In the more eastwardly prairie region fires have done much to prevent

the spread of the native groves, and throughout the whole woodless

plains the pastorage of the buffalo alone would suffice to prevent a

forest growth. The prairies were the proper feeding-grounds of the

bison, and the vast number of those animals is connected, as cause or

consequence, with the existence of these vast pastures. The bison,

indeed, could not convert the forest into a pasture, but he would do

much to prevent the pasture from becoming a forest.

There is positive evidence that some of the American tribes possessed

large herds of domesticated bisons. See Humboldt, Ansichten der Natur,

i., pp. 71-73. What authorizes us to affirm that this was simply the

wild bison reclaimed, and why may we not, with equal probability,

believe that the migratory prairie-buffalo is the progeny of the

domestic animal run wild?

There are, both on the prairies, as in Wisconsin, and in deep forests,

as in Ohio, extensive remains of a primitive people, who must have been

more numerous and more advanced in art than the present Indian tribes.

There can be no doubt that the woods where such earthworks are found in

Ohio were cleared by them, and that the vicinity of these fortresses or

temples was inhabited by a large population. Nothing forbids the

supposition that the prairies were cleared by the same or a similar

people, and that the growth of trees upon them has been prevented by

fires and grazing, while the restoration of the woods in Ohio may be due

to the abandonment of that region by its original inhabitants. The

climatic conditions unfavorable to the spontaneous growth of trees on

the prairies may possibly be an effect of too extensive clearings,

rather than a cause of the want of woods.

It is disputed whether the steppes of Russia were ever wooded. They were

certainly bare of forest growth at a very remote period; for Herodotus

describes the country of the Scythians between the Ister and the Tanais

as woodless, with the exception of the small province of Xylaea between

the Dnieper and the Gulf of Perekop. They are known to have been

occupied by a large nomade and pastoral population down to the sixteenth

century, though these tribes are now much reduced in numbers. The habits

of such races are scarcely less destructive to the forest than those of

civilized life. Pastoral tribes do not employ much wood for fuel or for

construction, but they carelessly or recklessly burn down the forests,

and their cattle effectually check the growth of young trees wherever

their range extends.

At present, the furious winds which sweep over the plains, the droughts

of summer, and the rights and abuses of pasturage, constitute very

formidable obstacles to the employment of measures which have been

attended with so valuable results on the sand-wastes of France and

Germany. The Russian Government has, however, attempted the wooding of

the steppes, and there are thriving plantations in the neighborhood of

Odessa, where the soil is of a particularly loose and sandy character.

The tree best suited to this locality, and, as there is good reason to

suppose, to sand plains in general, is the Ailanthus glandulosa, or

Japan varnish-tree. The remarkable success which has crowned the

experiments with the ailanthus at Odessa, will, no doubt, stimulate to

similar trials elsewhere, and it seems not improbable that the arundo

and the maritime pine, which have fixed so many thousand acres of

drifting sands in Western Europe, will be, partially at leaat,

superseded by the tamarisk and the varnish-tree.

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.] In any case the question will now be subjected to a practical

test, and the plantations are so extensive, and, as is reported, so

thrifty in growth, that one generation will suffice to determine with

certainty and precision how far climate is affected by clothing with

wood a vast territory naturally destitute of that protection.

I have thus far spoken only of the preservation and training of existing

woods, not of the planting of new forests, because European experience,

to which alone we can appeal, is conversant only with conditions so

different from those of our own climate, soil, and arboreal vegetation,

that precedents drawn from it cannot be relied upon as entirely safe

rules for our guidance in that branch of rural economy. [Footnote: Many

valuable suggestions on this subject will be found in Bryant, Forest

Trees, chap. vi. et seqq.]

I apprehend that one rule, which is certainly alike applicable to both

sides of the Atlantic--that, namely, of the absolute exclusion of

domestic quadrupeds from all woods, old or young, not destined for the

axe--would be least likely to be observed in our practice. The need of

shade for cattle, and our inveterate habits in this respect, are much

more serious obstacles to compliance with this precept than any inherent

difficulty in the thing itself; for there is no good reason why our

cattle may not be kept out of our woods as well as out of our

wheatfields. When forest-planting is earnestly and perseveringly

practised, means of overcoming this difficulty will be found, and our

husbandry will be modified to meet the exigency.

