ought to receive, in Germany, twenty-one centimetres of water per week,
and with less than half that quantity it is not advisable to incur the
expense of supplying it. The ground is irrigated twenty-five or thirty
times, and if the full quantity of twenty-one centimetres is applied, it
receives about two hundred inches of water, or six times the total
amount of precipitation. Puvis, quoted by Boussingault, after much
research comes to the conclusion that a proper quantity is twenty
centimetres applied twenty-five or thirty times, which corresponds with
the estimate just stated. Puvis adds--and, as our author thinks, with
reason--that this amount might be doubled without disadvantage.
Boussingault observes that rain water is vastly more fertilizing than
the water of irrigating canals, and therefore the supply of the latter
must be greater. This is explained partly by the different character of
the substances held in solution or suspension by the waters of the earth
and of the sky, partly by the higher temperature of the latter, and,
possibly, partly also by the mode of application--the rain being finely
divided in its fall or by striking plants on the ground, river water
flowing in a continuous sheet.
The temperature of the water is thought even more important than its
composition. The sources which irrigate the _marcite_ of
Lombardy--meadows so fertile that less than an acre furnishes grass for
a cow the whole year--are very warm. The ground watered by them never
freezes, and a first crop, for soiling, is cut from it in January or
February. The Canal Cavour, just now commenced--which is to take its
supply from the Po at Chivasso, fourteen or fifteen miles below
Turin--will furnish water of much higher fertilizing power than that
derived from the Dora Baltea and the Sesia, both because it is warmer,
and because it transports a more abundant and a richer sediment than the
latter streams, which are fed by Alpine icefields and melting snows, and
which flow, for long distances, in channels ground smooth and bare by
ancient glaciers, and not now contributing much vegetable mould or fine
slime to their waters.
[343] It belongs rather to agriculture than to geography to discuss the
quality of the crops obtained by irrigation, or the permanent effects
produced by it on the productiveness of the soil. There is no doubt,
however, that all crops which can be raised without watering are
superior in flavor and in nutritive power to those grown by the aid of
irrigation. Garden vegetables, particularly, profusely watered, are so
insipid as to be hardly eatable. Wherever irrigation is practised, there
is an almost irresistible tendency, especially among ignorant
cultivators, to carry it to excess; and in Piedmont and Lombardy, if the
supply of water is abundant, it is so liberally applied as sometimes not
only to injure the quality of the product, but to drown the plants and
diminish the actual weight of the crop.
Professor Liebig, in his _Modern Agriculture_, says: "There is not to be
found in chemistry a more wonderful phenomenon, one which more confounds
all human wisdom, than is presented by the soil of a garden or field. By
the simplest experiment, any one may satisfy himself that rain water
filtered through field or garden soil does not dissolve out a trace of
potash, silicic acid, ammonia, or phosphoric acid. The soil does not
give up to the water one particle of the food of plants which it
contains. The most continuous rains cannot remove from the field, except
mechanically, any of the essential constituents of its fertility."
"The soil not only retains firmly all the food of plants which is
actually in it, but its power to preserve all that may be useful to them
extends much farther. If rain or other water holding in solution
ammonia, potash, and phosphoric and silicic acids, be brought in contact
with soil, these substances disappear almost immediately from the
solution; the soil withdraws them from the water. Only such substances
are completely withdrawn by the soil as are indispensable articles of
food for plants; all others remain wholly or in part in solution."
The first of the paragraphs just quoted is not in accordance with the
alleged experience of agriculturists in those parts of Italy where
irrigation is most successfully applied. They believe that the
constituents of vegetable growth are washed out of the soil by excessive
and long-continued watering. They consider it also established as a fact
of observation, that water which has flowed through or over rich ground
is far more valuable for irrigation than water from the same source,
which has not been impregnated with fertilizing substances by passing
through soils containing them; and, on the other hand, that water, rich
in the elements of vegetation, parts with them in serving to irrigate a
poor soil, and is therefore less valuable as a fertilizer of lower
grounds to which it may afterward be conducted.
The practice of irrigation--except in mountainous countries where
springs and rivulets are numerous--is attended with very serious
economical, social, and political evils. The construction of canals and
their immensely ramified branches, and the grading and scarping of the
ground to be watered, are always expensive operations, and they very
often require an amount of capital which can be commanded only by the
state, by moneyed corporations, or by very wealthy proprietors; the
capacity of the canals must be calculated with reference to the area
intended to be irrigated, and when they and their branches are once
constructed, it is very difficult to extend them, or to accommodate any
of their original arrangements to changes in the condition of the soil,
or in the modes or objects of cultivation; the flow of the water being
limited by the abundance of the source or the capacity of the canals,
the individual proprietor cannot be allowed to withdraw water at will,
according to his own private interest or convenience, but both the time
and the quantity of supply must be regulated by a general system
applicable, as far as may be, to the whole area irrigated by the same
canal, and every cultivator must conform his industry to a plan which
may be quite at variance with his special objects or with his views of
good husbandry. The clashing interests and the jealousies of proprietors
depending on the same means of supply are a source of incessant
contention and litigation, and the caprices or partialities of the
officers who control, or of contractors who farm the canals, lead not
unfrequently to ruinous injustice toward individual landholders. These
circumstances discourage the division of the soil into small properties,
and there is a constant tendency to the accumulation of large estates of
irrigated land in the hands of great capitalists, and consequently to
the dispossession of the small cultivators, who pass from the condition
of owners of the land to that of hireling tillers. The farmers are no
longer yeomen, but peasants. Having no interest in the soil which
composes their country, they are virtually expatriated, and the middle
class, which ought to constitute the real physical and moral strength of
the land, ceases to exist as a rural estate, and is found only among the
professional, the mercantile, and the industrial population of the
cities.
[344] BOUSSINGAULT, _Economie Rurale_, ii, pp. 248, 249.
[345] The cultivation of rice is so prejudicial to health everywhere
that nothing but the necessities of a dense population can justify the
sacrifice of life it costs in countries where it is pursued.
It has been demonstrated by actual experiment, that even in Mississippi,
cotton can be advantageously raised by the white man without danger to
health; and in fact, a great deal of the cotton brought to the Vicksburg
market for some years past has been grown exclusively by white labor.
There is no reason why the cultivation of cotton should be a more
unhealthy occupation in America than it is in other countries where it
was never dreamed of as dangerous, and no well-informed American, in the
Slave States or out of them, believes that the abolition of slavery in
the South would permanently diminish the cotton crop of those States.
[346] _L'Italie a propos de l'Exposition de Paris_, p. 92.
[347] The very valuable memoirs of Lombardini, _Cenni idrografi sulla
Lombardia, Intorno al sistema idraulico del Po_, and other papers on
similar subjects, were published in periodicals little known out of
Italy; and the _Idraulica Pratica_ of Mari has not, I believe, been
translated into French or English. These works, and other sources of
information equally inaccessible out of Italy, have been freely used by
Baumgarten, in a memoir entitled _Notice sur les Rivieres de la
Lombardie_, in the _Annales des Ponts et Chaussees_, 1847, 1er semestre,
pp. 129 _et seqq._, and by Dumont, _Des Travaux Publics dans leurs
Rapports avec l'Agriculture_, note, viii, pp. 269 _et seqq._ For the
convenience of my readers, I shall use these two articles instead of the
original authorities on which they are founded.
[348] Sir John F. W. Herschel, citing Talabot as his authority,
_Physical Geography_ (24).
In an elaborate paper on "Irrigation," printed in the _United States
Patent Report_ for 1860, p. 169, it is stated that the volume of water
poured into the Mediterranean by the Nile in twenty-four hours, at low
water, is 150,566,392,368 cubic metres; at high water, 705,514,667,440
cubic metres. Taking the mean of these two numbers, the average daily
delivery of the Nile would be 428,081,059,808 cubic metres, or more than
550,000,000,000 cubic yards. There is some enormous mistake, probably a
typographical error, in this statement, which makes the delivery of the
Nile seventeen hundred times as great as computed by Talabot, and many
times more than any physical geographer has ever estimated the quantity
supplied by all the rivers on the face of the globe.
[349] The Drac, a torrent emptying into the Isere a little below
Grenoble, has discharged 5,200, the Isere, which receives it,
7,800 cubic yards, and the Durance an equal quantity, per
second.--MONTLUISANT, _Note sur les Dessechements, etc., Annales
des Ponts et Chaussees_, 1833, 2me semestre, p. 288.
The floods of some other French rivers scarcely fall behind those of the
Rhone. The Loire, above Roanne, has a basin of 2,471 square miles, or
about twice and a half the area of that of the Ardeche. In some of its
inundations it has delivered above 9,500 cubic yards per
second.--BELGRAND, _De l'Influence des Forets, etc., Annales des Ponts
et Chaussees_, 1854, 1er semestre, p. 15, note.
[350] The original forests in which the basin of the Ardeche was rich
have been rapidly disappearing, for many years, and the terrific
violence of the inundations which are now laying it waste is ascribed,
by the ablest investigators, to that cause. In an article inserted in
the _Annales Forestieres_ for 1843, quoted by Hohenstein, _Der Wald_, p.
177, it is said that about one third of the area of the department had
already become absolutely barren, in consequence of clearing, and that
the destruction of the woods was still going on with great rapidity. New
torrents were constantly forming, and they were estimated to have
covered more than 70,000 acres of good land, or one eighth of the
surface of the department, with sand and gravel.
[351] "There is no example of a coincidence between great floods of the
Ardeche and of the Rhone, all the known inundations of the former having
taken place when the latter was very low."--MARDIGNY, _Memoire sur les
Inondations des Rivieres de l'Ardeche_, p. 26.
I take this occasion to acknowledge myself indebted to the interesting
memoir just quoted for all the statements I make respecting the floods
of the Ardeche, except the comparison of the volume of its waters with
that of the Nile, and the computation with respect to the capacity
required for reservoirs to be constructed in its basin.
[352] In some cases where the bed of rapid Alpine streams is composed of
very hard rock--as is the case in many of the valleys once filled by
ancient glaciers--and especially where they are fed by glaciers not
overhung by crumbling cliffs, the channel may remain almost unchanged
for centuries. This is observable in many of the tributaries of the Dora
Baltea, which drains the valley of the Aosta. Several of these small
rivers are spanned by more or less perfect Roman bridges--one of which,
that over the Lys at Pont St. Martin, is still in good repair and in
constant use. An examination of the rocks on which the abutments of this
and some other similar structures are founded, and of the channels of
the rivers they cross, shows that the beds of the streams cannot have
been much elevated or depressed since the bridges were built. In other
cases, as at the outlet of the Val Tournanche at Chatillon, where a
single rib of a Roman bridge still remains, there is nothing to forbid
the supposition that the deep excavation of the channel may have been
partly effected at a much later period. See _App._, No. 45.
[353] _Memoire sur les Inondations des Rivieres de l'Ardeche_, p. 16.
"The terrific roar, the thunder of the raging torrents proceeds
principally from the stones which are rolled along in the bed of the
stream. This movement is attended with such powerful attrition that, in
the Southern Alps, the atmosphere of valleys where the limestone
contains bitumen, has, at the time of floods, the marked bituminous
smell produced by rubbing pieces of such limestone together."--WESSELY,
_Die Oesterreichischien Alpenlaender_, i, p. 113. See _Appendix_, No. 48.
[354] FRISI, _Del modo di regolare i Fiumi e i Torrenti_, pp. 4-19.
[355] SURELL, _Etude sur les Torrents_, pp. 31-36.
[356] CHAMPION, _Les Inondations en France_, iii, p. 156, note.
[357] Notwithstanding this favorable circumstance, the damage done by
the inundation of 1840 in the valley of the Rhone was estimated at
seventy-two millions of francs.--CHAMPION, _Les Inondations en France_,
iv, p. 124.
Several smaller floods of the Rhone, experienced at a somewhat earlier
season of the year in 1846, occasioned a loss of forty-five millions of
francs. "What if," says Dumont, "instead of happening in October, that
is between harvest and seedtime, they had occurred before the crops were
secured? The damage would have been counted by hundreds of
millions."--_Des Travaux Publics_, p. 99, note.
[358] TROY, _Etude sur le Reboisement des Montagnes_, Sec.Sec. 6, 7, 21.
[359] For accounts of damage from the bursting of reservoirs, see
VALLEE, _Memoire sur les Reservoirs d'Alimentation des Canaux, Annales
des Ponts et Chaussees_, 1833, 1er semestre, p. 261.
[360] Some geographical writers apply the term _bifurcation_ exclusively
to this intercommunication of rivers; others, with more etymological
propriety, use it to express the division of great rivers into branches
at the head of their deltas. A technical term is wanting to designate
the phenomenon mentioned in the text.
[361] MARDIGNY, _Memoire sur les Inondations de l'Ardeche_, p. 13.
[362] In the case of rivers flowing through wide alluvial plains and
much inclined to shift their beds, like the Po, the embankments often
leave a very wide space between them. The dikes of the Po are sometimes
three or four miles apart.--BAUMGARTEN, after LOMBARDINI, _Annales des
Ponts et Chaussees_, 1847, 1er semestre, p. 149.
[363] It appears from the investigations of Lombardini that the rate of
elevation of the bed of the Po has been much exaggerated by earlier
writers, and in some parts of its course the change is so slow that its
level may be regarded as nearly constant.--BAUMGARTEN, volume before
cited, pp. 175, et seqq. See _Appendix_, No. 49.
