PINE.

At this time he covers up the upper opening entirely, but without
hindering altogether the entrance of air and the issue of smoke :
small apertures being indispensable. On the other hand, much air
must not be admitted during the night, as then the moisture in the
wood is entirely evaporated, and the charcoal powder may be
converted into ashes.

"The carbonisation is completely finished when the workman
returns to his kiln on the following morning. Although the kiln has
not been hermetically sealed during the night there is but a slight
loss of charcoal ; the upper part only being affected by the air which
is moveover surcharged with carbonic acid.

"The workman now hastens to withdraw the charcoal, and to
extinguish it as completely as possible.

" By the lateral opening, he, with a little iron rake, draws out 2
hectolitres on to the inclined plane ; he then shuts the opening
instantly, and extinguishes the burning powder by watering it with
a gardener's watering pan. He applies one litre of water to the
hectolitre of powder ; this quantity is not enough to extinguish it
completely, but it is known that the powder is of better quality when
subjected to roulage, instead of employing an operation to be
immediately described, than it would be if more water were employed.
The workman then takes a wooden rake and spreads the charcoal
over an extent of about ten mi^tres. The charcoal is extinguished
all the sooner by coming in contact with the cold earth, and an
atmosphere composed of carbonic acid and steam. By this roulage
the powder is exposed to the air in thin layers. The workman being
careful to extinguish any sparks of fire.

" This operation is long and hurtful to the workman, he breathes
a dry powder which incites him to drink, and injures his lungs. The
workmen who drink abundantly of the bad water of the country often
fall victims to fever,

"A workman spends three hours in extinguishing by roulage
20 hectolitres of powder.

" The kiln of the Couscaudiere consumes in a summer day, when
supplied by two workmen, from 350 to 360 bourrees, and when
supplied by only one workman, 260 or 280 ; 360 bourrees yield from
18 to 22 hectolitres of powder, which contain braise in the proportion
of 6 to 15.

" This braise is separated from the powder by an iron sieve, the
interstices being 2 centimetres across. The yield of braise varies
according to the composition of the bourrees. The oak yields more
than the birch, and the latter more than the maritime pine.

MANUFACTURE OF CHARCOAL POWDER. 65

"As to the yield of powder, pine hourrees take the highest place.
Careful carboaisation also affects the yield, a certain quantity being
converted into ashes if the admission of air is not properly regulated.
" To prevent the necessity of continual superintendence, the work-
man is paid according to the yield. At La Motte-Beuvron he gets
15 centimes per hectolitre of powder.

" 100 hourrees may be carbonised at the following cost : —
Price of 100 hourrees, ... 2 francs 0 cents.

Carriage, ... ... 1 » 0 „

Cost of manufacturing 6 hectolitres

of powder, ... ... 0 ,, 90 „

Total, 3 francs 90 cents.

"From these 100 hourrees are obtained 6 hectolitres of powder,
which is worth on the spot 50 cents the hectolitre, or 4 francs for
6 hectolitres. The net profit is 60 centimes per 100 hourrees. In
this calculation I do not include the kiln, which costs very little, and
lasts for a number of years. If the work be done by proprietors, it
will be seen that their hourrees will bring them 2 fi'ancs 60 cents per
100.

" The expense of manufacture, at present 15 cents per hectolitre,
would be very much diminished if several kilns were made at the
same place. Whilst the hourrees are burning, the workman has a
good deal of spare time. When he has the care of two kilns he can
feed one while the hourrSes are burning in the other. He can roll
and extinguish the powder from one while attending to the fire in
the other. But it must be kept in mind that a collection of kilns
in one place increases the expense of carriage. If the roads be bad
the kilns should be isolated, and built at equal distances. The
expense of manufacture would be greater, but this would be largely
compensated by the reduction in the expense of carriage. A kiln
costs little, especially to proprietors who make their own brick and
lime.

" The tools required by the charcoal burner are simple in the
extreme,

" 1st, a wooden fork to put the hourrees in the oven ; 2nd, a long-
handled iron rake to draw out the charcoal ; 3rd, two gardener's zinc
watering-pans ; 4th, a wooden rake ; 5th, a wire sieve ; 6th, a half
hectolitre measure ; 7th, a large square shovel of sheet iron bent up
at the side, each side measuring 0'38 metres, with a wooden handle
0'80 metres in length.

I

QO EXPLOITATION OF THE MxlRITIME PINE.

" Of all these tools the only one requiring improvement is the sieve,
or riddle. It is of a rectangular shape, the longest side measures 1
mfetre, the shorter 65 centimetres, 4 pieces of wood about 25 centi-
metres high form the frame. The net- work meshes are 2 centimetres
in diameter, and are strengthened by transverse pieces of wood. It
is fixed to a post by a hook and a double handle, which serves for
putting in motion. It is with this sieve that the hraise and the
charcoal powder are separated.

" These two articles vary according to the composition of the
botirrees."

In the Industrial Museum of Edinburgh, and it may be in other
similar institutions situated elsewhere, there have been exhibited
specimens of the products of the Landes, before and after having
been reclaimed from the conditions of wastes of moving sand, and
specimens of the implements employed in collecting the resinous
products of the trees. They were presented by M. Leopold Javal,
Deputy of the French Empire.

From a statement accompanying the specimens referred to, it
appeared that the operations cai-ried out on the ground where they
were obtained were conducted by planting seedlings to the leeward
of the older plantations, in intersecting narrow belts, and sheltering
these with hurdles till they had taken root and begun to grow. This
they soon did, and, thriving well in such situations, they very soon
became strong enough to withstand the wind, and form live fences
enclosing squares of considerable extent.

These enclosures were then sown with rape, mustard, and other
rapid-growing crops, advantage being taken of wet weather to do
this. When the seed produced by these had been collected, the
remainder of the plant was ploughed in to produce vegetable mould,
and the process was repeated until sufficient vegetable mould to
support grain and other more valuable crops had been produced.

There were exhibited specimens of the sand, and of a bog iron ore
found about three feet below the surface, known as alios, with
specimens of the products of the land before cultivation. These con-
sisted chiefly of the common brake (Pteris aquilina) ; heather, or ling
(calluna vulgaris), which was used there, as elsewhere, for making
brooms ; the tree heath (erica arhorea), a heath indigenous in the south
of Europe, and there found with stems measuring about an inch in
diameter ; and the furze, or whin (ulex euroiKea).

Of products raised by cultivation there were exhibited white maize,

EOONOMIO PRODUCTS OF THE LANDES. 67

yellow maize, millet, little millet, buckwheat, rye, oats, wheat, and
tobacco. There were exhibited sections of the cork tree (qtiercus
siiber) ; of the black oak (Q. nigra), a native of North America ; of
the holly leaved oak (Q. gramtmtia), which is indigenous in France ;
and of the cluster pine (pinus pinaster), or Spardenny, of which the
maritime pine (P. maritima) is conjectured to be a variety ; there
were exhibited specimens of this cut into railway sleepers, railway
fencing, drain pipes, hop poles, shingle for roofing, and pavement
for streets, stables, and footpaths ; all of these had been infiltrated
with blue vitriol (sulphate of copper) by the process of Bouchard,
recommended as a prevention of rot and decay ; and there were
exhibited specimens of the following resinous products of the trees :
Soft resin, collected in covered vessels ; gallipot, or white resin,
obtained by scraping the trees ; barras, a coai'se resin ; sun turpen-
tine, prepared by exposing soft resin to the action of the solar rays,
and used in the manufacture of perfumery and of varnishes ;
bala turpentine, similar to the sun turpentine, but of inferior
quality ; Venice turpentine, which oozes through the joints of casks
filled with soft resin ; spirits of turpentine ; rectified spirits of
turpentine ; resin, residuum of the distillation of rough turpentine
or resin ; tar, a product of the distillation of rough turpentine, and
of the destructive distillation of wood ; empyreumatic oil, obtained in
the distillation of resin ; lubricating grease, a mixture of resin and
vegetable oils ; and torches of resin used chiefly in Bretagne.

Of implements there were exhibited a common hatchet, a hatchet
for making the broad shallow vertical grove in the bark and outer
concentric circles of the trunk, to allow of the escape of the resinous
sap, and for making the cut into which a zinc spout for collectiuo-
that sap is fixed : the edge was, an arc of a circle about 3J inches
broad, and the head and handle formed an angle of about 135°; a
course earthenware vessel in which the resinous sap is now generally
collected : it would hold about f pints, and was shaped like an
earthenware milk pan, or coarse flowerpot of equal width and depth ;
a shovel for detaching gallipot and digging holes : it was like a hoe in
shape, but solid ; a second of the same of about 2 inches in breadth ;
a scraper for the same purpose, of the same breadth, but bent round
like a crook to scrape downwards ; a ladder made of the side of a
young tree, with the edge cut into projecting angular steps.

The resins and the cereal products, exclusive of the fire-wood and
timber, were said to suffice to cover the expense of management
and to supply a satisfactory return for the capital invested in the

68 EXPLOITATION OP THE MARITIME PINE.

enterprise, and of the reclaimed land brought under annual culture.
And as regards the charcoal manufactured, it is remarked by M.
Boitel :

" This would evidently be a source of possible wealth if the forests
were easily accessible, but they are not so as yet at least in the
Dunes, and will not be so until the newly planted trees arrive at a
valuable age.

" Good roads are being made at present, and in future the maritime
pine may be cultivated for the sake of its timber as well as for its
resin.

" The culture of the maritime pine has conferred invaluable benefits.
A considerable extent of low lying marshy land has been brought in,
once a focus of pestilence which decimated the population. It has
made it healthy and productive, and has introduced industry and
comfort into districts which seemed doomed to misery. The
maritime pine has also arrested the advance of the Dunes and pre-
vented them from overwhelming houses and arable land. Its
importance must increase. In the department of the Landes alone,
the extent already planted is more than 500,000 hectares. In the
Gironde there is almost as much, and very soon barren wastes and
sandy dunes will be things of the past."

CHAPTER VII.

Sylviculture ox the Landes of La Solognb.

Besides the Landes of Gascony and the Landes of the Gironde which
are near the coast, we meet with Landes in inland situations in
France, arid regions, supporting but a sparse population, being
covered with heaths, and whins, and brooms, and other plants, which
take possession of waste and uncultivated lands, and yield little
nutriment for the support of man. Such are the Landes of La
Sologue, of which mention has been made in connection with details
given of the mauufactui-e of charcoal ; such also are the Landes of
Le Brenne, and of Le Limousin — with solitudes broken only by the
visits of poor shepherds tending or searching for their sheep,
contrasting strangely with the animation and bustle prevailing in
districts adjacent.

In these we meet with another phase of sand dunes and drifting
sands, and of the culture of the maritime pine.

There, as in many other places elsewhere, the growth of the
maritime pine is less luxuriant than it is in the district to which our
attention has hitherto been given.

In the Landes of the Gironde the maritime pine propagates itself
by natural reproduction by self-sown seeds. There, all conditions are
peculiarly favourable to its growth. It is otherwise in the Depart-
ment of Maine and in La Sologne,

In Sologne it is very rarely the case that a pinery is reproduced by
self-sown seed. In the first place the trees never attain to great age,
and they never furnish aught but a small quantity of seed. In the
second place a rejoeuplement, when it does make its appearance, soon
perishes under a dense covering of timber trees, which deprives it of
air and light. In fine, young saplings, which may have withstood
the injurious effects of too dense a shade, become oft-times the prey of
flocks of sheep, which the people have the bad custom to lead into
pineries, from which they should be strictly excluded.

Of the Landes of La Sologne and of La Brenne, it has been
remarked that they are less known than are those of Gascony,
because they do not lie upon the old great lines of communication.

70 SYLVICULTURE IN LA SOLOGNE,

They were once covered with a forest 1,200,000 acres in extent,
but this having been cleared away, they have relapsed into what
was their earlier condition, a barren sand waste, diversified by marsh
land, and marshes in abundance.

In writing of the " Desert World," M, Mangin, or his translator
into Enghsh, introducing his subject, says, " To those whose
imaginations have been kindled by glowing pictures of the African
Sahara and the Arabian wilderness, it will be, perhaps, a matter of
surprise to learn that even fertile and civilised Europe includes
within her boundaries regions which are scarcely less cheerless or
desolate, though happily of far inferior extent.

" In France, so richly cultivated, so laborious, and so blessed by
genial Nature as she is, there are, nevertheless, a few districts where
her sons may wholly forget — nay, almost disbelieve in the existence
of — her cities stirring with ' the hum. of men,' her vineyards and her
gardens, her grassy pastures, her prolific meadows, her well ordered
highways, and those ' iron roads ' which are the incessant channels of
such restless energy, movement, and vigorous life."

And after describing mountain solitudes in the gigantic ranges of
the Jura, the Vosges, and the Cevennes ; the first an outlying spur
of the great Alpine system, and situated on the border of Switzerland ;
the second separating the valley of the Ehine from that of the
Moselle ; the last separating the valley of the Loire from that of the
basin of the Rhone, he goes on to reckon among the uncultivated
regions of France, the marshes of the Bresse of Forez, and, with others,
those of the Sologne.

The Landes or heaths of the Sologne appear as a desert surrounded
by a magnificent girdle of cultivated land, fully developed in the
fertile valleys of the Loire ond the Cher. And, as is the case in
Gascony, the heath is surrounded on all sides by valleys, vineyards,
and gardens, in the highest state of cultivation. While in Corsica,
another sandy desert, the orange, the olive, and the chesnut adorn
spots surrounded with maquis, veritable heaths, with this, as the only
difference between them and the heaths of the Sologne, that under
that southern climate the whins and the meagre heaths are replaced
by the arbutus, the myrtle, arborescent heaths, cistuses, and
lentisques.

In all of the places mentioned, in Sologne, in Brenne, and in
Gascony, it is not rare to see farms of from 1,500 to 2,000 hectares,
in round numbers, 4,000 and 5,000 aci-es, with only from 150 to 200

PREPARATION OP THE SOIL, 71

hectares under cultivation ; and in Corsica nine-tentlis of the island
are covered by the maquis, or heaths. In Gascony, to one who would
urge the destruction of the heath, the ag-riculturist of Chalosse, or
of Beam would reply — N'o heath, no maize ; exactly, as elsewhere, one
would say — No dung, no wheat. And in that climate it is impossible
to carry out a rational and profitable cultur-e excepting on the bases
of two hectares of heath for one under culture.

And there, by students of agricultural economy, it is deemed proper
to seek the improvement of the poorer land by rearing trees upon it,
instead of attempting to introduce at once the appliances of what is
known as high farming. But even for woods the land here requires
preparation, and the preparation which is found to be most appropriate
is the culture of certain cereals, alternating with a growth of the
maritime pine, without which it would be hazardous to attempt the
growth of the Scots fir, the Corsican pine, and the Norway fir, and the
oak, and the birch, all of which have been cultivated here with the
best results.

But the land improver must wait many years before he can say
whether the land will bear the other coniferae ; and the oak, and
other broad-leaved trees, it is alleged grow but slowly and require
shelter. And even when the time has come to attempt the growth
of such, it is not uncommon to grow a mixture of the maritime pine
with the other coniferae, the oak, the birch, and the chesnut ; as,
should the others fail, it at least will grow ; and if all succeed it is easy
to sacrifice any one kind for the promotion of the growth of the others ;
and in any case it will give shelter to those which might suffer from
frost, and it will yield marketable products, while the oak and the
birch are still too young to be subjected to exploitation.

In Sologne we have a well-defined geological district, about
440,000 hectares, or above a million of acres in extent. The
superficial strata have been designated by geologists specifically as
the Sands and Glays of the Sologne, a formation reckoned amono-lthe
upper layers of the middle range of the tertiary period.

It may be represented, says Boitel in his volume entitled " Mis^'
en valeur des Terres Pauvres par le Pin Maritime," as a vast
calcareous basin, filled by alternate deposits of sand and of clay.
This basin, the wall of which crops out at a great many points alono-
the circumference of La Sologne, presents naturally different depths
at different localities.

In two borings, within yards of each other, at Savigny (Loiret)

72 SYLVICULTURE IN LA SOLOGNE,

we have in one a depth of 270 feet, and the other only 226| feet ;
and a third at Vannes (Loiret), we have only 168 feet. And owing
to accidental disturbances, and to the general inclination of the
surface from east to west, one and another of the layers of which the
deposit consists appear on the surface with a very great variation
in breadth, giving rise to superficial ground of silicious sand, of clay,
and of those elements associated in different proportions ; and the
sub-soil, which may be considered the true soil of the trees, presents
modifications not less important in character and in depth.

All the layers which appear have, as a common character, that
they are poor in lime and in fertilizing substances.

" In Sologne," says Boitel, " the lack of lime, the natural sterility
of the country, the ignorance of those who exploit its products, the
want of capital, the deficiency of labour, the undivided state of the
property, whether held by communes or by individuals, and the strik-
ing ruin of some inexperienced innovators, are the main obstacles which
have retarded the utilisation and improvement of the greater part of
the uncultivated land."

Following out the natural division of the layers into sandy, clayey,
and mixed lands, he says of these :

" Sandy silicious soil is formed of sand, more or less coarse, and
more or less white ; it is light and easily worked. Damp does not
make it cohere, or change it into a thick oily paste. If it lies on an
impermeable clay bed, without any fall, it becomes, in winter,
saturated with water, and almost inaccessible to animals, who would
sink into it up to their chests.

" But if there is a slight declivity it drains itself of its own accord,
and is liable to become too diy in summer. Farmers sow it only
with rye and buckwheat ; turnips and red clover also succeed pretty
well. In farms where no hoisement, or planting with trees, has
taken place for fifty years, it is often still arable. Old fashioned
farmers prefer it, because it is easily worked, and because the eff"ect
of manure soon becomes apparent on the buckwheat and rye.

" Intelligent farmers, on the contrary, dislike it because of its
rapid exhaustion, and because old manure can never be stored up in
it, so as to yield a good return. Even supposing that lime could be
had, it would be unsuitable for wheat and oats, it being poor in fertiliz-
ing substances, and because these cereals would sufi'er from drought
before coming to maturity. Farmers subject these sandy soils to a
fallow of lengthened duration; it then becomes covered with a
whitish hair-grass (aira canescens), with a species of woodruflf

SOILS IN LA SOLOGNE. 73

(asperula cynanchica), and sheep's bit (jasione montana). After a
repose of several years, a green compact moss follows, which is con-
sidered an indication that it will now bear one or two crops of barley
without manure. Isolated plantations of chestnuts also succeed when
the ground is deep and damp enough, also the oak and birch, but
the maritime pine is most suitable. All the sapinieres, or fir planta-
tions, established in Sologne for the last twenty-five years have been
planted in such ground.

" Clay Soil. — In Sologne sandy silicious soil covers the greatest
extent ; then comes clay, which is very diff"erent. When dry it
contracts, cracks, and is difiicult to work. When wet it is
impermeable, and forms an oily tough paste or clay, suitable for the
manufacture of tiles and bricks. These should not be made either
in very dry or very wet weather, but only at times of a certain degree
of dampness. Such soil is less easy to work than is sand ; it
requires stronger ploughs and more perfect implements. These
considerations made old fashioned farmers exclude it from the list of
arable soils. It is covered with oak woods and ponds, or is kept
as pasture for sheep.

" The white oak easily becomes fit for exploitation, either as coppice
or as timber trees. If the clay is pure and compact the chhie rouvre,
or red oak, the variety chiefly grown in France, is to be preferred.

" Clay soil produces a stronger and richer vegetation. The smaller
heaths being overtopped by the erica scoparia, vulgarly called
hremaille, which obtains the height of 1*50 metres. The dwarf whin
is also found (ulex nanus), some junipers and some grasses (molima
coerulea, agrostis vulgaris, and danthonia decumhens). Clay soils, al-
though more difficult to work, are more profitable than are sandy
ones ; when drained, limed, and well manured, they are neither too
hot nor too dry; the compost is not wasted, and it gives a good return.

" At the same time where argilo-silicious soils, which are better for
cultivation, are to be had, clay soils should be wooded. The mari-
time pine will not thrive on it, the oak and pine should be chosen.

"Soils Composed of Sand and Clay. — This class comprehends all
soils composed of mixtures of sand and clay, but such are rare in
Sologne, and this is unfortunate for its agricultural future.

*' If in place of elementary soils, pure sand and pure clay, the soil
in Sologne were like the average ground in France, the farmer would
be more frequently successful.

" The soils in Sologne are infinitely modified in composition ; and
then also modified through their connection with subterranean

74 SYLVICULTURE IN LA SOLOGNE.

springs. Before planting a firwood pinery it is necessary to ascertain
if the soil and sub-soil are suitable to the maritime pine, as this
tree pines in argilaceous, stiff, cold, and damp soils, and thrives in
such as are deep, sandy, and well drained."

M. Boitel supplies also the following information on the compara-
tive extents of wooded and arable ground in La Sologne : " About
1836 the forests covered an extent of about 38,730 hectares, which
included those belonging to the state, to communes, and to private
individuals. Since that time much sandy unproductive arable land
has been planted with maritime pines, and I am not far ft'om the
truth in fixing the total extent so occupied in Sologne at 50,000
hectares. Forests thus cover one-eighth of the whole surface. The
forest of Bruadan, lately uprooted, was famed for its size and for its
beautiful oaks. The forests of Boulogne and Chambord take a high
place. In the interior of Sologne may be mentioned those of Villette,
Chaon, and many others lately planted with pines. The oldest forests
are composed of white oak copse, growing under large timber of the
same tree. These usually occupy a stiff clay. The pedunculated oak
presents also a luxuriant appearance, reminding one of more fertile
countries. The good success of deciduous trees proves that they have
not so many requirements as herbaceous plants ; for, while the latter
cannot procure nourishment, the former, on the contrary, appear to
derive from the sub-soil and the atmosphere everything necessary for
their welfare.

" Such differences between these two classes of plants are often
apparent. The marl so useful for crops seems positively hurtful to
certain trees. The upper soil, exhausted by frequent cropping,
appears equally favourable to the germination and the development of
trees. The Solognese peasant says that sand is ripe for ti-ees when-
ever barley refuses to grow.

" Trees with deciduous leaves, the oak in particular, are certainly
the greatest improvement to the landscape; and when under the shade
of these magnificent specimens scattered here and there on the edges
of the farms, one questions whether the soil should be called sterile.
Every domain, and, it may be said, every farm, has one part of wood-
land assigned to the proprietor. The oldest forests are coppices of oak
and birch. The pedunculated or stalk-fruited oak occupies the
argilo-silicious soil, whilst the oak with sessile acorns, is found on
stiff clayey soil, where it succeeds as coppice better than any other
tree. The new forests, planted within the last thirty years, are usually

PREPARATION OP THE SOIL FOR SYLVICULTURE. 75

formed of maritime pines. Isolated portions often look neglected,
because the bad habit prevails of pasturing cattle in oak-coppice
woods. There are even proprietors who tolerate this abuse in les
haux. Plantations of maritime pines are better protected, but care-
less shepherds often allow their flocks to brouse on the young shoots.

" It may be remarked that boisements, or plantations of trees, are
gradually encroaching on the arable ground. It is more than thirty
years since this invasion began. The soil, naturally poor in lime and
fertilizing elements, is rapidly exhausted by the prevailing bad farm-
ing. What can be done with such soil 1 Simply to sow three or four
francs' worth of the seed of the maritime pine, and to wait for the
growth of the young forest. Such an insignificant outlay preparing
for a certain return being obtained from soil absolutely useless for
agriculture.

" These improvements often take place on land otherwise unproduc-
tive, because it is the interest of the proprietors to do this. Subse-
quently a portion is cleared and made arable, and when exhausted by
fifteen or twenty years' culture, it is again planted with wood. In
this way in sandy cantons the farmer, or small land-holder, succes-
sively clearing and planting, becomes an important agent in
re-converting the lands into forests."

In regard to the formation of pine woods in La Sologne, M. Boitel
supplies the following information :

" Frejxiration of the Ground. — The extension of sylviculture, which
would fall to be deprecated if it implied that the land planted with
trees was land withdrawn from agriculture, comes to be desirable
when it is carried out on laud fit for the growth of trees alone, and
which has become so only after a few years of temporary cultivation.
In Sologne nothing is more difficult than to convert a Lande at once
into a forest. The most experienced men carefully avoid attempting
to do so ; as when the soil of the Lande has been carefully prepared
to receive the seed, it is at once covered by a vigorous vegetation of
heath, broom, and gorse or whin, which never fail to choke the young
trees. Immediate boisement, or plantation with trees, succeeds rarely,
and only on very dry soils, where the heaths are stunted. Except in
such rare conditions, it may be said the natural growth (heaths,
broom, and gorse or whins) are stronger than the maritime pine, the oak,
and the birch ; when the seedlings come into collision, victory accrues
to the indigenous growth of the soil. Sologne, in this respect, is
very different from Gascony, where the maritime pine, by natural

76 SYLVICULTURE IN LA SOLOaNE.

sowing, invades the heaths when these are not under pasture ; and fur-
ther, on the Dunes of Gascony broom is employed successfully to
shelter the infant pines !

" Choice of Ground. — Either arable ground or Landes may be
planted. The latter cannot undergo the operation at once without
being subjected to cultivation for several years.

" The arable laud employed must of course be of the worst kind.
Sandy, permeable, light soil is generally destined to hoisement. Only
special circumstances ever induce a proprietor to plant with trees all
his property, whatever may be the nature of the soil ; but planting
may have to be carried on at the same time on pure sand, and on
sand which is more or less mixed with clay.

" Before fixing on the trees to be used, the nature of the soil, and
the requirements of convenience, must be consulted, and the selec-
tion should be of whatever will yield the highest and most pei'manent
annual return.

" Boisement in Sologne is either permanent or temporary ; per-
manent where it is in contemplation to farm a copse or a timber
forest ; temporary, when intended to prepare the soil for agriculture ;
and this may determine the choice of trees.

" For temporary hoisement, trees which soon attain maturity
should be chosen. The maritime pine, which in favourable circum-
stances attains the age of eighty years, rarely lasts more than twenty-
five in Sologne. After this age the bark is covered with lichens, the
growth is feeble, and it is at a loss if the exploitation be delayed.
The ground which is cleared will then yield excellent crops without
further expense than that of the working of the ground — thanks to
the organic remains with which it is enriched by the trees grown
upon it.

"In this way a rotation may be carried on according to the
following formula :

Maritime pine, ... ... 20 to 25 years,

Idem, ... ... ... „ „

Rye and buckwheat, ... ... so long as rye and

buckwheat continue to thrive without the addition of manure.

"The soil when again exhausted, is again replenished with
maritime pine, and so on continuously.

" In this rotation the pine plays the part of a doubly productive
fallow, because, besides its commercial value, it restores to the soil
the elements which are required in agriculture. We cannot too
much admire the marvellous property of trees whereby they collect

TEMPORARY AND PERMANENT BOISEMENT, 77

and restore to the exhausted soil, the substances withdrawn from
the air by their leaves [1] or from the subsoil by their roots. It
supplies us with one of the main instances in agriculture in which
time is of more value than money. With a great outlay in fertilizing
a poor soil, the return may be uncertain or even ruinous to the
cultivator. If, on the contrary, it be expended on hoisement, or plan-
tation of trees, where time is money, you attain your end by improv-
ing the fertility, and at the same time you produce the amelioration
by a money return. It is only in the case of very good soil that
time is here worth more than money.