The best general advice that can be offered, in the want of an

experimental code, is to make every plantation consist of a great

variety of trees, and this not only because nature favors a diversified

forest-crop, but because the chances of success among a multitude of

species are far greater than if we confine ourselves to one or two.

It will doubtless be found that in our scorching summer, especially on

bare plains, shade for young plants is even more necessary than in most

parts of Europe, and hence a fair proportion of rapidly growing trees

and shrubs, even if themselves of little intrinsic value, ought to be

regarded as an indispensable feature in every young plantation. These

trees should be of species which bear a full supply of air and light,

and therefore, in the order of nature, precede those which are of

greater value for the permanent wood; and it would be a prudent measure

to seed the ground with a stock of such plants, a year or two before

sowing or transplanting the more valuable varieties.

More specific rules than these cannot at present well be given, but very

brief experiments, even if not in all respects wisely conducted, will

suffice to determine the main question: whether in a given locality this

or that particular tree can advantageously be propagated or introduced.

The special processes of arboriculture suited to the ends of the planter

may be gathered partly from cautious imitation of European practice, and

partly from an experience which, though not pronouncing definitively in

a single season, will, nevertheless, suggest appropriate methods of

planting and training the wood within a period not disproportioned to

the importance of the object. [Footnote: For very judicious suggestions

on experiments in sylviculture, see the Rev. Frederick Starr's

remarkable paper on the American Forests in the Transactions of the

Agricultural Society for -.]

The growth of arboreal vegetation is comparatively slow, and we are

often told that, though he who buries an acorn may hope to see it shoot

up to a miniature resemblance of the majestic tree which shall shade his

remote descendants, yet the longest life hardly embraces the seedtime

and the harvest of a forest. The planter of a wood, it is said, must be

actuated by higher motives than those of an investment, the profits of

which consist in direct pecuniary gain to himself or even to his

posterity; for if, in rare cases, an artificial forest may, in a

generation or two, more than repay its original cost, still, in general,

the value of its timber will not return the capital expended and the

interest accrued. [Footnote: According to Clave (Etudes, p. 159), the

net revenue from the forests of the state in France, making no allowance

for interest on the capital represented by the forest, is two dollars

per acre. In Saxony it is about the same, though the cost of

administration is twice as much as in France; in Wurtemberg it is about

a dollar an acre; and in Prussia, where half the income is consumed in

the expenses of administration, it sinks to less than half a dollar.

This low rate in Prussia and other German states is partly explained by

the fact that a considerable proportion of the annual product of the

wood is either conceded to persons claiming prescriptive rights, or

sold, at a very small price, to the poor. Taking into account the

capital invested in forest-land, and adding interest upon it, Pressler

calculates that a pine wood, managed with a view to felling it when

eighty years old, would yield one-eighth of one per cent. annual profit;

a fir wood, at one hundred years, one-sixth of one per cent.; a beech

wood, at one hundred and twenty years, one-fourth of one per cent. The

same author gives the net income of the New Forest in England, over and

above expenses, interest not computed, at twenty-five cents per acre

only. In America, where no expense is bestowed upon the woods, the value

of the annual growth has generally been estimated much higher.

Forest-trees are often planted in Europe for what may be called an early

crop. Thus in Germany acorns are sown and the young seedlings cultivated

like ordinary field-vegetables, and cut at the age of a very few years

for the sake of the bark and young twigs used by tanners. In England,

trees are grown at the rate of two thousand to the acre, and cut for

props in the mines at the diameter of a few inches. Plantations for

hoop-poles, and other special purposes requiring small timber, would, no

doubt, often prove high remunerative.] But the modern improved methods

of sylviculture show vastly more favorable financial results; and when

we consider the immense collateral advantages derived from the presence

of the forest, the terrible evils necessarily resulting from its

destruction, we cannot but admit that the preservation of existing

woods, and the more costly extension and creation of them where they

have been unduly reduced or have never existed, are among the plainest

dictates of self-interest and most obvious of the duties which this age

owes to those that are to come after it.

Financial Results of Forest Plantation.

Upon the whole, I am persuaded that the financial statistics which are

found in French and German authors, as the results of European

experience in forest economy, present the question under a too

unfavorable aspect; and therefore these calculations ought not to

discourage landed proprietors from making experiments on this subject.