If the western coast of the Adriatic is undergoing a secular depression,
as many circumstances concur to prove, the sinking of the plain near the
coast may both tend to prevent the deposit of sediment in the river bed
by increasing the velocity of its current, and compensate the elevation
really produced by deposits, so that no sensible elevation would result,
though much gravel and slime might be let fall.
[364] To secure the city of Sacramento in California from the
inundations to which it is subject, a dike or levee was built upon the
bank of the river and raised to an elevation above that of the highest
known floods, and it was connected, below the town, with grounds lying
considerably above the river. On one occasion a breach in the dike
occurred above the town at a very high stage of the flood. The water
poured in behind it, and overflowed the lower part of the city, which
remained submerged for some time after the river had retired to its
ordinary level, because the dike, which had been built to keep the water
_out_, now kept it _in_.
According to Arthur Young, on the lower Po, where the surface of the
river has been elevated much above the level of the adjacent fields by
diking, the peasants in his time frequently endeavored to secure their
grounds against threatened devastation through the bursting of the
dikes, by crossing the river when the danger became imminent and opening
a cut in the opposite bank, thus saving their own property by flooding
their neighbors'. He adds, that at high water the navigation of the
river was absolutely interdicted, except to mail and passenger boats,
and that the guards fired upon all others; the object of the prohibition
being to prevent the peasants from resorting to this measure of
self-defence.--_Travels in Italy and Spain_, Nov. 7, 1789.
In a flood of the Po in 1839, a breach of the embankment took place at
Bonizzo. The water poured through and inundated 116,000 acres, or 181
square miles, of the plain, to the depth of from twenty to twenty-three
feet in its lower parts.--BAUMGARTEN, after LOMBARDINI, volume before
cited, p. 152.
[365] MOYENS _de forcer les Torrents de rendre une partie du sol qu'ils
ravagent, et d'empecher les grandes Inondations_.
[366] The effect of trees and other detached obstructions in checking
the flow of water is particularly noticed by Palissy in his essay on
_Waters and Fountains_, p. 173, edition of 1844. "There be," says he,
"in divers parts of France, and specially at Nantes, wooden bridges,
where, to break the force of the waters and of the floating ice, which
might endamage the piers of the said bridges, they have driven upright
timbers into the bed of the rivers above the said piers, without the
which they should abide but little. And in like wise, the trees which be
planted along the mountains do much deaden the violence of the waters
that flow from them."
[367] I do not mean to say that all rivers excavate their own valleys,
for I have no doubt that in the majority of cases such depressions of
the surface originate in higher geological causes, and hence the valley
makes the river, not the river the valley. But even if we suppose a
basin of the hardest rock to be elevated at once, completely formed,
from the submarine abyss where it was fashioned, the first shower of
rain that falls upon it after it rises to the air, while its waters will
follow the lowest lines of the surface, will cut those lines deeper, and
so on with every successive rain. The disintegrated rock from the upper
part of the basin forms the lower by alluvial deposit, which is
constantly transported farther and farther until the resistance of
gravitation and cohesion balances the mechanical force of the running
water. Thus plains, more or less steeply inclined, are formed, in which
the river is constantly changing its bed, according to the perpetually
varying force and direction of its currents, modified as they are by
ever-fluctuating conditions. Thus the Po is said to have long inclined
to move its channel southward in consequence of the superior mechanical
force of its northern affluents. A diversion of these tributaries from
their present beds, so that they should enter the main stream at other
points and in different directions, might modify the whole course of
that great river. But the mechanical force of the tributary is not the
only element of its influence on the course of the principal stream. The
deposits it lodges in the bed of the latter, acting as simple
obstructions or causes of diversion, are not less important agents of
change.
[368] The distance to which a new obstruction to the flow of a river,
whether by a dam or by a deposit in its channel, will retard its
current, or, in popular phrase, "set back the water," is a problem of
more difficult practical solution than almost any other in hydraulics.
The elements--such as straightness or crookedness of channel, character
of bottom and banks, volume and previous velocity of current, mass of
water far above the obstruction, extraordinary drought or humidity of
seasons, relative extent to which the river may be affected by the
precipitation in its own basin, and by supplies received through
subterranean channels from sources so distant as to be exposed to very
different meteorological influences, effects of clearing and other
improvements always going on in new countries--are all extremely
difficult, and some of them impossible, to be known and measured. In the
American States, very numerous watermills have been erected within a few
years, and there is scarcely a stream in the settled portion of the
country which has not several milldams upon it. When a dam is raised--a
process which the gradual diminution of the summer currents renders
frequently necessary--or when a new dam is built, it often happens that
the meadows above are flowed, or that the retardation of the stream
extends back to the dam next above. This leads to frequent lawsuits.
From the great uncertainty of the facts, the testimony is more
conflicting in these than in any other class of cases, and the obstinacy
with which "water causes" are disputed has become proverbial.
The subterranean courses of the waters form a subject very difficult of
investigation, and it is only recently that its vast importance has been
recognized. The interesting observations of Schmidt on the caves of the
Karst and their rivers throw much light on the underground hydrography
of limestone districts, and serve to explain how, in the low peninsula
of Florida, rivers, which must have their sources in mountains a hundred
or more miles distant, can pour out of the earth in currents large
enough to admit of steamboat navigation to their very basins of
eruption. Artesian wells are revealing to us the existence of
subterranean lakes and rivers sometimes superposed one above another in
successive sheets; but the still more important subject of the
absorption of water by earth and its transmission by infiltration is yet
wrapped in great obscurity.
[369] The sediment of the Po has filled up some lagoons and swamps in
its delta, and converted them into comparatively dry land; but, on the
other hand, the retardation of the current from the lengthening of its
course, and the diminution of its velocity by the deposits at its mouth,
have forced its waters at some higher points to spread in spite of
embankments, and thus fertile fields have been turned into unhealthy and
unproductive marshes.--See BOTTER, _Sulla condizione dei Terreni
Maremmani nel Ferrarese. Annali di Agricoltura, etc._, Fasc. v, 1863.
[370] Deep borings have not detected any essential difference in the
quantity or quality of the deposits of the Nile for forty or fifty, or,
as some compute, for a hundred centuries. From what vast store of rich
earth does this river derive the three or four inches of fertilizing
material which it spreads over the soil of Egypt every hundred years?
Not from the White Nile, for that river drops nearly all its suspended
matter in the broad expansions and slow current of its channel south of
the tenth degree of north latitude. Nor does it appear that much
sediment is contributed by the Bahr-el-Azrek, which flows through
forests for a great part of its course. I have been informed by an old
European resident of Egypt who is very familiar with the Upper Nile,
that almost the whole of the earth with which its waters are charged is
brought down by the Takazze.
[371] It is very probably true that, as Lombardini supposes, the plain
of Lombardy was anciently covered with forests and morasses (Baumgarten,
l. c. p. 156); but, had the Po remained unconfined, its deposits would
have raised its banks as fast as its bed, and there is no obvious reason
why this plain should be more marshy than other alluvial flats traversed
by great rivers. Its lower course would possibly have become more marshy
than at present, but the banks of its middle and upper course would have
been in a better condition for agricultural use than they now are.
[372] From daily measurements during a period of fourteen years--1827 to
1840--the mean delivery of the Po at Ponte Lagoscuro, below the entrance
of its last tributary, is found to be 1,720 cubic metres, or 60,745
cubic feet, per second. Its smallest delivery is 186 cubic metres, or
6,569 cubic feet, its greatest 5,156 cubic metres, or 182,094 cubic
feet.--BAUMGARTEN, following LOMBARDINI, volume before cited, p. 159.
The average delivery of the Nile being 101,000 cubic feet per second, it
follows that the Po contributes to the Adriatic six tenths as much water
as the Nile to the Mediterranean--a result which will surprise most
readers.
[373] We are quite safe in supposing that the valley of the Nile has
been occupied by man at least 5,000 years. The dates of Egyptian
chronology are uncertain, but I believe no inquirer estimates the age of
the great pyramids at less than forty centuries, and the construction of
such works implies an already ancient civilization.
[374] There are many dikes in Egypt, but they are employed in but a very
few cases to exclude the waters of the inundation. Their office is to
retain the water received at high Nile into the inclosures formed by
them until it shall have deposited its sediment or been drawn out for
irrigation; and they serve also as causeways for interior communication
during the floods. The Egyptian dikes, therefore, instead of forcing the
river, like those of the Po, to transport its sediment to the sea, help
to retain the slime, which, if the flow of the current over the land
were not obstructed, might be carried back into the channel, and at last
to the Mediterranean.
[375] The Mediterranean front of the Delta may be estimated at one
hundred and fifty miles in length. Two cubic miles of earth would more
than fill up the lagoons on the coast, and the remaining ten, even
allowing the mean depth of the water to be twenty fathoms, which is
beyond the truth, would have been sufficient to extend the coast line
about three miles farther seaward, and thus, including the land gained
by the filling up of the lagoons, to add more than five hundred square
miles to the area of Egypt. Nor is this all; for the retardation of the
current, by lengthening the course and consequently diminishing the
inclination of the channel, would have increased the deposit of
suspended matter, and proportionally augmented the total effect of the
embankment.
[376] For the convenience of navigation, and to lessen the danger of
inundation by giving greater directness, and, of course, rapidity to the
current, bends in rivers are sometimes cut off and winding channels made
straight. This process has the same general effects as diking, and
therefore cannot be employed without many of the same results.
This practice has often been resorted to on the Mississippi with
advantage to navigation, but it is quite another question whether that
advantage has not been too dearly purchased by the injury to the banks
at lower points. If we suppose a river to have a navigable course of
1,600 miles as measured by its natural channel, with a descent of 800
feet, we shall have a fall of six inches to the mile. If the length of
channel be reduced to 1,200 miles by cutting off bends, the fall is
increased to eight inches per mile. The augmentation of velocity
consequent upon this increase of inclination is not computable without
taking into account other elements, such as depth and volume of water,
diminution of direct resistance, and the like, but in almost any
supposable case, it would be sufficient to produce great effects on the
height of floods, the deposit of sediment in the channel, on the shores,
and at the outlet, the erosion of banks and other points of much
geographical importance.
The Po, in those parts of its course where the embankments leave a wide
space between, often cuts off bends in its channel and straightens its
course. These short cuts are called _salti_, or leaps, and sometimes
reduce the distance between their termini by several miles. In 1777, the
salto of Cottaro shortened a distance of 7,000 metres by 5,000, or, in
other words, reduced the length of the channel more than three miles;
and in 1807 and 1810 the two salti of Mezzanone effected a reduction of
distance to the amount of between seven and eight miles.--BAUMGARTEN, l.
c. p. 38.
[377] The fact, that the mixing of salt and fresh water in coast marshes
and lagoons is deleterious to the sanitary condition of the vicinity,
seems almost universally admitted, though the precise reason why a
mixture of both should be more injurious than either alone, is not
altogether clear. It has been suggested that the admission of salt water
to the lagoons and rivers kills many fresh water plants and animals,
while the fresh water is equally fatal to many marine organisms, and
that the decomposition of the remains originates poisonous miasmata.
Other theories however have been proposed. The whole subject is fully
and ably discussed by Dr. Salvagnoli Marchetti in the appendix to his
valuable _Rapporto sul Bonificamento delle Maremme Toscane_. See also
the _Memorie Economico-Statistiche sulle Maremme Toscane_, of the same
author.
[378] This curious fact is thus stated in the preface to Fossombroni
(_Memorie sopra la Val di Chiana_, edition of 1835, p. xiii), from which
also I borrow most of the data hereafter given with respect to that
valley: "It is perhaps not universally known, that the swallows, which
come from the north [south] to spend the summer in our climate, do not
frequent marshy districts with a malarious atmosphere. A proof of the
restoration of salubrity in the Val di Chiana is furnished by these
aerial visitors, which had never before been seen in those low grounds,
but which have appeared within a few years at Forano and other points
similarly situated."
Is the air of swamps destructive to the swallows, or is their absence in
such localities merely due to the want of human habitations, near which
this half-domestic bird loves to breed, perhaps because the house fly
and other insects which follow man are found only in the vicinity of his
dwellings?
In almost all European countries, the swallow is protected, by popular
opinion or superstition, from the persecution to which almost all other
birds are subject. It is possible that this respect for the swallow is
founded upon ancient observation of the fact just stated on the
authority of Fossombroni. Ignorance mistakes the effect for the cause,
and the absence of this bird may have been supposed to be the occasion,
not the consequence, of the unhealthiness of particular localities. This
opinion once adopted, the swallow would become a sacred bird, and in
process of time fables and legends would be invented to give additional
sanction to the prejudices which protected it. The Romans considered the
swallow as consecrated to the Penates, or household gods, and according
to Peretti (_Le Serate del Villaggio_, p. 168) the Lombard peasantry
think it a sin to kill them, because they are _le gallinelle del
Signore_, the chickens of the Lord.
The following little Tuscan _rispetto_ from Gradi (_Racconti Popolari_,
p. 33) well expresses the feeling of the peasantry toward this bird:
O rondinella che passi lo mare
Torna 'ndietro, vo' dirti du' parole;
Dammi 'na penna delle tue bell' ale,
Vo' scrivere 'na lettera al mi' amore;
E quando l' avro scritta 'n carta bella,
Ti rendero la penna, o rondinella;
E quando l' avro scritta 'n carta bianca,
Ti rendero la penna che ti manca;
E quando l' avro scritta in carta d' oro,
Ti rendero la penna al tuo bel volo.
O swallow, that fliest beyond the sea,
Turn back! I would fain have a word with thee.