" Permiuient or definite boisement. — Temporary hoisement makes the
poor soil of Sologne produce every year, pines, rye, and buckwheat.
Permanent hoisement excludes agriculture, and the annual produce is
exclusively that of the forest. This is obtained by mixing the oak,
bii*ch, and chesnut, with the pine, the coppice regime of which trees
follows the exploitation of the last named tree. In Sologne both
systems have both advocates and assailants. Unfortunately, discus-
sion will not decide the point, and we do not as yet possess sufficient
data to enable us to do so. But if we look at the subject from a philan-
thropic point of view, the first is to be preferred, because, instead of
producing alone fire-wood and charcoal, it furnishes cereals, over and
above, to a population at pi'esent obliged to have recourse to the im-
portation of these from a distance.

" Soiuings of pines along tvith other trees. — The maritime pine when
grown by itself is treated as has been already detailed. When
mixed with other trees there are no very important modifications
of this. It acts as a shelter to coppice woods of oak, birch, and
chestnut. These coppice woods continue growing while the pines
remain, but they do not become really productive until after the
exploitation of these. Instead of passing abruptly and completely
from the culture of the pine wood, to that of the coppice woods of
deciduous trees, there are sometimes left haliveaux, or standards,
of maritime pines. In this way we have there a coppice of oak and
birch under a timber forest of pines. This method is only to be
adopted on soil which is very favourable to the pine.

" For mixed hoisements it does not signify whether the soil is quite
suited to the pine or not. The good of the trees which will per-
manently occupy the soil is more to be consulted. In any case,
where the sand is shallow, Scots firs should be preferred.

" The trees to be mixed with pines should be, first, the red oak, on
stiff clay ; second, the white oak, on argilo-silicious soils ; third, the

78 SYLVICULTURE IN LA SOLOGNE.

birch, iu poor, damp, and deep sand ; fourth, the chestnut, on rich,
damp, and deep sand. The oak is veiy hardy ; in poor soils it is
the most productive.

" To conclude, it is not always easy to apply the rules laid down,
on account of the varieties of soil ; but to ensure success two kinds of
deciduous trees should be associated with the pine — for example, the
oak and birch.

" Fine coppice woods of chestuut are rare in Sologne, which seems
to prove that the soil is unsuitable. Nevertheless, solitary specimens
of chesnut trees of great beauty occur, but only in the neighbourhood
of the farms, where they have had the benefit of manure and culture.

" The year in which the pines are sown may not always be a good
year for acorns. In this case the latter may be pricked in later
among the young pines.

" When the pines and acoi'ns are sown at the same time, the acorns
are first scattered in furrows, and when the ground is harrowed they
are covered to the proper depth. The pine seed is then sown and
covered by being slightly hari'owed. Chestnuts are sown like acorns.

'' Birch seed is not sown in Sologne ; young plants, three years old,
collected in the neighbourhood of the old trees, are preferred."

M. Boitel goes on to say : " Having pointed out the trees to be
employed on hoisements, we may now consider the respective merits
of forests and agriculture as regards the general good.

" It is impossible to bring a poor soil at once into cultivation, and
it may be considered as proved beyond a doubt that rehoisement is the
best way of improving land, and at the same time securing a speedy
return.

" In Sologne, agriculture can only be profitably carried on iu
certain favoured spots where the soil, argilo-silicious or silicio-
argillaceous, has been drained and manui-ed ; but it is evident that
expensive improvements, in which the outlay exceeds the return, can
only be carried out on a very small scale in Sologne. A farm of 100
to 150 hectares will only contain 20 or 30 hectares which have been
treated in this way.

" It is impossible to establish the relative proportion which ought
to exist between agriculture and hoisement — local circumstances and
the position of the proprietor diff"er so very much.

" The most experienced men devote to hoisement, first, exhausted
land which is usually sandy ; second, Landes exceptionally poor.

" We have already said that these Landes cannot at once be

3 ,

0

j>

4 „ 50

»

2 ,

, 50

>j

9

-• >

, 50

>j

EXPENSE OF SOWING. 79

changed into forests ; but when grubbed out, and subjected to the
action of black cattle during two or three years, they yield crops,
which repay the expense of grubbing, and which destroy the weeds.

" I have tried boisements on a large scale on the Imperial domains
of Sologne. The following is the cost of sowing a hectare of
exhausted land :

10 kilogrammes of maritime pine seed

(winged) at 40 cents, ... 4 francs 0 cents.

1 kilogramme of Scotch fir seed

(winged) at 3 francs,
150 litres of acorns at 3 cents,
50 litres of chestnuts at 5 cents,
Scattering the seed, ...

Total, 16 francs 50 cents.

"The expense of draining, levelling, enclosing, and weeding,
varying according to locality, amounts, at the least, to 15 francs per
hectare, so that the reboisement of a hectare will cost about 32 francs
50 cents, partly the seed, partly for hand labour. The expense of
ploughing and harrowing must be added, but usually this is not
great in these sandy soils. Land left in furrows only requires to be
harrowed after the seed is scattered.

" This system of boisement is perfect and permanent, and free from
risk.

" If the Scots fir does not germinate, which often happens, it
should be replaced by the maritime pine, and vice versa. If resinous
trees fail, the oak, birch, and chestnut will cover the ground
sufiiciently.

" Some boisements cost only 4 or 5 francs per hectare instead of 32
francs 50 cents, in which case the seed of the maritime pine is sown
along with rye and buckwheat. The seed costs little, and the produce
of the mixed culture pays for the ploughing and harrowing. This
method has the drawback of risking all on a single tree, which may not
succeed. On the other hand, it is to be supposed that the ground is
not too far exhausted to be able to produce at least one other crop of
rye and buckwheat ; this is not usually the state of a field abandoned
by farmers or small land holders.

" The young pineries, called here scqnnieres, are treated according
to the method already described."

In the reclaiming of these Landes of La Sologne, we still find the

80 SYLVICULTURE IN LA 80L0GNE.

maritime pine playing an important part ; but it is a subordinate
role. It is employed here not as the one important culture, but as a
means of preparing the soil for the culture of some of the poorer of
the cereals, or as a manure to other trees, for the growth of which it
has to make way, having secured its purpose, and in doing so
exhausted its growth. In this respect, as in others, the Landes of
Gascony and the Landes of La Sologne differ greatly ; and thus a
fuller study of these, more especially in particulars in which they
differ from each other, may be desirable.

CHAPTER VIII.

Inland Sand-Wastes, and Sand-Wastes on the Coast.

The diflFerent conditions of the mai-itime pine grown on the Landes of
Gascony, and of that tree grown on the Landes of La Sologne, indicate
that there must be some great difference in the conditions of the
sand-wastes themselves ; and I deem it of much more importance to
have this fact recognised by those who, without previous experience,
may contemplate the reclaiming of sand-wastes by sylviculture, than
to have the diiTerence referred to precisely specified. All sand-wastes
are not alike : there are sand-wastes ; and there are sand-wastes ;
and there are trees which will grow luxuriantly upon one, which upon
another will pine away and die.

Climate has to do with such results as well as soil. Sea air, and
saline constituents of the soil, destructive to some trees, may be, like
elements, life to others. The mobility of a drifting sand dune on the
coast may be a condition of life to one tree, while the comparative
fixity of an inland sand-waste maybe essential to the growth of another.
Something has been gained by the discovery that even the maritime
pine, which has produced such wonderful results on the Landes of
Gascony and of the Gironde, will not grow everywhere, even on sand-
wastes in France. And the teaching of this is, that in every case in
which it is sought thus to arrest and utilize sand-wastes, the culture
must be determined by a special acquaintance with the case.

A previous study of the natural history of sand drifts and sand
dunes might facilitate the acquisition of such an acquaintance with
any one case as is referred to. But this comes not within the scope
of this volume, which is limited to the single chapter of that subject
indicated by its title. And it is the appeai'ance presented by planta-
tions ovi drift sands, and by lands adjacent to the pine plantations in
Gascony alone, which have as yet been detailed. Points of similarity
and of difference between these sands and the sands of La Sologne
have only come before us incidentally.

With the fact before us, however, that there are differences in the con-
ditions of sand-wastes, we may find it satisfactory to advance a little
further in the study of these sand-wastes of France, less with a view
of ascertaining the difference between the sand-wastes of the coast

L

82 SAND-WASTES IN FRANCE.

and those of the interior of France, than with a view to becoming
acquainted more extensively with the less superficial conditions of
these sand-wastes than those previously detailed, whether common
to all or peculiar to certain localities-
According to Herr Wessley, to whose work, entitled Der Utcropdische
Flugsand unci Seine KulUir* I have already had occasion to refer,
the "Landes" covering 270 German square miles (5,550 English
square miles) of the province of Gascony, form the area of the basin
of Bordeaux, a triangle bounded by the Atlantic, and formed by the
land lying between the lower portion of the beds of the Garonne and
of the Adour.

On the coast are the " Landes Sauvages," or coast dunes, covering
an area of 19 German square miles, (nearly 400 English square
miles), which, through drifting, have extended to a breadth which is
unusual, and thereby has it frequently happened that the river courses
far inland have been stopped up, and thus, through their waters
penetrating into the Kehlen, or bared grooves, and hollows amongst
the dunes, which cover more than half the land, have these waters
been converted into lagoons and marshes.

The inland portion of the " Landes " forms a kind of plain from 250
to 300 feet above the level of the sea, an extensive sand heath
covered with dunes, very much cut up, and of a composition so
unfavourable to vegetation that in many parts it is throughout the
year perfectly barren. It is only of late, as he says, that by extensive
sylviculture, chiefly of the maritime pine, a considerable extent of
forest has been produced, following mainly the water courses, and
thereby a better produce from the land has been obtained.

The superficial covering of these heaths is composed principally of
a very poor sand, devoid alike of clay and lime from 1-9 to 2*5 feet in
depth, resting on an impenetrable under stratum, from 11 to 15
inches in thickness, which consists of sand cemented by calcareous
and vegetable matter and is almost identical with the so-called
German " Ortstein." Under this stratum of ortstein again lies sand,
and although in some places they have dug to a depth of 63 feet
the lower extremity of this sand layer has not been reached.

In the summer season there is neither spring nor brook to be seen
in these Landes. In the winter, however, being so near the sea, there
is a plentiful fall of rain ; and formerly, because of the little slope of

* Vienna : Fraesy and Freck. 1873.

RETENTION OF WATER,

83

the ground preventing a flowing off on any side, and the ortstein
preventing its sinking into the ground, they were frequently flooded,
and in this state they continued till the water was finally evaporated
by the summer heat ; and then things went to the other extreme,
namely, a drought, because the vapour of the subterranean water
could not pass through the stratum of ortstein. But here and
there, where the ortstein was awanting, or had been broken through,
places might be seen which were not so water drenched ; on these
grew wood very well, and showed that the barrenness was not
attributable to the composition of the superficial layers.

The level of the subterranean water is about 3f feet below the
surface. Water for drinking brought from that level is yellowish in
colour, and harsh to the taste ; it is only when brought from a depth
of from 12 to 15 feet that the water begins to be drinkable.

In the wet localities desci'ibed no oak can grow, for during the
season of spring the whole heat is required for the evaporation of
the water lodged there, and the oaks then expand their buds, and if
these retain vitality at all it is only in the end of May, when the
excess of moisture has disappeared, that they can burst forth, and
then the delicate buds are exposed to the summer heat, and they
succumb to the scorching sun of July.

The maritime pine has also its buds ; and the period of its vege-
tation is also reduced by about two months by the stagnant waters ;
and by the ground ever passing through the alternation between exces-
sive drought and excessive moisture, this tree also suffers in its growth,
and on spots which do not become dry until the middle of summer
it does not grow at all.

The importance of effects produced by the ortstein, of which men-
tion has previously been made, under its local designation, alios, calls
for some additional information being given in regard to it.

In writing of the Water Supply in South Africa, I have had occa-
sion to refer to an impermeable layer in the sands of Namaqualand and
other districts operating as does the ortstein here. There travellers,
when driven to extremity for water, have found, on hollowing out a
basin in the sand, that at a little depth they reached a layer of other
matter ; and after a time, more or less protracted, water collected in
this basin, draining thither from and through the permeable sand, and
retained there by the impermeable stratum, often not thicker than a
penny, formed probably of clay, lime, and other matter washed down
from the superincumbent sand. It is impermeable to water ;

84 SAND-WASTES OP FRANCE.

but great care has to be taken not to fracture it, as whenever this
happens the water is lost, draining off to a lower depth.

In the Landes the stratum of impermeable matter spoken of by
Herr Wessley, and there known as alios, contains iron in its composi-
tion ; it has been spoken of as bog-iron-ore, and has been mentioned
(ante p. %Q) under this name among the products of the Landes
exhibited by M. Leopold Javal.

The origin of this has been discussed by M. Faye, Director-General
of the Administration of Forests in France, in a paper which appeared
in the translation of the Academic des sciences, from a notice of
which, in the Athenceum, it appears that M. Faye was engaged to
level a portion of the Landes between the lakes on the coast
and the basin of A.rcachon, and made use of the opportunity to
study the peculiarities of the soil. According to this notice : " At
about three feet below the surface of the Landes, there lies every-
where an impermeable stratum called alios, a stony substance of a
brown colour, variable in thickness, which is nowhere great, and
covering an indefinite bed of sand, identical with that which lies above
it. This invisible waterproof stratum has always had a great influence
on the health of the inhabitants of the country. Retaining the pro-
ducts of vegetable decomposition from the upper soil, where there
was scarcely any slope, the alios has for centuries fixed intermittent
fever in and around the Landes ; but reclamation has driven away
the fever, and the alios seems now to have no other eff'ect than that
of forcing the roots of the marine pines to grow horizontally instead
of vertically. The sand of the Landes is white, intermixed with a
few black grains, containing peroxide of iron and oxide of manganesia.
Washed, first by the water of the ocean, and afterwards by rain for
centuries, it holds no soluble matter, and the alios, which is of a dark
reddish brown colour, sufficiently compact to require a pick-axe to
break it up, is a stratum of the same sand cemented together by some
organic and slightly ferruginous substance. In the summer a hole
made in the soil down to the alios fills gradually by lateral infiltration
with yellowish water not fit for drinking ; but if the alios is pierced
an abundant supply of perfectly limpid water is obtained.

" The question is — How is this alios formed 1 It is evident that it
was produced in situ, and the presence of the organic matter already
mentioned leads to the supposition that the latter plays some part in
the formation of this peculiar stratum.

" The alios is found everywhere in the Landes except in the marshes,
on the banks of ponds, and in the downs, even when the latter,

FORMATION OP THE ALIOS, 85

protected by old forests, have never been swept by the winds for
centuries. Soundings, and the knowledge of these exceptions, led M,
Faye to the discovery of the mode in which the alios was formed.
In winter and early spring the nearly level surface of the Landes is
covered with rain-water, but during summer the level of this water
descends by evaporation, to the depth of one or two mfetres, a level
which also corresponds with that of the ponds which border the chain
of downs. If now we take into consideration the decomposition of
vegetable matter which takes place in the water, and the deposit
which must be produced at the lower level, it is easy to see why an
agglomeration of sand and organic matter should take place at the
depth already mentioned. This operation being repeated annually
during many centuries, an increasing stratum of alios is naturally
formed, which doubtless continues to grow at the present moment.

" It is not surprising then that no alios is to be found in the
marshes which are always under water, nor in the downs which are
not inundated, like the Landes, by a periodical sheet of water carried
off regularly by evaporation, the rain as it falls being carried away
by the slopes to the sea.

" But Whence come the traces of ferruginous matter which aid in
the agglomeration of the alios and in giving it its red tint 1 It was
shown long ago that the decomposition of roots and other vegetable
matter brings the peroxide of iron contained in the soil into a state
of inferior oxidation, and renders it liable to be attacked by the weak
acids resulting from vegetable decay; more recently, M. Daubree
attributed the formation of the limonitic iron of the Swedish lakes to
this chemical action, showing that iron thus rendered soluble over
great areas is collected together by springs and rivulets, re-assumes
its primitive oxidation, when the waters come in contact with the air,
and is then deposited in the form of slime, and forms mineral strata
of great richness. The same effect, but produced on the spot, would
account for the small quantity of iron found in the alios. Vegetable
decay has, in fact, produced in places the identical efiFect on the
blackish portions of the sand of the Landes ; where a fall in the level
has caused a great accumulation of water there has been a concen-
tration of iron, and in past times a certain number of furnaces worked
up the iron, which is now exhausted.

" M. Faye, having explained the origin of alios, showed what eflfect
an impermeable subsoil has on the salubrity of a district ; the escape
of the water is stopped, the subsoil becomes a centre of putrefaction
and infection, and endemic malaria devastates the country. In the

86 SAND-WASTES OP FRANCE.

Landes the evil has been remedied by cutting rather deep drains to
carry oflf the water, and the roots of fern and other plants, which
partly perish every year, have been replaced by those of the maritime
pine. Thus the contamination of the air by the subsoil has been
stopped, and with it the intermittent fevers which had given to the
inhabitants a peculiar character of debility. M. Faye, after much
observation, arrives at what he believes to be a principle, namely,
that wherever an impermeable subsoil is found at a depth of two or
three feet from the surface there will always be intermittent fever if
the soil be contaminated by vegetable putridity, and fevers of a
typhoidal character if animal decomposition be present. As to the
remedy, it consists evidently either in draining, as adopted in the
Landes, or in the removal of the vegetable or animal decomposition."
But of this stratum. Marsh says : " The alios, which, from its
colour and consistence, was supposed to be a ferruginous formation,
appears from recent observations to contain little iron, and to owe
most of its peculiar properties to vegetable elements carried down
into the soil by the percolation of rain-water. See Revue des Eaux et
Forets, for 1870, p. 301."

Whatever the source of the material and the process of its forma-
tion, the effects of its presence on the moisture of the sand-wastes
and on vegetation there is great.

And from what has been advanced it appears that, in so far as
moisture is concerned, dunes and sand plains are not always so
devoid of water as they seem, and as the common expression Dry
Sand would suggest.

Marsh, in connection with a remark made by himself, in which he
says in regard to sand hillocks : " it is observed that from capillary
attraction, evaporation from lower strata, and retention of rain-water,
they are always moist a little below the surface," cites in a foot-note
the following observations : " Dunes are always full of water, from
the action of capillary attraction. Upon the summits one seldom
needs to dig more than a foot to find the sand moist ; and in the
depressions fresh water is met with near the surface. Forchhammer
in Leonhard und Broun for 1841, p. 5.

" On the other hand, Andresen, who has very carefully investi-
gated this as well as all other dune phenomena, maintains that the
humidity of the sand ridges cannot be derived from capillary
attraction. He found by experiment that a heap of drift sand was
not moistened to a greater height than eight and a half inches, after

ABSORPTION OP WATER. 87

standing with its base a whole night in water. He states the mean
minimum of water contained by the sand of the dunes one foot below
the surface, after a long drought, at two per cent. ; the maximum,
after a rainy month, at four per cent. At greater depths the quantity
is larger. The hygroscopicity of the sand of the coast of Jutland he
found to be 33 per cent., by measure, or 21 '5 by weight. The
annual precipitation on that coast is 27 inches, and, as the
evaporation is about the same, he argues that rain-water does not
penetrate far beneath the surface of the dunes, and concludes that
their humidity can be explained only by the evaporation from
below. Om Klit formationen, pp. 106-110.

" In the dunes of Algeria water is so abundant that wells are
constantly dug in them at high points on their surface. They are
sunk to the depth of three or four metres only, and the water rises
to the height of a m^tre in them. Laurent. Memoire sur le Sahara,
pp. 11, 12, 13.

" The same writer observes (p. 14), that the hollows on the dunes
are planted with palms which find moisture enough a little below the
surface. It would hence seem that the proposal to fix the dunes
which are supposed to threaten the Suez Canal, by planting the
maritime pine and other trees upon them, is not altogether so absurd
as it has been thought to be by some of those distinguished philan-
thropists of other nations who were distressed with fears that French
capitalists would lose the money they had invested in that great
undertaking.

" Ponds of water are often found in the depressions between the
sand hills of the dune chains in the North American desert."

I have had occasion, in the volume on " Reboisement in France," to
refer to certain experiments by Thurmann, in which cubes of difl^erent
minerals, thoroughly dried, weighing each 100 grammes, were im-
mersed in water for five minutes. He states that these gave the follow-
ing results : — Liassic triassic, compact Jurassic, liassic triassic, and
oolithic limestones, granite, serpentine, basalt, dolerites, trachytes,
&c., gave a mean absorption of 0-50 grammes of water. Similar mine-
rals, including gneiss and compact marl schist somewhat disinteg-
rated and changed, gave a mean absorption of 1-50 grammes; lime-
stone still further decomposed, ferruginous oolites of Mt. Jura, liassic
schists and grits from the Vosges, and eruptive rocks perceptibly
changed, a mean absorption of 4 grammes ; variegated grits, green
coloured grits, calcareous chalks, gravelly clay, and sands, 7 grammes ;
and clays, Oxford marls, and kaolin, an absorption of from 10 to 30
grammes.

88 SAND-WASTES OP FRANCE.

These observations, I there stated, Marchand considered indi-
cative of the absorption of water being proportional to the state of
sub-division of the material composing the rock ; and this effect he
resolved into their hygroscopicity and their capillarity — the former,
the power of each molecule of the rock to retain around it a layer of
moisture difficult to withdraw — the latter, the property possessed by
many molecules of earth, to retain, in interstices by which they are
separated, small globules of water.

From experiments and observations cited by Wessley, it appears
that, of all the constituents of soil, sand manifests the least capa-
bility of absorbing water into its composition.

According to experiments by Schuebler, recorded in his Agriadtur-
Chemie (1830), a cubic metre of the following substance contained of
water the quantities stated :

Kilogrammes.
Quartz sand, 499

Pure grey clay, 875

Fine carbonate of lime, 808
Humid acid, 935

Field earth, 745

Garden earth, 821

The size of the grains of sand has an influence, and the capability
of absorbing moisture is increased with the fineness of the grains, —
but much more by the admixture of clay and lime, and most of all by
the addition of humid acid.

Pure quartz sand has no power of attracting moisture from the
atmosphere, but it gains this power by the admixture of other sub-
stances; and the operation is promoted by the reduction of the size
of the grains.

According to statements in Heyer's Forstliche Bodenhunde, founded
on investigations by Schuebler, 5 grammes of the following sub-
stances spread out over 360 square centimetres, attracted from the
air in 72 hours the affixed number of centi-grammes ; and the pro-
portions would have been the same whatever weight had been taken :
Pure quartz sand, ... ... ... 0"0

Pure grey clay, ... ... ... 24"5

Powdered carbonate of lime, ... ... 17"5

Humid acid, ... ... ... 60*

Field earth, ... ... ... 11-6

Garden earth, ... ... ... 26*

Weight.

In volume.

•25

•50

•70

•87

•85

•81

1-90

•94

•52

•75

•89

•82

MOISTURE OF SAND, 89

Again we find the effect intensified most of all by the admixture
of humus, the operation of which is some three-fold that of clay and
lime. Sand again is desiccated more rapidly than the other sub-
stances mentioned.

According to Schuebler, of 100 parts of absorbed water, reduced
to the extent of 90 parts by exposure to a temperature of 15°, these
substances yielded it up in the following times stated :

In one hour.

lu four hours.

Pure quartz sand,

4-07

88-4

Pure clay,

11-28

31-9

Powdered lime,

12-83

28-

Humid acid.

17-55

20-5

Field earth,

11-25

32-

Garden earth.

U-82

24-3

Further, it has been found by experiments by Kerner, that the
finer the sand the longer does it retain moisture. And the observa-
tions cited show, that while this property is increased by an admixture
of clay or lime, it is increased most of all by an admixture of humus.

The rainfall sinks quickly into porous sand. When rain falls
slowly we find no puddles ; the rain is drawn off to feed subterranean
waters, while, when it falls in deluges, it falls faster than it can sink,
and, instead of flowing away over the surface, it flows away, carrying
the sand with it, and often depositing this on ground at a lower level,
to its utter devastation.

The coarser the sand the more quickly is it permeated by water.
Kerner, in experiments, found the time to vary with this from two to
twenty minutes.

With sand soil manured for agriculture it is otherwise, Grouven
found, on experiments with turnip ground of diluvial sand, that in
two hours 72 grammes of water dropped through an 8-inch layer, but
he found the quantity in five other specimens to range from 15 to 62
grammes only ; while in five others it was doubled, ranging from 117
to 119 grammes; while in four other specimens it was fourfold as
much, ranging from 261 to 286.

The capillary attraction manifested by sand is remarkable. It not
only operates quickly, but more quickly from below upward than
water sinks from above downward when it falls in quantity.

According to Meister, quoted by Mayer in his AgricuUur-Chemie^
1871, the ascent of water by capillary attraction in different sub-
stances was as follows :

M

90 SAND-WASTES OP PBANOB.

In i an hour.

In 2i hours.

In 2H hours.

Clayey soil,

34

115

200

Humus,

40

114

177

Garden ground,

29

98

161

Quartz sand.

44

97

117

Peaty soil,

27

57

114

Sandy soil,

45

66

90

Chalky soil.

6

54

70

In consequence of this, it is remarked by Wessley, the level of the
subterranean water stands high in drift sand layers ; and standing or
running waters can with ease diffuse themselves sideways in sand
layers.

The power of absorbing nutritive elements of vegetation is
possessed by sand in a degree remarkably limited in comparison
with the degree in which it is possessed by other soil. According to
experiments by Grouven, 1,000 grammes of pressed northern diluvial
sand, field soil absorbed :

Of potash, ... ... ... 24-1

Of ammonia, ... ... ... 18"6

Of phosphoric acid, ... ... 6*4

And the same quantity of loamy northern diluvial sand, field soil
absorbed :

Of potash, ... ... ... 22-5

Of ammonia, ... ... ... 21'5

Of phosphoric acid, ... ... 21*5

While 22 samples of turnip field soil of different kinds absorbed :
Of potash, ... ... from 66 to 137

Of ammonia, ... ... from 35 to 134

Of phosphoric acid, ... from 32 to 135

The power of absorbing ammonia from the atmosphere is, we see,
possessed in the lowest degree by sand. Clay, mergel, and humus
surpass all other soil in this. It is the same with the power of
absorbing carbonic atmosphere from the air possessed by all of these
substances in a wet state ; this is least of all in sand, but it exists
in the greatest degree in humus.

This power of the sand increases with the fineness of its particles ;
it may be observed to be proportional to the minute sub-division
of the bodies operated on, and this property may be intensified
in the sand by the admixture with it of the other substances
mentioned.

COMPOSITION OF SAND. 91

The size of the grains of sand is very different in different places.
The largest grains measure about a cubic millimetre, but the averages
in diffei-ent drift sands vary from 0'02 millimetres to 0-47.

The coarsest sands in Europe are those of the Northern Binnen
Sands; those of the strand are disproportionately finer; in sand
basins the particles are finest in the direction in which the diluvial
waters found their exit ; the sand is finer in dunes than in the blown
out hollows between them; and in an extensive sand-waste the
particles are finer at the extremity towards which the wind blows
than at that by which it comes. The size of the particles has an
influence, we have seen, not only on the degree to which it is liable to
drift, but in the degree in which it may manifest many properties
important to soil, amongst others, those of retaining moisture, one
which is absolutely necessary to vegetation.

In accordance with what has been advanced is the testimony of
Clav6 :

"Composed of pure sand resting on an impermeable stratum
called alios, the soil of the Landes was for centuries," writes Clav6,*
" considered incapable of cultivation. Parched in summer, drowned
in winter, it produced only ferns, rushes, and heath, and scarcely
furnished pasturage for a few half starved flocks. To crown its
miseries, this plain was continually threatened by the encroachments
of the dunes, vast ridges of sand thrown up by the waves, for a
distance of more than fifty leagues along the coast, and continually
renewed, were driven inland by the west wind ; and as they rolled
over the plain they buried the soil and the hamlets, overcame all
resistance, and advanced with fearful regularity. The whole
province seemed doomed to certain destruction when Bremontier
invented his method of fixing the dunes by plantations of the
maritime pine."