These statistics apply to woods whose present condition is, in an

eminent degree, the effect of previous long-continued mismanagement; and

there is much reason to believe that in the propitious climate of the

United States new plantations, regulated substantially according to the

methods of De Courval, Chambrelent, and Chevandier, and accompanied with

the introduction of exotic trees, as, for example, the Australian

caruarina and eucalyptus [Footnote: Although the eucalyptus thrives

admirably in Algeria--where it attains a height of from fifty to sixty

feet, and a diameter of fifteen or sixteen inches, in six years from the

seed--and in some restricted localities in Southern Europe, it will not

bear the winters even of Florence, and consequently cannot be expected

to flourish in any part of the United States except the extreme South

and California. The writer of a somewhat enthusiastic article on this

latter State, in Harper's Monthly for July, 1872, affirms that he saw a

eucalyptus "eight years from a small cutting, which was seventy-five

feet in height, and two feet and a half in diameter at the base."

The paulownia, which thrives in Northern Italy, has a wood of little

value, but the tree would serve well as a shelter for seedlings and

young plants of more valuable species, and in other cases where a

temporary shade is urgently needed. The young shoots, from a stem polled

the previous season, almost surpass even the eucalyptus in rapidity of

growth. Such a shoot from a tree not six inches in diameter, which I had

an opportunity of daily observing, from the bursting out of the bud from

the bark of the parent stem in April till November of the same year,

acquired in that interval a diameter of between four and five inches and

a height of above twenty feet.] which, latter, it is said, has a growth

at least five, and, according to some, ten times more rapid than that of

the oak--would prove good investments even in an economical aspect.

[Footnote: The economical statistics of Grigor, Arboriculture,

Edinburgh, 1868, are very encouraging. In the preface to that work the

author says: "Having formed several large plantations nearly forty years

ago, which are still standing, in the Highlands of Scotland, I can refer

to them as, after paying every expense, yielding a revenue equal to that

of the finest arable land in the country, where the ground previously to

these formations was not worth a shilling an acre." See also Hartig,

Ueber den Wachsthumsgang und Ertrag der Buche, Eiche und Kiefer, 1869,

and especially Bryant, Forest Trees, chap. ix.]

There is no doubt that they would pay the expenses of their planting at

no distant period, at least in every case where irrigation is possible,

and in very many situations, terraces, ditches, or even horizontal

furrows upon the hillsides, would answer as a substitute for more

artificial irrigation. Large proprietors would receive important

indirect benefits from the shelter and the moisture which forests

furnish for the lands in their neighborhood, and eventually from the

accumulation of vegetable mould in the woods. [Footnote: The fertility

of newly cleared land is by no means due entirely to the accumulation of

decayed vegetable matter on its surface, and to the decomposition of the

mineral constituents of the soil by the gases emitted by the fallen

leaves. Sachs has shown that the roots of living plants exercise a most

powerful solvent action on rocks, and hence stones are disintegrated and

resolved into elements of vegetable nutrition, by the chemical agency of

the forest, more rapidly than by frost, rain, and other meteorological

influences.] The security of the investment, as in the case of all

real-estate, is a strong argument for undertaking such plantations, and

a moderate amount of government patronage and encouragement would be

sufficient to render the creation of new forests an object of private

interest as well as of public advantage, especially in a country where

the necessity is so urgent and the climate so favorable as in the United

States.

Instability of American Life.