A feather oh grant, from thy wing so bright!
For I to my sweetheart a letter would write;
And when it is written on paper fine
I'll give thee, O swallow, that feather of thine;
--On paper so white, and I'll give thee back,
O pretty swallow, the pen thou dost lack;
--On paper of gold, and then I'll restore
To thy beautiful pinion the feather once more.
Popular traditions and superstitions are so closely connected with
localities, that, though an emigrant people may carry them to a foreign
land, they seldom survive a second generation. The swallow, however, is
still protected in New England by prejudices of transatlantic origin;
and I remember hearing, in my childhood, that if the swallows were
killed, the cows would give bloody milk.
[379] MOROZZI, _Dello stato antico e moderno del fiume Arno_, ii, p. 42.
[380] MOROZZI, _Dello stato, etc., dell' Arno_, ii, pp. 39, 40.
[381] Torricelli thus expressed himself on this point: "If we content
ourselves with what nature has made practicable to human industry, we
shall endeavor to control, as far as possible, the outlets of these
streams, which, by raising the bed of the valley with their deposits,
will realize the fable of the Tagus and the Pactolus, and truly roll
golden sands for him that is wise enough to avail himself of
them."--FOSSOMBRONI, _Memorie sopra la Val di Chiana_, p. 219.
[382] Arrian observes that at the junction of the Hydaspes and the
Acesines, both of which are described as wide streams, "one very narrow
river is formed of two confluents, and its current is very
swift."--ARRIAN, _Alex. Anab._, vi, 4.
[383] This difficulty has been remedied as to one important river of the
Maremma, the Pecora, by clearings recently executed along its upper
course. "The condition of this marsh and of its affluents are now,
November, 1859, much changed, and it is advisable to prosecute its
improvement by deposits. In consequence of the extensive felling of the
woods upon the plains, hills, and mountains of the territory of Massa
and Scarlino, within the last ten years, the Pecora and other affluents
of the marsh receive, during the rains, water abundantly charged with
slime, so that the deposits within the first division of the marsh are
already considerable, and we may now hope to see the whole marsh and
pond filled up in a much shorter time than we had a right to expect
before 1850. This circumstance totally changes the terms of the
question, because the filling of the marsh and pond, which then seemed
almost impossible on account of the small amount of sediment deposited
by the Pecora, has now become practicable."--SALVAGNOLI, _Rapporto sul
Bonificamento delle Maremme Toscane_, pp. li, lii.
The annual amount of sediment brought down by the rivers of the Maremma
is computed at more than 12,000,000 cubic yards, or enough to raise an
area of four square miles one yard. Between 1830 and 1859 more than
three times that quantity was deposited in the marsh and shoal water
lake of Castiglione alone.--SALVAGNOLI, _Raccolta di Documenti_, pp. 74,
75.
[384] The tide rises ten inches on the coast of Tuscany. See Memoir by
FANTONI, in the appendix to SALVAGNOLI, _Rapporto_, p. 189.
On the tides of the Mediterranean, see BOeTTGER, _Das Mittelmeer_, p.
190. Not having Admiral Smyth's Mediterranean--on which Boettger's work
is founded--at hand, I do not know how far credit is due to the former
author for the matter contained in the chapter referred to.
[385] In Catholic countries, the discipline of the church requires a
_meagre_ diet at certain seasons, and as fish is not flesh, there is a
great demand for that article of food at those periods. For the
convenience of monasteries and their patrons, and as a source of
pecuniary emolument to ecclesiastical establishments and sometimes to
lay proprietors, great numbers of artificial fish ponds were created
during the Middle Ages. They were generally shallow pools formed by
damming up the outlet of marshes, and they were among the most fruitful
sources of endemic disease, and of the peculiar malignity of the
epidemics which so often ravaged Europe in those centuries. These ponds,
in religious hands, were too sacred to be infringed upon for sanitary
purposes, and when belonging to powerful lay lords they were almost as
inviolable. The rights of fishery were a standing obstacle to every
proposal of hydraulic improvement, and to this day large and fertile
districts in Southern Europe remain sickly and almost unimproved and
uninhabited, because the draining of the ponds upon them would reduce
the income of proprietors who derive large profits by supplying the
faithful, in Lent, with fish, and with various species of waterfowl
which, though very fat, are, ecclesiastically speaking, meagre.
[386] Macchiavelli advised the Government of Tuscany "to provide that
men should restore the wholesomeness of the soil by cultivation, and
purify the air by fires."--SALVAGNOLI, _Memorie_, p. 111.
[387] GIORGINI, _Sur les causes de l'Insalubrite de l'air dans le
voisinage des marais, etc., lue a l'Academie des Sciences a Paris_, le
12 Juillet, 1825. Reprinted in SALVAGNOLI, _Rapporto, etc._, appendice,
p. 5, _et seqq._
[388] See the careful estimates of ROSET, _Moyens de forcer les
Torrents, etc._, pp. 42, 44.
[389] Rivers which transport sand, gravel, pebbles, heavy mineral matter
in short, tend to raise their own beds; those charged only with fine,
light earth, to cut them deeper. The prairie rivers of the West have
deep channels, because the mineral matter they carry down is not heavy
enough to resist the impulse of even a moderate current, and those
tributaries of the Po which deposit their sediment in the lakes--the
Ticino, the Adda, the Oglio, and the Mincio--flow, in deep cuts, for the
same reason.--BAUMGARTEN, l. c., p. 132.
[390] "The stream carries this mud, &c., at first farther to the east,
and only lets it fall where the force of the current becomes weakened.
This explains the continual advance of the land seaward along the Syrian
coast, in consequence of which Tyre and Sidon no longer lie on the
shore, but some distance inland. That the Nile contributes to this
deposit may easily be seen, even by the unscientific observer, from the
stained and turbid character of the water for many miles from its
mouths. A somewhat alarming phenomenon was observed in this neighborhood
in 1801, on board the English frigate Romulus, Captain Culverhouse, on a
voyage from Acre to Abukir. Dr. E. D. Clarke, who was a passenger on
board this ship, thus describes it:
"'26th July.--To-day, Sunday, we accompanied the captain to the wardroom
to dine, as usual, with his officers. While we were at table, we heard
the sailors who were throwing the lead suddenly cry out: "Three and a
half!" The captain sprang up, was on deck in an instant, and, almost at
the same moment, the ship slackened her way, and veered about. Every
sailor on board supposed she would ground at once. Meanwhile, however,
as the ship came round, the whole surface of the water was seen to be
covered with thick, black mud, which extended so far that it appeared
like an island. At the same time, actual land was nowhere to be
seen--not even from the masthead--nor was any notice of such a shoal to
be found on any chart on board. The fact is, as we learned afterward,
that a stratum of mud, stretching from the mouths of the Nile for many
miles out into the open sea, forms a movable deposit along the Egyptian
coast. If this deposit is driven forward by powerful currents, it
sometimes rises to the surface, and disturbs the mariner by the sudden
appearance of shoals where the charts lead him to expect a considerable
depth of water. But these strata of mud are, in reality, not in the
least dangerous. As soon as a ship strikes them they break up at once,
and a frigate may hold her course in perfect safety where an
inexperienced pilot, misled by his soundings, would every moment expect
to be stranded.'"--BOeTTGER, _Das Mittelmeer_, pp. 188, 189.
[391] The caves of Carniola receive considerable rivers from the surface
of the earth, which cannot, in all cases, be identified with streams
flowing out of them at other points, and like phenomena are not uncommon
in other limestone countries.
The cases are certainly not numerous where marine currents are known to
pour continuously into cavities beneath the surface of the earth, but
there is at least one well-authenticated instance of this sort--that of
the mill streams at Argostoli in the island of Cephalonia. It had been
long observed that the sea water flowed into several rifts and cavities
in the limestone rocks of the coast, but the phenomenon has excited
little attention until very recently. In 1833, three of the entrances
were closed, and a regular channel, sixteen feet long and three feet
wide, with a fall of three feet, was cut into the mouth of a larger
cavity. The sea water flowed into this canal, and could be followed
eighteen or twenty feet beyond its inner terminus, when it disappeared
in holes and clefts in the rock.
In 1858, the canal had been enlarged to the width of five feet and a
half, and a depth of a foot. The water pours rapidly through the canal
into an irregular depression and forms a pool, the surface of which is
three or four feet below the adjacent soil, and about two and a half or
three feet below the level of the sea. From this pool it escapes through
several holes and clefts in the rock, and has not yet been found to
emerge elsewhere.
There is a tide at Argostoli of about six inches in still weather, but
it is considerably higher with a south wind. I do not find it stated
whether water flows through the canal into the cavity at low tide, but
it distinctly appears that there is no refluent current, as of course
there could not be from a basin so much below the sea. Mousson found the
delivery through the canal to be at the rate of 24.88 cubic feet to the
second; at what stage of the tide does not appear. Other mills of the
same sort have been erected, and there appear to be several points on
the coast where the sea flows into the land.
Various hypotheses have been suggested to explain this phenomenon, some
of which assume that the water descends to a great depth beneath the
crust of the earth, but the supposition of a difference of level in the
surface of the sea on the opposite sides of the island, which seems
confirmed by other circumstances, is the most obvious method of
explaining these singular facts. If we suppose the level of the water on
one side of the island to be raised by the action of currents three or
four feet higher than on the other, the existence of cavities and
channels in the rock would easily account for a subterranean current
beneath the island, and the apertures of escape might be so deep or so
small as to elude observation. See _Aus der Natur_, vol. 19, pp. 129,
_et seqq._ See _Appendix_, No. 53.
[392] "The affluents received by the Seine below Rouen are so
inconsiderable, that the augmentation of the volume of that river must
be ascribed principally to springs rising in its bed. This is a point of
which engineers now take notice, and M. Belgrand, the able officer
charged with the improvement of the navigation of the Seine between
Paris and Rouen, has devoted much attention to it."--BABINET, _Etudes et
Lectures_, iii, p. 185.
On page 232 of the volume just quoted, the same author observes: "In the
lower part of its course, from the falls of the Oise, the Seine receives
so few important affluents, that evaporation alone would suffice to
exhaust all the water which passes under the bridges of Paris."
This supposes a much greater amount of evaporation than has been usually
computed, but I believe it is well settled that the Seine conveys to the
sea much more water than is discharged into it by all its superficial
branches.
[393] Girard and Duchatelet maintain that the subterranean waters of
Paris are absolutely stagnant. See their report on drainage by artesian
wells, _Annales des Ponts et Chaussees_, 1833, 2me semestre, pp. 313,
_et seqq._
This opinion, if locally true, cannot be generally so, for it is
inconsistent with the well-known fact that the very first eruption of
water from a boring often brings up leaves and other objects which must
have been carried into the underground reservoirs by currents.
[394] _Physikalische Geographie_, p. 286. It does not appear whether
this inference is Mariotte's or Wittwer's. I suppose it is a conclusion
of the latter.
[395] _Physical Geography of the Sea._ Tenth edition. London, 1861, Sec.
274.
[396] PARAMELLE, _Quellenkunde, mit einem Vorwort von_ B. COTTA, 1856.
[397] _Etudes et Lectures_, vi, p. 118.
[398] "The area of soil dried by draining is constantly increasing, and
the water received by the surface from atmospheric precipitation is
thereby partly conducted into new channels, and, in general, carried off
more rapidly than before. Will not this fact exert an influence on the
condition of many springs, whose basin of supply thus undergoes a
partial or complete transformation? I am convinced that it will, and it
is important to collect data for solving the question." BERNHARD COTTA,
Preface to PARAMELLE, _Quellenkunde_ (German translation), pp. vii,
viii. See _Appendix_, No. 54.
[399] See the interesting observations of KRIEGK on this subject,
_Schriften zur allgemeinen Erdkunde_, cap. iii, Sec. 6, and especially the
passages in RITTER'S _Erdkunde_, vol. i, there referred to.
Laurent, (_Memoires sur le Sahara Oriental_, pp. 8, 9), in speaking of a
river at El-Faid, "which, like all those of the desert, is, most of the
time, without water," observes, that many wells are dug in the bed of
the river in the dry season, and that the subterranean current thus
reached appears to extend itself laterally, at about the same level, at
least a kilometre from the river, as water is found by digging to the
depth of twelve or fifteen metres at a village situated at that distance
from the bank.
The most remarkable case of infiltration known to me by personal
observation is the occurrence of fresh water in the beach sand on the
eastern side of the Gulf of Akaba, the eastern arm of the Red Sea. If
you dig a cavity in the beach near the sea level, it soon fills with
water so fresh as not to be undrinkable, though the sea water two or
three yards from it contains even more than the average quantity of
salt. It cannot be maintained that this is sea water freshened by
filtration through a few feet or inches of sand, for salt water cannot
be deprived of its salt by that process. It can only come from the
highlands of Arabia, and it would seem that there must exist some large
reservoir in the interior to furnish a supply which, in spite of
evaporation, holds out for months after the last rains of winter, and
perhaps even through the year. I observed the fact in the month of June.
The precipitation in the mountains that border the Red Sea is not known
by pluviometric measurement, but the mass of debris brought down the
ravines by the torrents proves that their volume must be large. The
proportion of surface covered by sand and absorbent earth, in Arabia
Petraea and the neighboring countries, is small, and the mountains drain
themselves rapidly into the wadies or ravines where the torrents are
formed; but the beds of earth and disintegrated rock at the bottom of
the valleys are of so loose and porous texture, that a great quantity of
water is absorbed in saturating them before a visible current is formed
on their surface. In a heavy thunder storm, accompanied by a deluging
rain, which I witnessed at Mount Sinai in the month of May, a large
stream of water poured, in an almost continuous cascade, down the steep
ravine north of the convent, by which travellers sometimes descend from
the plateau between the two peaks, but after reaching the foot of the
mountain, it flowed but a few yards before it was swallowed up in the
sands.