The mobility of the sand is also most effectually arrested and
prevented by moisture, and it is only renewed as desiccation takes
place.

It may have been remarked that the sand on the sea-shore does
not begin to drift so long as it is moist — that it only does so when it
has become thoroughly dry ; and that it ceases so soon as it is again
moistened, whether by rain or by the rising tide. But what is
mainly contemplated here is simply to show how it comes to pass

* Etudes Forestieres, p. 250, See also Reclus. La Terre, I,, 105-106.

92 SAND-WASTES OF FRANCE.

that vegetation can be extended over sand-wastes — even moisture
existing there.

The alios is met with in the sands of the Landes of the Gironde,
at a depth of about three feet below the surface. It is often about a
foot in thickness, and underneath this is sand of unknown depth.
Diggings have been made to a depth of upwards of 60 feet without
reaching other material. In the winter season these Landes are
covered with water which has no fall, and cannot sink through this
layer ; but in summer neither pool nor moisture is to be seen, the
water having been evaporated, and the layer preventing an ascent of
moisture from below. But, as has been intimated, there are spots
where this stratum is awanting or has been broken, and on these
grow bushes and trees, the ground neither being drenched in winter
nor altogether devoid of moisture in summer.

Both in connection with notices of the drift sands of the Landes on
the coast, and of the sand-wastes of La Sologue, mention has been
made of peat lands and of marshes. These are found on sand-wastes
in so many lands that the existence of them in such lands appears to
be the rule, and the absence of them the exception. Suffice it here to
state that a sand ridge may pi'event escape of the waters by flow,
and a stratum of alios or ortstein, or clay, or other impervious substance,
may prevent escape by percolation.

From the treatise by Herr Wessley entitled, Der Europaische
Flugsand und seine Kultur already cited, much information may be
gathered in regard to the composition and condition of the sand-
wastes of Europe.

In regard to the general appearance and composition of the drift
sands of Europe, he says that in all places they consist in a vastly
preponderating degree of fine somewhat rounded grains of quartz,
with which only a small percentage of other materials are com-
mingled.

The admixture consists primarily of felspar, which in old sand has
for the most part experienced the disintegrating and decomposing
efi'ects of weathering, of lime, mostly fragments of shells ; of mica ; of
magnetic, or Titanian ironstone ; and finally, of difierent other
minerals, hornblend, augite, hypersthen, basalt, and carbon.

The separate grains are more or less covered with a fine mould,
on which depends next the fertility of the drift sands. For this
depends in general on an admixture of products of the weathering
just spoken of, or on those which the sand, the natural vegetation

SPECIFIC GRAVITY OF SAND. 93

and watering, or the culture, produces or attracts, of appropriate
nutriment of plants.

The drift sand, strictly speaking, though variegated by a sprinkling
of somewhat rare grains of darker coloured substances, is a mass of
a light colour. Amongst the lightest coloured is the washed out sand
of the north, whicli is of a gi'eyish white. Amongst the darkest is the
drift sand of the Bannat in Hungary, covered with a strong mould
containing iron, which is of a yellowish light brown. In a wet
state all drift sands are of a dark hue. So far as the surface is
acquiring or has acquired a covering of vegetation of some years
standing, it appears of a dai'ker colour, varying with the kind of
plant, with the richness of the vegetation in humus, and with the
age of this, varying, for example, from a light grey brown to a
black brown hue.

Many drift sands have also an admixture of a coarser form of
sand, which on sea strand dunes is as large as pearls, and in inland
situations goes indefinitely beyond this : round pieces, even to the
size of blocks ; concretions of lime of the most varied forms ; shells of
snails and of mussels ; cemented clods ; and the whole layer is hardened
like stone. These larger sized materials are altogether absent in the
wind-raised dunes. Such is the European drift sand in general. In
individual cases, however, the character varies with the district,
the origin and the thickness of the layer, and the transformations
occasioned by geological changes, by vegetation, &c.

He reports the specific gravity of the different constituents, which,
with the exception of the humus, which, on the authority of experi-
ments by Schueblei*, recorded in his Agricultur-Chemie, he gives as
1-370, ranges from 2-468 to 2-722; and he shows that the differences
between 1-370 and 2-468 of specific gravity in sands, may be attri-
buted to varying quantities of humus or products of vegetable decay
in their composition.

As the result of numerous detailed experiments cited in an
appendix embracing the composition of sands existing in numerous
parts of Germany and Austria, he gives the specific gravity of the
sands of North Germany as 2-5-2-9 ; average, 2-7 ; of the sands of
Hungary, as 2-1-2-65 ; average, 2-5 : attributing the greater weight
of the former to the smaller quantity of lime, and the greater
quantity of iron-ore, and mica in their composition. And, for
comparison, he gives, on the authority of M. Schuebler, the specific
gravity of arable land generally as 2-401, and of garden ground as
2-332 ; and on the authority of Hauer, that of the celebrated fields
of Banat as 1-8-2-5 ; average, 1-18.

94 SAND-WASTES OF FRANCE.

The coherence of sands of varied composition, as determined by
Schuebler and others, give the following result :

" Taking perfectly dry, pure quartz sand as zero, a mixture of 4 per
cent, of water gives it so much consistency that it may be pressed in
the hand and cease to be driven of the wind ; and this latter result
follows an admixture of 4 per cent, of clay or 16 per cent, of lime,
or 10 per cent, of humus. But what is thus gained by an admixture
of humus, clay or lime, is lost by its being frozen in a moist state,
on its being thawed, a peculiarity which it shares with all soils.

This, if it be so, may be attributable to the affinity of these sub-
stances for moisture, of which sand has little or none, leading to their
absorbing all the free moisture, and leaving the quartzose sand dry
and free to be blown away.

The commixture of lime and of clay with sand, so beneficial to
the latter, has also this bad effect when it is considerable — that after
heavy rains, followed by rapid desiccation, sometimes there is left
on the surface of the sand a crust detrimental to vegetation.

Pure sand does not shrink in bulk in drying.

The following table, prepared in accordance with observations re-
ceived by Schuebler, will make apparent the difference between pure
sand and other earthy matters :

Pure sand loses in bulk in drying.

Fine carbonate of lime,

Pure clay,

Humid acid, ...

Field earth, ...

Garden earth.

The latter numbers are indicative of there being contained in these
bodies, as found on sandy regions, an admixture of humus or of clay.

Reference has been made to the effect of moisture in arresting and
in preventing the drifting of sand. In view of the effect of heat in
desiccating sand, and also in view of the eflfect of temperature on
vegetation, the degree in which the properties of absorbing and
of transmitting heat are possessed by sand deserve consideration.

The following results of experiments by Schuebler show the com-
parative capability of becoming heated possessed by sand. In the
month of August, with an atmospheric temperature in the shade of
from 22° to 25° R., 81° to 88° Fahr., the temperature of the following
substances exposed to the bright sunshine were, according to the
scale of Reaumeur :

0]

per cent.

5

18-3

20

12

15

Wet.

Dry.

37-2

44-7

37-4

44-6

39-7

47-4

36-9

44-2

37-5

45-2

of becoming he

TEMPERATURE OF 8A.ND. 95

Quartz sand, pure yellowish grey in colour,
Pure clay, yellowish grey,
Humid acid, brownish black,
Field earth, grey,
Garden earth, blackish grey.
This table shows, first, that the power <
possessed by pure sand may be appreciably increased by an admix-
ture of humus, apparently in consequence of the dark colour of this
substance. The dry sand becomes heated some 21°, and the wet
13° R., 79° and 61° Fahr. above the temperature of the atmosphere;
and while the sand is a bad conductor of heat, the heat does not
penetrate to a great depth ; much more is communicated by conduc-
tion and radiation to the superincumbent stratum of air, Kerner
found on still warmer days than these on which Schuebler experi-
mented that the temperature of drift-sand at Pesth half an inch
below the superficial stratum was only 40° odds, and at three inches
deep only 25° odds.

The faculty of retaining heat, or, in other words, the rapidity with
which it is discharged, is something different _from the capability of
absorbing it, and the result of experiment by Schuebler, shows that
representing the time required for cooling by lime as 100, the time
required by other substances compared with it was as follows :
Quartz sand, ... ... ... 96

Pure clay, ... ... ... ... 67

Fine carbonate of lime, ... ... 61

Humid acid,... ... ... ... 49

Field earth, ... ... ... ... 70

Garden earth, ... ... ... 65

After sunset the temperature of the superficial layers of the drift
sand sinks very rapidly. Kerner saw on a broiling day in June, on
the drift sand at Pesth, a thermometer sunk half an inch deep, which
at sunshine showed 35|^, within three hours had sunk to 16*^,
from 112^^ to 68^ Fahr.

The most superficial layer of the Hungarian drift sand shows
the extraordinary great variation of temperature of from 40° to 45° R.,
122° to 133^^ Fahr. But at the depth of only three inches the
variation is only 25*^, or 88^ Fahr., and at four inches, at which
depth the temperature in winter does not sink below the freezing
point, the variation of temperature does not exceed 20'^, 77° Fahr.
But at the depth of three fathoms the annual variation does not

96 8 AND- WASTES OP FRANCE.

amount to |° or 1^ Fahr,, and at that depth, at the elevation of about
300 feet above the sea level, the temperature is almost stationary at
10° K, or 541'* Fahr.

By directing our attention to the sand drifts of Sologne, and the
sand drifts of the Landes of Gascony, we find we have had two
different phases of sand drifts brought under our consideration ; and
as these two phases of these are to be met with again and again,
sometimes in the same countries elsewhere, or the one and the other
of them presenting themselves in lands which are far apart, the
opportunity may be taken, before proceeding further, to consider
at some length an important point in which they differ.

Of the two forms of sand deposit thus brought under considera-
tion, " The one," to quote Marsh, " is that of dune or shifting
hillock upon the coast ; the other that of bai'ren plain in the
interior. The coast dunes are composed of sand washed up
from the depths of the sea by the waves, and heaped in more
or less rounded knolls and undulating ridges by the winds. The
sand with which many plains are covered appears sometimes to
have been deposited upon them while they were yet submerged
beneath the sea ; sometimes to have been drifted from the
sea coast and scattered over them by wind currents ; sometimes to
have been washed upon them by running water. In these latter
cases, the deposit, though in itself considerable, is comparatively
narrow in extent, and irregular in distribution, while in the former
it is often evenly spread over a very wide surface.

" In all great bodies of either sort, the silicious grains are the
principal constituent, though, when not resulting from the disintegra-
tion of silicious rocks and still remaining in place, they are generally
accompanied with a greater or less admixture of other mineral particles,
and of animal and vegetable remains; and they are also usually
somewhat changed in consistence by the ever varying conditions of
temperature and moisture to which they have been exposed since their
deposit. Unless the proportion of these latter ingredients is so large
as to create a considerable adhesiveness in the mass, in which case
it can no longer properly be called sand, it is infertile, and, if not
charged with water, it is partially agglutinated by iron, lime, or other
cement, or confined by alluvion resting upon it. It is much inclined
to drift, whenever by any chance the vegetable network which in
most cases thinly clothes it, and at the same time confines it, is broken.

" Human industry has not only fixed the flying dunes by plan-
tations ; but by mixing clay and other tenacious earths with the

TERTIARY SANDS. 9T

superficial stratum of extensive sand plains, and by the application
of fertilizing substances, it has made them abundantly productive
of vegetable life."

From the information supplied, it appears that many inland expanses
of sand di'ifts may be considered a resuscitation of sand deposits,
which may have been quiescent for ages, fixed naturally by a similar
mantle of vegetation to that by which man is artificially arresting
and utilizing the same sand drifts or others situated elsewhere.
With sand drifts on the sea coast it is to a great extent otherwise,
though in some, even of these, there may be seen a resuscitation of
sand previously partially fixed by vegetation in some of the earlier
stages of the operation whereby extensive regions of sand dunes have
for ages been confined.

Several of these are spoken of as belonging to the Tertiary forma
tion, in explanation of which term it may be stated :

Geologists, in classifying the stratified layers of mineral substances
covering the granite, consider that those of gneiss, and schist, and
clay slates, were first deposited, and these are described by them as
primary formations. Following these in order, and in many cases
superimposed on them, are sandy slates, Silurian limestones, and
what is Jinown as the old red sandstone. These are described by
them as transition formations. They are followed by mountain lime-
stone, coal beds, magnesian limestone, new red sandstone, shell lime-
stone, lias limestone, oolite limestone, chalk beds, and green sand ;
and these are designated secondary formations. Above these are
found blue and plastic clays, marls, and limestones, sands, and
calcareous grits ; and these are spoken of as tertiary formations ; and
above this, indicative of a later deposit, are diluvial clay deposited
from seas or lakes, and boulders, alluvial clay deposited by rivers,
and sand and gravel ; and overlying these, the vegetable soil resulting
from the decomposition of vegetable mould, and the admixture of the
products with the superficial mineral layer.

From this it appears that the sand now spoken of is supposed to
have been deposited in times long past.

An account has been given, cited from Boitel, of the way in
which, on the Landes of La Sologne, heaths on these old sands are
planted with the maritime pine. In other inland situations we find
these sands of the tertiary formation throughout extensive districts
covered with forests of trees of other kinds, varying according to
conditions and circumstances — such, for example, is the famous forest

N

98 BAND-WASTES OP PRANOB.

of Fontainbleau, visited constantly by many of the visitors to Paris.

The forest of Fontainbleau covers an area of about 64 square
miles. But it by no means corresponds with the idea generally
entertained of a forest ; it is anything but an old, shado\^y, leafy,
and almost impervious forest. To quote the description given of it
by Mangin : " Despite its enormous trees, its rudely broken surface,
its stags and roebucks, reserved for imperial sport ; despite its few
adders and problematical vipers, it is now little better than a rendezvous
for amateur artists and listless idlers. Its well-kept avenues resound
with rapid wheels, and you can scarcely stir a step without finding
the associations of the place interrupted by the stalls of vendors of
cakes, or the apparatus of itinerant gamblers — a profanation to be
regretted, for the forest exhibits many landscapes of surpassing
interest in the rocks of Franchart, the glens of Apremont, and, above
all, that Sahara in miniature, the sands of Arbonue."

An article by M. Clav6 in the Revue des Deux Mondes for May,
1863, on La Foret de Fontainhlemo, contains much valuable and
interesting information in regard to this forest, and in regard to
matters connected with it. " Oaks," says he, " mingled with birches
in due proportion, may arrive at the age of five or six hundred years
in full vigour, and they attain dimensions which I have never seen
surpassed ; when, however, they are wholly unmixed with other trees
they begin to decay, and die at the top at the age of forty or fifty
years, like men old before their time, weary of the world, and long-
ing to quit it. This has been observed in most of the oak planta-
tions of which I have spoken, and they have not been able to attain
to full growth. When the vegetation was perceived to languish, they
were cut, in the hope that the new shoots would succeed better than
the original trees ; and, in fact, they appeared to be recovering for
the first few years. But the shoots were attacked with the same
decay, and the operation had to be renewed at shorter and shorter
intervals, until at last it was found necessary to treat as coppice-woods
plantations originally designed for the full grown system. Nor was
this all : the soil, periodically bared by those cuttings, became im-
poverished, and less suited to the growth of the oak. ... It
was then proposed to introduce the pine, and plant with it the
vacancies and glades. ... By this means the forest was saved
from the ruin which threatened it, and now more than 10,000 acres
of pines from fifteen to thirty years old are disseminated at various
points, sometimes intermixed with broad-leaved trees, sometimes
forming groves by themselves."

INDIGENOUS FORESTS. Vr)

The soil of the forest of Fontainbleau is composed almost entirely
of sand, interspersed with ledges of rock. The sand forms ninety-
eight per cent, of the earth, and it is almost without water ; it would
be a drifting desert but for the trees growing and artifically propa-
gated upon it.

In reference to such superficial sand formations, the following
remarks are made by Wessley :

*' It is scarcely to be supposed that all inland sand drifts have
been lying exposed, and drifted about since anti-diluvian times. On
the contrary, we find almost everywhere that diluvial sands, by a
slow but ever advancing natural process, become gradually covered
with herbage, and ultimately with bush or forest, whereby they
become so fixed as to be unmoved by the wind. And this process
goes on all the more rapidly if man do not disturb it — if he do not
promote it.

" And what has been eff'ected thus in pre-historic times, is both
denser and more during that what has been effected in later years :
as the soil of that is richer in humus than is any planted by the hand
of man. And these oldest plant-bearing sands may be described, as
we sometimes describe nations, as the aboriginal vegetation of the
ground on which they are found." Such seems to be the case with
the oak forest of Fontainbleau.

Other forests growing indigenously on sands of the tertiary
formation might be cited ; but it is considered that one case of such
is sufficient to show that forests may be produced and grow
permanently on sands, and to give some idea of appearances pro-
duced by these.

What was at one time in the world's history, the natural state of
these lands of La Sologne, a country more or less covered with forest
trees, is what sylviculture is seeking to reproduce there, and to pro-
duce artificially on the Landes of Gascony and elsewhere ; and what
has been efiected by self-sown seed may be efi"ected again by artificial
culture, if the natural history of the trees employed be known.

We have seen the good efi'ect with which this has been done in
Belgium, and on the Landes of the Gironde and of Gascony ; and with
what similar efi'ect it has been done on the Landes of La Sologne. By
Jules Clav6, a student of forest science of world-wide fame, it is stated
in a paper in the Bevue des Deux Mondes for March, 1866, that the
district of Sologne, flat and marshy as it is, was salubrious until its
forests were felled. It then became pestilential, but of late years its
healthfulness has been restored with its forest plantations.

CHAPTER IX.

Natural History and General Culture op the Sootoh Fir in
France.

Op the trees spoken of as cultivated on the sand-wastes of France,
the principal are the maritime pine (pt/ms maritima), and the Scotch
fir (pinus sylvestris), the former on the new dunes and drift sands of
the coast, the latter on the more consolidated old sand-wastes of the
tertiary formation in the interior of the country. Besides these have
been mentioned several varieties of the oak, the birch, and the
chestnut, as grown on spots of greater or lesser extent within these
sand-wastes ; and in other countries a much greater variety of trees
are raised upon sands and sandy soil. But it is the pine plantations
alone of which this volume treats.

Mention has also been made of the modern system of forest
management having been adopted in France ; the Fachwerke Methode
of Hartig and Cotta, known in France as La methode des co7n2mrtiments,
whereby are secured in combination a sustained production of
material by the forest, a progressive improvement of the state of the
forest, and a natural reproduction of it from self-sown seed. As this
method of forest management, now practised generally on the continent
of Europe, and of late years inti'oduced into the management of
forests in the Indian Empire, differs entirely from the system known
as Jardinage, followed in some of our colonies, and in what are called
policies in Britain, and from the method a tire et aire, previously
practised in France, resembling in some respects the method adopted
with plantations of coniferous trees in Scotland, the following details
are given in view of its application to the different species of pine
trees grown on the sand -wastes of France.

And on the assumption that it may be more acceptable to my
readers, as well as in more perfect keeping with all besides advanced
in the volume, that I should give the natural history of the trees
mentioned as this is given in France than as it is given elsewhere,
I shall follow this course.

Of the Pinus SyliKstris, the Pin Sylvestre of France, M M., Lorentz,
and Parade, wrote in a volume entitled, Cours Hementaire de culture

DESCRIPTION OF THE TREE. 101

des Bois cree a VEcole Forestiere de Nancy. " This tree, the Pi7ms
sylvestris, of Linnseus, is known under numerous names — the wild
pine, the pine of the north, of Riga, of Hagenau, and of Geneva,
the pinasse, &c., and it is one of which the red pine or Scotch pine is
only a variety, recognisable by its shorter leaves, by its cones being
smaller and grouped in whorls, and by the reddish tinge of its young
shoots. It constitutes the principal tree in a great many forests of
considerable extent in which it is found mixed with the oak and birch.
'^Climate, Situation, and Exposure. — The temperate climates are
those in which it manifests greatest vigour of growth ; but cold coun-
tries are not inimical to it, for in the north of Europe, in Russia more
especially, and in Sweden, it acquires most valuable qualities and
dimensions, and by itself alone covers great extents of country. It
grows on the plain as well as on slopes ; but high elevations do not suit
it. In these situations the snow and hoar-frost accumulate in great
quantities on its leaves, and that to a greater degree than on the
other resinous trees of cold countries, whereby often branches are
torn oflF, and sometimes the trunk itself is broken,

" It succeeds on all exposures, not exclusive of the full south, when
it is undertaken to replenish wide spaces, or deteriorated forests with
a south exposure. It is a tree greatly in demand, not only because
it is satisfied with a poor and dry soil, but because the you.ng plants
better sustain the sun's heat than do those of the other coniferae."
But they remark that in saying this they are only speaking of the
more temperate districts of France ; that the departments in the south
of France have other trees which grow there, such as the maritime
pine, and the Alleppo pine ; and that it is probable that the pm
sylvestre would succeed ill there unless at elevations at which the
beat is less intense. It is mentioned that in the Pyrenees it is found
at an altitude of 1,200 metres.

" Terrain, or Soil. — It demands a deep light soil, it is found even
on sand entirely devoid of cohesion, and the wood produced on such
ground is of better quality than is that grown on more substantial
soil ; compact earths are unfriendly to it ; and, although it does
succeed on marls, its growth on these is much inferior to what it is
on silicious ground.

" It is sometimes found on moist and turfy spots ', but its vegetation
there is in a languishing condition, and it there presents itself
ordinarily in so peculiar an aspect that it has been taken for a totally
different species of tree.

" Flowering and Fructification. — The flowers are monoeceous ; they
appear in April or in May, according to the temperature.

102 NATURAL HISTORY OP SCOTCH FIR.

" The strobile or cone remains very small during the first year of its
appearance. In the following spring it begins to enlarge, and it attains
its full development towards the end of summer. It is ripe in the
beginning of November ; but it does not open its scales to allow the
seed to escape until the spring following, so it requires in all at least
eighteen months to ripen, or about two years to mature and drop
the seed.

" The first warmth of the spring acts on the cones ; the scales open
without detaching themselves from the axis, and thus they allow the
seed to escape ; this is small and winged.

" The tree attains its complete fertility towards the fortieth year of
its age ; the fruit appears about every two or three years.

" Young Plants. — These are very robust from their first appearance;
but they do not stand a protracted shade. In general they may be
reared without shelter ; but on ground which is very dry, or with a
complete southern exposure, it would be beneficial to have them
shaded during the first year of their growth,

" Leafage. — The leaves are somewhat long ; but as they rarely re-
main on the tree above three years, it follows that it creates only a
lightish shade.

" Roots. — These are strong and disposed to bury themselves.
When the soil permits the tap-root descends a mfetre or more, although
a less depth can suffice to ensure the tree a pretty fine vegetation.
In ground which is moist, or poor, or deficient in depth, the tap-root
disappears almost entirely, and the lateral roots run along the
surface and manifest a disposition, as do some other coniferae, to
introduce and fix themselves in the fissures of rocks ; but this super-
ficial growth of the roots is not so favourable to the growth of the
tree.

" Growth and Longevity. — The vegetation is very rapid from the
first years of its growth ; when the soil is adapted to it, it lengthens
sometimes in its youth a mkre or more per annum. It lives for 200
years, and attains to a height of 33 metres and more, with a diameter
of from 1 m^tre to 1 mfetre 20 centimetres at the base."

I have met with few trees more extensively difi'used over Europe
than is this. I have met with it in different countries under different
names, but the tree was the same, and the botanical designation
everywhere the same. The specific sameness of varieties or sub-
varieties presenting very different appearances, has been demonstrated
by M. de Yilmorin, on property belonging to him at Barres, in the

l'eOOLB PORBSTIBRB DBS BARRB8. 103

department of the Loiret, which is now maintained by the Govern-
ment as L'Ecole Forestiere des Barres. This, strictly speaking, is a
Forest School ; while that at Nancy, strictly speaking, is a School
of Forestry.

The designation Ecole Forestiere, or Forest School, was given to
the establishment apparently in contradistinction, on the one hand,
to Nursery, a designation borrowed from domestic life ; and in contra-
distinction, on- the other hand, to a plantation or forest, it being a
collection of trees raised from seed obtained from forests, or from
nurserymen and seedsmen of note, and reared with a view to the
study of their habits, their identity, and their diflferences.

The design of M. de Vilmorin and the results of his operation
we learn from himself. He died in March, 1862, a venerable man,
full of years and of honour, — Memhre de la Societe Impenale et
Gentrale d^ Agriculture de France, and Correspondent de VInstitut.

The Bureau de la Societe d' Agriculttire, in collecting documents, of
which they might avail themselves in preparing a historical notice
of their honoured colleague, learned that he had written a history of
his experiments, and procured from his family a copy of this docu-
ment, with permission to publish it in their memoirs.

In the introduction to this record, which related exclusively to
this establishment, which was only one of many experiments and
related researches with which his valuable life was occupied, he
says : — " The work or treatise, of which this is but the first part,
has for its object to report collected observations made during a
long course of years on the trees composing the collection forestiere,
which I have made on my estate of Barres. Studies of this kind
have at this day a much greater interest for France than they ever
have had before.

" The forests which, in a former day covered a great part of her
territory, are, if not entirely destroyed, at least so much reduced
that the products are far below her actual requirements.

" For a long time now France has been dependent on the foreigner
for a considerable portion of the timber requisite for the maintenance
of her navy, and more especially for wood suitable for masts.
Throughout nearly the whole of the last century masts for the navy
were only to be found in the Baltic ports, and chiefly in Riga, and
now that timber of very great dimensions fit for this purpose is only
to be obtained at great price, we find it necessary to draw a great
portion of our supplies from the United States.

104 NATURAL HISTORY OF SCOTCH FIR.

" This condition of things is not only a heavy burden on the
treasury, but it may become matter of grave concern in case of
eventualities against which it is necessary to provide.

" France, by the siugle fact of her geographical position, with her
two hundred leagues of coast on two seas, with her colonies, and
Algeria, and her distant commerce to protect in all parts of the
world, cannot avoid being a maritime power of the first order — it is
one of the necessaries of her existence. She can no more relieve her-
self of an imposing naval force than of an army.

" But for the construction and maintenance of numerous vessels of
war, it is needful that she be able to find on her own soil the needed
timber.

" Those portions of the soil which have been conquered from the
forest by agriculture cannot be recovered. But France still
possesses considerable resources besides these. For instance, a large
extent of the mountains have been despoiled of forests ; the
re-covering of these with trees is acknowledged by every one to be
an urgent and indispensable measure ; besides, there are hundreds
of thousands of hectares in one district of the west and of the south
central France which have continued hitherto in a state approaching
utter unproductiveness, which are capable of bearing beautiful timber
forests of resinous trees. It is on these lands, and by the employ-
ment for the purpose of resinous trees, and more particularly of
pines, that we must operate to restore our forests. And it is at this
point especially that a knowledge of the difierent species of pines,
and of their principal varieties, becomes important ; we may, indeed,
according as we employ one or other of these, create on the same
soil forests of the poorest or of the greatest value.

" This holds true especially of the Pinus Sylvestris.