All human institutions, associate arrangements, modes of life, have

their characteristic imperfections. The natural, perhaps the necessary

defect of ours, is their instability, their want of fixedness, not in

form only, but even in spirit. The face of physical nature in the United

States shares this incessant fluctuation, and the landscape is as

variable as the habits of the population. It is time for some abatement

in the restless love of change which characterizes us, and makes us

almost a nomade rather than a sedentary people. [Footnote: It is rare

that a middle-aged American dies in the house where he was born, or an

old man even in that which he has built; and this is scarcely less true

of the rural districts, where every man owns his habitation, than of the

city, where the majority live hired houses. This life of incessant

flitting is unfavorable for the execution of permanent improvements of

every sort, and especially of those which, like the forest, are slow in

repaying any part of the capital expended in them. It requires a very

generous spirit in a landholder to plant a wood on a farm he expects to

sell, or which he knows will pass out of the hands of his descendants at

his death. But the very fact of having begun a plantation would attach

the proprietor more strongly to the soil for which he had made such a

sacrifice; and the paternal acres would have a greater value in the eyes

of a succeeding generation, if thus improved and beautified by the

labors of those from whom they were inherited. Landed property,

therefore, the transfer of which is happily free from every legal

impediment or restriction in the United States, would find, in the

feelings thus prompted, a moral check against a too frequent change of

owners, and would tend to remain long enough in one proprietor or one

family to admit of gradual improvements which would increase its value

both to the possessor and to the state.] We have now felled forest

enough everywhere, in many districts far too much. Let us restore this

one element of material life to its normal proportions, and devise means

of maintaining the permanence of its relations to the fields, the

meadows, and the pastures, to the rain and the dews of heaven, to the

springs and rivulets with which it waters the earth. The establishment

of an approximately fixed ratio between the two most broadly

characterized distinctions of rural surface--woodland and

ploughland--would involve a certain persistence of character in all the

branches of industry, all the occupations and habits of life, which

depend upon or are immediately connected with either, without implying a

rigidity that should exclude flexibility of accommodation to the many

changes of external circumstance which human wisdom can neither prevent

nor foresee, and would thus help us to become, more emphatically, a

well-ordered and stable commonwealth, and, not less conspicuously, a

people of progress.

CHAPTER IV.

THE WATERS.

Land Artificially won from the Waters--Great Works of Material

Improvement--Draining of Lincolnshire Fens--Incursions of the Sea in the

Netherlands--Origin of Sea-dikes--Gain and Loss of Land in the

Netherlands--Marine Deposits on the Coast of Netherlands--Draining of

Lake of Haarlem--Draining of the Zuiderzee--Geographical Effects of

Improvements in the Netherlands--Ancient Hydraulic Works--Draining of

Lake Celano by Prince Torlonia--Incidental Consequences of draining

Lakes--Draining of Marshes--Agricultural Draining--Meteorological

Effects of Draining--Geographical Effects of Draining--Geographical

Effects of Aqueducts and Canals--Antiquity of Irrigation--Irrigation in

Palestine, India, and Egypt--Irrigation in Europe--Meteorological

Effects of Irrigation--Water withdrawn from Rivers for

Irrigation--Injurious Effects of Rice-culture--Salts Deposited by Water

of Irrigation--Subterranean Waters--Artesian Wells--Artificial

Springs--Economizing Precipitation--Inundations in France--Basins of

Reception--Diversion of Rivers--Glacier Lakes--River Embankments--Other

Remedies against Inundations--Dikes of the Nile--Deposits of Tuscan

Rivers--Improvements in Tuscan Maremma--Improvements in Val di

Chiana--Coast of the Netherlands.

Land artificially won from the Waters.

Man, as we have seen, has done much to revolutionize the solid surface

of the globe, and to change the distribution and proportions, if not the

essential character, of the organisms which inhabit the land and even

the waters. Besides the influence thus exerted upon the life which

peoples the sea, his action upon the land has involved a certain amount

of indirect encroachment upon the territorial jurisdiction of the ocean.

So far as he has increased the erosion of running waters by the

destruction of the forest or by other operations which lessen the

cohesion of the soil, he has promoted the deposit of solid matter in the

sea, thus reducing the depth of marine estuaries, advancing the

coast-line, and diminishing the area covered by the waters. He has gone

beyond this, and invaded the realm of the ocean by constructing within

its borders wharves, piers, light-houses, breakwaters, fortresses, and

other facilities for his commercial and military operations; and in some

countries he has permanently rescued from tidal overflow, and even from

the very bed of the deep, tracts of ground extensive enough to

constitute valuable additions to his agricultural domain. The quantity

of soil gained from the sea by these different modes of acquisition is,

indeed, too inconsiderable to form an appreciable element in the

comparison of the general proportion between the two great forms of

terrestrial surface, land and water; but the results of such operations,

considered in their physical and their moral bearings, are sufficiently

important to entitle them to special notice in every comprehensive view

of the relations between man and nature.