[400] It is conceivable that in large and shallow subterranean basins
the superincumbent earth may rest upon the water and be partly supported
by it. In such case the weight of the earth would be an additional, if
not the sole, cause of the ascent of the water through the tubes of
artesian wells. The elasticity of gases in the cavities may also aid in
forcing up water.
A French engineer, M. Mullot, invented a simple method of bringing to
the surface water from any one of several successive accumulations at
different depths, or of raising it, unmixed, from two or more of them at
once. It consists in employing concentric tubes, one within the other,
leaving a space for the rise of water between them, and reaching each to
the sheet from which it is intended to draw.
[401] Many more or less probable conjectures have been made on this
subject, but thus far I am not aware that any of the apprehended results
have been actually shown to have happened. In an article in the _Annales
des Ponts et Chaussees_ for July and August, 1839, p. 131, it was
suggested that the sinking of the piers of a bridge at Tours in France
was occasioned by the abstraction of water from the earth by artesian
wells, and the consequent withdrawal of the mechanical support it had
previously given to the strata containing it. A reply to this article
will be found in VIOLETT, _Theorie des Puits Artesiens_, p. 217.
In some instances the water has rushed up with a force which seemed to
threaten the inundation of the neighborhood, and even the washing away
of much soil; but in those cases the partial exhaustion of the supply,
or the relief of hydrostatic or elastic pressure, has generally produced
a diminution of the flow in a short time, and I do not know that any
serious evil has ever been occasioned in this way.
[402] See a very interesting account of these wells, and of the workmen
who clean them out when obstructed by sand brought up with the water, in
Laurent's memoir on the artesian wells recently bored by the French
Government in the Algerian desert, _Memoire sur le Sahara Oriental,
etc._, pp. 19, _et seqq._ Some of the men remained under water from two
minutes to two minutes and forty seconds. Several officers are quoted as
having observed immersions of three minutes' duration, and M. Berbrugger
alleges that he witnessed one of five minutes and fifty-five seconds.
The shortest of these periods is longer than the best pearl diver can
remain below the surface of salt water. The wells of the Sahara are from
twenty to eighty metres deep.
It has often been asserted that the ancient Egyptians were acquainted
with the art of boring artesian wells. Parthey, describing the Little
Oasis, mentions ruins of a Roman aqueduct, and observes: "It appears
from the recent researches of Aim, a French engineer, that these
aqueducts are connected with old artesian wells, the restoration of
which would render it practicable to extend cultivation much beyond its
present limits. This agrees with ancient testimony. It is asserted that
the inhabitants of the oases sunk wells to the depth of 200, 300, and
even 500 ells, from which affluent streams of water poured out. See
OLYMPIODORUS in _Photii Bibl._, cod. 80, p. 61, l. 17, ed.
Bekk."--PARTHEY, _Wanderungen_, ii, p. 528.
In a paper entitled, _Note relative a l'execution d'un Puits Artesien en
Egypte sous la XVIII dynastie_, presented to the Academie des
Inscriptions et Belles Lettres, on the 12th of November, 1852, M.
Lenormant endeavors to show that a hieroglyphic inscription found at
Contrapscelcis proves the execution of a work of this sort in the Nubian
desert, at the period indicated in the title to his paper. The
interpretation of the inscription is a question for Egyptologists; but
if wells were actually bored through the rock by the Egyptians after the
Chinese or the European fashion, it is singular that among the numerous
and minute representations of their industrial operations, painted or
carved on the walls of their tombs, no trace of the processes employed
for so remarkable and important a purpose should have been discovered.
See _Appendix_, No. 56.
It is certain that artesian wells have been common in China from a very
remote antiquity, and the simple method used by the Chinese--where the
borer is raised and let fall by a rope, instead of a rigid rod--has been
lately been employed in Europe with advantage. Some of the Chinese wells
are said to be 3,000 feet deep; that of Neusalzwerk in Silesia--the
deepest in Europe--is 2,300. A well was bored at St. Louis, in Missouri,
a few years ago, to supply a sugar refinery, to the depth of 2,199 feet.
This was executed by a private firm in three years, at the expense of
only $10,000. Another has since been bored at the State capitol at
Columbus, Ohio, 2,500 feet deep, but without obtaining the desired
supply of water.
[403] "In the anticipation of our success at Oum-Thiour, every thing had
been prepared to take advantage of this new source of wealth without a
moment's delay. A division of the tribe of the Selmia, and their sheikh,
Aissa ben Sha, laid the foundation of a village as soon as the water
flowed, and planted twelve hundred date palms, renouncing their
wandering life to attach themselves to the soil. In this arid spot, life
had taken the place of solitude, and presented itself, with its smiling
images, to the astonished traveller. Young girls were drawing water at
the fountain; the flocks, the great dromedaries with their slow pace,
the horses led by the halter, were moving to the watering trough; the
hounds and the falcons enlivened the group of party-colored tents, and
living voices and animated movement had succeeded to silence and
desolation."--LAURENT, _Memoires sur le Sahara_, p. 85.
[404] The variety of hues and tones in the local color of the desert is,
I think, one of the phenomena which most surprise and interest a
stranger to those regions. In England and the United States, rock is so
generally covered with moss or earth, and earth with vegetation, that
untravelled Englishmen and Americans are not very familiar with naked
rock as a conspicuous element of landscape. Hence, in their conception
of a bare cliff or precipice, they hardly ascribe definite color to it,
but depict it to their imagination as wearing a neutral tint not
assimilable to any of the hues with which nature tinges her atmospheric
or paints her organic creations. There are certainly extensive desert
ranges, chiefly limestone formations, where the surface is either white,
or has weathered down to a dull uniformity of tone which can hardly be
called color at all; and there are sand plains and drifting hills of
wearisome monotony of tint. But the chemistry of the air, though it may
tame the glitter of the limestone to a dusky gray, brings out the green
and brown and purple of the igneous rocks, and the white and red and
blue and violet and yellow of the sandstone. Many a cliff in Arabia
Petraea is as manifold in color as the rainbow, and the veins are so
variable in thickness and inclination, so contorted and involved in
arrangement, as to bewilder the eye of the spectator like a disk of
party-colored glass in rapid revolution.
In the narrower wadies, the mirage is not common; but on broad expanses,
as at many points between Cairo and Suez, and in Wadi el Araba, it mocks
you with lakes and land-locked bays, studded with islands and fringed
with trees, all painted with an illusory truth of representation
absolutely indistinguishable from the reality. The checkered earth, too,
is canopied with a heaven as variegated as itself. You see, high up in
the sky, rosy clouds at noonday, colored probably by reflection from the
ruddy mountains, while near the horizon float cumuli of a transparent
ethereal blue, seemingly balled up out of the clear cerulean substance
of the firmament, and detached from the heavenly vault, not by color or
consistence, but solely by the light and shade of their prominences.
[405] _[OE]uvres de Palissy, Des Eaux et Fontaines_, p. 157.
[406] Id., p. 166. See _Appendix_, No. 57.
[407] BABINET, _Etudes et Lectures sur les Sciences d'Observation_, ii,
p. 225. Our author precedes his account of his method with a complaint
which most men who indulge in thinking have occasion to repeat many
times in the course of their lives. "I will explain to my readers the
construction of artificial fountains according to the plan of the famous
Bernard de Palissy, who, a hundred and fifty [three hundred] years ago,
came and took away from me, a humble academician of the nineteenth
century, this discovery which I had taken a great deal of pains to make.
It is enough to discourage all invention when one finds plagiarists in
the past as well as in the future!" (P. 224.)
[408] M. G. DUMAS, _La Science des Fontaines_, 1857.
[409] In the curiously variegated sandstone of Arabia Petraea--which is
certainly a reaggregation of loose sand derived from particles of older
rocks--the contiguous veins frequently differ very widely in color, but
not sensibly in specific gravity or in texture; and the singular way in
which they are now alternated, now confusedly intermixed, must be
explained otherwise than by the weight of the respective grains which
compose them. They seem, in fact, to have been let fall by water in
violent ebullition or tumultuous mechanical agitation, or by a
succession of sudden aquatic or aerial currents flowing in different
directions and charged with differently colored matter.
[410] _De Bodem van Nederland_, i, pp. 243, 246-377, _et seqq._ See also
the arguments of Bremontier as to the origin of the dune sands of
Gascony, _Annales des Ponts et Chaussees_, 1833, 1er semestre, pp. 158,
161. Bremontier estimates the sand annually thrown up on that coast at
five cubic toises and two feet to the running toise (ubi supra, p. 162),
or rather more than two hundred and twenty cubic feet to the running
foot. Laval, upon observations continued through seven years, found the
quantity to be twenty-five metres per running metre, which is equal to
two hundred and sixty-eight cubic feet to the running foot.--_Annales
des Ponts et Chaussees_, 1842, 2me semestre, p. 229. These computations
make the proportion of sand deposited on the coast of Gascony three or
four times as great as that observed by Andresen on the shores of
Jutland. Laval estimates the total quantity of sand annually thrown up
on the coast of Gascony at 6,000,000 cubic metres, or more than
7,800,000 cubic yards.
[411] _De Bodem van Nederland_, i, p. 339.
[412] The conditions favorable to the production of sand from
disintegrated rock, by causes now in action, are perhaps nowhere more
perfectly realized than in the Sinaitic Peninsula. The mountains are
steep and lofty, unprotected by vegetation or even by a coating of
earth, and the rocks which compose them are in a shattered and
fragmentary condition. They are furrowed by deep and precipitous
ravines, with beds sufficiently inclined for the rapid flow of water,
and generally without basins in which the larger blocks of stone rolled
by the torrents can be dropped and left in repose; there are severe
frosts and much snow on the higher summits and ridges, and the winter
rains are abundant and heavy. The mountains are principally of igneous
formation, but many of the less elevated peaks are capped with
sandstone, and on the eastern slope of the peninsula you may sometimes
see, at a single glance, several lofty pyramids of granite, separated by
considerable intervals, and all surmounted by horizontally stratified
deposits of sandstone often only a few yards square, which correspond to
each other in height, are evidently contemporaneous in origin, and were
once connected in continuous beds. The degradation of the rock on which
this formation rests is constantly bringing down masses of it, and
mingling them with the basaltic, porphyritic, granitic, and calcareous
fragments which the torrents carry down to the valleys, and, through
them, in a state of greater or less disintegration, to the sea. The
quantity of sand annually washed into the Red Sea by the larger torrents
of the Lesser Peninsula, is probably at least equal to that contributed
to the ocean by any streams draining basins of no greater extent.
Absolutely considered, then, the mass may be said to be large, but it is
apparently very small as compared with the sand thrown up by the German
Ocean and the Atlantic on the coasts of Denmark and of France. There
are, indeed, in Arabia Petraea, many torrents with very short courses,
for the sea waves in many parts of the peninsular coast wash the base of
the mountains. In these cases, the debris of the rocks do not reach the
sea in a sufficiently comminuted condition to be entitled to the
appellation of sand, or even in the form of well-rounded pebbles. The
fragments retain their angular shape, and, at some points on the coast,
they become cemented together by lime or other binding substances held
in solution or mechanical suspension in the sea water, and are so
rapidly converted into a singularly heterogeneous conglomerate, that one
deposit seems to be consolidated into a breccia before the next winter's
torrents cover it with another.
In the northern part of the peninsula there are extensive deposits of
sand intermingled with agate pebbles and petrified wood, but these are
evidently neither derived from the Sinaitic group, nor products of local
causes known to be now in action.
I may here notice the often repeated but mistaken assertion, that the
petrified wood of the Western Arabian desert consists wholly of the
stems of palms, or at least of endogenous vegetables. This is an error.
I have myself picked up in that desert, within the space of a very few
square yards, fragments both of fossil palms, and of at least two
petrified trees distinctly marked as of exogenous growth both by annular
structure and by knots. In ligneous character, one of these almost
precisely resembles the grain of the extant beech, and this specimen was
wormeaten before it was converted into silex.
[413] BOeTTGER, _Das Mittelmeer_, p. 128.
[414] The testimony of divers and of other observers on this point is
conflicting, as might be expected from the infinite variety of
conditions by which the movement of water is affected. It is generally
believed that the action of the wind upon the water is not perceptible
at greater depths than from fifteen feet in ordinary, to eighty or
ninety in extreme cases; but these estimates are probably very
considerably below the truth. Andresen quotes Bremontier as stating that
the movement of the waves sometimes extends to the depth of five hundred
feet, and he adds that others think it may reach to six or even seven
hundred feet below the surface.--ANDRESEN, _Om Klitformationen_, p. 20.
Many physicists now suppose that the undulations of great bodies of
water reach even deeper. But a movement of undulation is not necessarily
a movement of translation, and besides, there is very frequently an
undertow, which tends to carry suspended bodies out to sea as powerfully
as the superficial waves to throw them on shore. Sandbanks sometimes
recede from the coast, instead of rolling toward it. Reclus informs us
that the Mauvaise, a sandbank near the Point de Grave, on the Atlantic
coast of France, has moved five miles to the west in less than a
century.--_Revue des Deux Mondes_, for December, 1862, p. 905.