" In the greater part of the woods of resinous trees formed on a
pretty large scale in Maine, in some parts of Brittany, and more
recently in Sologne, it is to the Pinus Maritima that a preference has
been given, because its growth is rapid, successful culture is easily
ensured, and the seed is abundant and cheap ; but, as is known to
all foresters, the Pinus Sylvestris is capable of furnishing products
infinitely superior in quality, in dimensions, and in value to those
■which can be obtained from the Pinus Maritima. And in connection
with this subject there is a question which it is very important should
be resolved, it is that relating to the relation of the Riga pine and
the varieties of the Pinus Sylvestris. The comparative culture, on
the same land, of trees, of which it is desired to determine the

L'^COLB FORBSTIBRB DBS BARRES, 105

identity or the difference, is what I have undertaken and carried into
execution, as may be seen by statistical details relative to these
species.

'* I have brought together, in clumps more or less extensive,
according to their importance, the pwiz^s sylvestris of every variety
indicated by authors, and all those which, by whatever name known,
it appeared to me might prove useful in this collection. In regard to
the Riga pine, I have not been confined to a solitary lot : independent
of seeds which I procured from the north, from sources the most
certain, wherever I had knowledge of old plantations in France,
known or presumed to have had the same origin, I have managed to
obtain seeds or plants which, added to the lots introduced, directly
furnished the means of studying further the question.

" These plantations have had for their special object the solution
of numerous questions of botany and of forest economy, of which
some are of great importance to France.

" Commenced thirty years ago, and with this view, and augmented
every year since, they form now perhaps one of the most interesting
and most useful collections of this kind in any country. They com-
prise, amongst other species, an assemblage of more than thirty lots
of the pinus sylvestris, obtained from as many diflferent quarters and
sources, for the study of the varieties of the species, and more
particularly of the mast pines, or Riga pine, of absolutely certain
origin, planted to admit of comparison with other varieties of the
pinus sylvestris, by means of which might be cleared away the
doubts which have hitherto existed in regard to this tree, so im-
portant for naval architecture ; an ecole of pinus mugho, pinus
2nimilio, and innus uncinata, a necessary complement to the other
in view of forest study ; all the pines of the series of the Laricios,
trees of great interest in sylviculture, but trees in regard to which
there exists at this time in books great confusion. The clumps of
this series constitute one of the most beautiful portions of the plan-
tations at Barres ; one variety hitherto little known, the Laricio of
Calabria, commands attention by its great vigour and beauty, as does
also the Pine of the Pyrenees, a very beautiful tree of recent intro-
duction ; a plantation of Cedar of Lebanon, growing rustically among
the pines, is thriving well ; a collection of the forest oaks of South
America, amongst which the most important, such as the Quercitron,
the Red Oak, &c., have established themselves in massive plots;
plantations of American Nuts, of Bouleazc d, Canot, of the Alnus
CordifoUa, and of other exotic trees, the qualities of which and their

O

106 NATURAL HISTORY OF SCOTCH FIR.

vegetation on the soil of France cannot yet be known, from the
limited numbers under cultivation ; plantations of various oaks,
particularly schools of oaks of Europe and of Asia, amongst which
are worthy of note, Quercus Fastigiata, Cerris, Tauzi, Aegilops or
Velani, in the avenues and borders ; some new and remarkable
poplars, &c.

" These plantations, if not complete, at least very extensive, will
furnish to the man of science and to the practical man great means
of study. The opinion, on this subject, of foresters and of dis-
tinguished agrinomes who have visited them have almost made it
obligatory to publish the results I have obtained ; and, having to
some extent anticipated this, I fulfil the duty now with the more
satisfaction, seeing that my conviction has always been in accordance
with that which has been expressed to me. To make plantations of
this sort fulfil the design of them, or to have the chance of doing so,
supposing they should exist their full terms, it is necessary that the
lots of which they are composed should be found with ease and with
certainty when those who have created them shall be no more : for
this every necessary arrangement has been made."

As has been stated, the one principal object aimed at by M.
Vilmorin in the establishment of this Experimental Forest was to
determine the varieties of the j9i?i?is s^lvestris and the properties of
each, with their adaptation for culture in different districts of
France ; but other trees received also a large share of his attention.

I had the privilege of visiting the plantation and seeing it
under the guidance of M. Henri Vilmorin, grandson of the founder,
the honoured representative of three successive generations of
noble-minded men, who distinguished themselves in this field of
labour.

Of the Scotch Fir (Pimis Sylvestris) there were rows of trees, raised
from seed or seedlings received from difi'erent parts of the Continent
and from Scotland, representing thirty varieties or sub-varieties of
the tree ; and rows of other coniferae, representing the products of
nearly a hundred different parcels of seeds or seedlings received from
various parts of the world ; rows of oaks, representing the products
of upwards of sixty different parcels of acorns and seedlings collected
from all quarters ; and rows, or one or more single trees, representing
upwards of a hundred and fifty other hard-wood trees. There were
in all some two hundred and twenty-five different species and varieties
of trees, and numerous specimens of some of these, selected, some for

l'eCOLE FOBESTIERE DES BARRBS. 107

their worth, some for their renown, and some for purposes of com-
parison and experiment ; and they were planted alone or in.^clumpa
as might be necessary to bring oat their characteristic points.

Since the death of M. Vilmorin, the founder, the portion of his
estate containing the experimental forest has been purchased by the
Government, that it may be maintained as a national establishment.

Of the pinus sylvestris, M. Vilmorin reports : — " Of the different
questions which I have proposed to myself to solve, by means of the
Barres plantations, none is more important fi'om a practical point of
view than that concerning the varieties of pinus sylvestris.

" At the sametime there is not one on which more contradictory,
and sometimes inexact, notions are to be found in books ; so I shall
be obliged, before proceeding to the direct observations which I give,
to enter into rather full preliminary observations in regard to it. It
is an unhappy necessity, but circumstances render it inevitable.

'* It being of importance that this should be well understood, I
shall first speak of the pine and whence it comes. I shall then show
the principal opinions advanced on this subject, stopping at those
which, establishing errors essentially hurtful iu practice, demand dis-
cussion ; then, lastly, I shall arrive at the special work which is the
object of this memoir — viz., the examination of the collection which
I have gathered together at Barres.

" The pwms sylvestris, the most widely diffused of those which form
the pine forests of Europe and the north of Asia, is at the same time
one of the best and most useful. Robust, and somewhat indifferent
in regard to soil, it succeeds in sands too damp, and in situations too
much exposed to frost for the maritime pine, and, by a remarkable
contrast, on lime and chalk soils, where the latter cannot live.

" Its wood, strong and durable, at the same time light and elastic,
is much used in civil and naval constructions, for it is principally it
which furnishes the excellent pine masts of the north, of which no
other pine offers the equivalent.

" But with these remarkable qualities this tree has one peculiarity
which tends to diminish its value, and which has created much con-
fusion, in reports concerning it — viz., its being liable to change and
vary to such a degree that perhaps nothing similar exists in any
other species.

" Thus, whilst in the forests of Russia aud Lithuania it attains the
size of the largest firs, and furnishes admirable trunks, which sell in
our ports and iu those of England for from 1,000 to 5,000 francs and

108 NATURAL HISTORY OP SCOTCH FIR.

more. A large number of the trees which grow in Switzerland and
Germany are middling trees, badly formed, often incapable of fur-
nishing even a passable plank ; in short, having no resemblance in
anything to those of which we have just spoken. This great
diversity of the pimis sylvestris, noticed in the middle of the last
century, has given place to questions and doubts regarding it on which
opinions are still much divided. Some have thought that the
pine or Scotch fir, as it was then called, did not form a single species
as was pretty generally believed, but formed several which had been
mistakenly united till then ; two or more have been described and
named accordingly; others have explained this diversity in the species
by the existence of varieties or races which are reproduced in suc-
cessive generations. Others rejecting every distinction of this nature
have maintained that the differences, however great they may be,
which are to be seen in the pinus sylvestris are entirely owing to the
soil, to the climate, and to the influence of exterior circumstances.
These contrary opinions have been often reproduced for nearly a
century, without deciding the question. It has even become more
confused and complicated through the discussions, and it remains still
almost entirely yet to be resolved.

" As a fact, it is now almost generally admitted that the species is
one, and that of this there are varieties. To every one is known, at
least the names, Riga pine, Haguenau pine, and Scotch fir, &c., but
if one seeks in books for the differences between these, they are not
to be found ; there are also vague descriptions, or rather, what is
worse, botanical descriptions which, under their precise and scientific
form, are inexact and contradicted by the trees themselves, when
one tries the application on a sufficient number of specimens which
are unlike. Such an uncertainty is evidently troublesome and injurious
on an essentially pi-actical subject. It is more so than ever now, when
the condition of forests in France naturally entails that the culture of
pines should be considerably increased, and that, on the other side,
the ^>^?^MS sylvestris, more appreciated than formerly, begins to be
associated with the maritime pine, or even to replace it in the
construction of composition of woods of resinous trees. It ia then
evidently necessary to arrive at some notions more precise than those
which have existed till now in regard to it.

" The English have advanced far before us in the culture of the
pinus sylvestris. It is in England also that the remarkable diff'erences
between the individuals of this species have been remarked. The
first printed notice is to be found in a treatise on forest trees,

l'^cole forestibre des barres, 109

published in 1760, by a great Scottish proprietor, the Earl of
Haddington.

" Here is what he says on the subject :

*' ' Although I have been assured that there is only one species of
Scotch fir, and that the differences which are to be found in the wood
of these trees are due only to their age, and the soil in which they
have grown, I am nevertheless convinced that it is otherwise, and
here is the reason. When I ordered the pines planted by my father
to be cut down because they were too near the house, several men
still lived who remembered to have seen them reared. The seed
had been sown in the same bed, removed to the nursery, and after-
wards planted on the same day. Then I saw that when I cut the
trees, I found that some had white and spongy wood, and others red
hard wood, and they were examined within a few days of each other.
This observation has had such an effect on me that I have ordered
the cones to be only gathered fi'om the reddest trees.'

" It is a very remarkable thing that the first observation which was
made on this question has pointed out the solution, the truest, in my
opinion at least, first as to the principle that natural varieties exist
independant of the soil and climate, and then as to the practice, that
in choosing between two varieties, the one good and the other bad, only
the first should be chosen for reproduction.

" One might say that these two ideas of the Earl of Haddington
contain a complete theory and practice in connection with this great
question of the spontaneous variation of species applied to the wants
of man, and to the advancement of rural economy.

In France, where the question was opened rather later than in
England, it has been much more discussed : the botanists have
interfered, and each has settled it in his own way. Bosc, in studying
the piims sylvestris, thought he had discovered four very distinct
types, which he has described as so many species : first, the x>i^^'^s
sylvestris, properly so called ; second, the Scotch fir ; third, the
Eiga pine, or pine suitable for masts; fourth, that of Geneva or
Tartary. This opinion not having been adopted by any one, except
in regard to the Scotch fir, I will not discuss it. But another
opinion, which it is more necessary to combat, is that which places
the piims sylvestr^is on the one side, and the pinus rubra of Miller on
the other. It has been supported principally by M. Deslongchamps,
and by M. de Candolle. With the authority which these two names
give to it, especially that of M. de Candolle, or rather because of this,
I feel that I must combat it, being convinced that it is an error.

110 NATURAL HISTORY OP SCOTCH FIR.

" The first remark to be made is, that Miller never pretended in
establishing his species, ^jm2«s rubra, to make any distinction from the
pinus sybestris of the authors who preceded him ; it is only a new
name, which, for some reason, he has given to this species. The
sentences from Ray, from Bauhin, from Duhamel, which they quote
as synonymous, leave no doubt as to this. Nevertheless, the 2^^''^^''^
rubra of Miller, by a singular error, has been regarded as a second
species, made by him in the pwi^s sylvestris. This fact may be
explained naturally enough by the following circumstances : At
the same time that he established the 2)i>i'US sylvestris under the name
piiius rubra, Miller almost beside it described another species under
the name ^Ji/iws sylvestris, and among the numerous synonymes which
he assigns to the latter is to be found 2^i>^us sylvestris, No. 471,
Bauhin, wild pine of Geneva. For all readers, a little hasty in
forming a judgment, and there is no lack of such even among
botanists, there was here an indication, or even an evident proof that
Miller had established two species in the pinus sylvestris. Now, when
one reads the text even of the article relative to his No. 1, he sees
that the latter is no other than the maritime pine, or pine of Bordeaux.
In spite of the evidence of this fact, the contrary version has
prevailed, and some botanists, having to treat of the pines, have
adopted as distinct the two species, 2}i'>ius sylvestris and pinus rubra.
This basis adopted, it was necessary to find characteristics for the
latter ; now Miller did not furnish any, as with him the pinus rubra
being identical with the ])inus sylvestris of all authors, he had applied
to it the characteristics of the latter.

" Hence have come distinctions which I will not call imaginary,
for doubtless they ai'e applicable to individuals, but certainly not
to all, nor do they possess the generality or the comprehensiveness
of specific descriptions.

" This may be judged of by the examination which I am going to
make of the characteristics attributed to the P. rubra in the new
Duhamel and in the French Flora.

" Differences between P. sylvestris and P. rubra. — Let us quote the
new Duhamel :

" First, the wood of the first is rather reddish — no observations
to make on this point.

" Second, the leaves are in general of a more glaucous green.

" There are in my plantation several lots of the P. rubra of the
north, coming from diflferent provinces of Russia, and as well
characterised as possible. Their leaves are plainly less glaucous than

L'bOOLB FORESTIERE DBS BARRES. Ill

those of the common P. sylvestris of France and of Germany, planted
comparatively near them.

" Third, their cones are almost always arranged in whorls of three,
four, and five ; according to the same author, in the sylvestris they
are often by twos. I have many times, in all the lots of sylvestris in
the school, counted as many cones.

" I have constantly found in all, however different they may be,
some individuals with one, two, or three cones, very rarely with four;
nay more, this variety is often to be found on the same tree, some
branches bearing single cones, whilst on others they are grouped by
twos or threes. I have also noticed that this varies decidedly on one
tree in different years, apparently according to whether the flowering
has taken place during favourable weather or not. This characteristic
then is of no use whatever.

" Fourth, the projecting part of the scales form a more decided
pyramid in the P. rubra, and the lozenge formed by its base has its
greatest diameter in the vertical direction.

" In the P. sylvestris, on the contrary, the greatest diameter of the
lozenge, according to the same author, is horizontal.

" I have made, with a view to recognise the characteristics, nume-
rous examinations of the cones coming from different trees belono-inf ,
to the two supposed species, and here is what I discovered — first,
that the projection of the scales, though variable in both, formed a
much less decided pyramid in the cones of the P. rubra than in those
of the P. sylvestris, which is precisely the contrary of what the author
says ; second, that in the same lot, either of P. sylvestris or of P.
rtibra, and sometimes on the same tree, the greatest diameter was
sometimes in a vertical and sometimes in a horizontal direction, so
that this characteristic is useless as a means of specific verification.

" Fifth, Bosc and De CandoUe give as characteristic to theiy Scotch
fir, or P. rubra, that it has the young sprouts red.

" Now the most freely planted lots of the red pine of the north in
my school are, on the contrary, distinguished by the tender green of
their sprouts in the spring. I have besides amongst my lots a con-
siderable number of Scotch firs coming directly from Scotland. The
trees in it are extremely varied in character. One finds among them
types of all the P. sylvestris possible, except the specimens with red
sprouts, which, far from being in the majority, are only met with as
rare exceptions ; the great mass have green shoots.

" Besides, if Miller had recognised this as a chai-acteristic of his P.
rubra, he would have given it, and he says nothing of it. It is not

112 NATURAL HISTORY OF SCOTCH FIR,

then from this that the author must have taken this specific name.
Apparently it was for him only a translation and introduction into
botanical language of the name of the pine or red fir (red deal),
under which it is generally known in the trade, and in the ports of
England, and the Baltic, the wood of the P. sylvesti-is coming from
Russia and Lithuania. The result of this description is that the P.
rubra cannot be admitted as distinct and separate from the sylvestris."

There follow details of the varieties of trees composing VEcole des
Pins sylvestre, with the observations made. Of these details the
following is a free translation in which I have deemed it expedient to
alter in some places the order in which some of the trees are
described, and to abbreviate or abridge in some cases the details
given :

" This collection is composed of all the specimens of the pinus
sylvestris of different districts and countries I could procure. I sought
especially that it should comprise those in regard to which doubts
and discussions have arisen, and still more especially those which
having received the names of varieties are more generally regarded as
distinct. The Pin de mdture, or red pine of the north, and those of
Hagenau, of Scotland, and of Geneva, have supplied in this respect
the first foundation of the plantation; and the first of these (le 2)in de
mdture), mast pines, the red pine of the north, those of Hagenau,
of Scotland, and of Geneva, the basis of the plantation. The first of
these (le pin de mdture) being the most important, is that in regard
to which I have exerted myself to multiply as much as possible the
means of studying. Through the assistance of my connections, and
the obliging co-operation of many French and Russian amateurs,
I have obtained from different provinces of Russia, and of Lithuania,
celebrated for the production of these pines, seeds, the products of
which are to be seen in the plantation. To these lots obtained thus
direct from the localities have been added many others produced from
plantations made in France, at previous times, the Russian origin of
which was well established; and further, with a view to multiplying
as much as possible the means of comparison, I have added specimens
of the ;;m sylvestre from diff'erent parts of France.

" The whole presents a collection of some thirty lots, but to prevent
the formation of an exaggerated idea of these, it may be stated that
they are not all equal in strength, age, or extent, nor are they in
some other respects susceptible of exact comparison; they are on
the contrary, unequal in the extreme. Some form masses more or

l'^COLE FORESTIERB DBS BARRBS. 113

less considerable, while others consist only of some single trees ; their
ages range from that of ten or twelve years to that of thirty years
and upwards. This inconvenience is inevitable in a creation of a
plantation of this kind. To reduce as much as possible the dis-
advantages of this inequality, I shall take care to indicate in the
details given of each lot the differences which may have an influence
on the actual appreciation of their character."

In regard to his practical classification of the varieties in I'Ecole,
he says : " The differences, be it between individuals or between
masses growing together, sufficiently marked to enable one to find
on them the distinctions of varieties are of two kinds : those which
relate to the appearance and conformation of the tree, and those which
relate to the botanic characters furnished by one or more of these
characteristics, or to the appearance and conformation of their organs,
cones, flowers, leaves, &c.

"Botanists who have taken up this question have in general given
a preference to this last basis of classification. This, however, I
have not adopted, and that for the following reason : Varieties
founded on differences which are exclusively or principally botanical,
may not be such when viewed from the stand-point of forest economy.
Thus, for example, let a pin sylvestre have the summit of the scale
formed in the manner of that of the P. mugho, or have three
leaves in place of two in the sheathe of a cone more or less pro-
jecting, bent as in a hook ; let the greater diameter of the losenge
formed by the sides of the cones be horizontal or vertical ; let the
side of the anthers in the male flowers be more or less projecting —
that would be a curious variation, very interesting botanically in
being a departure from the general character of the species ; but if,
besides this, this tree and those reproduced from its seed did not
present in their vegetation and in their physical qualities marked
differences from those amongst which they were growing, the exis-
tence of this variety would remain outside of every useful practical
application ; it would be only an interesting fact of natural history.

" It is altogether otherwise with distinctions founded on the bear-
ing and conformation or habit of the trees. In these, differences
represent qualities or defects, or rather they are, in reality, the one
or other. Between a pine of an elongated trunk perfectly straight,
with a regular head, and one with a crooked trunk, knotty, with head
diffuse and spreading, there is all the difference between a very good
tree and a bad one.

P

114 NATURAL HISTORY OF SCOTCH FIR.

" This mode of determining varieties is then one in direct relation
with the views of forest culture, and may contribute efficaciously to its
good result. It is in this respect one, for our purpose, very much pre-
ferable to that of which I have spoken as adopted by the botanist.
But this is not its only advantage; instead of minute characteristics,
often difficult to catch by the eye without the assistance of a lens,
there are thus given characters of an order less recondite, call them
even vulgar, if you will, but they are easily caught by anybody and
everybody. And, in fine, another consideration in favour of the
adoption of them is, that they are at least as constant as those of a
nature more sti'ictly, and essentially scientific, or botanical. But by
this remark I mean not to condemn these last."

These reasons, says he, have led me to adopt the mode of classifi-
cation described in comparing together, and grouping according to
their analogies, the numerous lots constituting VEcole ; and proceed-
ing to detail the classification of the pin sylvestre, in the collection
formed and studied by him, he says :

" The direction taken by the branches, according as this may be
ascending or horizontal, has ever appeared to me to be the character-
istic most generally connected with the good or bad quality of the
trees, and I have adopted this as the basis of the classification of
the lots.

" From this have resulted two principal divisions — first, that of
trees with ascending branches ; and second, that of trees with
horizontal branches.

" Then, some sub-divisions being still required to bring together
trees presenting analogies of secondaiy importance, and to obtain
groups less comprehensive, I have introduced three into the first and
two into the second of these grand divisions, and these give the
following five series or divisions :
" I. Branches ascending corresponding to P. sylvestris var-ruhra.

" A. Ascending, close, and pyramidal branches.

" B. Ascending, scattered branches, with a regular crown.

" C. Ascending, scattered branches, with an ir-regular crown, and
the branches often qourmandes, or overgrown, as if feeding rapaciously
on the sap of the tree.
" 11. Branches horizontal corresponding to P. sylvestris var-vulgaris.

" D. Horizontal branches in successive tiers or stages.

" E. Horizontal branches, thick-set and regular."

These five divisions correspond to local varieties generally recog-

CLASSES OP PINES. 115

nised ; and he gives again the same divisons under the names of
these as shorter and more precise :
" Ascending branches.

" A. Pin de Riga, 'pyramide-elance, elongated tapering pyramidal.

" B. Pin de Riga, pyramide-elarge.

" C. Pin d'Haguenau ; Pin d'Allemagne, irregular expanded
pyramidal.
** Horizontal branches.

" D. Pin de Geneve elanc4-etale, tapering, but straggling.

" E, Pin de Geneve ramass6. Pin des Haictes Alpes, oil, de Brianc^on,
thick-set and compact."

Of the first of these types, the Pin de Riga pyramide elance,
elongated tapering and pyramidal, he gives the following characters :

" The trunk is very vertical, sustaining well its great size, often
almost cylindrical through upwards of half its height. The branches,
of moderate strength, manifestly of equal growth amongst themselves,
form a series of regular and symmetrical crowns the tout ensemble^
of which, by its pyramidal form, recals the habit of the Italian poplar.
The bark is of a decided reddish yellow, from 1 or 2 metres above
the base."

Under this type he places in his pinetum, pines raised from two
different parcels of seed of the Riga pine, received by him from
Russia, and a Witepsk pine, raised by him also from seed received
from Riga.

Of this he writes :

" Of the different lots which I have received directly from Russia,
the Riga pine, raised from seed furnished by M. Zigra, is that which
offers the most complete type of the elongated tapering pyramidal
variety. The mass presents the following characters : The trunk is
in almost all perfectly vertical, sustaining well its great bulk, and it
is often almost cylindrical throughout half its height or more, the
crown is regular and symmetrical, composed of bi'auches somewhat
strong, and of manifestly equal growth ; the general form recalling
the habit of the Italian poplar. The bark is of a decided reddish
yellow from about 1 or 2 metres from the ground, and scaling off;
that of the base is not so good, and it is not so rent with cracks as
is the case in the greater part of the other lots.

"The shoots are more forward in spring than those of the Haguenau,
and much more, to the extent even often of fifteen days, than those of
the Geneva pine, the pine of Ard^che, and their analogies. It is of a
pale green and in no way of a reddish hue, the leaf is not so glaucous,

116 NATURAL HISTORY OP SCOTCH FIR."

not SO long, and not so straight as that of the Haguenau, and it stands
more erect against the branches.

" It is, on the contrary, longer and narrower than are those of
the Geneva variety.

" The cone is smaller and shorter than that of some others, more
particularly than that of the Geneva pine and some of its analogies ;
it is generally grey, and sometimes, but rarely, of a somewhat purplish
hue.

*•' The bud or young shoot varies in hue from yellowish to reddish-
it is smaller and less resinous than it is in the greater part of the
lots of the varieties having horizontal branches ; the colour of the
male catkin varies from a yellowish hue to that of a pale red."

Of Riga pines, raised from seed obtained from Riga through M.
Helmond, he writes :

" This is identical, or almost absolutely so, with those just described,
with which I could with all propriety have united it, but I mention
it apart, because it forms on the grounds separate very marked
clumps of trees, of the same origin, but of different years' growth ;
the proportion of trees with scattered branches, or even horizontal
ones, is much greater than in those just described. I shall have
occasion to revert to this fact of which the Russian series of pines
presents other examples."

In 1838 he writes : " M. Wagner, nurseryman and seedsman in
Riga, sent to me some cones produced in four of the provinces of Russia
known to furnish beautiful pine masts. Although the trees raised from
them are few in number and younger by ten or fifteen years than
my older Russian pines, I consider that I ought to classify them,
provisionally at least, according to their actual appearance." And of
one of these lots, that of the pine of Witepsk, he says : " By the
regularity and the very decided ascending direction of its crowns, and
by the tout ensemble of its characteristics, it belongs evidently to the
section of the elongated tapering pyramidal varieties ; it will probably
prove identical with the Riga pine first described.

" Intermediate between this class and the second, are the Smolensk
pine, the Wilna pine, the TschernigoS" pine, and the Volliynia pine
from another province of Russia, Riga pines raised from seeds collected
at Barres from trees raised from the first mentioned parcels of seeds
received from Russia, and a pine tree raised from the seed of a
pyramidal tree at Verrieres, near Paris, which, from its port or
bearing, might be included in the first section, and from its bark in
the second."

EXPANDED PYRAMIDAL RIGA PINE. 117

The second division is described under the head of the expanded
pyramidal Riga pine, of which he writes :

" The principal characteristic by which this section differs from
the preceding consists in this, that the branches, longer, stronger,
and more separated from the trunk, form a more expanded pyramid.
The trunks in the greater part of the lots of this series are larger at
the same age than those of the elongated pyramids, and they are at
least as high; but the proportion of trees perfectly straight and
regular is less than in these. The colour of ' the bark is also less
uniformly reddish. In fine, in the tout ensemble of their characters
the natural grown trees are less elegant, less perfect in general in
their proportions than those of the elongated pyramids, but more
vigorous, and appeared destined to acquire greater dimensions ; it
is amongst them more especially that we should find trunks of the
exceptional dimensions, which serve for masts to vessels of the first
rank. They present then, in this respect, as much interest as do those
of the first section."

The pine of Smolensk was raised from some of the cones ob-
tained from M. Wagner. " This," says M. Vilmorin, " was dis-
tinguished from the others thus obtained in having the direction
taken by its bx-anches very much diversified. Of the nine individuals
of which the lot consists, three have these horizontal, and very
prolonged j of the six others, two are excellent types of the elongated
pyramidal series, and four belong to the series of regular expanded
pyramidal form. Notwithstanding these differences, all, with perhaps
one or two exceptions, present thus far the essential characteristics
of the best Pins du Nord, the trunk is clean and elongated, the
crowns regular, the bark, in fine, is thin, delicate, and of a decided
reddish colour.

" The mixture of trees with horizontal branches," he adds, " o-iyes
to the lot, limited in number though it be, a particular interest for
subsequent study."

Of the Wilna pine, raised also I suppose from the seeds supplied
by M. Wagner, there were only seven specimens. " Their crowns ''
writes M. Vilmorin, " are in general regular, but they are manifestly
stronger, larger, and more clothed with leaves and branches than is
the case with any which have been yet described. The base of the
trunk is more clumsy and covered with a bark more brown and more
cracked ; altogether, it is a very vigorous pine, but one which, if an
opinion may be based on the observation of a number so- small will
furnish a smaller proportion of perfectly regular trunks than will
these already mentioned.