There are cases, as on the western shores of the Baltic, where, in

consequence of the secular elevation of the coast, the sea appears to be

retiring; others, where, from the slow sinking of the land, it seems to

be advancing. These movements depend upon geological causes wholly out

of our reach, and man can neither advance nor retard them. [Footnote: It

is possible that the weight of the sediment let fall at the mouths of

great rivers, like the Ganges, the Mississippi, and the Po, may cause

the depression of the strata on which they are deposited, and hence if

man promotes the erosion and transport of earthy material by rivers, he

augments the weight of the sediment they convey into their estuaries,

and consequently his action tends to accelerate such depression. There

are, however, cases where, in spite of great deposits of sediment by

rivers, the coast is rising. Further, the manifestation of the internal

heat of the earth at any given point is conditioned by the thickness of

the crust at such point. The deposits of rivers tend to augment that

thickness at their estuaries. The sediment of slowly-flowing rivers

emptying into shallow seas is spread over so great a surface that we can

hardly imagine the foot or two of slime they let fall over a wide area

in a century to form an element among even the infinitesimal quantities

which compose the terms of the equations of nature. But some swift

rivers, rolling mountains of fine earth, discharge themselves into

deeply scooped gulfs or bays, and in such cases the deposit amounts, in

the course of a few years, to a mass the transfer of which from the

surface of a large basin, and its accumulation at a single point, may be

supposed to produce other effects than those measurable by the

sounding-line. Now, almost all the operations of rural life, as I have

abundantly shown, increase the liability of the soil to erosion by

water. Hence, the clearing of the valley of the Ganges, for example, by

man, must have much augmented the quantity of earth transported by that

river to the sea, and of course have strengthened the effects, whatever

they may be, of thickening the crust of the earth in the Bay of Bengal.

In such cases, then, human action must rank among geological influences.

To the geological effects of the thickening of the earth's crust in the

Bay of Bengal, are to be added those of thinning it on the highlands

where the Ganges rises. The same action may, as a learned friend

suggests to me, even have a cosmical influence. The great rivers of the

earth, taken as a whole, transport sediment from the polar regions in an

equatorial direction, and hence tend to increase the equatorial

diameter, and at the same time, by their inequality of action, to a

continual displacement of the centre of gravity, of the earth. The

motion of the globe, and of all bodies affected by its attraction, is

modified by every change of its form, and in this case we are not

authorized to say that such effects are in any way compensated.]

There are also cases where similar apparent effects are produced by

local oceanic currents, by river deposit or erosion, by tidal action, or

by the influence of the wind upon the waves and the sands of the

seabeach. A regular current may drift suspended earth and seaweed along

a coast until they are caught by an eddy and finally deposited out of

the reach of further disturbance, or it may scoop out the bed of the sea

and undermine promontories and headlands; a powerful river, as the wind

changes the direction of its flow at its outlet, may wash away shores

and sandbanks at one point to deposit their material at another; the

tide or waves, stirred to unusual depths by the wind, may gradually wear

down the line of coast, or they may form shoals and coast-dunes by

depositing the sand they have rolled up from the bottom of the ocean.

These latter modes of action are slow in producing effects sufficiently

important to be noticed in general geography, or even to be visible in

the representations of coast-line laid down in ordinary maps; but they

nevertheless form conspicuous features in local topography, and they are

attended with consequences of great moment to the material and the moral

interests of men. The forces which produce these limited results are all

in a considerable degree subject to control, or rather to direction and

resistance, by human power, and it is in guiding, combating, and

compensating them that man has achieved some of his most remarkable and

most honorable conquests over nature. The triumphs in question, or what

we generally call harbor and coast improvements, whether we estimate

their value by the money and labor expended upon them, or by their

bearing upon the interests of commerce and the arts of civilization,

must take a very high rank among the great works of man, and they are

fast assuming a magnitude greatly exceeding their former relative

importance.

The extension of commerce and of the military marine, and especially the

introduction of vessels of increased burden and deeper draught of water,

have imposed upon engineers tasks of a character which a century ago

would have been pronounced, and, in fact, would have been,

impracticable; but necessity has stimulated au ingenuity which has

contrived means of executing them, and which gives promise of yet

greater performance in time to come.