The action of currents may, in some cases, have been confounded with
that of the waves. Sea currents, strong enough, possibly, to transport
sand for some distance, flow far below the surface in parts of the open
ocean, and in narrow straits they have great force and velocity. The
divers employed at Constantinople in 1853 found in the Bosphorus, at the
depth of twenty-five fathoms and at a point much exposed to the wash
from Galata and Pera, a number of bronze guns supposed to have belonged
to a ship of war blown up about a hundred and fifty years before. These
guns were not covered by sand or slime, though a crust of earthy matter,
an inch in thickness, adhered to their upper surfaces, and the bottom of
the strait appeared to be wholly free from sediment. The current was so
powerful at this depth that the divers were hardly able to stand, and a
keg of nails, purposely dropped into the water, in order that its
movements might serve as a guide in the search for a bag of coin
accidentally lost overboard from a ship in the harbor, was rolled by the
stream several hundred yards before it stopped.
[415] Few seas have thrown up so much sand as the shallow German Ocean;
but there is some reason to think that the amount of this material now
cast upon its northern shores is less than at some former periods,
though no extensive series of observations on this subject has been
recorded. On the Spit of Agger, at the present outlet of the Liimfjord,
Andresen found the quantity during ten years, on a beach about five
hundred and seventy feet broad, equal to an annual deposit of an inch
and a half over the whole surface.--_Om Klitformationen_, p. 56.
This gives seventy-one and a quarter cubic feet to the running foot--a
quantity certainly much smaller than that cast up by the same sea on the
shores of the Dano-German duchies and of Holland, and, as we have seen,
scarcely one fourth of that deposited by the Atlantic on the coast of
Gascony. See _ante_, p. 453, note.
[416] Sand heaps, three and even six hundred feet high, are indeed
formed by the wind, but this is effected by driving the particles up an
inclined plane, not by lifting them. Bremontier, speaking of the sand
hills on the western coast of France, says: "The particles of sand
composing them are not large enough to resist wind of a certain force,
nor small enough to be taken up by it, like dust; they only roll along
the surface from which they are detached, and, though moving with great
velocity, they rarely rise to a greater height than three or four
inches."--_Memoire sur les Dunes, Annales des Ponts et Chaussees_, 1833,
1er semestre, p. 148.
Andresen says that a wind, having a velocity of forty feet per second,
is strong enough to raise particles of sand as high as the face and eyes
of a man, but that, in general, it rolls along the ground, and is
scarcely ever thrown more than to the height of a couple of yards from
the surface. Even in these cases, it is carried forward by a hopping,
not a continuous, motion; for a very narrow sheet or channel of water
stops the drift entirely, all the sand dropping into it until it is
filled up.
The character of the motion of sand drifts is well illustrated by an
interesting fact not much noticed hitherto by travellers in the East. In
situations where the sand is driven through depressions in rock beds, or
over deposits of silicious pebbles, the surface of the stone is worn and
smoothed much more effectually than it could be by running water, and
you may pick up, in such localities, rounded, irregularly broken
fragments of agate, which have received from the attrition of the sand
as fine a polish as could be given them by the wheel of the lapidary.
Very interesting observations on the polishing of hard stones by
drifting sand will be found in the Geological Report of William P.
Blake: _Pacific Railroad Report_, vol. v, pp. 92, 230, 231. The same
geologist observes, p. 242, that the sand of the Colorado desert does
not rise high in the air, but bounds along on the surface or only a few
inches above it.
[417] Wilkinson says that, in much experience in the most sandy parts of
the Libyan desert, and much inquiry of the best native sources, he never
saw or heard of any instance of danger to man or beast from the mere
accumulation of sand transported by the wind. Chesney's observations in
Arabia, and the testimony of the Bedouins he consulted, are to the same
purpose. The dangers of the simoom are of a different character, though
they are certainly aggravated by the blinding effects of the light
particles of dust and sand borne along by it, and by that of the
inhalation of them upon the respiration.
[418] In the narrow valley of the Nile, bounded as it is, above the
Delta, by high cliffs, all air currents from the northern quarter become
north winds, though, of course varying in partial direction, in
conformity with the sinuosities of the valley. Upon the desert plateau
they incline westward, and have already borne into the valley the sands
of the eastern banks, and driven those of the western quite out of the
Egyptian portion of the Nile basin.
[419] "The North African desert falls into two divisions: the Sahel, or
western, and the Sahar, or eastern. The sands of the Sahar were, at a
remote period, drifted to the west. In the Sahel, the prevailing east
winds drive the sand-ocean with a progressive westward motion. The
eastern half of the desert is swept clean."--NAUMANN, _Geognosie_, ii,
p. 1173.
[420] In parts of the Algerian desert, some efforts are made to retard
the advance of sand dunes which threaten to overwhelm villages. "At
Debila," says Laurent, "the lower parts of the lofty dunes are planted
with palms, * * * but they are constantly menaced with burial by the
sands. The only remedy employed by the natives consists in little dry
walls of crystallized gypsum, built on the crests of the dunes, together
with hedges of dead palm leaves. These defensive measures are aided by
incessant labor; for every day the people take up in baskets the sand
blown over to them the night before and carry it back to the other side
of the dune."--_Memoires sur le Sahara_, p. 14.
[421] Organic constituents, such as comminuted shells, and silicious and
calcareous exuviae of infusorial animals and plants, are sometimes found
mingled in considerable quantities with mineral sands. These are usually
the remains of aquatic vegetables or animals, but not uniformly so, for
the microscopic organisms, whose flinty cases enter so largely into the
sandbeds of the Mark of Brandenburg, are still living and prolific in
the dry earth. See WITTWER, _Physikalische Geographie_, p. 142.
The desert on both sides of the Nile is inhabited by a land snail, and
thousands of its shells are swept along and finally buried in the drifts
by every wind. Every handful of the sand contains fragments of them.
FORCHHAMMER, in LEONHARD Und BRONN's _Jahrbuch_, 1841, p. 8, says of the
sand hills of the Danish coast: "It is not rare to find, high in the
knolls, marine shells, and especially those of the oyster. They are due
to the oyster eater [_Haemalopus ostralegus_], which carries his prey to
the top of the dunes to devour it." See also STARING, _De Bodem van_, N.
I. p. 321.
[422] There are various reasons why the formation of dunes is confined
to low shores, and this law is so universal, that when bluffs are
surmounted by them, there is always cause to suspect upheaval, or the
removal of a sloping beach in front of the bluff, after the dunes were
formed. Bold shores are usually without a sufficient beach for the
accumulation of large deposits; they are commonly washed by a sea too
deep to bring up sand from its bottom; their abrupt elevation, even if
moderate in amount, would still be too great to allow ordinary winds to
lift the sand above them; and their influence in deadening the wind
which blows toward them would even more effectually prevent the raising
of sand from the beach at their foot.
Forchhammer, describing the coast of Jutland, says that, in high winds,
"one can hardly stand upon the dunes, except when they are near the
water line and have been cut down perpendicularly by the waves. Then the
wind is little or not at all felt--a fact of experience very common on
our coasts, observed on all the steep shore bluffs of two hundred feet
in height, and, in the Faroe Islands, on precipices two thousand feet
high. In heavy gales in those islands, the cattle fly to the very edge
of the cliffs for shelter, and frequently fall over. The wind, impinging
against the vertical wall, creates an ascending current which shoots
somewhat past the crest of the rock, and thus the observer or the animal
is protected against the tempest by a barrier of air."--LEONHARD und
BRONN, _Jahrbuch_, 1841, p. 3.
The calming, or rather diversion, of the wind by cliffs extends to a
considerable distance in front of them, and no wind would have
sufficient force to raise the sand vertically, parallel to the face of a
bluff, even to the height of twenty feet.
It is very commonly believed that it is impossible to grow forest trees
on sea-shore bluffs, or points much exposed to strong winds. The
observations just cited tend to show that it would not be difficult to
protect trees from the mechanical effect of the wind, by screens much
lower than the height to which they are expected to grow. Recent
experiments confirm this, and it is found that, though the outer row or
rows may suffer from the wind, every tree shelters a taller one behind
it. Extensive groves have thus been formed in situations where an
isolated tree would not grow at all.
Piper, in his _Trees of America_, p. 19, gives an interesting account of
Mr. Tudor's success in planting trees on the bleak and barren shore of
Nahant. "Mr. Tudor," observes he, "has planted more than ten thousand
trees at Nahant, and, by the results of his experiments, has fully
demonstrated that trees, properly cared for in the beginning, may be
made to grow up to the very bounds of the ocean, exposed to the biting
of the wind and the spray of the sea. The only shelter they require is,
at first, some interruption to break the current of the wind, such as
fences, houses, or other trees."
[423] The careful observations of Colonel J. D. Graham, of the United
States Army, show a tide of about three inches in Lake Michigan. See "A
Lunar Tidal Wave in the North American Lakes," demonstrated by
Lieut.-Colonel J. D. Graham, in the fourteenth volume of the
_Proceedings of the American Association for the Advancement of
Science_.
[424] STARING, _De Bodem van Nederland_, i, p. 327, note.
[425] The principal special works and essays on this subject known to me
are:
BREMONTIER, _Memoire sur les Dunes, etc._, 1790, reprinted in _Annales
des Ponts et Chaussees_, 1833, 1er semestre, pp. 145-186.
_Rapport sur les differents Memoires de M. Bremontier_, par LAUMONT et
autres, 1806, same volume, pp. 192, 224.
LEFORT, _Notice sur les Travaux de Fixation des Dunes, Annales des Ponts
et Chaussees_, 1831, 2me semestre, pp. 320-332.
FORCHHAMMER, _Geognostische Studien am Meeres Ufer_, in LEONHARD und
BRONN, _Jahrbuch, etc._, 1841, pp. 1, 38.
J. G. KOHL, _Die Inseln und Marschen der Herzogthuemer Schleswig und
Holstein_, 1846, vol. ii, pp. 112-162, 193-204.
LAVAL, _Memoire sur les Dunes du Golfe de Gascogne, Annales des Ponts et
Chaussees_, 1847, 2me semestre, pp. 218-268.
G. C. A. KRAUSE, _Der Duenenbau auf den Ostsee-Kuesten West-Preussens_,
1850, 1 vol. 8vo.
W. C. H. STARING, _De Bodem van Nederland_, 1856, vol. i, pp. 310-341,
and 424-431.
Same author, _Voormaals en Thans_, 1858, pages cited.
C. C. ANDRESEN, _Om Klitformationen og Klittens Behandling og
Bestyrelse_, 1861, 1 vol. 8vo, x, 392 pp., much the most complete
treatise on the subject.
ANDRESEN cites, upon the origin of the dunes: HULL, _Over den Oorsprong
en de Geschiedenis der Hollandsche Duinen_, 1838, and GROSS's
_Veiledning ved Behandlingen af Sandflugtstraekningerne_, 1847; and upon
the improvement of sand plains by planting, PANNEWITZ, _Anleitung zum
Anbau der Sandflaechen_, 1832. I am not acquainted with either of the
latter two works but I have consulted with advantage, on this subject,
DELAMARRE, _Historique de la Creation d'une Richesse millionaire par la
culture des Pins_, 1827; BOITEL, _Mise en valeur des terres pauvres par
le Pin maritime_, 1857; and BRINCKEN, _Ansichten ueber die Bewaldung der
Steppen des Europaeischen Russlands_, 1854.
[426] "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 BRONN, for 1841, p. 5,
note.
On the other hand, Andresen, who has very carefully investigated 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 drift sand was not moistened to a greater height than
eight and a half inches, after standing a whole night in water. He
states the 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 thirty-three per cent. by measure, or 21.5 by weight. The annual
precipitation on that coast is twenty-seven 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 evaporation from below.--_Om
Klitformationen_, 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
metre in them.--LAURENT, _Memoire sur le Sahara_, pp. 11, 12, 13.
The same writer observes (p. 14) that the hollows in 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 is thought
to be by some of those disinterested philanthropists of other nations
who are distressed with fears that French capitalists will lose the
money they have 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.
[427] According to the French authorities, the dunes of France are not
always composed of quartzose sand. "The dune sands" of different
characters, says Bremontier, "partake of the nature of the different
materials which compose them. At certain points on the coast of Normandy
they are found to be purely calcareous; they are of mixed composition on
the shores of Brittany and Saintonge, and generally quartzose between
the mouth of the Gironde and that of the Adour."--_Memoire sur les
Dunes, Annales des Ponts et Chaussees_, t. vii, 1833, 1er semestre, p.
146.
In the dunes of Long Island and of Jutland, there are considerable veins
composed almost wholly of garnet. For a very full examination of the
mechanical and chemical composition of the dune sands of Jutland, see
ANDRESEN, _Om Klitformationen_, p. 110.
[428] _De Bodem van Nederland_, i, p. 323.
[429] J. G. KOHL, _Die Inseln und Marschen der Herzogthuemer Schleswig
und Holstein_, ii, p. 200.
[430] STARING, _De Bodem van Nederland_, i, p. 317. See also, BERGSOeE,
_Reventov's Virksomhed_, ii, p. 11.
"In the sand-hill ponds mentioned in the text, there is a vigorous
growth of bog plants accompanied with the formation of peat, which goes
on regularly as long as the dune sand does not drift. But if the surface
of the dunes is broken, the sand blows into the ponds, covers the peat,
and puts an end to its formation. When, in the course of time, marine
currents cut away the coast, the dunes move landward and fill up the
ponds, and thus are formed the remarkable strata of fossile peat called
Martoerv, which appears to be unknown to the geologists of other parts of
Europe."--FORCHHAMMER, in LEONHARD und BRONN, 1841, p. 13.