118 NATURAL HISTORY OF SCOTCH FIR.

" Its proper place should have been towards the end of section B,
amongst those which constitute a connecting link between that
section and the pines of Haguenau (section C, with crowns too ir-
regular for comparison with one another), but I have thought that it
would be better to keep together all the lots obtained directly from
the Russian produce."

The pine of Tschernigoff is another of these. The lot consists of
12 trees, generally good or very good. They come near to the
Witepsk pine, and I had, says M. Vilmorin, in my first verifications
placed them next in order amongst the elongated pyramidal pines,
but their crowns, although remaining regular, having latterly assumed
more strength and extension, the tree finds or would find now a more
appropriate place amongst the expanded pyramidal shaped pines of
which it may be taken as one of the good types.

Of the pine of Volhynia, he writes :

" Volhynia being one of the Russian provinces, which, according to
information for which I am indebted to M. de la Roquette, furnishes
the most beautiful pines for masts. I am delighted to have met
personally with a proprietor from that country, M. Camille Petrowski,
an enlightened and obliging amateur student of the pine, who has
kindly sent to me seeds from the district.

" The trees raised from these are by far the youngest of those
raised from seed received directly from Russia. They have now
been but ten years planted, but it may already be foreseen that they
will be amongst the best in the collection. In the first years of their
growth they presented so striking a resemblance to what had been
the appearance of the Riga pines already described when they were of
the same age, that I had then no doubt of their being of the same
race ; but within the last two or three years they have begun to
assume an aspect peculiar to themselves. From having an appear-
ance of feebleness and suffering, which they presented at first, they
have become extremely vigorous, their leaves have become greatly
elongated ; their tint, which was of a pale green, has become on the
branches of the year's growth of a decided glaucous shade ; and
many, the first crowns of which had been very symmetrical, have
produced of late years very vigorous feeders, gourmandes, and this
to such an extent as to show a tendency to deform the trunk.

" I attribute this change to this, that the roots must have passed
through the bed of pot clay, which is very near the surface in this

EXPANDED PYRAMIDAL PINE. 119

ground, and come to a sandy sub-soil, eminently favourable to their
growth ; it may be also attributed to this, that, planted as they have
been in a long row directly facing the south, this position may have
helped to give to one portion of the branches an extraordinary
development. Notwithstanding these unfavourable circumstances,
the greater number have thus far preserved in their trunk, their
crowns, and their bark, the characteristics of the best Pin dii Nord ;
and in view of everything, while regretting much that they have not
been planted in a 'close clump, I do not doubt that one portion of
them at least may one day be the most beautiful joms sylvestres in the
school. On the other hand, this lot will be all the more interesting
to examine in their after growth — that it exists in sufficient extent to
supply studies somewhat conclusive ; it comprises about 400 trees."

Under this second head he classes a Riga pine raised from seed
which had been sent to him by M. Noel, gardener of the Jardin
hotaniqice de la marine, which had been gathered on a plantation at
Guiparaz, near Brest, which again had been raised from seeds brought
from the north in 1802 by an officer of marine ; a Riga pine raised
from seeds brought originally from the north by the late M. Penna-
nech, of Morlaix, with which he formed a plantation on his property
at Bretagne ; a Riga pine from seed raised by M. Pousson, d'HoUande
of Bergerae ; a Riga pine from seed raised by M. Batelat, of Vie ; and
trees of P. sylvestris, raised from the seed of a tree in the garden
of M, Picot-Lapeyrouse.

Of Riga pines, raised from seeds yielded by trees grown from seed
obtained from Russia, he writes :

" When my Riga pines, raised from seed obtained directly from
the forests, began to yield seeds, I caused these to be collected, with
a view to ascertain whether the race would reproduce itself with its
peculiar characteristics. The plants which have been thus produced,
though they cannot be yet judged with certainty, have in general a
decided analogous appearance to that of their parents. A certain
number, however, presenting some defects in the trunk, or having
their crowns too strong, I do not wish to place them in the first
series, but would rather put them provisionally in the second series,
which contains many lots which are still young, and upon which an
approximate judgment only can be formed. Whatever may be the
definite place of these, the mass promises thus far to be very good."

The second series, Riga pines of expanded pyramidal outline,
have the branches ascending and spreading, and the crown regular.

120 NATURAL HISTORY OF SCOTCH FIR.

Of the first of these, the Riga pine, from a plautatiou at
Guiparaz, near Brest, of which there were in the school several
clumps, he says : " Their trunk is in general very vertical and
elongated, but the branches are perceptibly longer and stronger than
are those of the first and second mentioned Riga pines, described as
of elongated pyramidal outline. The crowns are, however, regular in
the greater part of them. The red coloured bark begins a little
higher than in the elongated pyramidal series. It is of a tint rather
more pale, but sufficiently decided to show that the pine certainly
belongs to the red pines of the north. It is, moreover, remarkable
for its great vigour, and it constitutes in its tout ensemble one of the
good samples of a variation from the elongated pyramidal type. The
leaf is longer and more glaucous than those of the specimens referred
to, and resembles somewhat those of the pine of Haguenau ; the cone
also is more elongated and narrower in the upper half."

The Riga pine, furnished by M. Pennanech, is like the last, a pine
of Russian origin, raised by culture in Brittany, and resembles it in
most particulars. It differs from it chiefly, that amongst the trees
raised horizontal crowns are more numerous, and the bark is more
uniformly and more decidedly red in hue, and it approximates that
of the two first mentioned.

During the first years of growth the lot of Riga pines had a
marked resemblance to the Scotch fir, obtained from Aberdeen, which
will be afterwards described.

Amongst the variations seen in the lot, which are numerous,
more particularly in regai'd to the direction of the branches, one
meets here and there individuals which are perfect models of the
elongated pyramidal type. Altogether, the mass is very good, not-
withstanding the want of uniformity which has just been noticed.

Of the Riga pine from Bergerae, he writes : " The sowings of
Russian pines, made by M. Pousson, de Hollande, on his estate near
Bergerae have been known long from the mention made of them
by M. Delamarre, in his work entitled, Traite Fratique de la Culticre
cles pins. His son has had the kindness to give me seeds gathered
from the trees thus raised, and it is of trees produced from these
that I write. These pines, planted in 1840, cannot yet be classed
with certainty. They are very vigorous, too vigorous even, and
belong probably to that variety of the Fins du JVord, which seed,
through excess of strength, and tend to approximate this race to that
of Haguenau. The proportion of regular specimens in that is at all

"l'^cole forestiere des barres. 121

times, as at present, sensibly greater than in this. This lot, when it
shall be older, it appears to me, is likely to approach nearly in its
quality that of Gniparaz,"

Of the 2'^in sylvestre, supplied by M. Picot-Lapeyrouse, M. Vilmorin
writes : " This lot, which does not consist of above a dozen of trees,
though not numerous, deserves a somewhat detailed notice in
consequence of the interest attaching to itself, and of the uncertainty
attaching to its forest origin.

" At a time when I was much occupied with researches on the
genuine pimis tincinata of Raymond, I addressed myself amongst
others to M. Ferrieres, chief gardener of the botanic garden at
Toulouse. He replied that he could certainly procure it for me,
seeing that in the garden of M. Picot-Lapeyrouse there was a tree
of this species brought back by that botanist from one of his
excursions in the Pyrenees, and which was producing cones. I
accepted his offer, and he sent me some. These cones resembled in
every respect those of the j3i/i?fs sylvestris ; but I sowed them, and,
when the plants made apparent that there must have been a mistake
somewhere, I planted a row of them in the school. The trees, which
are now twenty-eight years of age, and about 15 metres (50 feet)
in height, are very beautiful red pines of the north, and of the
section expanded pyramidal. They resemble much the Riga pines
of Guiparaz, to which they may be likened.

" Notwithstanding the disappointment which they have occasioned
to me, I have always felt a great interest in these trees, and that
more especially fi'om the question to which their first origin haa
given rise. It may be supposed that the tree in the garden of M.
Picot-Lapeyrouse had been brought by him from the Pyrenees, as
believed by M. Ferrieres, in which case it follows that on some place
on these mountains there were pins sylvestres, in every respect like
those of Russia, and belonging to the same race. If, on the contrary,
the tree was produced fi'om a plant of the Fins du Novel, received by
M. Lapeyrouse, it matters not whence, (he had, as director of the
botanic garden, widely extended connections with establishments of
the same nature, and with amateurs), the consequences which would
follow would not be less important, namely these : that a pine of this
race, planted and reared in the climate of Toulouse must have so
preserved sufficiently its original character, that trees produced from
it are at this day in the plantations at Barres bearing comparison
with the good lots produced directly from Russia.

Q

122 NATURAL HISTORY OF SCOTCH FIR..

" These questions, it may be seen, touch closely upon practical
applications, and so warrant my pausing to give these details.

" It so happens that an accidental circumstaiice adds to the interest
awakened by these pines. They are planted contiguous to a small
clump of ''pines of Briangon, or of the High Alps, to which they
present a most striking contrast. A glance at these two clumps
planted on the same day would suffice to convince the most
incredulous that there exist of the ^^i/i sylvestre well marked varieties,
independent of the differences due to the effects of soil and of
climate."

Intermediate between this class and the third class he places
a pin sylvestre from a plantation near Louvain, presumed to be
of Russian origin. Of this he writes : " The seeds from which this
lot was produced were sent to me by an amateur at Louvain, M.
Stuppaert, as the produce of a veiy beautiful plantation, the produce
of seeds brought from Russia. The character of the trees confirms the
probability of the account.

"Of two parcels sent to me at different times, one has produced
trees which stand much too far apart, occasioned by numerous blanks,
which are veritable Haguenaux, of a very strong trunk, but often
deformed by enormous overgrown branches ; the other, sown where
they grow, has, on the contrary, generally the trunks very straight
and elongated, well proportioned, the crowns also large and strong,
but symmetrical, and the bark fairly reddish ; in fine, the characters of
those pins du Nord, which the excess of vigour renders very
unequal, but which evidently belong fundamentally to the race ; and
therefore the tree has found its place in this series."

Intermediate between the same class, and the fourth class, he
classes a Scotch fir, the seed of which was furnished by Mr James
Reid, of Aberdeen ; and another, the seed of which was furnished by
Mr W. Malcolm, and a p)in sylvestre, from the seed of a tree with
semi-horizontal branches growing at Verrieres, near Paris.

Of the first of these he writes :

" The Scotch fir ought necessarily to make part of the collection
of which I am here giving a report, since it is considered the type of
the species, at least it is that which has furnished the common
name under which for a long time it has been known, a name
still much used, especially in England. I have accordingly obtained
seeds and plants from Scotland. These have not by any means all

l'eOOLE FORESTIEEE DES BARRES. 123

grown. The principal lot has been raised from seed furnished by Mr
James Eeid, a highly esteemed nurseryman in Aberdeen.

" Of all the lots of sylvestris in the school, this is perhaps the most
difficult to class. It does not conform itself well to any of the divisions
which I have established. It shows an intermixtui'e of elongated
pyramidals, but these in but a small proportion, and of expanded pyra-
midal, some regular, others with strong gourmandes crowns, and
finally, of those of the race of Geneva, with horizontal branches ; the
bark in a pretty great number of specimens is of a questionable red
mixed with grey, a slightly preponderating proportion approach more
to the expanded pyramidal type than the others, and those I class
amongst the last lots of that division, in which I have been influenced
by this, that notwithstanding the extreme diversity seen in them
the Scotch firs have pretty generally the vertical trunks, and the crowns
of these, though strong, are rarely deformed by gourmandes as in the
Haguenau. In regard to quality this is upon the whole rather good
than bad.

" Such is the estimate as exact as I could form it of the principal
lot of Scotch firs at Barres. I must however repeat what I have said
elsewhere, and speaking only of those trees which I have under my eyes,
I do not intend by any means to express an opinion in regard to all
the pines on Scottish soil, nor even of those of the county of Aberdeen
whence these were obtained."

The Scotch firs, raised from seed furnished by M. Malcolm, and also
lots, consisting one of the ordinary pines, and the other of the
horizontal pine of Eui'ope, which he has classed here, were all too
imperfect to wan-ant the expression of an opinion in regard to them.

Of the trees raised from the seed of a pyramidal specimen grown
at Verri^res, and of another lot which he has classed among the lots
intermediate between the first section and the second connecting
itself with the first by its habit, and with the second by its bark,
he says :

" These were planted with a special view to determine by experi-
ment if the natural variation seen in individual trees would reproduce
themselves in their descendants in proportions so considerable that
there might be deduced from this useful applications in practice. It
is generally so in nature, but all species do not comport themselves
absolutely the same in this respect, and one cannot be assured in
regard to how it will happen with each but by direct proof.

" This I had in my power to try with two trees of very diflferent

124 NATURAL HISTORY OF SCOTCH FIR.

habits which I had under treatment in a garden at Verriferes near
Paris ; the one forming a pyramid a little heavy and spi-eading, but
going up well and regular ; the other, extending its branches
horizontally in such a way as to leave the trunk bare between the
crowns. I caused to be collected and sown separately the seeds of
these two trees, and their produce, planted opposite each other, are
now to be seen in the school. Both have preserved their original
characters in a very marked degree. Two thirds and more of the
individuals have the crowns ascending and pyramidal in the first
lot, while they are horizontal and spreading in the second. This
result being by much the most interesting aspect of the experi-
ment, I shall enlarge but little on what concerns it beside.

" The pyramidal pine, from Verrieres, presents generally good and
promising trees, with a straight trunk and a regular crown; the
bark is only one degree less marked than on excellent Rigas, which
approximates it to the pine of Guiparaz, or perhaps still more to
selected specimens of the Scotch fir, raised from seed supplied by Mr
Reid."

The third series, the German pine and the pine of Haguenau, is
characterised by having the branches ascending and extended, the
crowns irregular, and the branches often overgrown gourmandes.

Of the typical tree of this series he writes : " Though more
vigorous than those of the preceding series, the Haguenau pine is
not so good as they. Its crown is too dense and too strong, often
intermixed with overgrown branches, which tend to destroy the regu-
larity of its trunk. It also frequently shows knees or defects which
greatly diminish its value.

" The bark is reddish in most specimens, but it is not so uniformly
so as it is in the first section, or even as it is in the greater part of
the lots in the second ; that of the base is more brown and more rent.

" The leaf is longer, more glaucous, and less pressed against the
twig than that of the elongated pyramidal section. The bud is less
forward in spring by eight or ten days."

Under this third head he classes a pine from the forest of Haguenau
a^jwi sylvestre from Darmstadt, and a ^;Mii«s sylvestris maritima received
also from Darmstadt.

Of these he writes :

" There are many clumps produced from seed obtained directly from
Haguenau, some sown, others planted, from 1823 to 1831.

l'eicole FORESTIERE DES BARRES. ' 125

*' The characteristic feature and the principal defect of the Haguenau
pine consist in excess of vigour, and, above all, of a vigour ill distri-
buted, which is carried often into the branches, to the detriment of
the trunk. It is in this that it differs essentially from the true Riga
pines. Its trunk is in general much less vertical and less regular,
often crooked, warped, or abruptly falling off in size, in consequence
of the enormous overgrown branches, which grow out to a great
distance, and destroy all regularity in the tree. In one variety
which is often met with the tree is more compact, and the general
habit more regular ; but the crowns, much too strong, transform the
summit into a pyramid excessively dense and bushy, in the middle of
which the trunk is almost lost. On the other hand, the reddish
colour of the bark is less uniform and less decided than in the good
lots of the Riga pine ; it commences generally 1 or 2 metres higher ;
pretty often indeed the bark throughout the whole body of the tree is
grey, or much mixed with grey rather than reddish. That at the
base of the trunk is more brown, more thick zoned, and more full of
rents.

" Such are in general the Haguenau pines in the school of Barres.
And from this it may be seen that this variety is not identical with
the mast pine of the north, as has been thought by Bosc, and many
foresters with him; and that, on the other hand, notwithstanding
its superiority in vigour and in rapidity of increase, it is much
inferior to it in quality.

** Truth requires it should be stated that there are to be found in
the mass of the Haguenaux some individual trees which constitute
an exception to the rest, being quite regular in trunk and in crown, with
a bark fairly red, and retaining, at the same time, the superiority of
vigour belouging to the race. These may be compared to the best
pines of the north of the series of strong crowns (those of the
elongated pyramids). Also, when one shall come — if that happen
— to create, by choice of individuals, the best possible races, certain
varieties of these may present, at a pinch, very good points of
departure from the characteristics of the most to lead to that
result.

" Independent of the differences which I have indicated above, the
pine of Haguenau is distinguished from the Rigas, and from those
more especially of the first series, by its having the leaf longer, more
spreading from the branch, ordinarily a little curved or rounded
off, of a more glaucous green about the shoot, and later in spring to
the extent of about eight days. The bud is a little more coloured,

126 NATUBAL HISTORY OF SCOTCH FIR.

the cones of a less uniform grey, often of a slightly violet coloured
tint, dull or reddish; but the characters, be they taken from the
bads, be they taken from the cones, are not sufficiently marked, nor,
above all, sufficiently constant to furnish good_,means of distinction —
at least I have not found them such.

" It is then essentially on those characteristics which I have given
above that I have founded my separation of the Haguenau from the
Eigas, and made it the type of the third series.

"Of the pm sylvestre of Darmstadt some were sown in 1831 and
others planted in 1838. They have the same faults and the same
qualities as the preceding ; form disorderly and irregular ; trunk
thickened and vigorous, but often knotty and deformed by gour-
mandes ; the bark scarcely red, sometimes even grey, throughout the
whole height. As in the Haguenau, so in this, there are individuals
exempt from the faults of the mass, and promising for the future
very fine and good trees, or which ai-e such already ; but these are
few in number.

" Of the pinus sylvestris var-montana, received also from Darm-
stadt, a row was planted in 1833.

" These, from their descent, and the greater part of their characters,
it appears to me, cannot be classed otherwise than amongst the
Haguenau, but in a rank below both of the preceding.

" Although their crowns may be less goii,r mandes than theirs, their
trunk is still more faulty — not so large in the first place, and very
much bent in half and more of the trees, and the bark is grey or
brown in almost all. This pine is one of those which show clearly
that there exist local varieties and bad varieties of the pin sylvestre,
which it is of importance to avoid in the formation of woods of this
pine."

Intermediate between this class and that which follows, he places
a pin sylvestre from Champagne, of which he writes : " Two rows
were sown in 1831. The seeds were given to me by M. le Vicomte
Rinnard, one of the principal planters of pine forests on the chalk
soils of Champagne, and were the produce of these plantations. The
trees produced from them have not the character of the race, and
cannot be classed in any one of the series which I have established.
At first sight they look like a mixture of not very vigorous Haguenau
pines and pines of I'Ardeche. Examined more closely, it is seen that
the greater part are rather intermediate between the two. In regard

l'^cole forestierb des barres. 127

to trunks, crowns, and bark, they are in general rather passable, or
mediocre than good, or very good."

The second grand division consists of those with horizontal
branches,* among which we find the fourth section, designated the
horizontal tapering, of which the type is the expanded elongated pine
of Geneva, of which M. Vilmorin gives the following characteristics :

'* The branches, spreading horizontally, sometimes even depressed ;
generally very much elongated and flexuous ; united in regular
cx'owns, which leave the trunk bare in the intervals between these.
This is rarely very straight ; the curvations not so acute as on the
Haguenau ; but, on the other hand, its grossessement is much less.

" Tlie bark is tolerably red in some of the lots of this race, but
more commonly grey^ or very much mixed with grey.

" The leaf is larger and shorter than in all the preceding series.
The bud in spring later by from eight days to a fortnight in ex-
panding."

Under the fourth head, the horizontal elongated but straggling
Geneva pine : a section of the trees having horizontal branches, he
classes — The Ard^che pine ; the Geneva pine ; the Tarare pine ; the
pin sylvestre di(, Maine ; pines raised from the seed of a specimen,
having straggling branches, growing at Verrieres ; a pin sylvestre, given
as a Riga pine by M. Leblond, of Bordeaux ; and a pinus sangidnea,
received from M. Barthude, of Toulouse.

Of the three first mentioned he writes : " Though of different ages,
the first sown or planted in numerous masses from 1823-1831, the
second planted in mass in 1840, the last planted in row in 1833 and
1835, they have always appeared to me identical ; I include, there-
fore, the whole in the same description. I give the preference to the
Ardeche pine, because, being the eldest of the three, and by far the
most numerous in the school, it best represents the series to which
it belongs, and may therefore give of it the best idea.

" The trunks in this race are in about half of them pretty straight and
elongated, but too much swelling out and drawn out in rat-tail form.
The other half present knees more or less decided, but less strongly
so, than in the bad types of the Haguenau pine, and in the sylvestre
of the High Alps previously described. The branches, excepting those
of two or three of the higher crowns, are very generally horizontal, and

^Corresponding to the Pinus Sylvestris Vulgarit.

128 NATURAL HISTORY OP SCOTCH FIR.

at times even declining, not very strong, very much elongated, and
often flexuous ; those of the inferior stages almost naked, ramifying
themselves in feeble twigs, which carry at their extremity little tufts
of short and outspreading leaves, while those of the ascending
branches are, on the contrary, very closely pressed towards the branch.
The crowns, by I'eason of their being somewhat equal, are in regular
stages, so that they show the trunk bare between them.

" The bark is in general more grey than red, very often of an unde-
termined shade between the two. That of the base is manifestly less
thickened, less brown, and less rent than that of the Haguenau.
In regai'd to enlargement, this pine is inferior to the Rigas raised
from Russian seed, and much more so than some of the Rigas raised
from French seed, but, above all, than those of the lot of Haguenaux,
which, at the same age, have almost doable the magnitude ; and its
increase in height is in a similar measure less than in all those
named. It does not, in this respect, surpass any but its analogue
the pine of Brianc^on, to be afterwards described.

"A botanical character, somewhat constant in the pines of this
series, is, that the leaf is shorter, broader, and firmer than in the
others, and especially than in the Haguenau. Their bud in spring
is behind that of these, and especially that of the Russian pine, by
from eight days to a fortnight.

" The exceptions to the general characters, which I have just noted,
consist principally in the following : A small number of individuals
are elongated pyramidal, and as regular as some of the best Riga
pines first described ; others somewhat more numerous are expanded
pyramidal, some regulai-, others with strong gourmandes branches.
The individuals of these variations, almost including the last, have
a pretty mai-ked advantage over the others in regard to increase
in height, but more in regard to enlai'gement of trunk; the bark of
these is not sensibly better than in the mass. There ai'e found here
and there, but far separated, trees of which the bark is of a marked
and uniform reddish tinge ; but this exception is not more frequent
amongst the pyramidal than amongst the horizontal.

" To sum up the whole, the Ardeche pine is, or at least appears for
the present, inferior in every respect to the red pines of the North,
both those raised from Russian, and those raised from French seed.
It does not nearly equal in value the Scotch fir, so unequal as these
are compared with the Haguenau ; this may be doubted, because it is
exempt from the great defects of that race, but it has not the good
qualities of that tree ; and, in view of the whole, the first appears to

L'^COLE FORESTIERE DE8 BARRES. 129

me, In default of a better, preferable for most cases, and that more,
especially when it is proposed to plant or sow the pin sylvestre in
poor dry lands, whether sandy or chalk."

Of the ;5m sylvestre du Maine, of which there is a clamp In four
rows planted in 1830, he says :

** The pin sylvestre does not exist in Maine but as a cultivated tree,
and the plantations of it which are there met with have necessarily
diversified origins, and do not constitute a local race. But the
desire of multiplying the points of comparison led me to plant one
lot of them, for the seed producing, which I am indebted to the
obliging disposition of M. V^tillard.

" These pines belong to the race of Ardfeche and of Geneva, but they
present a very large proportion of good, and of pretty good, trees, and
the bark is more frequently of a pretty decided reddish grey. It is
a good type of the race, apparently improved in Maine by eucoessive
selection of individuals."

Of the pin sylvestre, raised from the seed of a specimen with
spreading branches, existing at Verri^res, of which there were four
rows planted from 1832-1835, he says, in reference to the account
given of his design in planting these, and others of a pyramidal form,
that this also has produced many trees like the parent. Those of
this lot have the decided characters of the Geneva pines ; the branches
of almost all are horizontal, the bark grey, or very little reddish ;
they are further pretty vigorous, and are of the number of those
which promise to be the best of this series.

Under the fifth head, the Thick-set horizontal pine, he classes a
pine from Briangon, and a Scotch fir obtained from Mr. Lawson,
of Edinburgh.

Writing of the Briangon pine of the High Alps, of which he had
planted three rows in 1826, he says : "The tree, which constitutes
by itself the fifth section, was given to me by M. Faure (of Briangon),
who had the kindness to get seed gathered for me, as being the Pinus
suffix of the Brian gonuais. This should have been — if Duhamel be
not misled in the application of the name — a P. muglio. But, be
it a mistake of Duhamel, or of the men who had gathered the cones,
the pines produced from this seed are true Sylvestres. On this point I
have no regrets, for I am thus supplied in my collection, with the two
extreme types (this and the elongated Riga pine), which exist In

R

130 NATURAL HISTORY OF SCOTCH FIR

the species of pimis sylvestris, a comparison of wliich shows most
manifestly the existence of local varieties and the necessity of dis-
tinguishing them. A trunk, thick and knotty, and thick-set, covered
with a bark, coarse and much cleft, brown in the lower part, and grey
on the rest of the tree ; the crowns horizontal, very much drawn to-
gether, lining the tree from its base, composed of strong branches
often flexuous, which famish and at times annihilate the trunk, and
the ensemhle of which forms an enlarged and diffused head ; such are,
with about five or six exceptions, among the thirty individuals of
which this lot is composed, the pins sylvestres of the High Alps.

" It may be seen from this that they are amongst the lowest rank
of the species to which they belong, and that in the formation of pine
woods they should be avoided. But this exclusion ought not to
extend to all possible cases ; there is one in which the Briangon pine
may not only be useful, but better than all others of the species ; it
may be so where plantations are formed on the brows of mountains,
or on their plateaux exposed to the violence of winds. The little dis-
position manifested by it to attain height, the thickness of its base,
the strength of its lower branches, which are persistent for a length
of years, almost carpeting the ground, make it more suitable than
any other of the pwis sylvestres to hold on and grow in such situ-
ations ; also when one is re-clothing mountains with woods, the Brian-
9on pine may be employed with great advantage conjointly with the
Mugho — the former to garnish the middle region of the declivity, the
Mugho for the higher zone — for these are the respective places which
Nature has assigned them on the brows of mountains."

In writing of the fivefold series, which he had formed, M. Vilmorin
says :

" These five divisions are not by any means equally good, or nearly
BO. The first and the last (the elongated pyramidal Riga pine and
the pine of Briangon) present the only two types absolutely distinct ;
the others have characters much less decided. This could not be
avoided, and pertains to the very nature of the species in which the
individuals as well as the local masses differ — one may say indefinitely.
And thus between the two opposite types which I have just named,
the lots in the school form an unbroken chain, which binds together
these two extremes. The sub-divisions, as I have said, were necessary,
as may be seen indeed by the definition of the five series adopted.

" The outline, such as I have been able to give it, does not yet
suffice for a convenient classification of all the lots. A certain num-

INSTRUCTIONS GIVEN IN SCHOOL OP FORESTRY. 131

ber present intermediate characters, but too ill-defined to allow of
them being taken as typical forms, and thus to increase the number
of divisions ; others have no characteristics of their own, but a mix-
ture of many types, without a marked predominance of any. In
these two cases I have placed these lots, under supplementary
titles at the end of the series to which they most closely ap-
proached.