[431] The lower strata must be older than the superficial layers, and
the particles which compose them may in time become more disintegrated,
and therefore finer than those deposited later and above them.
[432] "On the west coast of Africa the dunes are drifting seawards, and
always receiving new accessions from the Sahara. They are constantly
advancing out into the sea." See _ante_, p. 16, note.--NAUMANN,
_Geognosie_, ii, p. 1172. See _Appendix_, No. 58.
[433] Forchhammer, after pointing out the coincidence between the
inclined stratification of dunes and the structure of ancient tilted
rocks, says: "But I am not able to point out a sandstone formation
corresponding to the dunes. Probably most ancient dunes have been
destroyed by submersion before the loose sand became cemented to solid
stone, but we may suppose that circumstances have existed somewhere
which have preserved the characteristics of this formation."--LEONHARD
und BRONN, 1841, p. 8, 9.
Such formations, however, certainly exist. I find from Laurent (_Memoire
sur le Sahara, etc._, p. 12), that in the Algerian desert there exist
"sandstone formations" not only "corresponding to the dunes," but
actually consolidated within them. "A place called El-Mouia-Tadjer
presents a repetition of what we saw at El-Baya; one of the funnels
formed in the middle of the dunes contains wells from two metres to two
and a half in depth, dug in a sand which pressure, and probably the
presence of certain salts, have cemented so as to form true sandstone,
soft indeed, but which does not yield except to the pickaxe. These
sandstones exhibit an inclination which seems to be the effect of wind;
for they conform to the direction of the sands which roll down a scarp
occasioned by the primitive obstacle." See _Appendix_, No. 59.
The dunes near the mouth of the Nile, the lower sands of which have been
cemented together by the infiltration of Nile water, would probably show
a similar stratification in the sandstone which now forms their base.
[434] Forchhammer ascribes the resemblance between the furrowing of the
dune sands and the beach ripples, not to the similarity of the effect of
wind and water upon sand, but wholly to the action of the former fluid;
in the first instance, directly, in the latter, through the water. "The
wind ripples on the surface of the dunes precisely resemble the water
ripples of sand flats occasionally overflowed by the sea; and with the
closest scrutiny, I have never been able to detect the slightest
difference between them. This is easily explained by the fact, that the
water ripples are produced by the action of light wind on the water
which only transmits the air waves to the sand."--LEONHARD und BRONN,
1841, pp. 7, 8.
[435] American observers do not agree in their descriptions of the form
and character of the sand grains which compose the interior dunes of the
North American desert. C. C. Parry, geologist to the Mexican Boundary
Commission, in describing the dunes near the station at a spring
thirty-two miles west from the Rio Grande at El Paso, says: "The
separate grains of the sand composing the sand hills are seen under a
lens to be angular, and not rounded, as would be the case in regular
beach deposits."--_U. S. Mexican Boundary Survey, Report of_, vol. i,
_Geological Report of C. C. Parry_, p. 10.
In the general description of the country traversed, same volume, p. 47,
Colonel Emory says that on an "examination of the sand with a microscope
of sufficient power," the grains are seen to be angular, not rounded by
rolling in water.
On the other hand, Blake, in _Geological Report, Pacific Railroad Rep._,
vol. v, p. 119, observes that the grains of the dune sand, consisting of
quartz, chalcedony, carnelian, agate, rose quartz, and probably
chrysolite, were much rounded; and on page 241, he says that many of the
sand grains of the Colorado desert are perfect spheres.
On page 20 of a report in vol. ii of the _Pacific Railroad Report_, by
the same observer, it is said that an examination of dune sands brought
from the Llano Estacado by Captain Pope, showed the grains to be "much
rounded by attrition."
The sands described by Mr. Parry and Colonel Emory are not from the same
localities as those examined by Mr. Blake, and the difference in their
character may denote a difference of origin or of age.
[436] LAURENT (_Memoire sur le Sahara_, pp. 11, 12, and elsewhere)
speaks of a funnel-shaped depression at a high point in the dunes, as a
characteristic feature of the sand hills of the Algerian desert. This
seems to be an approximation to the crescent form noticed by Meyen and
Poeppig in the inland dunes of Peru.
[437] _Travels in Peru_, New York, 1848, chap. ix.
[438] Notwithstanding the general tendency of isolated coast dunes and
of the peaks of the sand ridges to assume a conical form, Andresen
states that the hills of the inner or landward rows are sometimes
_bow-shaped_, and sometimes undulating in outline.--_Om
Klitformationen_, p. 84. He says further that: "Before an obstruction,
two or three feet high and considerably longer, lying perpendicularly to
the direction of the wind, the sand is deposited with a windward angle
of from 6 deg. to 12 deg., and the bank presents a concave face to the wind,
while, behind the obstruction, the outline is convex;" and he lays it
down as a general rule, that a slope, _from_ which sand is blown, is
left with a concavity of about one inch of depth to four feet of
distance; a slope, _upon_ which sand is dropped by the wind, is convex.
It appears from Andresen's figures, however, that the concavity and
convexity referred to, apply, not to the _horizontal longitudinal_
section of the sand bank, as his language unexplained by the drawings
might be supposed to mean, but to the _vertical cross-section_, and
hence the dunes he describes, with the exception above noted, do not
correspond to those of the American deserts.--_Om Klitformationen_, p.
86.
The dunes of Gascony, which sometimes exceed three hundred feet in
height, present the same concavity and convexity of _vertical_
cross-section. The slopes of these dunes are much steeper than those of
the Netherlands and the Danish coast; for while all observers agree in
assigning to the seaward and landward faces of those latter,
respectively, angles of from 5 deg. to 12 deg., and 30 deg. with the horizon, the
corresponding faces of the dunes of Gascony present angles of from 10 deg.
to 25 deg., and 50 deg. to 60 deg..--LAVAL, _Memoire sur les Dunes de Gascogne,
Annales des Ponts et Chaussees_, 1847, 2me semestre.
[439] Krause, speaking of the dunes on the coast of Prussia, says:
"Their origin belongs to three different periods, in which important
changes in the relative level of sea and land have unquestionably taken
place. * * * Except in the deep depressions between them, the dunes are
everywhere sprinkled, to a considerable height, with brown oxydulated
iron, which has penetrated into the sand to the depth of from three to
eighteen inches, and colored it red. * * * Above the iron is a stratum
of sand differing in composition from ordinary sea sand, and on this,
growing woods are always found. * * * The gradually accumulated forest
soil occurs in beds of from one to three feet thick, and changes,
proceeding upward, from gray sand to black humus." Even on the third or
seaward range, the sand grasses appear and thrive luxuriantly, at least
on the west coast, though. Krause doubts whether the dunes of the east
coast were ever thus protected.--_Der Duenenbau_, pp. 8, 11.
[440] LAVAL, _Memoire sur les Dunes de Gascogne, Annales des Ponts et
Chaussees_, 1847, 2me semestre, p. 231. The same opinion had been
expressed by BREMONTIER, _Annales des Ponts et Chaussees_, 1833, 1er
semestre, p. 185.
[441] "In the Middle Ages," says Willibald Alexis, as quoted by Mueller,
_Das Buch der Pflanzenwelt_ i, p. 16, "the Nehrung was extending itself
further, and the narrow opening near Lochstadt had filled itself up with
sand. A great pine forest bound with its roots the dune sand and the
heath uninterruptedly from Danzig to Pillau. King Frederick William I
was once in want of money. A certain Herr von Korff promised to procure
it for him, without loan or taxes, if he could be allowed to remove
something quite useless. He thinned out the forests of Prussia, which
then, indeed, possessed little pecuniary value; but he felled the entire
woods of the Frische Nehrung, so far as they lay within the Prussian
territory. The financial operation was a success. The king had money,
but in the elementary operation which resulted from it, the state
received irreparable injury. The sea winds rush over the bared hills;
the Frische Haff is half-choked with sand; the channel between Elbing,
the sea, and Koenigsberg is endangered, and the fisheries in the Haff
injured. The operation of Herr von Korff brought the king 200,000
thalers. The state would now willingly expend millions to restore the
forests again."
[442] STARING, _Voormaals en Thans_, p. 231. Had the dunes of the
Netherlandish and French coasts, at the period of the Roman invasion,
resembled the moving sand hills of the present day, it is inconceivable
that they could have escaped the notice of so acute a physical
geographer as Strabo; and the absolute silence of Caesar, Ptolemy, and
the encyclopaedic Pliny, respecting them, would be not less inexplicable.
The Old Northern language, the ancient tongue of Denmark, though rich in
terms descriptive of natural scenery, had no name for dune, nor do I
think the sand hills of the coast are anywhere noticed in Icelandic
literature. The modern Icelanders, in treating of the dunes of Jutland,
call them _klettr_, hill, cliff, and the Danish _klit_ is from that
source. The word Duene is also of recent introduction into German. Had
the dunes been distinguished from other hillocks, in ancient times, by
so remarkable a feature as the propensity to drift, they would certainly
have acquired a specific name in both Old Northern and German. So long
as they were wooded knolls, they needed no peculiar name; when they
became formidable, from the destruction of the woods which confined
them, they acquired a designation.
[443] The sands of Cape Cod were partially, if not completely, covered
with vegetation by nature. Dr. Dwight, describing the dunes as they were
in 1800, says: "Some of them are covered with beach grass; some fringed
with whortleberry bushes; and some tufted with a small and singular
growth of oaks. * * * The parts of this barrier, which are covered with
whortleberry bushes and with oaks, have been either not at all, or very
little blown. The oaks, particularly, appear to be the continuation of
the forests originally formed on this spot. * * * They wore all the
marks of extreme age; were, in some instances, already decayed, and in
others decaying; were hoary with moss, and were deformed by branches,
broken and wasted, not by violence, but by time."--_Travels_, iii, p.
91.
[444] Bergsoee (_Reventlovs Virksomhed_, ii, 3) states that the dunes on
the west coast of Jutland were stationary before the destruction of the
forests to the east of them. The felling of the tall trees removed the
resistance to the lower currents of the westerly winds, and the sands
have since buried a great extent of fertile soil. See also same work,
ii, p. 124.
[445] "We must, therefore, not be surprised to see the people here deal
as gingerly with their dunes, as if treading among eggs. He who is lucky
enough to own a molehill of dune pets it affectionately, and spends his
substance in cherishing and fattening it. That fair, fertile, rich
province, the peninsula of Eiderstaedt in the south of Friesland, has, on
the point toward the sea, only a tiny row of dunes, some six miles long
or so; but the people talk of their fringe of sand hills as if it were a
border set with pearls. They look upon it as their best defence against
Neptune. They have connected it with their system of dikes, and for
years have kept sentries posted to protect it against wanton
injury."--J. G. KOHL, _Die Inseln u. Marschen Schleswig-Holsteins_, ii,
p. 115.
[446] Sand banks sometimes connect themselves with the coast at both
ends, and thus cut off a portion of the sea. In this case, as well as
when salt water is enclosed by sea dikes, the water thus separated from
the ocean gradually becomes fresh, or at least brackish. The Haffs, or
large expanses of fresh water in Eastern Prussia--which are divided from
the Baltic by narrow sand banks called Nehrungen, or, at sheltered
points of the coast, by fluviatile deposits called Werders--all have one
or more open passages, through which the water of the rivers that supply
them at last finds its way to the sea.
[447] ANDRESEN, _Om Klitformationen_, pp. 68-72.
[448] Id., pp. 231, 232. Andresen's work, though printed in 1861, was
finished in 1859. Lyell (_Antiquity of Man_, 1863, p. 14) says: "Even in
the course of the present century, the salt waters have made one
eruption into the Baltic by the Liimfjord, although they have been now
again excluded."
[449] FORCHHAMMER, _Geognostische Studien am Meeres-Ufer_. LEONHARD und
BRONN, _Jahrbuch_, 1841, pp. 11, 13.
[450] ANDRESEN, _Om Klitformationen_, pp. 68, 72.
[451] _Voormaals en Thans_, pp. 126, 170.
[452] See a very interesting article entitled "Le Littoral de la
France," by ELISEE RECLUS, in the _Revue des Deux Mondes_, for December,
1862, pp. 901, 936.
[453] _De Bodem van Nederland_, i, p. 425. See _Appendix_, No. 60.
[454] The movement of the dunes has been hardly less destructive on the
north side of the Gironde. Sea the valuable article of ELISEE RECLUS
already referred to, in the _Revue des Deux Mondes_, for December, 1862,
entitled "Le Littoral de la France."
[455] LAVAL, _Memoire sur les Dunes du Golfe de Gascogne, Annales des
Ponts et Chaussees_, 1847, p. 223. The author adds, as a curious and
unexplained fact, that some of these pools, though evidently not
original formations but mere accumulations of water dammed up by the
dunes, have, along their western shore, near the base of the sand hills,
a depth of more than one hundred and thirty feet, and hence their
bottoms are not less than eighty feet below the level of the lowest
tides. Their western banks descend steeply, conforming nearly to the
slope of the dunes, while on the northeast and south the inclination of
their beds is very gradual. The greatest depth of these pools
corresponds to that of the sea ten miles from the shore. Is it possible
that the weight of the sands has pressed together the soil on which they
rest, and thus occasioned a subsidence of the surface extending beyond
their base? See _Appendix_, No. 61.
[456] ANDRESEN, _Om Klitformationem_, pp. 56, 79, 82.
[457] STARING, _De Bodem van Nederland_, i, pp. 329-331. Id., _Voormaals
en Thans_, p. 163. ANDRESEN, _Om Klitformationen_, pp. 280, 295.
The creation of new dunes, by the processes mentioned in the text, seems
to be much older in Europe than the adoption of measures for securing
them by planting. Dr. Dwight mentions a case in Massachusetts, where a
beach was restored, and new dunes formed, by planting beach grass.
"Within the memory of my informant, the sea broke over the beach which
connects Truro with Province Town, and swept the body of it away for
some distance. The beach grass was immediately planted on the spot; in
consequence of which the beach was again raised to a sufficient height,
and in various places into hills."--_Dwight's Travels_, iii, p. 93.
[458] STARING, i, pp. 310, 332.
[459] There is some confusion in the popular use of these names, and in
the scientific designations of sand plants, and they are possibly
applied to different plants in different places. Some writers style the
gourbet _Calamagrostis arenaria_, and distinguish it from the Danish
Klittetag or Hjelme.
[460] Bread, not indeed very palatable, has been made of the seeds of
the arundo, but the quantity which can be gathered is not sufficient to
form an important economical resource.----ANDRESEN, _Om
Klitformationen_, p. 160.
[461] BERGSOeE, _Reventlovs Virksomhed_, ii, p. 4.
[462] Measures were taken for the protection of the dunes of Cape Cod,
in Massachusetts, during the colonial period, though I believe they are
now substantially abandoned. A hundred years ago, before the valley of
the Mississippi, or even the rich plains of Central and Western New
York, were opened to the white settler, the value of land was relatively
much greater in New England than it is at present, and consequently some
rural improvements were then worth making, which would not now yield
sufficient returns to tempt the investment of capital. The money and the
time required to subdue and render productive twenty acres of sea sand
on Cape Cod, would buy a "section" and rear a family in Illinois. The
son of the Pilgrims, therefore, abandons the sand hills, and seeks a
better fortune on the fertile prairies of the West.
Dr. Dwight, who visited Cape Cod in the year 1800, after describing the
"beach grass, a vegetable bearing a general resemblance to sedge, but of
a light bluish-green, and of a coarse appearance," which "flourishes
with a strong and rapid vegetation on the sands," observes that he
received "from a Mr. Collins, formerly of Truro, the following
information:" "When he lived at Truro, the inhabitants were, under the
authority of law, regularly warned in the month of April, yearly, to
plant beach grass, as, in other towns of New England, they are warned to
repair highways. It was required by the laws of the State, and under the
proper penalties for disobedience; being as regular a public tax as any
other. The people, therefore, generally attended and performed the
labor. The grass was dug in bunches, as it naturally grows; and each
bunch divided into a number of smaller ones. These were set out in the
sand at distances of three feet. After one row was set, others were
placed behind it in such a manner as to shut up the interstices; or, as
a carpenter would say, so as to break the joints. * * * When it is once
set, it grows and spreads with rapidity. * * * The seeds are so heavy
that they bend down the heads of the grass; and when ripe, drop directly
down by its side, where they immediately vegetate. Thus in a short time
the ground is covered.
"Where this covering is found, none of the sand is blown. On the
contrary, it is accumulated and raised continually as snow gathers and
rises among bushes, or branches of trees cut and spread upon the earth.
Nor does the grass merely defend the surface on which it is planted; but
rises, as that rises by new accumulations; and always overtops the sand,
however high that may be raised by the wind."--_Dwight's Travels in New
England and New York_, ii, p. 92, 93.
This information was received in 1800, and it relates to a former state
of things, probably more than twenty years previous, and earlier than
1779, when the Government of Denmark first seriously attempted the
conquest of the dunes.
The depasturing of the beach grass--a plant allied in habits, if not in
botanical character, to the arundo--has been attended with very
injurious effects in Massachusetts. Dr. Dwight, after referring to the
laws for its propagation, already cited, says: "The benefit of this
useful plant, and of these prudent regulations, is, however, in some
measure lost. There are in Province Town, as I was informed, one hundred
and forty cows. These animals, being stinted in their means of
subsistence, are permitted to wander, at times, in search of food. In
every such case, they make depredations on the beach grass, and prevent
its seeds from being formed. In this manner the plant is ultimately
destroyed."--_Travels_, iii, p. 94.
On page 101 of the same volume, the author mentions an instance of great
injury from this cause. "Here, about one thousand acres were entirely
blown away to the depth, in many places, of ten feet. * * * Not a green
thing was visible except the whortleberries, which tufted a few lonely
hillocks rising to the height of the original surface and prevented by
this defence from being blown away also. These, although they varied the
prospect, added to the gloom by their strongly picturesque appearance,
by marking exactly the original level of the plain, and by showing us in
this manner the immensity of the mass which had been thus carried away
by the wind. The beach grass had been planted here, and the ground had
been formerly enclosed; but the gates had been left open, and the cattle
had destroyed this invaluable plant."
[463] ANDRESEN, _Om Klitformationen_, pp. 237, 240.
[464] "These plantations, perseveringly continued from the time of
Bremontier now cover more than 40,000 hectares, and compose forests
which are not only the salvation of the department, but constitute its
wealth."--CLAVE, _Etudes Forestieres_, p. 254.
Other authors have stated the plantations of the French dunes to be much
more extensive.
[465] KRUSE, _Duenenbau_, pp. 34, 38, 40.
[466] These processes are substantially similar to those employed in the
pineries of the Carolinas, but they are better systematized and more
economically conducted in France. In the latter country, all the
products of the pine, even to the cones, find a remunerating market,
while, in America, the price of resin is so low, that in the fierce
steamboat races on the great rivers, large quantities of it are thrown
into the furnaces to increase the intensity of the fires. In a carefully
prepared article on the Southern pineries published in an American
magazine--I think Harper's--a few years ago, it was stated that the
resin from the turpentine distilleries was sometimes allowed to run to
waste; and the writer, in one instance, observed a mass, thus rejected
as rubbish, which was estimated to amount to two thousand barrels. See
_Appendix_, No. 62.
[467] ANDRESEN, _Om Klitformationen_, pp. 78, 262, 275.
[468] LAVAL, _Memoire sur les Dunes du Golfe de Gascogne, Annales des
Ponts et Chaussees_, 1847, 2me semestre, p. 261. See _Appendix_, No.
63.
[469] There are extensive ranges of dunes on various parts of the coasts
of the British Islands, but I find no estimate of their area. Pannewitz
(_Anleitung zam Anbau der Sandflaechen_), as cited by Andresen (_Om
Klitformationen_, p. 45), states that the drifting sands of Europe,
including, of course, sand plains as well as dunes, cover an extent of
21,000 square miles. This is, perhaps, an exaggeration, though there is,
undoubtedly, much more desert land of this description on the European
continent than has been generally supposed. There is no question that
most of this waste is capable of reclamation by simple planting, and no
mode of physical improvement is better worth the attention of civilized
Governments than this.
There are often serious objections to extensive forest planting on soils
capable of being otherwise made productive, but they do not apply to
sand wastes, which, until covered by woods, are not only a useless
incumbrance, but a source of serious danger to all human improvements in
the neighborhood of them.
[470] BOITEL, _Mise en valeur des Terres pauvres par le Pin maritime_,
pp. 212, 218.
[471] See _Appendix_, No. .
[472] For details, consult ANDRESEN, _Om Klitformationen_, pp. 223, 236.
[473] When the deposit is not very deep, and the adjacent land lying to
the leeward of the prevailing winds is covered with water, or otherwise
worthless, the surface is sometimes freed from the drifts by repeated
harrowings, which loosen the sand, so that the wind takes it up and
transports it to grounds where accumulations of it are less injurious.
[474] _Travels and Researches in Chaldaea_, chap. ix.
[475] _Etudes Forestieres_, p. 253.
[476] LAVERGNE, _Economie Rurale de la France_, p. 300, estimates the
area of the Landes of Gascony at 700,000 hectares, or about 1,700,000
acres. The same author states (p. 304), that when the Moors were driven
from Spain by the blind cupidity and brutal intolerance of the age, they
demanded permission to establish themselves in this desert; but
political and religious prejudices prevented the granting of this
liberty. At this period the Moors were a far more cultivated people than
their Christian persecutors, and they had carried many arts, that of
agriculture especially, to a higher pitch than any other European
nation. But France was not wise enough to accept what Spain had cast
out, and the Landes remained a waste for three centuries longer. See
_Appendix_, No. 64.
The forest of Fontainebleau, which contains above 40,000 acres, is not a
plain, but its soil is composed almost wholly of sand, interspersed with
ledges of rock. The sand forms not less than ninety-eight per cent. of
the earth, and, as it is almost without water, it would be a drifting
desert but for the artificial propagation of forest trees upon it.
[477] _Economie Rurale de la Belgique, par_ EMILE DE LAVELEYE, _Revue
des Deux Mondes_, Juin, 1861, pp. 617-644.
[478] _Geognosie_, ii, p. 1173.
[479] According to HOHENSTEIN, _Der Wald_, pp. 228, 229, an extensive
plantation of pines--a tree new to Southern Russia--was commenced in
1842, on the barren and sandy banks of the Ingula, near Elisabethgrod,
and has met with very flattering success. Other experiments in
sylviculture at different points on the steppes promise valuable
results.
[480] "Sixteen years ago," says an Odessa landholder, "I attempted to
fix the sand of the steppes, which covers the rocky ground to the depth
of a foot, and forms moving hillocks with every change of wind. I tried
acacias and pines in vain; nothing would grow in such a soil. At length
I planted the varnish tree, or _ailanthus_, which succeeded completely
in binding the sand." This result encouraged the proprietor to extend
his plantations over both dunes and sand steppes, and in the course of
sixteen years this rapidly growing tree had formed real forests. Other
landowners have imitated his example with great advantage.--RENTSCH,
_Der Wald_, p. 44, 45.
[481] _Souvenirs d'un Naturaliste_, i, pp. 204 _et seqq._
[482] "If we suppose the narrow isthmus of Central America to be sunk in
the ocean, the warm equatorial current would no longer follow its
circuitous route around the Gulf of Mexico, but pour itself through the
new opening directly into the Pacific. We should then lose the warmth of
the Gulf Stream, and cold polar currents flowing farther southward would
take its place and be driven upon our coasts by the western winds. The
North Sea would resemble Hudson's Bay, and its harbors be free from ice
at best only in summer. The power and prosperity of its coasts would
shrivel under the breath of winter, as a medusa thrown on shore shrinks
to an insignificant film under the influence of the destructive
atmosphere. Commerce, industry, fertility of soil, population, would
disappear, and the vast waste--a new Labrador--would become a worthless
appendage of some clime more favored by nature."--HARTWIG, _Das Leben
des Meeres_, p. 70.
[483] I know nothing of Captain Allen's work but its title and its
subject. Very probably he may have anticipated many of the following
speculations, and thrown light on points upon which I am ignorant.
[484] "Some haue writt[=e], that by certain kings inhabiting aboue, the
_Nilus_ should there be stopped; & at a time prefixt, let loose vpon a
certaine tribute payd them by the _Aegyptians_. The error springing
perhaps fr[=o] a truth (as all wandring reports for the most part doe)
in that the _Sultan_ doth pay a certaine annuall summe to the _Abissin_
Emperour for not diuerting the course of the Riuer, which (they say) he
may, or impouerish it at the least."--GEORGE SANDYS, _A Relation of a
Journey, etc._, p. 98.
[485] The Recca, a river with a considerable current, has been
satisfactorily identified with a stream flowing through the cave of
Trebich, and with the Timavo--the Timavus of Virgil and the ancient
geographers--which empties through several mouths into the Adriatic
between Trieste and Aquileia. The distance from Trieste to a suitable
point in the grotto of Trebich is thought to be less than three miles,
and the difficulties in the way of constructing a tunnel do not seem
formidable. The works of Schmidl, _Die Hoehlen des Karstes_, and _Der
unterirdische Lauf der Recca_, are not common out of Germany, but the
reader will find many interesting facts derived from them in two
articles entitled _Der unterirdische Lauf der Recca_, in _Aus der
Natur_, xx, pp. 250-254, 263-266.
[486] BARTH, _Wanderungen durch die Kuesten des Mittelmeeres_, i, p. 353.
In a note on page 380, of the same volume, Barth cites Strabo as
asserting that a similar practice prevailed in Iapygia; but it may be
questioned whether the epithet [Greek: tracheia], applied by Strabo to
the original surface, necessarily implies that it was covered with a
continuous stratum of rock.
[487] PARTHEY, _Wanderungen durch Sicilien und die Levante_, i, p. 404.
[488] _Geognostische Studien am Meeres Ufer_, LEONHARD und BRONN,
_Jahrbuch_, 1841, pp. 25, 26.
[489] KOHL, _Schleswig-Holstein_, ii, p. 45.
[490] _Wanderungen durch Sicilien und die Levante_, i, p. 406.
[491] LANDGREBE, _Naturgeschichte der Vulkane_, ii, pp. 19, 20.
[492] Soon after the current issues from the volcano, it is covered
above and at its sides, and finally in front, with scoriae, formed by the
cooling of the exposed surface, which bury and conceal the fluid mass.
The stream rolls on under the coating, and between the walls of scoriae,
and it was the lateral crust which was broken through by the workmen
mentioned in the text.