" In this mode of classification, the two extreme types, the elongated
pyramidal Riga pine on the one part, and the Briangon on the other,
are perfectly distinct ; a third and intermediate type, the Haguenau
pine, although less characteristic, is yet sufficiently so to allow of my
admitting it as such."

The following are instructions given in the School of Forestry In
regard to the exploitation of a forest of Scotch firs ; but there are
employed several terms not in general use in speaking of the manage-
ment of woods and forests in England, of which it may be well to
give some explanation. One of these terms is revolution. This is
applied to the time occupied in the complete reproduction of a forest
in the state in which it may be at any one time, as, for example, from
the sowing, or from the felling of one crop to the sowing or felling of
a second. Fellings executed at diff'erent periods of the growth of the
trees, with a view to the effecting of different objects have different
designations given to them. Amongst these are the following : coupe
cVensemencevient, a designation given to a thinning of the seedlings or
saplings, and of trees left to give shade to seed in germination, and
to seedlings in the early stages of their growth ; coupe secondaire, a
designation given to a second thinning of the same kind executed
seven years later ; and coupe definitive, a designation given to a third
felling of the same kind, when all trees of the previous crop left
growing to supply shade and shelter to the rising crop are felled,
leaving of that crop only such as are destined for the production of
seed by which the ground may again be sown, to which standards the
designation Bcdiveaux Anglice, staddles, is given.

There are other technical designations given to fellings or thinnings
in other circumstances, with a view to the accomplishment of other
objects ; but with these we do not here come in contact. There are,
however, other terms which it may be well to explain, such as Bois
hlanc, Morts-bois, and Gualis. The first designation ia applied to
wood of little value, such as that of willows and poplars, etc., the
second is applied to worthless brush- wood, or undergrowth, junipers,

132 NATURAL HISTORY OF SCOTCH FIR.

hazles, elders, cornels, etc. ; the last, to perches and poles, from which
the lower branches have fallen through want of nourishment.

To resume then our account of the instruction given in the School
of Forestry at Nancy, in regard to the exploitation of a forest of
Scotch fir.

" In countries in which this tree, pimcs sylvestris, is very common,
they do not allow it to become aged. In effect the annual increase
of forest masses of this tree attains its maximum when it attains
the age of 60, 70, or 80 years ; then, after maintaining this for some
20 years, it begins to diminish with the advance of age. When then,
the primary object is to procure firewood, it is best to fix the revolution
cycle, or crop, at from 80 to 90 years. And this may be worth
attending to in countries in which this is the perdominating tree ;
but even in such a case, parts of the forest should be submitted to
a more protracted revolution to get useful timber of good quality.

" In France, where timber is more scarce than firewood, the State
cannot fail to profit by delaying the exploitation of the pine. At the
period of its maximum increase, its wood ia not of the best quality.
It is only at a later period of growth that the grain of the wood
becomes compact, thatjt becomes charged with condensed resin, and
thus acquires the elasticity and durability which makes it valuable in
the construotiou of great works, and more especially for the navj.
hi view of such cousideratious, it would be well to apply to it a
revoluttoH of 120 years on lauds ou which its growth is active, and
not to exploit it till it have attained the age of from 140 to 160
years in dry soil of sufficient depth, like the siliceous sands in which
this tree delights, and acquires more especially the qualities which
fit it for employment in great works.

" It must however, be remarked, that protracted revolutions have
this inconvenience, they compromise the fertility of the soil. After
a time, in the course of this protracted cycle, the pine forest no longer
constitutes a close mass, and it comes at an advanced age to be
converted into something like a glade. It follows that in course of
time it becomes covered with hurtful undergrowth, the wind disperses
the bed of dead leaves, and at the termination of the cycle the ground
finds itself sodden, dry, impoverished, and in circumstances moat
favourable for the multiplication of very hurtful lepidopterous
insects, the caterpillars of which only earth themselves in the
driest soils.

" When then a cycle of 120 years or upwards is decided on, not
only should all deciduous broad-leaved woods, which naturally oome

INSTRUCTIONS GIVEN IN SCHOOL OF FORESTRY. 133

up uuder the pines, be carefully preserved, but it may be well to
introduce towards the middle of the cycle a subsidiary tree, designed
to protect and to ameliorate the soil. The yoke elm, the beech, or
the Norwegian pine, would prove well adapted for fulfilling this
function. The last mentioned especially, placed in a second range,
gives to the growth of the pine a magnificent upward growth.

"Fellings preparatory for a succeeding cro]). — With a view to a
natural resowing of the soil, it is not necessary that a deep shade be
preserved, and, without disadvantage, the trees left standing may be
so dispersed that the branches of them may be from 5 to 6 mfetres
distant.

" In selecting trees to be reserved, it is not the straightest and
tallest which are to be preferred ; it is more advantageous to reserve
those which are of a medium height and branching; such are
ordinarily more fertile in seed, and they better resist the winds. In
the actual state of the forests in France there is as yet little room
for choice ; but it is expected that after a time, when the forests
shall have felt the effect of regular management, there will be found
not only on the outer skirt of the forest, but over the whole area,
trees of a medium height loaded with branches.

*' [n spacing out the trees to be reserved, precautions must be taken
against the havoc of the winds, and the invi^sion of herbs or hurtful
plants. The pine sends down a tap-root, and otherwise roots itself
firmly : but, nevertheless, ou parts very mucli exposed to the wind,
and where experience has proved that this tree with difficulty resists
it, it may be well to leave a pretty dense reserve. The second in-
convenience is frequent in pine forests, and on some grounds almost
unavoidable. It may, however, be mitigated by not making the
coitjje d'ensemencement, or first felling, excepting when assured of an
early and abundant fructification, which, in the case of the pines, is
pretty frequent, and may be foreseen eighteen months in advance.
Further, in the autumn or the winter preceding the scattering of
the seed, it may be well to proceed to the extraction of the stumps,
and to till the ground in rays, or in narrow furrows, at the bottom of
which it may be stopped, and shall find a mobile fresh earth favour-
able to the germination of it and to the growth of the young plant.

" In the majority of cases these labours will not be unremunerative
for the stumps of pines, from the resin which can be extracted from
them, are a more lucrative product than are those of other trees.

" After the coupe d' ensemencement, when the replenishing is com-
plete, and the young plants have attained to near the height of from

134 NATURAL HISTORY OP SCOTCH FIR.

16 to 24 centimetres, it maybe proper to proceed to the coupe de-
finitive. It may be imagined that the vigorous nature of the young
plant renders unnecessary the coupe secondaire, and that it is necessary
to hasten the withdrawal of the covering which is altogether contrary
to its requirements.

" In despite of the prudential measures taken to re-produce a pine
forest by self-sown seed, we are driven to acknowledge that it is
extremely rare that we meet with complete and satisfactory replen-
ishings in forests of this pine. To such an extent is this the case
that many foresters are disposed to renounce coupes d'' eiisemencement
ia pine forests — to make a clean sweep, and to have recourse to
artificial sowings, which succeed readily and well.

" In view of the general facts, it is necessary to say that this
opinion is not without good foundation. Let the reserves from the
coupe d^ensemencement be numerous or otherwise, let the coupe de-
finitive be expedited or delayed, one often sees the best and most
complete natural re-sowings come into jeopardy at the end of some
years — diminish and disappear in places to such an extent as to give
access to the mort bois and to the bois Mane, The cause of this it
is rather difficult to ascertain. Some writers attribute it to insects,
such as the worm of the Maybug, the Pissode note, and the Hylobe,
which attack, the one the stems and the other the roots of the
young pines. Mr. Berg thinks, with reason according to my judg-
ment, that we must seek the cause or occasion of the evil in the
superficial position of the roots of the old pines, the very abundant
fibrous tufts of which cover and penetrate the soil in every way,
and absorb thus in its entirety the nutritious moisture, being
manifestly much more vigorous than the feeble rootlets of the
young plants.

" Accepting this opinion, one is led to conclude that natural
replenishings have no chance of success excepting in ground pretty
wet and pretty deep, in which the pine, advancing in age, may extend
its roots to a lower depth than the layer in which the young plants
throw out theirs during the early years of their growth. But it is
well known that pine forests occupy in general the less fertile soils,
and thus we can account for natural replenishings being rarely satis-
factory and complete.

" Were it not the important consideration of the expense of replen-
ishing artificially through the purchase of seed, which is deai', and
the expense of labour, and further, the risk run of not always pro-
curing good seed when it is pu rchased, one would be led, from what

INSTRUCTIONS GIVEN IN SCHOOL OP FORESTRY. 135

has been stated, to lay it down as a principle that the reproduction
of this pine ought to be carried on by making a clean sweep of the
trees, followed immediately by artificial sowing ; and that coupes
d'ensemenceme7it ought only to be practised in exceptional circum-
stances, as, for example, on ground on a declivity. Forest science
counsels the former mode of procedure ; but financial considerations
enforce most frequently the adoption of the latter."

M. Nanquette states in a note that the most important forests
of the pin sylvestre were formerly subjected to the mode cl tire et aire.
Thus were they treated till 1820, when the system des compartiments
was substituted for this, in so far as the principal fellings were con-
cerned. In these fellings there were reserved a certain number of
trees, with a view to securing a re-sowing of the ground, and in
order to render more certain the natural reproduction. There is laid
upon the purchaser the burden of pulling up bushes and mosses, and
giving to the soil a slight tillage in alternate bands.

"Such is, in few words, the treatment formerly given to those forests
in which we find to-day woods produced by self-sown seed perfectly
complete, and of all ages anterior to 1840.

" The power of imposing works in connection with fellings having
been suppressed, now well nigh forty years ago, they ceased to cultivate
le 'parUrre of coiipes d' ensemencement. But soon they perceived that the
fellings were not replenished, or were replenished badly — or at the
least that they must wait too long a time before obtaining a sowing
sufficiently complete, and at that time they adopted the plan of
recovering them by artificial replenishings.

" The easy execution, and the so to speak assured success of this
operation on the one hand, and the unsuccessful issue of coupes d'ense-
mencement on ground not prepared for them on the other hand
gradually gave rise to the conviction that it was for the general
interest to substitute in a general way artificial for the natural
replenishing. But they were not long in discovering that the new
mode of replenishing gave no better results than that it had super-
seded, and, as it is much more costly, they returned quite naturally
to the old practice of coiqjes d^ ensemencement, and the preparation of
the ground for these fellings.

" A very light tillage, a simple scraping of the moss which spreads
over dry ground, the opening of strips or of furrows in the soil too
strongly covered with herbage or bushes, suffices to ensure the
natural replenishing of fellings with a little delay.

136 NATURAL HISTOHY OF SCOTCH FIR.

" The replenishings thus obtained are not generally so thick and
so good as can be obtained by hand sowing ; but they offer many
important advantages which these do not : in point of fact, the young
plants of the ^^mi sylvestre are very robust, and grow with rapidity in
their first youth if they be rather sparsely sown ; their lower branches
display themselves, the foot of the trunk becomes thick and strong,
and by degrees the forest mass forms itself, and becomes so compact as
to give a very complete replenishing before arriving at the state of
gaulis.

" The natural sowings, probably because they are less dense,
escape almost entirely the grave evil of defoliation which generally
comes upon artificial sowings, and often retards their development
during many years.

" Finally, in despite of the advantage which may be had from
practising a great clearing amongst the saplings, the difficulty of
carrying out this delicate operation on an extensive scale prevents
recourse being had to it ; and the artificial sowings, too thick at the
first, do not present more when they arrive at the state of gaulis
than long weak stems, and often they have not a future because the
young pines are liable to bend or break under the weight of snow
or of hoar frost, on account of their branches being spread and their
leaves long, and also it may be from the snow often falling in large
flakes, and in great quantities at a time in the climate inhabited by
this tree ; hence it may be concluded that they will stand only a very '
partial clearing. But this tree, after it has passed the stage of gaulis,
sustains but badly a dense mass : branches which cross each other
lose their leaves, and are not slow to perish ; the head of the tree,
instead of developing, becomes lanky, narrow, and, when this ab-
normal condition continues long, most of the tops become deformed,
the trunks themselves contract diseases, and the whole mass becomes
at times unfit to attain an advanced age or fine dimensions. To
prevent this last and grave inconvenience, without at the same time
exposing the young pine forest to being destroyed by the snow, the
most certain method, the efficacy of which has been tested by ex-
perience, consists in executing the first thinning, contrary to the
general theory, while the wood is still in the state of thicket at the
time when the lowermost branches begin to dry, and in carrying
this out unsparingly. In point of fact, it may come to pass in this
way that the produce so abundant in the first youth of a pine forest,
may find itself restricted or at least diminished ; but this incon-
venience will only be temporaiy, till the remaining stems, having

1N8TBU0TIONS GIVEN IN SCHOOL OP FORESTRY. 137

more room to extend their branches, in a short time give to the
ground a thick cover, while, on the other hand, they form a fine
conical head, such as ensures a good ultimate growth, and at the
same time a stem more thick and short, and strong enough to bear
up under the weight of the snow.

*' The subsequent thinnings ought to succeed each other at
moderate times apart, which will have effect of rendering them less
productive ; but in their entirety they will yield more, and exercise
on the vegetation of the stems, destined to grow to the completion
of the cycle, the salutary influence for which such thinnings are

" The wood of the pin sylvestre is used both in building and in
manufactures, as balks, beams, boards, planks, staves, shingles, etc.
When it has attained its maturity it is considered as solid and as
durable as that of the oak. In ship carpentry and wooden bridge
building it is used as flooring ; and it is almost the only tree of which
masts are made. For this use it is obtained in France from the
north of Europe. It is only in the higher regions of the principal
mountain ranges, where the growth is slow, and the ligneous fibre very
dense, that there is a hope of timber being produced of the degree of
suppleness and elasticity required for masts. And attention is being
given to the seeking out sheltered spots in these regions where the
tree will be comparatively safe from snow-loads and hoar-frosts, with
a view to the cultivation of forest masses destined to meet this
important public requirement.*

" The firewood furnished by this tree is very superior to what is
supplied by some others of the coniferae ; and charcoal produced by
it is in demand for forges.

*' The pin sylvestre produces one portion of the pitch and tar made
use of in the French navy.

" It is the stumps and roots which yield most of this, which is
abstracted by subjecting them in furnaces to a slow and gradual
distillation.

"The wood thus deprived of resinous matters is reduced to a
charcoal which is used for various purposes. And there are in many
countries very productive contract sales of the stumps of this tree,
with the privilege to erect such furnaces.

* A valuable memoir on this subject by MM. Bravais and Martina appeared
in the second volume of the Annales Foreati^res, 1843, pp. 369-561.

138 NATUBAIi HISTORY OF SCOTCH FIR.

" In some localities marauders have a practice of cutting deeply
notches in the trunk of the tree to remove some portions richly
charged with resin which they recognise by a deep yellow colour, and
by a strong odour which is exhaled. These portions cut into small
pieces are very inflamable, and are sold in place of matches and fire
quickeners. It is scarcely necessary to say that this practice is most
prejudicial to the trees."

The authorities of the Forest School of Nancy give the following
instructions relative to the collection and preservation of the seeds ;
" The collecting of the cones should take place from the month of
November till that of March. When it is requisite to make great
provision for sowings this should be done as soon as they have
attained maturity ; in other cases it is preferable not to collect them
until after the cold, as the nearer this action approaches to the period
of natural dispersion of the seed, with the greater facility is this
extracted.

*' The extraction of the seed may be efi'ected either by solar or arti-
ficial heat, but the former is preferable, -as thus are obtained seeds of
a superior quality ; but the latter is more generally employed, as it is
more expeditious and better admits of making collections in great
quantities."

Hartig, the father of Modern Forest Science in Germany, has
given a description of the arrangements adopted in such cases, of
which the following is a translation :

" There is used an apartment in the lower storey of a stone
building. There are placed in such an apartment one or more stoves,
fitted up with grates that they may be heated by the combustion of
emptied cones ; and there proceed from these stoves a circuit of
pipes conveying heated air as in green-house, hot-house, or stove,
that in every part the room may be heated to a sufficient temperature.
In this hot-house there are constructed against the walls and in the
centre scaffolding on which may be placed trays of wooden lattice
work, or of wire work from 1 metre 66 centimetres, to 2 metres in
length by 82 centimetres in breadth, in stages of about 16 centi-
metres between. Under the lowest range of trays are placed drawers
to receive the seed.

" They then charge the trays with cones, and heat the stove to as
high a temperature as a man conveniently can stand, (20° to 25° R.)
^0* to 90° Fahr." ; and Cotta, who followed Hartig, Kays that the

DBSOBIPTION OP sAOHERIES. 139

temperature may be raised to 30°=100° Fahr,, or even 35''=112°
Fahr., without injury to the germinative power of the seed. "This heat
is maintained until the cones open, they are then stirred or shaken
briskly in all the trays, commencing with the highest series, that
the seeds may fall from tray to tray till they reach the drawers
under the lowest tier. To facilitate this shaking of the trays, they
have been made moveable on rollers in two grooves, so that, by pulling
and pushing the tray, all the cones contained in it may be easily
moved.

" When all the cones have opened as extensively as possible they
are withdrawn, and the seeds still remaining in them are collected.
For this purpose they are placed in a vessel like a churn, in which
there is a suitable opening by which the seeds may pass and be
received into a vessel placed beneath. The cones are thus briskly
agitated until they are completely emptied of seeds, and the empty
cones are employed to feed the fire.

" When solar heat is to be employed, the scaffolding is supported
against the wall of a building on a southern exposure. On this the
trays are disposed at such a height between that the sun's rays may
fall on all, the highest and lowest alike. Under the lowest trays are
drawers, provided with coverings of thick cloth, that if rain fall the
seed may be easily covered and kept dry.

" The whole apparatus is covered with a light roof, the slope of
which is towards the north.

" When there is a powerful sun and great heat the cones are
shaken, commencing with the trays in the upper tiers, and proceeding
in regular succession to those of the lowest row ; and the seeds are
then collected in the drawer. At last, when it is considered that the
cones have opened as much as possible, they are taken away and put
in a churn such as has been described for the extraction of those seeds
which may remain in them."

MM. Parade, etc., say " that the apparatus employed in connection
with solar heat has been practically perfected by attaching to each
tray a moveable cover which is closed during the night, and when it
rains, and can be opened to varying extents according to the heat of
the sun. And that this cover may better reflect the sun's rays upon
the cones, the lower surface is painted of a white colour or is varnished.

" To these houses constructed for the drying of seeds, the
designation Secher'ies is given in France.

" The Forest Administration of Forests in France has in the forest

140 NATURAL HISTORY OP SCOTCH FIR.

of Haguenau (Bas-Rhin) an establishment of this kind, which annually
supplies seeds of the pine which are shed in the forests of the state.

" When it is desired to divest the seeds of their wings, they
moisten them, and after having put them into a sack, filling it only to
the extent of one fourth, they rub it until the wings are detached.
Then, after having spread them out in a well-aired place, to expedite
their desiccation, they are cleaned completely by meaus of a winuow-
ing fan.

" Moistening the seed may be avoided, which it is preferable to
do, by spreading out the sacks filled, as has been described, on a thrash-
ing floor, and thrashing with a flail to beat the seed.

" The divesting the seeds of wings is advantageous, as it facilitates
transport by diminishing both bulk and weight ; and further, seed so
treated sows better, and runs less risk of being dispersed by the
wind. But, in general, the seeds which have not been subjected to
this operation, especially such as are obtained in commerce, keep
better than those which have been so treated. In the establishments,
more especially those of Germany, where they prepare immense
quantities of seed for sale, they sometimes put the seed into a heap
after having well moistened it, and leave it there until, on the
insertion of the hand, there is felt a slight heat, and then the wing
may be detached with the greatest ease. It may readily be seen
that such a process pre-disposes the seed for germination ; and if the
sowing be delayed it may be found that there are a great many which
have lost their power of germination.

" The seed of this pine designed to be sown may be preserved for
three or four years ; but when this is to be done it should not be
divested of its wings. And it will be preserved still more certainly
if it be left enclosed in the cones, and if these be not gathered till
the end of winter.

" Seed of the jiiniis sylvestris, when of good quality, is firm and well
filled ; its smell on opening it is fresh and resinous. When crushed
on the nail, the small kernel leaves there a greasy substance with
an oleaginous smell. The seeds of the pine are black or white.

" A greater number of empty ones are to be found amongst the
latter than amongst the others. It may therefore be well, in purchasing
seed, if the white be in excess, to test them with the more care.

"Seed of the Scotch fir should weigh from 120 to 140 grammes
per litre if winged ; and from 440 to 500 grammes if divested of the
wing."

INSTRUCTIONS GIVEN IN SCHOOL OF FORESTRY. 141

In regard to the sowing of the seed, the following are the
instructions given ; " The seed may be sown on alternate bands, of
from 66 centimetres to a metre in breadth, or by placing a few seeds
each in a shallow hole somewhat sheltered, but not much shelter is
requisite. In southern slopes covered by heaths, on which the pine
is often sown, it is necessary to adopt a particular precaution in
preparing the soil, namely, to dig the bands or the holes to the layer
of soil below the blank soil found on the surface, and which is
generally designated heath soil [peat ?] In sowing the seed on heath
soil, which has no firmness, which is incapable of retaining moisture,
and which, from its colour, absorbs heat in a high degree, the seeds
almost always fail ; and frequently the heath soil contains an acid
principle which makes germination completely abortive,

" It is stated that this is acetic acid, and it has been proposed to
neutralise it by employing ecohuage, or burning the turf, which, by the
ashes which it produces, would accomplish this end. This operation
may suffice to prepare for the culture of certain plants which require
little moisture, and for the growth of such as return to the soil
almost the whole of the mineral elements of their structure, in such
a way as to mix with the layer of earth the mineralogical element
of the soil. But for forest trees it would not be the same, for in
abstracting from the ground one noxious principle, the ashes would
add to the lightness of the soil already too great, and to its
defective power of absorbing moisture from the air.

" The seeds ought not to be covered to a greater depth than from
4 to 6 millimetres ; it may even suffice to mix them with the earth
by means of a rake. Ordinarily the young plants appear at tlie end
of from four to six weeks, when the sowing has taken place in spring,
which is most advisable; but it also often happens when the seeds have
been too deeply buried, or too much heated in the extraction, that
they do not germinate till the second year.

" In some parts of Germany, where the seeds of the pine are very
abundant, they are accustomed to sow simply the cones in the bands,
or in the holes prepared for this purpose ; then, as the heat of spring
begins to act on the scales, they shake the cones roughly with a rake,
to cause the seeds to fall out and to distribute them as equally as
possible. This proceeding has first the advantage of saving the expense
of extraction and divesting the seeds of wings ; in the second place,
the seeds are generally of the best quality ; and the cones which cover
the soil may give some protection to the sprouting plants. But, on
the other hand, a portion of the seeds are lost, for they can never

142 NATURAL HISTORY OF SCOTCH FIR.

succeed in getting all out from the cones ; they are not so equally

spread over the ground ; and the cones are more cumbersome

for transport.

" The quantity of seed to be employed for a partial sowing per

hectare are :

Winged seeds, ... ... 12 to 14 kilogrammes.

Seeds divested of wings, ... 9 to 11 „

Cones, ... ... ... 18 to 20 hectolitres."

CHAPTER X.

Natural History and General Culture of the Maritime Pine
IN France.

Sect. I. — Commendation hestotved 07i the Maritime Pine.

The success which has followed the endeavours of M. Bremontier to
arrest and utilise the dunes and sand-drifts of the landes of Gascony,
by planting them with the pinus maritima, has led to the name of
this pine being closely associated with thoughts of these landes, not
only there, but in lands far remote, in which attention has been given
to the subject.

The growth of the maritime pine in France is not confined to
Gascony, but is carried out elsewhere as a temporary application of
sylviculture to prepare the soil for agriculture, or for the intro-
duction of trees better adapted to the climate, or to the wants of the
inhabitants of the country adjacent, or more remote. In some of the
districts in which this is done the trees do not attain so great an age
and size as they do on the landes of the Gironde and adjacent dunes.
This is the case on La Sologne, in the district of the Loire and the
Cher, where they generally have to be felled after a growth of
twenty years, at which age the trees may supply supports for tele-
graphic wires, and wood which may be applied to similar uses ; but
it is chiefly as firewood that the produce can command a sale, and
in such districts special attention has been given to the conversion of
these products into fuel.

M. Boitel says of the maritime pine : " The rapid growth of this
evergreen tree has made it a favourite with foresters. What other
tree becomes productive at seven or eight years of age, and even
then exhibits a strength and beauty which completely changes the
aspect of the country by changing desert ground into a forest !

" Add to these advantages that it thrives in light poor soil unfit
for any other purpose, and we can easily comprehend how much it is
prized.

" The forester of the Landes or of Sologne exhibits with pride
heaths turned into forests by the labour of his hands. So a desert

144 NATURAL HISTOKY OF MARITIME PINE.

inhabited by a few wretched sheep has succeeded an immense timber
forest, supplying in abundance timber, firewood, and resinous sub-
stances.

" Many are the villages which owe their foundation to the intro-
duction of the maritime pine, before which there was a dearth of
timber and of firewood for baking the bricks and tiles, which are
indispensable for building purposes in a country devoid of means of
transport.

" I cannot enumerate here all the benefits to mankind rendered by
this tree; let it suffice to briefly notice some of the chief uses of the
tree.

** Immense sandy plains in Gascony, Orleanais, Touraine, and
Maine have become profitable through its culture.

" Certain cantons, formerly desert and uninhabited, owe their im-
provement to the maritime pine, which furnishes materials in-
dispensable for houses and workshops ; its timber and resin are
useful for domestic purposes ; the baker needs firewood, the painter
turpentine and varnish, and the sailor tar for ropes, timber and pitch
for his vessels and boats ; and by this tree all these are supplied.

" On the sea-shore the growth of the Bordeaux pine is the only
means of arresting the invasion of the dunes, which, like an ocean of
sand with moving waves, lays waste the fields and carries misery and
desolation into important populous centres.

" Its protecting shelter from the caustic action of the salt winds
permits cultivation to be carried on in spots where this would other-
wise be impossible, and it withstands tempests better than any other
tree.

" The maritime pine is met with all over France ; in fertile ground
where it would be the reverse of profitable, it occupies an important
place in landscape gardening.

"To sum up, in cleared land it appears as the first symptom of
civilisation and progress, and is connected with one of the most
wonderful discoveries of the age, for with two of its relatives it shares
the privilege of supporting the wires, which in a second convey human
thought to the ends of the earth."

In another connection he writes thus on the same theme :

" The maritime pine is at home in Gascony, there it attains the

largest size, and, provided that sheep are absent, it] multiplies

indefinitely when once introduced. Sologne does not suit it nearly

so well, it suffers from the inclemency of the climate and the badness

BEMARK8 BY BOITEL. 145

of the soil. Without culture the pine would never have formed
forests in that district, and it may be asserted that the plantation
would soon disappear if they were not kept up artificially. This tree,
which lives for a hundred years in the south of France, often in
Sologne, reaches maturity at 25 or 30 years. This gi-eat difference
naturally involves important modifications of its culture and ex-
ploitation.

" The inhabitant of the Landes who can count on the longevity of
his pines, expects them to produce resin and timber, firewood being
only a secondary consideration.

" The Solognese, on the contrary, knowing that his pines are rarely
large enough for timber, or to be subjected to regular ^emma^^e, values
them chiefly as firewood, Cotrets hoiirrSes, charcoal, and charcoal
powder are the most important productions in Sologne. Only here
and there do some woods situated in deep moist soil furnish trees
fit for the carpenter.

" Of late years, quantities of telegraph poles are supplied by Sologne,
for this purpose trees are required about the age of 20 or 25 years.

" Although wood that has not been tapped appears to last a shorter
time under water, not long ago some of the finest trees in Sologne
were selected to form piles as the basis of a new bridge lately built
at Mayenne.

" I am led to conclude, from some recent experiments, that
it would seem to be advantageous to tap the pines in Sologne,
especially those which are to be felled.

*' Gemmage should be practised in Sologne with prudence and
circumspection. We must remember that the tree so far north
generally lacks strength and vigour.

"Too great a gemmage practised on feeble, sickly trees would
certainly shorten their lives, and a loss of timber would result, for
which the resin obtained would not be compensation.

" Only trees on the point of being felled should be subjected to
the process. As to others, they should be let alone to grow before
it is attempted.

" So soon as the trees appear strong enough to support the operation
they should be carefully operated on, only one incision made on each
tree, and this incision a small one, this being essential to the health of
the tree."

M. Samanos, in the introduction to his Traite de la Culture du Pin
Maritime, says : " There has long been realised In the district of our

146 NATURAL HISTORY OF MARITIME PINE.

landes the Importance of creating a plantation of the maritime pine ;
and yet, for all that, it may be said that but a few yeara separate
us from the time when the Landes of Gascony, veritable French
Savannahs, presented to the eye of the saddened traveller ouly a
picture of desolation and of death. Far as his eye could reach he
could see only heart-sickening monotony and gloom ; and it seemed
to him as if on this bare and naked land sterile Nature had cast her
heavy curse.

"While the whole of France elsewhere expanded herself under
the rays of progress, the Landes remained there — always uncultivated
and unproductive — always immersed in their unmeasured sadness —
giving shade in the brilliant picture of the fruitful conquests of
civilisation, and presenting to all men the great and gruesome
spectacle of a fatal neglect ; for, as Viscount Izarn-Freissinet remarks,
in his Coup d'oeil sur les Landes de Gascogne — ' parce que tout y etait
d, faire, rien n^y a ete fait.'' Because everything in connection with
it had to be done — nothing at all in connection with it has been done.

" Such neglect and such abandonment of the land could not last
always. There came at length the day when societies were formed
for the clearing and cultivation of these lanies. But those who
took the direction of the measures to be adopted were mainly imbued
with notions essentially and exclusively agricultural. They wished to
establish on a grand scale the culture of vegetables which the
geological conditions of our sand-wastes could not support. They
were foiled. Advancing with giant steps they landed themselves
the more precipitately in ruin, and they were forced to stop, buried
as they were under the weight of failure, so much the more over-
whelming that it was unexpected.

" Behold then once more our landes abandoned and uncultivated
and alone in their immensity ; they seemed to be for the future
doomed to everlasting sterility.

" But if there had been a want of success it was the fault of man,
not of the landes. To change all that, it was only necessary to act
more wisely. This has been done, and now it has come about that
the four hundred thousand hectares of these desolate landes have
become four hundred thousand hectares of young and vigorous
forests. Almost everywhere the plough has produced its furrows,
and the hand of man has stocked these savage deserts with maritime
pines, which will become for the country a fruitful source of wealth,
and supply some day the wants of the whole of France.

" Writings on the maritime pine were for a time quite the rage.

CEITIQUE BY SAMANOS. 147

Societies being formed for the clearing and sowing of the landes it
was needful to give instructioua to the shareholders or capitalists of
these companiea, and show to them the great advantages which they
might derive from this — to malce palpable to them the supposition
which might engage them to lay out on uncultivated and arid lands
money, of which the interest would be invested on their hopeful
promises — to remove from their minds the unwarranted prejudices
which seemed to exist against our landes, and to prevent their
receiving the attention they deserved ; and it was necessary, in fine,
for the success of the enterprises, that by descriptions, always
exaggerated, our country should be shown to be another Louisiana,
which should be exploited by another law. And this is what our
economists have done. The question relating to the improvement of
our landes was almost always treated of by men to whom a creative
imagination supplemented the lowest modicum of knowledge in regard
to the forest culture of our maritime pine ; and these, seizing with
itching hand the pen dipped in vapouring exaggerations, extolled
the sterile plains which they described,. and, by aid of subtile logic,
they insinuated into the ideas of their readers ideas which had only
for the greater part of the time absurd and incoherent foundations.
With them our maritime pine was the veritable tree bearing apples
of gold."

To expose the fallaciousness of these writings he cites some passages,
for which, says he, common sense alone may supply pitiless refutations.

Delamarre thus writes (Trait'e de la culture des pins d, grandes
dimensions ; page 306 ; third edition) : " The culture of pinea
supplies the means of acquirino; wealth. As the proprietor of unculti-
vated grounds, a hundred Parisian arpents for example (correspond-
ing to thirty-four hectares) in extent, more or less unfit for every
other crop, may, by a moderate advance of two or three thousand
francs, and such attention as should be a work of pleasure, may
flatter himself, not only to be reimbursed the outlay, capital, and
interest in some ten, twelve, or fifteen years, but of obtaining from it
from the first pretty considerable profits, and ultimately, in some
fifty or sixty years from the commencement of the enterprise, a
wealth to be reckoned by millions for himself, and perhaps as much
for those whom, from the very nature of the undertaking, he will
find he has associated with himself in the magnificent and honourable
benefit which he has given ; for even in localities in which the price
of wood does not exceed twenty sous per cubic foot, his personal
benefit should exceed fifteen hundred thousand francs."

148 NATUEAL HISTORY OF MARITIME PINE.

And again in the same work he writes, (page 289) : *< Thus
one may say explicitly that in maritime pines the creator of woods
is more than remunerated his advances, that he is even, in the benefits
obtained dui-ing twelve years, reimbursed his first advances. I might
even say that he is so within from eight to nine yeai-s ; for, in the
examples I have given, the net produce of the two first thinnings
executed, the one at seven years and the other at eight years from
the sowing, has been three hundred francs, while at this moment the
advances, capital, and interest, have not come to this amount."

Such statements M. Samanos ridicules, and goes on to say: "J.
L. Crinon, in his work bearing the title le Forestier praticien, (page
50) writes in these terms : ' I see amongst these, pines which would
measure from ten to fourteen cubic decisteres, and which have not
been planted more than from forty-five to fifty years. These trees on
an average scarcely occupy twenty-five centiares of ground. If we
estimate their value at forty francs each — they cannot be less than
this in value — and, reckon that there are to be found four hundred of
them in a hectare, we shall find that a hectare planted in pines
will avail for seventeen thousand francs worth of wood, after from
fifty to sixty years ! What is the kind of wood which ofi'ers like
advantages to this ? ' "

" Evidently," says M. Samanos, "it has not an equal ! " But he says
it ironically, and goes on to say :

" I might go on to cite a host of opinions by many authors, such as
Emile B6res, Baudrillard, Ballet-Petit, etc, all marked by numerous
errors.

** 'Although the value of these woods,' said, in 1826, M. Bilaudel to
the shareholders, * varies according as the situation is more or less
near to the cultivated lands, still, and that according to calculations
in which there is nothing taken for granted, there is not even in the
actual state of things any speculation in agriculture more sure and
more probable than this is.' "

All such statements M. Samanos condemns. I cite them as views
which have been advanced, founded it may be upon isolated cases,
but I cite them with the qualification of the critique by M. Samanos,
whose treatise is valued highly by my correspondents in France.

Sect. II. — General Gultui^e and Exploitation of the Maritime Pine.

The maritime pine, so exclusively cultured on the landes of the
Qironde, is nearly allied to the Spardenny, or cluster pine (Pinus

INSTRUCTIONS GIVEN IN SCHOOL OF FORESTRY. 149

pinaster), grown at the Cape of Good Hope, and they have several
characterstics in common. By some these trees are considered
varieties of one species.

Much valuable information in regard to the natural history and
artificial culture of this tree is given in the volume just cited by
M. Eloi Samanos, Membre de la Socidte d' Agriculture des Landes*
But the treatment of the subject in that volume is complete in itself ;
and I deem it more expedient to refer the student to this in its
entirety than to cite passages apart from the connection in which
they occur ; and I give here information I have gleaned from other
sources.

The following is the information embodied in the " Cours eUmeti-
taire de Ctdture de Bois" at the School of Forestry at Nancy :

" Le Pin Maritime, the maritime pine (Pimis maritima, Lamark)
forms portions of considerable forests in the Landes in Provence, in
Languedoc, and in Corsica.

" Climate, Situation, and Exposure. — Although this tree belongs
more especially to warm climates, it is nevertheless cultivated
successfully in the western Departments of France ; but if it be
exposed to frosts it does not live long, and the wood is worthless,
its height and size are curtailed, and its usefulness is impaired.
This is the case with sowings of it made at Fontainbleau, and in the
suburbs or neighbourhood of Paris. There is no doubt that the
maritime pine could not be acclimatised if planted farther north, as it
is very sensitive to cold.

" In a suitable temperature it thrives on plains, on hills, or even on
mountains of medium height. Its tap-root and lateral roots give it a
strong hold of the ground, and enable it to resist storms which make
it so much the more useful on the sea-shore, where it is planted
extensively.

" Soil. — The maritime pine will grow on poor soil provided there be
depth enough. It will even thrive very well on pure quartz sand,
such as is brought down by rivers or heaped up on the sea-shore.
Stiff and marshy soils are injurious to it.

" Flower and Fruit. — The blossom is monosceous. It flowers in
March and April in the South of France, and in May in more temperate
regions. The seed is larger than that of the Scotch fir, and is furnished
with a wing proportionate to its size ; it is ripe about the same time
as that seed, and it also falls at the same season.

* Traiie, de la Culture du Fin Maritime.

150 NATURAL HISTORY OP MARITIME PINE.

" The fertility of this tree is extraordinary ; it bears fruit almost
every year, beginning at the age of twelve or fifteen, sometimes earlier ;
to ensure, however, the goodness of this, seed should always be
collected from older trees.

" Young Plants. — The maritime pine is hardy from the first ; and
all prolonged shelter is hurtful. It is only on the burning dunes of
Gascony, and in the warm exposures of the south of France, that shelter
is needed for the first few years.

" Foliage. — Although the leaves of the maritime pine are very long
they only cast a feeble shade. They fall in the third year like those
of the Scotch fir.

" Boots. — This tree has a tap-root which buries itself deeply in the
ground ; it has besides creeping roots which all along their length
throw out loug tap-roots; this tendency, along with its rapid growth,
makes it very suitable for binding the moving sand on the Dunes.

*' Growth and Length of Life. — The maritime pine grows very rapidly
and it attains a large size. In one district of the Dunes of Gascony,
where the soil is deep and nutritious, several trees, from which the
resin has not been extracted, are to be seen about from 27 to 30
metres in height by about 2, 3, and 4 in circumference, at the height
of one metre above the ground. The size is well proportioned and the
trees have a cylindrical form. They reach an age of 150, or 170,
years without showing symptoms of decay. We may therefore believe
that the maritime pine may reach an age of 200 in suitable soil.

" Qualities and Uses. — The wood of the maritime pine is considered
inferior to that of the Scotch fir and many other resinous trees. But
it is not the less made use of for various structures. In dock-yards
it is made into props and stays to support vessels during the process
of building. It is also sold for vine props and planks.

" The firewood and charcoal of this pine are of indiflferent quality.

" We may, however, be deceived regarding the value of the mari-
time pine. In order to the formation of an authoritative judgment,
it ought above all things to be grown in suitable conditions of soil and
climate, and to be treated according to the best methods of exploi-
tation, besides which, it should be protected from pruning and the
extraction of resin.

" Now, in the department of the Gironde and of the landes, this
extraction, called gemmage, and gemmer, has been carried on on the
Dunes for several centuries ; and in districts elsewhere called landes,
where the soil is usually poor and gemmage uafrequent, the maritime
pine is exploited when very young, either for joiners' work, or for tre)-

INSTRUCTIONS GIVEN IN SCHOOL OP FORESTRY. 151

Hcing vines. In both these cases it is therefore impossible to know
accurately the qualities of this tree.

" The process employed in order to extract the resinous juice of
this tree will give an idea of the injury thus inflicted, Gemmage is
usually begun when the tree is twenty-five years old, and goes on
from April till September. The first thing is to remove a strip of
bark from 12 to 16 centimetres in breadth, extending from the foot
of the tree to a height of from 33 to 50 centimetres. The incision is
deep enough to cut through the alburnum, for the resinous juice
issues chiefly from the ligneous trunk, and from between the bark
and the wood. Every week the wound is re-opened. These incisions
in following years are carried upward to a height of from 4 to 5
metres. A new incision at the root of the same tree is then begun.
It is parallel to the first, from which it is separated only by a width
of from 5 to 6 centimetres ; it, as well as later incisions, extends to
the same height. These incisions are carried all round the tree, and
are called qiiarres.

" This method of gemmage is the most gentle ; it is called gemmage
d, vie. When it is wished to go to greater lengths two incisions are
made simultaneously, one at the top the other at the foot, the first
is called quarre haute, the second hasson. Sometimes incisions are
made all round the tree at the same time. This operation is called
gemmer d, mort, or ct pin, perdu. Up to the present time the maritime
pine is chiefly cultivated for its resinous juice, which furnishes
articles of undoubted value, consisting of turpentine, pitch, tar, and
lamp-black. As a source of revenue there is no doubt that the
present mode of exploitation is the most profitable, and is therefore
quite justifiable. But in the departments of Gironde and the Landes
they go further, and assert that the maritime pine, if it is to be of
any use at all, ought to bo resine. It is even affirmed, despite of
examples quoted to the contrary, that the extraction of the resin is
indispensable for its prosperity and even its existence.

" We may easily see that gemmage must interfere injuriously with
the growth of the tree. Nature has not given it a resinous juice for
nothing, and this juice, independent of the sap, seems, in combination
with the latter, to promote nutrition and growth. As a proof of this
when pines which have been gemme are felled, they exhibit very
narrow annual layers, which bear witness to a retarded growth, whilst
the opposite has been seen in pines which, without having been
gemmi, have grown in precisely similar conditions ; but it has been
ascertained that the timber of resinous trees is more solid, and has

152 NATURAL HISTORY OF MARITIME PINE.

more resisting power, in proportion as the layers are close and
compact. Further, gemmage promotes an active current of turpen-
tine from the centre to the circumference, which leaves a considerable
quantity of concrete resin behind in the wood tissues which it has
traversed. It can thus be understood that gemmage, by retarding the
growth, imparts at the same time to the wood qualities which it would
only in a state of nature have acquired at a much greater age."

In regard to semis, or sowings of the maritime pine, it is stated
generally that these have to be conducted in every respect as are
sowings of the p^7^^^s sylvestris, or Scotch fir; and the following
details are given in regard to the pinus maritima :

" Examination of the Seed. — The seed of this pine is much larger
than that of the Scotch fir ; it is grey or brown upon one side, and
shining bjack on the other ; otherwise it possesses the same character-
istics as the seed of the Scotch fir.

" Putting in the Seed. — All the various methods of cultivation with
which we are acquainted are applicable to the maritime pine. The
plough is usually employed for preparing the earth, and the harrow
for covering the seed ; the seed being larger requires to be covered
with a greater depth of earth.

" The quantity of seed employed per hectare varies much. In
Sologne, for example (as reported by M. A. Brongniart), for a full
sowing, about 10 to 20 kilogrammes are used. The difference is
owing doubtless to the quality of the seed, or it may be according
as the trees are to be close together, or the reverse. We think
that from 15 to 1 8 kilogrammes of seed with the wings on, and 12
to 14 kilogrammes of seed with the wings off, will be enough, bearing
in mind that the seed of the maritime pine is usually of very
good quality. For partial sowings these quantities should be
diminished by one third.

" The maritime pine has been cultivated much more extensively
lately in several districts in the west and centre of France on account
of the peculiar products of this tree. But it is more especially in
the Landes and in the La Gironde that it is of chief importance. It
is well known that in these departments along the sea-shore from the
mouth of the Gironde to that of the Adour, there extends a district
called the Dunes of the Gulf of Gascony, which occupies an area of
about 240 kilometres in length, by an average breadth of 5 kilometres.
The soil of this district, composed exclusively of a very fine quartzose
saud deposited on the strand by the waves, becomes so light when

INSTRUOriONS aiVEI^ IN SCHOOL OP FORESTRY. 163

dry that the winds carry it to a great distance. The smallest obstacle,
such as a little hillocli of soil, a tree, some tufts of broom, or of bent
grass (arundo arenaria) are enough to stop the sand ; it then
accumulates much faster and forms larger heaps than when deposited
by the waves, as the winds blow for a long time in the same
direction. Such is the origin of the Dunes, of which the height and
form vary like the conditions which have created them. Some are
to be found from 20 to 30 and even 50 or 100 metres in height.

" It is by a mixed system of wicker-work barriers and reboisement
with maritime pines that the ini'oads of the sand which threatened
the neighbouring communes have been nearly everywhere arrested ;
and it is one of the triumphs of the Corps des Fonts et Ghaussees, to
whom the Government entrusted this great and important work, and
who have not only completed the undertaking, but they have by
degrees improved and simplified the work and operations required,
and have thus brought it within the power of any one to carry on
similar work elsewhere."

To render intelligible to those who are unacquainted with the
more advanced system of forest management followed on the
Continent of Europe, the additional statements to be made, it may be
well for me to state, that it differs considerably from the arboriculture
which is generally practised in Britain, and from the Jardinage, and
Sartage, practised in British Colonies and in the United States of
America, and to supply here the following information in regard to it ;
and to repeat in substance what I have already said in speaking of
the culture of the Scotch fir :

In the general management of forests on the Continent, in accord-
ance with the most advanced forest science, three things are aimed
at, and so far as practicable each is sought to be attained without
detriment to either of the others : the sustained production, natural
reproduction, and progressive amelioration of the forest. In prosecu-
tion of this there is determined, according as quantity, quality, or
pecuniary profit may be mainly sought, at what age the trees shall
mostly be felled. This in French is spoken of as the exploitability
of the woods. But before this age is attained there are several
successive thinnings executed, each with a special object, in accordance
with which it has a specific designation.

The wood being the product of natural reproduction, or self-sown
seed, there is often required a thinning out of the seedlings . This is
known as the cou,pe d'ensemencement.

There may be required one or more successive thinnings as the

Ii54 NATURAL HISTORY OP MARITIME PINE.

growth of the tree advances. These are known as coupes d^Mneliora-
tion. There are subsequently thinnings executed to leave sufficient
ground cleai'ed and open for the reception of seed cast from, the trees
left standing. These are designated coxipes de regeneration. After
which follows the final felling, or coiop definitive, in which only trees
required to give shade to the young seedlings, etc., are left standing.
But there are exceptional cases, in which artificial sowing is deemed
preferable. In these cases coupes de regeneration are not necessary,
and the coupe definitive takes the form of a clean sweep, known in
technical phrase as la coupe cb hlanc Hoc.

In regard to the treatment of the maritime pine, the instruc-
tions given at Nancy are in several points founded on those given in
regard to the exploitation of the Scotch fir.

In these instructions we meet with the two terms coupes de regenera-
tion and coupie d^ amelioration, in addition to the similar designations
formerly explained. The former of these designations is applied to
all the fellings or thinnings to which the forest may be subjected in
the course of its reproduction ; and the latter is applied to fellings or
thinnings carried out with a view to the improvement of the forest in
any way.

The corresponding instructions given in regard to the treatment
of the maritime pine are these :

" Exploitahility. — To ascertain what size this tree may attain, and
at what period its exploitahility should be fixed, it must first be
cultivated without any injury being done to its growth, for until we
gain light from experience we can only judge by analogy.

" Trees which grow rapidly when young generally attain their
maximum development sooner than do others. This is particularly
true of the maritime pine. Nevertheless, in the south, where the
climate is favourable, it continues to increase in size for a long time,
and on this account it ought not to be exploited for 100 or 120 years,
according to the nature of the soil, that the timber may acquire the
desired solidity for building and other purposes.

" Of course, in adopting this revolution, gemmage is not permissible.

" Coupes de regeneration. — The maritime pine never having as yet
been subjected to systematic culture, the method to be followed is
uncertain. But from the nature of the seed, the constitution of the
young plant, and the arrangement of the roots, we may conclude that
it ought to be exploited in the same way as the Scotch fir. At the
same time, at the coupe d'e7isemencement there may be left fewer plants
as this pine is better able to resist the wind. Indeed, the seed is a

INSTRUCTIONS GIVEN IN SCHOOL OF FORESTRY. 155

little larger and heavier than that of the Scotch fir, but the mem-
braneous wing is also larger, which favours its dispersion to a distance.
The secondary coupe will be unnecessary, on account of the hardy
constitution of the young plant and the extreme rapidity of its growth,
which lead us to believe that the coupe definitive should follow the
coupe d^ensemencement as soon as possible, that is to say, in the year
after the repeiiplejnent, or within two years at the latest.

" Coupes d'amelioration. — What we have said on this head regarding
the Scotch fir, equally applies to the maritime pine. The first
thinning should be expedited on account of the rapidity of its growth,
and the intervals between those which follow should be abridged.

" The rules we have laid down for the exploitation are only
applicable when the trees are not subjected to gemmage. When trees
are to be gemme these rules should be modified. For, on the one
hand this operation diminishes the growth and shortens the life of
the tree, and on the other it is not timber, but resin which becomes
the chief product of the forest. The first circumstance renders much
shorter revolutions necessary ; the other, that the thinnings should be
made at very short intervals, according to a method practised in the
south of France, of which an account has been given.

" It being evidently the interest of the proprietor to hasten the
period of gemmage as much as possible, it is of great consequence to
promote the growth of the stem and summit in every way. For this
end the young trees are thinned for the first time, at the age of seven,
and afterwards the operation is repeated every six years until they are
twenty-five years old, at which age they are supposed to have attained
a suitable size. In these operations the pines are isolated by degrees.
After the two first fellings the mass, although thinned, should still be
preserved so as to promote the development of height ; but after the
third the number of trunks is reduced to 700 or 800 per hectare j
and after the fourth only 500 remain; five years later these are again
reduced to 400. The 100 trees doomed to fall in the fifth thinning
are gemmes cb mort, between the fourth and that, the others are
gemmes d, vie.

" These 400 pines remain standing from thirty to sixty years, and
are gemmes every five years. At the expiry of sixty years, 100 trees
are marked to be gemmes cb mort, and are then cut down, while the 300
still remaining stand until the final coupe at the end of seventy or
eighty years, sometimes of one hundred years, according to the state
of the timber and the quality of the soil.

" We have already described how coupes de regeneration should be

156 NATURAL HISTORY OP MARITIME PINE.

made. But it is believed that usually la coupe ct blanc etoc, followed
by artificial sowing, will be preferred. Indeed, in both systems
the plough is indispensable, for, on account of the great distance
between the pines, the ground cannot fail to be covered with all sorts
of bushes and weeds ; besides, the seed of the maritime pine costs very
little and is easily gathered and winnowed, the quality is almost
always good, and the sowings succeed well ; everything tends to make
the artificial way the preferable."

Both in the treatise by M. Eloi Samanos,* and In that by M. Am^d6
Boitel,t are given details in regard to the culture and exploitation of
the maritime pine in Gascony, and in regard to the general culture
of it elsewhere, additional to what has been given in this volume,
inclusive of what relates to the gemmage or collection of the resinous
sap, and the distillation and manufacture of the difierent products
yielded by it,

* TraiU de la Culture du Pin Maritime.
fMise en valeur dea Terres Pauvrespar le Pin Maritime.

CHAPTER XI.

Diseases and Injurious Influences to which the Maritime Pine
13 Subject.

Sect. I. — Choking hy an Over-growth of Local Vegetation.

Besides failures in the culture of the maritime pine, attributable to
bad seed, and to unsuitable soil, it often succumbs to other injurious
influences, which operate, not always singly and alone, but in com-
bination, and one preparing the way for another. It suffers from
cold, from hail, from snow, and from wind. When the tap-root comes
upon a subterranean sheet of water, a layer of compact clay, or
rocks somewhat coherent and continuous, it becomes covered with
mosses and lichens, and it languishes, and dies ; and yet subterranean
aridity is not less opposed to its healthy growth.

In Sologne, where the natural shrubs are destructive to young
seedlings, the precaution is taken of sowing the seed on newly cleared
land ; and recourse is had to some of the usages of husbandry, and
the growth of annual crops, eflfective in themselves or their culture
In cleaning the land, to destroy the noxious plants which might
defile the ground to be converted into pineries.

M. Vilmorin has recorded that in his experience the couch grass,
and some other of the grasses, such as the agrostis stolonifera, marsh
bent grass, the holcits mollis, creeping soft grass, the agrostis vulgaris,
fine bent grass, and many species of festuca, or fesque grass, may so
take possession of the ground as to prove destructive to the young
produce of sowings of pine trees ; and in Sologne the growth of
hromus, or brome grass, starves and kills the seedlings of the mari-
time pine, while in Gascony the broom is sown with this pine to
shelter and protect it in infancy against the sunshine and the sea
breezes ; but there the seedling pines are stifled by a vigorous growth
of heaths, such as the erica cinerea, the fine leaved heath, and calluna
vulgaris, the ling or heather of Scotland.

Sect. II. — Destructive ravages hy Birds, and Squirrels, and Insects.

Many birds, remarks Boitel, are destructive or injurious by eat-

158 INJURIES TO MARITIME PINE.

ing up seed not completely covered ; and the squirrels which abound
in pine woods gnaw the cones and destroy the seed while it is yet on
the tree. But these do also still greater damage, by eating away the
bark near the sprout, whereby not only is the growth arrested, but
the stem enfeebled at this point is often broken across by the wind.
But, contrary to what occurs in Sologue and some other districts in
which the tree is of feeble growth, and the ravages of the squirrel are
most detrimental, in some places on the coast, where the growth is
luxuriant, the finest trees are found on places where the squirrel
abounds. This is attributed to their destroying the cones which are
so abundant as to enfeeble trees by their production, and these being
destroyed, the vigour, which otherwise might have gone out in pro-
vision for reproduction, is directed to the self-development of the
tree. Sheep also are destructive to young seedlings, by browsing on
the sprout and the more tender buds; this is the work of a few
seconds, but the seedling, deprived of the sprout on the main shoot,
remains ever after irregular in its growth, stunted and bushy.

But the most destructive effects are found to be connected with
the appearance of certain insects on the trees. It is open to question,
however, whether these insects be the cause or the effect of the evil
done, or whether, as I think not unlikely, judging from what I have
seen in similar cases, with other insects and other trees, their increase
be not a result of disease, and the cause or occasion of death. Under
the ravages of insects sometimes whole forests suffer, and the entire
destruction of all the woods in a province seems imminent, while
man is powerless to arrest the evil; and the maritime pine, like other
trees, is subject to such damage.

M. Perris, of Mont-de-Marsan, in the Landes, an eminent French
entomologist, who for years found occupation in observing the habits
and transformations of insects which there prey upon this tree, so
early as 1864 had recorded in the Annales de la Societe entomologique
of France, that upwards of 120 species of insects live upon it
parasitically.

Certain of these insects attack the leaves or the terminal buds of
shoots, and so produce physiological effects, which enfeeble the tree,
and induce a state of disease. Amongst these are the caterpillars of
the Bomhyx pityocampa, of the Tortrix hiioliana, and of the Hylurgus
piniim-da. Others attack the wood, and betake themselves to the
wood and the bark. Amongst these are the Tomicus stenographus,
laricis and hidens, the Melanophila tarda, and the Fissodes notaUis. It
is alleged to be indisputable that the former class attack trees in a

RAVAGES BY INSECTS. 159

state of health ; it is in regard to some, if not all, of the latter class
alone, that there is any question.