The distance to which lava flows, before its surface begins to solidify,
depends on its volume, its composition, its temperature and that of the
air, the force with which it is ejected, and the inclination of the
declivity over which it runs. In most cases it is difficult to approach
the current at points where it is still entirely fluid, and hence
opportunities of observing it in that condition are not very frequent.
In the eruption of February, 1850, on the east side of Vesuvius, I went
quite up to one of the outlets. The lava shot out of the orifice upward
with great velocity, like the water from a spring, in a stream eight or
ten feet in diameter, throwing up occasionally volcanic bombs, but it
immediately spread out on the declivity down which it flowed, to the
width of several yards. It continued red hot in broad daylight, and
without a particle of scoriae on its surface, for a course of at least
one hundred yards. At this distance, the suffocating, sulphurous vapors
became so dense that I could follow the current no farther. The
undulations of the surface were like those of a brook swollen by rain. I
estimated the height of the waves at five or six inches by a breadth of
eighteen or twenty. To the eye, the fluidity of the lava seemed as
perfect as that of water, but masses of cold lava weighing ten or
fifteen pounds floated upon it like cork.
The heat emitted by lava currents seems extremely small when we consider
the temperature required to fuse such materials and the great length of
time they take in cooling. I saw at Nicolosi ancient oil jars, holding a
hundred gallons or more, which had been dug out from under a stream of
old lava above that town. They had been very slightly covered with
volcanic ashes before the lava flowed over them, but the lead with which
holes in them had been plugged was not melted. The current that buried
Mompiliere in 1669 was thirty-five feet thick, but marble statues, in a
church over which the lava formed an arch, were found uncalcined and
uninjured in 1704. See SCROPE, _Volcanoes_, chap. VI. Sec. 6.
[493] FERRARA, _Descrizione dell' Etna_, p. 108.
[494] LANGREBE, _Naturgeschichte der Vulkane_, ii, p. 82.
[495] _Physikalische Geographie_, p. 168. Beds of peat, accidentally set
on fire, sometimes continue to burn for months. I take the following
account of a case of this sort from a recent American journal:
"A CURIOUS PHENOMENON.--When the track of the railroad between Brunswick
and Bath was being graded, in crossing a meadow near the populous
portion of the latter city, the 'dump' suddenly took on a sinking
symptom, and down went the twenty feet fill of gravel, clay, and broken
rocks, out of sight, and it was a long, _long_ time before dirt trains
could fill the capacious stomach that seemed ready to receive all the
solid material that could be turned into it. The difficulty was at
length overcome, but all along the side of the sinkage the earth was
thrown up, broken into yawning chasms, and the surface was thus elevated
above its old watery level. Since that time this ground, thus slightly
elevated, has been cultivated, and has yielded enormously of whatever
the owner seemed disposed to plant upon it. Some three months ago, by
some means unknown to us, the underlying peat took fire, and for weeks,
as we had occasion to pass it, we noticed the smoke arising from the
smouldering combustion beneath the surface. Rains fell, but the fire
burned, and the smoke continued to arise. Monday we had occasion to pass
the spot, and though nearly a week's rain had been drenching the ground,
and though the surface was whitened with snow, and though pools of water
were standing upon the surface in the immediate neighborhood, still the
everlasting subterranean fire was burning, and the smoke arising through
the snow."
[496] One of the sublimest, and at the same time most fearful
suggestions that have been prompted by the researches of modern science,
was made by Babbage in the ninth chapter of his _Ninth Bridgewater
Treatise_. I have not the volume at hand, but the following explanation
will recall to the reader, if it does not otherwise make intelligible,
the suggestion I refer to.
No atom can be disturbed in place, or undergo any change of temperature,
of electrical state, or other material condition, without affecting, by
attraction or repulsion or other communication, the surrounding atoms.
These, again, by the same law, transmit the influence to other atoms,
and the impulse thus given extends through the whole material universe.
Every human movement, every organic act, every volition, passion, or
emotion, every intellectual process, is accompanied with atomic
disturbance, and hence every such movement, every such act or process
affects all the atoms of universal matter. Though action and reaction
are equal, yet reaction does not restore disturbed atoms to their former
place and condition, and consequently the effects of the least material
change are never cancelled, but in some way perpetuated, so that no
action can take place in physical, moral, or intellectual nature,
without leaving all matter in a different state from what it would have
been if such action had not occurred. Hence, to use language which I
have employed on another occasion: there exists, not alone in the human
conscience or in the omniscience of the Creator, but in external
material nature, an ineffaceable, imperishable record, possibly legible
even to created intelligence, of every act done, every word uttered,
nay, of every wish and purpose and thought conceived by mortal man, from
the birth of our first parent to the final extinction of our race; so
that the physical traces of our most secret sins shall last until time
shall be merged in that eternity of which not science, but religion
alone, assumes to take cognizance.
APPENDIX.
No. 1 (page 19, _note_). It may be said that the cases referred to in
the note on p. 19--and indeed all cases of a supposed acclimation
consisting in physiological changes--are instances of the origination of
new varieties by natural selection, the hardier maize, tomato, and other
vegetables of the North, being the progeny of seeds of individuals
endowed, exceptionally, with greater power of resisting cold than
belongs in general to the species which produced them. But, so far as
the evidence of change of climate, from a difference in vegetable
growth, is concerned, it is immaterial whether we adopt this view or
maintain the older and more familiar doctrine of a local modification of
character in the plants in question.
No. 2 (page 24, _note_). The adjectives of direction in _-erly_ are not
unfrequently used to indicate, in a loose way, the course of winds
blowing from unspecified points between N.E. and S.E.; S.E. and S.W.;
S.W. and N.W. or N.W. and N.E. If the employment of these words were
understood to be limited to thus expressing a direction nearer to the
cardinal point from whose name the adjective is taken than to any other
cardinal point, they would be valuable elements of English
meteorological nomenclature.
No. 3 (page 31). I find a confirmation of my observations on the habits
of the beaver as a geographical agency, in a report of the proceedings
of the British Association, in the London Athenaeum of October 8, 1864,
p. 469. It is there stated that Viscount Milton and Dr. Cheadle, in an
expedition across the Rocky Mountains by the Yellow Head, or Leather
Pass, observed that "a great portion of the country to the east of the
mountains" had been "completely changed in character by the agency of
the beaver, which formerly existed here in enormous numbers. The shallow
valleys were formerly traversed by rivers and chains of lakes which,
dammed up along their course at numerous points, by the work of those
animals, have become a series of marshes in various stages of
consolidation. So complete has this change been, that hardly a stream is
found for a distance of two hundred miles, with the exception of the
large rivers. The animals have thus destroyed, by their own labors, the
waters necessary to their own existence."
When the process of "consolidation" shall have been completed, and the
forest reestablished upon the marshes, the water now diffused through
them will be 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.
No. 4 (page 33, _note_). The lignivorous insects that attack living
trees almost uniformly confine their ravages to trees already unsound or
diseased in growth from the depredations of leaf-eaters, such as
caterpillars and the like, or from other causes. The decay of the tree,
therefore, is the cause not the consequence of the invasions of the
borer. This subject has been discussed by Perris in the _Annales de la
Societe Entomologique de la France_, for 1851 (?), and his conclusions
are confirmed by the observations of Samanos, who quotes, at some
length, the views of Perris. "Having, for fifteen years," says the
latter author, "incessantly studied the habits of lignivorous insects in
one of the best wooded regions of France, I have observed facts enough
to feel myself warranted in expressing my conclusions, which are: that
insects in general--I am not speaking of those which confine their
voracity to the leaf--do not attack trees in sound health, and they
assail those only whose normal conditions and functions have been by
some cause impaired."
See, more fully, Samanos, _Traite de la Culture du Pin Maritime_, Paris,
1864, pp. 140-145.
No. 5 (page 34, _note_). Very interesting observations, on the agency of
the squirrel and other small animals in planting and in destroying nuts
and other seeds of trees, may be found in a paper on the Succession of
Forests in Thoreau's _Excursions_, pp. 135 _et seqq._
I once saw several quarts of beech-nuts taken from the winter quarters
of a family of flying squirrels in a hollow tree. The kernels were
neatly stripped of their shells and carefully stored in a dry cavity.
No. 6 (page 40, _note_). Schroeder van der Kolk, in _Het Verschil
tusschen den Psychischen Aanleg van het Dier en van den Mensch_, cites
from Burdach and other authorities many interesting facts respecting
instincts lost, or newly developed and become hereditary, in the lower
animals, and he quotes Aristotle and Pliny as evidence that the common
quadrupeds and fowls of our fields and our poultry yards were much less
perfectly domesticated in their times than long, long ages of servitude
have now made them.
Perhaps the half-wild character ascribed by P. Laestadius and other
Swedish writers to the reindeer of Lapland, may be in some degree due to
the comparative shortness of the period during which he has been
partially tamed. The domestic swine bred in the woods of Hungary and
the buffaloes of Southern Italy are so wild and savage as to be very
dangerous to all but their keepers. The former have relapsed into their
original condition, the latter have not yet been reclaimed from it.
Among other instances of obliterated instincts, Schroeder van der Kolk
states that in Holland, where, for centuries, the young of the cow has
been usually taken from the dam at birth and fed by hand, calves, even
if left with the mother, make no attempt to suck; while in England,
where calves are not weaned until several weeks old, they resort to the
udder as naturally as the young of wild quadrupeds.--_Ziel en Ligchaam_,
p. 128, _n._
No. 7 (page 60, _first note_). At Pie di Mulera, at the outlet of the
Val Anzasca, near the principal hotel, is a vine measuring thirty-one
inches in circumference. The door of the chapter-hall in the cloister of
the church of San Giovanni, at Saluzzo, is of vine wood, and the boards
of which the panels were made could not have been less than ten inches
wide. Statues and other objects of considerable dimensions, of vine
wood, are mentioned by ancient writers.
No. 8 (page 63, _second note_). Cartier, A. D. 1535-'6, mentions "vines,
great melons, cucumbers, gourds [courges], pease, beans of various
colors, but not like ours," as common among the Indians of the banks of
the St. Lawrence.--_Bref Recit_, etc., reprint. Paris, 1863, pp. 13, a;
14, b; 20, b; 31, a.
No. 8 (page 65, _second paragraph_). It may be considered very highly
probable, if not certain, that the undiscriminating herbalists of the
sixteenth century must have overlooked many plants native to this
island. An English botanist, in an hour's visit to Aden, discovered
several species of plants on rocks always reported, even by scientific
travellers, as absolutely barren. But after all, it appears to be well
established that the original flora of St. Helena was extremely limited,
though now counting hundreds of species.
No. 9 (page 66, _first note_). Although the vine _genus_ is very
catholic and cosmopolite in its habits, yet particular _varieties_ are
extremely fastidious and exclusive in their requirements as to soil and
climate. The stocks of many celebrated vineyards lose their peculiar
qualities by transplantation, and the most famous wines are capable of
production only in certain well-defined, and for the most part narrow
districts. The Ionian vine which bears the little stoneless grape known
in commerce as the Zante currant, has resisted almost all efforts to
naturalize it elsewhere, and is scarcely grown except in two or three of
the Ionian islands and in a narrow territory on the northern shores of
the Morea.
No. 10 (page 68, _first note_). In most of the countries of Southern
Europe, sheep and beeves are wintered upon the plains, but driven in the
summer to mountain pastures at many days' distance from the homesteads
of their owners. They transport seeds in their coats in both directions,
and hence Alpine plants often shoot up at the foot of the mountains, the
grasses of the plain on the borders of the glaciers; but in both cases,
they usually fail to propagate themselves by ripening their seed. This
explains the scattered tufts of common clover, with pale and flaccid
blossoms, which are sometimes seen at heights exceeding 7,000 feet above
the sea.
No. 11 (page 73, _last paragraph_). The poisonous wild parsnip, which is
very common in New England, is popularly believed to be identical with
the garden parsnip, and differenced only by conditions of growth, a
richer soil depriving it, it is said, of its noxious properties. Many
wild medicinal plants, such as pennyroyal for example, are so much less
aromatic and powerful, when cultivated in gardens, than when self-sown
on meagre soils, as to be hardly fit for use.
No. 12 (page 74, _second note_). See in Thoreau's _Excursions_, an
interesting description of the wild apple-trees of Massachusetts.
No. 13 (page 86, _first paragraph_). It is said at Courmayeur that a
very few ibexes of a larger variety than those of the Cogne mountains,
still linger about the Grande Jorasse.
No. 14 (page 92, _first note_). In Northern and Central Italy, one often
sees hillocks crowned with grove-like plantations of small trees, much
resembling large arbors. These serve to collect birds, which are
entrapped in nets in great numbers. These plantations are called
_ragnaje_, and the reader will find, in Bindi's edition of Davanzati, a
very pleasant description of a ragnaja, though its authorship is not now
ascribed to that eminent writer.
No. 15 (page 93, _second note_). The appearance of the dove-like grouse,
_Tetrao paradoxus_, or _Syrrhaptes Pallasii_, in various parts of
Europe, in 1859 and the following years, is a noticeable exception to
the law of regularity which seems to govern the movements and determine
the habitat of birds. The proper home of this bird is the steppes of
Tartary, and it is not recorded to have been observed in Europe, or at
least west of Russia, until the year abovementioned, when many flocks of
twenty or thirty, and even a hundred individuals, were seen in Bohemia,
Germany, Holland, Denmark, England, Ireland, and France. A considerable
flock frequented the Frisian island of Borkum for more than five months.
It was hoped they would breed and remain permanently in the island, but
this expectation has been disappointed, and the steppe-grouse seems to
have disappeared again altogether.