" Authors," says M. Ferris,* " seem generally disposed to admit
that insects, the larvae of which are developed in the trees, while
they are yet growing, are the primary cause of the death of these.
There has thus been attributed to the Pissodes notatus the loss of an
immense quantity of pines, which covered, in 1835, 190 hectares of
the forest of Rouvray.

" The Marquis of Chambray, in his beautiful work on the resinous
trees, speaks of an insect of the gemts Bostriche, which, when it in-
creases in great quantities, can destroy entire forests of the maritime
pine. We read in the Histoire de V administration en France, par
A.nthelme Costaz, t. I., p. 248, that in the seventeenth and eighteenth
centuries the pine forests of Germany were so ravaged by the scolyte
that the Hanoverian province of the Hartz feared a total loss of fuel,
and was delivered from the fear mainly by the effects of several cold
and wet winters, which caused the insects to perish in great numbers.

" As for myself," says he, " I cannot admit that these insects are
the primary cause of the death of the trees which they attack, and in
fifteen years, during which I have, without intermission, studied their
habits in one of the best wooded countries in France, I have observed
a sufficiency of facts to justify me in expressing my opinion, which is,
that insects in general (not including those which attach themselves
solely to the foliage, as miners, etc.) do not attack those trees which
are in good health, but they only address themselves to those whose
health and functions have suffered, from some cause or other ;" and
he subsequently expresses it as his painful conviction, that lignivorous
insects are only to be dreaded by sickly trees. They are like some
mosses and lichens which only attach themselves to enfeebled trees,
while healthy, well-growing trees, preserve a smooth bark, and
repulse these vegetable parasites.

'' In the department of the Landes," says he, '5" where we reckon the
pine trees by millions, I have never witnessed, and tradition has not
preserved the recollection of a single case of these forest razzias which
have afSicted other countries. Now the pine is exposed to a crowd of
enemies, and the number of individuals of the most injurious of these
is incalculable, and yet it is but seldom the case that one of those trees
perishes, and I have still to find one which has been actually killed

• Annal Soc. Ent. France, 2mo Series, X, 513.

160 INJURIES TO THE MARITIME PINE,

by insects. This comes about, according to my views, from this ; the
maritime pine being there in its true home, it there developes itself with
vigour, then lives in good health, and thus braves the innumerable
enemies which surround it.

" But let the pines become sickly through the effect of a hail storm,
or of an insect having destroyed the leaves or the bud, and when,
in consequence of the sickliness affecting the roots and spreading
itself from one to another, this may invade the whole forest, if by
a circular ditch the contagion be not arrested, then those lignivorous
insects, divining the morbid condition of these sick trees, even while
no external indication betrays the existence of the evil, throw
themselves in mass upon their victims, and finish them off in a few
weeks. ...

" The insects most destructive to the maritime pine," writes M.
Perris, " are first the Bomhijx pytiocampa, the caterpillar of which
devours the leaves of this tree, and may, if it multiply beyond measure,
occasion such physiological derangements that there may result a
disease, the cousequence of which, through the ravages of the
xylophages, or woodeaters, shall be fatal ; second, the tomicus steno-
grajohus, laricis and hidens, the melanophila tarda, and the pissodes
notatus, which destroy with great rapidity every so diseased tree.

" There has been recommended, as precautionary measures against
these last mentioned insects, the destruction of all dead woods, the
removal of stumps, the working up, or at least the removal of the
bark of all felled trees, the placing in different parts of the forests
attractive trees to allure the matured insects to lay their eggs there^
and then destroying the larvae ; but how can it be effected that
these measures shall be carried out simultaneously, that is to say, by
everybody at the same time, throughout the whole extent of a
department, with many conterminous departments'? Moreover,
would the results be very appreciable, when there are in the higher
and almost inaccessible parts of trees so many dead or diseased
branches 1 And, furthermore, in practice it is impossible to carry out
a really successful raid upon the insects ; and this is indisputable
with those who are acquainted with the management and exploitation
of our forests, with the inadequacy of our agricultural population,
and the indifference which, born of abundance and security, ignores
all proceedings which involve trouble,

" With regard to the chenille processio/iaire, the local name given to
the larvae of the Bombyx, which passes the winter in numerous com-
munities in large nets of silk attached to the branches, it may be

DESTRUCTION OF THE CHENILLE PROCESSION AIRE. 161

said that it might be easy to master it. The legislative arrange-
ments, which relate to the destruction of other larvae, might with
all propriety be extended to this ; and as there are four months
during which the work might be carried on, there appears to be no
reason why it might not be effected. But, it is well it should be
known that the greater proportion of the nests are situated on the
extremities of the upper branches of high trees, where it would be
almost always impossible to reach them, and always dangerous to
make an attempt to do so ; it must also be told, that in order to get
these nests it is necessary to cut down the branches which bear them,
and that if each branch have one of them, as may be seen, it would
be as well to fell the tree at oace, as to subject it to the deadly
operation of cutting off all its branches.

" We are then obliged to let things take their course, and to leave
it to the birds, to the numerous parasites, and to meteorological
phenomena, to bring, and to maintain within proper limits, the multi-
plication of devastating insects.

" There have been some years in which the vast forests of pines, in
the department of the Landes, have been invaded by the chenille
processionaire in numbers so prodigious that every branch and almost
every twig had its nest of these. Before winter a great portion of
the leaves had been devoured, and in spring the larvae coming out
of their winter's torpor, finished by browsing on the rest ; so that in
the month of March one might have said that a fire had swept over
the whole.

" These ravages, which nothing could be done to prevent, were
continued two years, and caused many trees to perish. The people
were in a state of excitement ; and for my own part I did not hesitate
to declare that if this went on for two or three years longer, this
would probably be the case with the greatest number of our pines,
the enfeebled condition of which would be followed by organic
derangements sufficiently grave to attract the hostriches, the buprestes,
the innumerable liguivorous insects always ready to throw them-
selves upon diseased trees, and the attacks of which are a signal of
death.

" So, as I have said, this condition of things continued two years.
In the third year, what was our astonishment to see that there was
scarcely a nest upon the trees ! The Chenilles had, so to speak,
disappeared. The titmice, the magpies, the cuckoos, and other birds
had doubtless destroyed great numbers, and doubtless some millions
had become the prey of carniverous and parasitic insects ; but, in

X.

162 INJURIES TO MARITIME PINE.

reckoning up all the partial destructions of them, we would be far
from accounting for what had happened : some general plague must
have fallen upon this innumerable race of devastators, and the
following is my conjecture :

" In the month of May the Chenilles processionaires bury them-
selves in the ground, there to be transformed into the chrysalis state ;
but they bury themselves at but little depth, in order that the
butterfly may experience no great difficulty .in taking its flight. The
process of organic metamorphosis which takes place in the chrysalis,
requires, as is known, that the insects be protected against too great
aridity ; now the months of May and .June in that year were
remarkable for very intense heat and unbroken drought ; the sandy
soil of the pine woods became desiccated to a great depth ; it was
broiling hot, and the chrysalises, being unable to develope in that
medium, became almost all abortive. Birth was given to few butter-
flies ; and thence it followed there were few chenilles. Two circum-
stances appear to me to justify fully this explanation : these are,
first, in woods which were somewhat colder than others, and on
margins adjacent to moist places, in the following year there were
found nests in pretty great numbers ; second, since then, two other
years, 1848 and 1849, have been marked by an aridity which was,
so to speak, exceptional ; and one result of this was, in the winter
1849-1850, great distances might be traversed without finding a
single nest. In 1851 they ceased to be so rare, and I remember I
prognosticated that this would be the case, in consequence of some
rains which fell in June and July, 1850.

" Thus a drought has sufficed to put an end to disquieting devasta-
tions, against which man had no remedy, and to-day (1851), the
number of chenilles processionaires is reduced to one of no great
magnitude ; they are, moreover, surrounded by so many enemies that
they have for a long time ceased to be redoubtable.

" Apart from drought or other meteorological accident, the chenilles
processionaires might have found, as has happened with other species,
in their excessive multiplication itself the cause of ruin and mortality.
The number might have been so great that food would have failed
them before their complete development, and then they would have
perished of hunger before transformation."

Such were the views advanced by M. Perris, Vice-President of the
Societe d' Agriculture des Laudes, and distinguished as an entomologist
who had given special attention to the insects living on the maritime
pine.

DESTRUCTION OF TREES FOLLOWING CHARCOAL BURNING. 163

According to the views of M. Ferris, ia the destruction of many of
the trees, they were enfeebled by the destruction of leaves and leaf-
buds ; they were thus brought into an abnormal condition, and then,
having become food atti-active to lignivorous insects, they died in
consequence of their ravages. And when other means than the
primary ravages of the leaf devouring insects produce like effects
to those thus produced by them, like consequences may follow.

Sect. III. — Destructive Consequences following the Effects of
Charcoal Burning.

Professor Bagneris remarks in regard to a disease to be found in
certain plantations :

" Frequently a pine is seen to wither and die, and the disease then
seems to spread in a circular form, the diameter of which gradually
increases. I have not been able to find out the cause. In Sologne
origins more or less imaginary were assigned to this. May not this
disease be caused by a fungus attacking the woody tissue 1 The form
it assumes would lead one to suppose so, and the curative means
employed strengthens the belief. In the Landes, a trench of
0'70 metres in depth is dug all round the place attacked, and the
circle of disease spreads no farther."

The following observations throw additional light upon the
phenomenon, and seem to reveal the origin of the evil ; if they do
not determine also the question raised as to the possibility of a
fungoid growth contributing towards the destructive result :

" In the district of Orleans", says M. Boitel, " the maritime pine does
not present that vigorous production which in the south it owes to a
soil and a climate which are pai'tioularly favourable to it. The sands
of the Sologne are often deficient in depth, and when thence it comes to
passthat the tap-root of the maritime pine comes uponabedof tenacious
and impermeable clay, the tree begins to languish, and its trunk and
branches become covered with mosses and lichens. A good many pine
woods find themselves in this condition when only fifteen years old.
The trees stand out against the evil till they reach the age of twenty or
five and twenty years ; but beyond that they become stationaiy, and
if they do not necessitate exploitation they are liable to be invaded and
destroyed by insects which become developed in innumerable swarms
in the bark and the wood.

" It has often fallen to my lot to ascertain and verify ravages thus

164 INJURIES OP MARITIME PINE.

committed in the pineries of the Sologne, and more especially in the
imperial domains, the forests of which have been under my direction
for some time. In the Grillaire, an imperial domain in the vicinity of
Motte-Beuvron, the lignivorous insects have carried out their ravages
in the middle of an immense forest of pines from twenty to twenty-
five years of age. The ravages had taken place simultaneously on
a great number of points which served as centres to lacunes in the
forest, the extent of which went on augmenting year by year in circular
zones concentric with the primal circle; and in the radii of these
concentric circles the trees were more diseased in proportion to their
proximity to the centre.

" At the centre the trees had fallen and strewed the ground with
heaps of their debris ; farther away they remained standing, but
dried up in all their parts ; finally, at the extreme points of the
circumference the leaves and the buds were beginning to get yellow,
which announced the invasion of the insects ; and the presence of these
it was not difficult to ascertain otherwise, on examining between the
wood and the bai*k, where the wood was literally ploughed up by
numerous galleries which the myriads of lignivorous insects had dug
and inhabited. In the middle of these gaps, where not a maritime
pine was left standing, there were to be seen here and there some
Scotch firs, pimis sylvestris, which, respected by the insects, mani-
fested an astonishing vigour alongside of the languishing condition of
the maritime pine.

" This fact," says he, " corroborates the opinion of M. Perris, who
does not admit that lignivorous insects attack the trees in a healthy
state. I accept willingly this opinion, supported besides, as it is,
by numerous observations conscientiously made ; and I think, with
the distinguished entomologist of Mont-de-Marsan, that the pineries
of La Sologne would be spared by these insects if the pines found
themselves in circumstances more favourable to their develop-
ment.

" In the Grillaire the circular lacunes ravaged by the insects pre-
sent often an area of several hectares. The entire forest would have
disappeared under the destructive action of these parasites if measures
had not been taken to exploit them at once, and to forward the pro-
duce to Paris.

" It is noteworthy that there is found generally in the centre of
each lacune charcoal debris, which marks the site of an old charcoal
furnace. The pine is very sensible to the efi"ects of fire and of smoke.
In the forest of Villette (Loiret) the maritime pines are dead, from

DESTRUCTION OF TREES FOLLOWING CHARCOAL BURNING. 165

having been exposed to the smoke of a brick kiln, from which they
were distant about 50 metres.

" Invariably, when there is established a charcoal kiln in the
middle of a pinery, there are seen many circular ranges of pines,
which, through the effect of the fire and of the smoke, become
diseased, and they are not slow to dry up and perish.

" These diseased and languishing pines become the cradle of
lignivorous insects which invade the forest throughout its extent,
if after having completed the work of destruction on the first trees in
which they were developed, they find themselves in the middle of a
miserable pinery, covered with mosses and lichens, the diseased con-
dition of which is so favourable to the propagation of these parasites.

" Sometimes, however, the ravages of the lignivorous insects
manifest themselves notwithstanding that there are no charcoal
furnaces there, or these are far distant. In these exceptional cases,
in Sologne, the primary cause of the disease of the pineries can be
attributed only to the humidity or to the unfavourable nature of the
soil.

" After the enfeebling influence which reduces the trees to an
impoverished condition, comes that of the vegetable parasites, which
carry on farther the enfeebling of the trees ; then come the insects
which seize possession of a prey incapable of offering any resistance.
According to some observations which I have made, it seems to me
that the lignivorous insects occasionally allow themselves to precede
those which betake themselves to the leaves, and buds, and young
shoots. If this be the case, one may be struck with the harmony
which ranges among the causes which tend to destroy a vegetable
from the time that it is in other than the normal conditions of
development. First, the soil produces its effect, then follow the
parasitic vegetables, and then the lignivorous insects, which, in arrest-
ing the circulation of the sap, bring the final cou}:) to the vegetable
attacked in its every part.

" There come into operation in Sologne yet other causes to favour
the invasion of the pineries by insects at the periods of the first
thinnings. Great negligence is manifested in the operations carried
on with a view to giving to the pine the air and light favourable to
its development.

" Pines growing too densely in their infancy famish one another, the
more vigorous destroy the more feeble, which become thus the food
of the insects ; at a later period, in the expectation that the expense
of the thinning will be covered by the faggots obtained, or by the

166 INJURIES TO MARITIME PINE.

manufacture of charcoal, there are carried on simultaneously and
vigorously thinning and pruning, which give to the pine in super-
abundance the air and the light of which up to that time it had
been deprived. Is it astonishing that trees so ill-treated and
mis-managed should experience a physiological disturbance which
renders them diseased and accessible to the numerous insects, which,
after having multiplied in the faggot, the cords of charcoal, and the
twigs with which the ground remains strewed, find later on subjects
perfectly prepared to receive them 1

" In all the circumstances of the case, the proprietors would find it
for their interest in every way to secure to the trees that vigour and
that health which defends them so well against the attacks of insects.
They would ensure thus the duration of their pineries, and not expose
them to premature decimation, which compels them to exploit them
at an age at which it would be advantageous to maintain their con-
servation.

" Independently of these indirect evils occasioned to proprietors by
insects, it is necessary to reciion also amongst the damages done by
them those dead trees which rot upon the place, which can no longer
serve for the making of charcoal, and it would be reckoned fraud to
introduce that dead wood in the making up of the faggots, which, to
possess the combustible qualities sought for by bakers, should be
composed exclusively of living wood."

He goes on to say : " The forester has an interest in making him-
self well acquainted with the parasitic insects most hurtful to the
pine, and in appreciating correctly the ravages committed by them,
and the causes which tend to augment or to diminish these. The
study of these will show to him that it is useful to give to the pines
those periodical attentions which will ensure their vigour and success-
ful growth j and as soon as a devastating insect may appear on his
pinery, he will know what redoubtable enemy he will have to combat,
and what are the urgent measures imposed upon him with a view to
the restriction and diminution of damages very prejudicial to his
interests." And he speaks in high terms of the work by M. Ferris
as supplying requisite instructions.

Amongst other specimens of the products of the Landes. under the
system of sylviculture adopted, exhibited in the Industrial Museum
in Edinburgh, were specimens of wood cut up into galleries by the
Bomb y X 2')ytiocampa, -Awdi other lignivorous insects, and specimens of
the same restored to healthy growth by a process devised by Dr.

DESTEUCTIVE RAVAGES BY THE MOLE. 167

Roberts, with specimens of wood treated by M. Courval for similar

defects.

Sect. IV. — Destructive Ravages occasioned hy the Mole.

Another source of trouble in such plantations of the maritime pine
is the subterranean galleries created by the mole. In regard to this
M. Boitel writes :

" The mole is to be found everywhere in sand or clay, in dry or
damp soil. Its operation seems to be measured by the opposition
which the ground makes to its efforts. In light sandy ground it
makes very long galleries ; it makes shorter ones where the clay is
tenacious. It does not, however, dislike the latter kind of ground ;
on the contrary, it prefers it, either on account of the solidity which
it confers on the galleries, or on account of the abundance of earth
worms in it. Although it can swim, and can easily protect its retreat
from water, it does not inhabit low wet places, unless it finds some
elevated spot in the midst of the surrounding moisture, such as the
edge of a dituh, where it can construct a healthy and convenient
nest. It delights in the soil of oases, sometimes found on the edge
of bogs, which abound in earth worms. In general it does not care
for bare exposed places; it prefers spots sheltered by walls, bushes, or
trees. It seems to know instinctively that it is safe whei-e its runs
are hidden by vegetation. Moles hidden in the banks of ditches are
hopeless to catch. It is easier to catch ten in a field than one under
a hedge, or on the wooded banks of a ditch.

" The mole is remarkably watchful and active. Its hearing is
very acute, although its ears are hardly visible amidst its fur. It ig
frightened by the least noise. The mole-catcher, or the dog that
wishes to capture it, must walk very gently else it will instantly dis-
appear. It sees perfectly with eyes no larger than the head of a pin.
It does not fear water, and can swim in order to reach a desired
point. This explains how gardens surrounded with water are not
exempt from its ravages. It is a solitary animal when adult. It is
said that the female drives away the male from her nest. Moles
only pair at one season, when two may sometimes be caught in the
same trap. The female takes care of her brood for some time.
With these exceptions the mole is eminently solitary. I have tried
in vain to induce two moles of different sexes to li\e in a box filled
with earth. They fought continually, and there was no peace until
one was killed and partly eaten. The male wars against every in-

168 INJURIES TO MARITIME PINE.

truder, and fights to the death with other moles, also with weasels
and field mice. It is uncommon that both combatants survive.
The weasel ever falls a victim.

"Besides the runs and ordinary mole-hills, moles make large
heaps of earth, under which are a kind of special nest, measuring
from O'lo metres, to 0'20 metres across.

" These are made of the leaves of trees, dry grass, and the green
leaves of cereals or other plants within their reach. When they can
make a selection they prefer the withered leaves of the oak. They
do not, as some say, pull down grass by the roots. They always put
out their snouts to collect materials for their nests. They are wise
enough to bring their materials from a distance for fear of discovering
their retreat, especially when they cut down green corn. It is
perfectly proved that everything required for their nests is brought
from above ground, and that roots of plants are never made use of.

" What is called impropei'ly the mole's nest is only a warm and
comfortable retreat, where it lives permanently and habitually. The
males have their nests as well as the females. This habitation is
the central point of all its operations, it is the spot most frequently
visited. The mole reaches it by all kinds of runs, both horizontal
and vertical ; it contains its food magazines abundantly supplied with
pieces of earth-worms still in life, so as to preserve them for a longer
time. This animal, so active and strong in scraping, is never long
without visiting its nest, it sleeps and eats there generally. It is
often found warm when uncovered by the mattock. The most able
mole-catchers have never surprised the mole in its nest. At the first
sound they disappear in their deepest and best concealed runs.
The nest is often renewed without the position being much changed.
Under the same heap of earth may be found three or even four nests
of different ages. The same mole has sometimes several central
dwellings which it occupies irregularly so as to escape the snares of
its enemies. The heap which conceals the nest is always larger than
the usual mole heap, they are 0-50 metres in height, nearly 1 m^tre
across.

" The nest is not always under one of these large heaps which are
so easily seen. Sometimes it is placed under an adjoining ordinary
sized hill. The female usually makes use of this ruse so as to
conceal her young. Nests placed under very large hills are what
mole-catchers call false or male's nests.

" The experienced mole-catcher can easily distinguish the nest of
the female, because, not being so strong, they cannot throw up so

DESTRUCTION OP MOLES. 169

much earth, and their mole-hills are smaller and flatter. The mole-
hills furnish valuable indications. An experienced man can divine
the sex of the animals from the appearance of the mole-hills ; amongst
the numerous runs they can fix on the chief road between two im-
portant centres, and the mole can hardly escape a trap placed where
it must be passed a thousand times in a day. From these indications,
the mole-catcher can deal with the females and young ones so as to
suit his own interest, which he never fails to do when he is paid at
so much per head. The female has in the year two litters of four
or five each. Young moles produced in spring have a litter before
the end of the first year. The first litter is produced in the month
of April, and it is of great consequence to catch them at that time,
as one mother caught means four or five less on the estate. The
real nests can be easily detected, as we have said above.

" I will now point out the best way of getting rid of them. Only a
man trained specially will do any good ; others will not pursue the
moles with the order, regularity, and intelligence necessary. The good
mole-catcher knows the habits and instincts of the animal, and that
preliminary knowledge will suggest modes of destruction which would
escape any other person.

" I am acquainted with one skilful mole-catcher ; three times a
year he comes from Normandy to work on some of the important
estates in Sologne. From his zeal and activity, he seems born for the
trade. He undertakes to destroy the moles at so much per head, or
so much per hectare. If he receives 25 centimes a head (the usual
price), he cares more for the number of his victims that for doing his
work thoroughly. He tries to catch males rather than females, who
are the hope of the future. On this point I may relate what happened
to one of my neighbours with the mole-catcher in question. The first
time he was employed, it was fixed that he should receive 25 centimes
per mole. At the end of two days he brought eighty-nine moles, of
which seventy-two were males. It was evident that the females had
been spared. It is better to make arrangements by the quantity of
ground. In Sologne 1 franc 50 centimes are given per hectare without
food.

" The skilful mole-catcher, when visiting his traps, keeps an
attentive eye on the mole-hills and runs. Whenever he sees a mole
disturbing the ground, he approaches slowly, with one stamp he inter-
cepts the new run in such a way as to cut off all retreat, and one blow
of the mattock secures his victim. The mattock is also used in getting

Y

170 INJURIES TO MARITIME PINE.

at the nests with young ones ; and it is used for sounding the earth
and finding out runs."

Sect. V. — Destructive Ravages hy Forest Fires.

M. Eloi Samanos, in his volume entitled Traitd de la Culture du
Pin Maritime, to which reference has been made, remarks : " One of
the greatest scourges to which a pine-wood plantation is exposed is
beyond contradiction that of fire ; it reaches a height with such
facility, and spreads with such fearful rapidity.

" There is preserved in our district (apparently that of Cape Breton)
the memory of a fire which devastated our forests, on an extent of
from five and twenty to thirty kilometres; such occurrences may well
sufifice to create a most reasonable fear in proprietors, and to urge
upon them the adoption of the greatest measures of precaution.

" Such occurrences are almost always occasioned by workmen
who light fires in the forest without seeing to these being completely
extinguished ; they may also be occasioned by storms falling upon a
forest, as happened in the imperial domain of Solferiuo.

" One precautionary measure against fire, adopted by some care-
ful foresters, consists in separating resinous woods by planting broad
bands of deciduous trees between them.

" This has been carried out by the intelligent engineer, M,
Crouzet, in the imperial domains of Solferino, under his direction, in
which he has plantations of deciduous trees dividing the woods of
maritime pines. By this means the fury of the fire at least is
diminished, and it becomes easy to circumscribe and confine its
ravages.

"Besides this, t^^cvo is omp mf^ans employed in our district to combat
conflagrations, known under the name of contre-feu. It is this : when
the inhabitants have been congregated on the scene of the disaster,
and they judge the extinction of the fire by direct means impossible,
they go in the direction in which the fire is advancing, and at some
distance from it, having armed themselves with well clothed pine
branches, they form in line, and burning there the thorns, heaths, or
other dry woods between them and the fire they prevent this fire
from spreading in the different directions and smother it ; and this
being done, the conflagration, on advancing to that place, finds no food
for its continuation, and often dies out."

To rely entirely on such means, M. Samanos considers inexpedient,
and he says : " Plantations of deciduous trees ought also to be em-

DESTRUCTION BY FOREST FIRES. 171

ployed amongst the precautions taken for the conservation of forests,
and it is impossible to do too much to make known and to introduce
such a measure."

In accordance with this account of the contre-feu is the following
statement by M. Bartro, in an article on the maritime pine in the
Adour, a joarnal of Bayonne :

" Resin-yielding- forests are extremely combustible. Their soil is
strewed with ferns, with brooms, and with dried leaves ; it is covered
with trunks of trees, which distil resin, drops of which are seen every-
where ; a single spark, or the wadding of a gun, may suffice to set
the country on fire. When this misfortune happens the tocsin is
sounded in the adjacent communes. The population arm themselves
with shovels and hatchets ; they march under the leadership of the
mayors, who direct the operations and compose a guard, the duty of
which is to work themselves and to prevent desertion by the other
workers. They note the wind under which the conflagration spreads,
and regulate their procedui-e accordingly. By this combination of
labours the fire finds itself encircled by the population of the diff'erent
communes, who proceed to extinguish it, and, unless the wind be
very strong, and carry the burning flakes behind the workers, in
which case they are veiy much exposed to be themselves surrounded
by the fire, they find it pretty easy to master it, and that they do
thus :

" The workers, one after another, furnish themselves with green
and branching boughs ; they take their place at what is deemed a
proper distance in line in front of the advancing fire ; they set fire
to the ferns and other combustibles in front of them, w^hich they
extinguish, as they progressively advance toward the fire, by smiting
them with their green branches, and covering them with earth by
means of their shovels. This is what is called making a contre-feu
When the fire comes it finds no food, and it is forced to go out. This
is the only means of which use is made to stop the conflagration in
forests of resinous trees."

Boitel, in reference to this, compares it to the horaoepathio treat-
ment of disease by physicians acting on the principle — Like cures Like
— it is fire extinguished by fire, and he goes on to say :

" Forest fires would be less common if the police were less negli-
gent ; if herdsmen, shepherds, resin-collectors, and woodmen did not
take pleasure in lighting fires in the heart of the pignadas, or pine

172 INJURIES TO MARITIME PINE,

forests, for the most trivial objects, the embers of which they keep
constantly glowing to supply them with fire for their pipes, for their
ineture, a preparation of Indian corn, and to broil their salt fish and
their sardines, culinary operations which ought to be attended to
before leaving their homes. These fires in the open air are left
burning on ground covered with combustible matter while the work-
men go about their work. Is it surprising then that there should be
so many fires %

" Insurance companies bring themselves with difficulty to insure
pignadas ; moreover, they cannot do otherwise than require a high
premium, which the greater part of proprietors will not agree to pay.

" The provident cultivator, who wishes to protect his forests against
a general conflagration, takes the prudent precaution to interpose in
his forest masses cultivated clearings sufficiently large to form a
barrier which cannot be overleapt by the destructive scourge. This
preventative costs less than the premium of insurance.

" Forest fires occasion more damage in young pineries than in those
w .' '\ arein a state of decadence; for the old trunks are not con-
sumed bv the fire, and they have lost nothing of their fitness to yield
wood for carpentry work, and the employment of them in this way
affords some indemnity to the proprietor ; it is otherwise with young
pineries, which the fire destroys without giving any compensation."