Indeed, although man, detached from the solid earth, is almost powerless

to struggle against the sea, he is fast becoming invincible by it so

long as his foot is planted on the shore, or even on the bottom of the

rolling ocean; and though on some battle-fields between the waters and

the land he is obliged slowly to yield his ground, yet he retreats still

facing the foe, and will finally be able to say to the sea, "Thus far

shalt thou come and no farther, and here shall thy proud waves be

stayed!" [Footnote: It is, nevertheless, remarkable that in the

particular branch of coast engineering where great improvements are

most urgently needed, comparatively little has been accomplished. I

refer to the creation of artificial harbors, and of facilities for

loading and discharging ships. The whole coast of Italy is, one may

almost say, harborless and even, wharfless, and there are many thousands

of miles of coast in rich commercial countries in Europe, where vessels

can neither lie in safety for a single day, nor even, in better

protected heavens, ship or land their passengers or cargoes except by

the help of lighters, and other not less clumsy contrivances. It is

strange that such enormous inconveniences are borne with so little

effort to remove them, and especially that break-waters are rarely

constructed by Governments except for the benefit of the military

marine.]

Great Works of Material Improvement.

Men have ceased to admire the vain exercise of power which heaped up the

great pyramid to gratify the pride of a despot with a giant sepulchre;

for many great harbors, many important lines of internal communication,

in the civilized world, now exhibit works which in volume and weight of

material surpass the vastest remains of ancient architectural art, and

demand the exercise of far greater constructive skill and involve a much

heavier pecuniary expenditure than would now be required for the

building of the tomb of Cheops. It is computed that the great pyramid,

the solid contents of which when complete were about 3,000,000 cubic

yards, could be erected for a million of pounds sterling. The breakwater

at Cherbourg, founded in rough water sixty feet deep, at an average

distance of more than two miles from the shore, contains double the mass

of the pyramid, and many a comparatively unimportant canal has been

constructed at twice the cost which would now build that stupendous

monument.

The description of works of harbor and coast improvement which have only

an economical value, not a true geographical importance, does not come

within the plan of the present volume, and in treating this branch of my

subject, I shall confine myself to such as are designed either to gain

new soil by excluding the waters from grounds which they had permanently

or occasionally covered, or to resist new encroachments of the sea upon

the land. [Footnote: Some notice of great works executed by man in

foreign lands, and probably not generally familiar to my readers, may,

however, prove not uninteresting.

The desaguadero, or canal constructed by the Viceroy Revillagigedo to

prevent the inundation of the city of Mexico by the lakes in its

vicinity, besides subsidiary works of great extent, has a cutting half a

mile long, 1,000 feet wide, and from 150 to 200 feet deep.--Hoffmann,

Encyclopaedie, art. Mexico.

The adit which drains the mines of Gwennap in Cornwall, with its

branches, is thirty miles long. Those of the silver mines of Saxony are

scarcely less extensive, and the Ernst-August-Stollen, or great drain of

the mines of the Harz, is fifteen miles long.

The excavation for the Suez Canal were computed at 75,000,000 cubic

metres, or about 100,000,000 cubic yards, and those of the Ganges Canal,

which, with its branches, had a length of 3,000 miles, amount to nearly

the same quantity.

The quarries at Maestricht have undermined a space of sixteen miles by

six, or more than two American townships, and the catacombs of Rome, in

part, at least, originally quarries, have a lineal extent of five

hundred and fifty miles. The catacombs of Paris required the excavation

of 13,000,000 cubic yards of stone, or more than four times the volume

of the great pyramid.

The excavation for the Mt. Cenis tunnel, eight miles in length, wholly

through solid rock, amounted to more than 900,000 cubic yards, and

16,000,000 of brick were employed for the lining.

In an article on recent internal improvements in England, in the London

Quarterly Review for January, 1858, it is stated that in a single

rock-cutting on the Liverpool and Manchester railway, 480,000 cubic

yards of stone were removed; that the earth excavated in the

construction of English railways up to that date amounted to a hundred

and fifty million cubic yards, and that at the Round Down Cliff, near

Dover, a single blast of nineteen thousand pounds of powder blew down a

thousand million tons of chalk, and covered fifteen acres of land with

the fragments.

In 1869, a mass of marble equal to one and a half times the cubical

contents of the Duomo at Florence, or about 450,000 cubic yards, was

thrown down at Carrara by one blast, and two hours after, another equal

mass, which had been loosened by the explosion, fell of itself.

Zolfanelli, La Lunigiana, p. 43.

The coal yearly extracted from the mines of England averages not less

than 100,000,000 tons. The specific gravity of British coal ranges from

1.20 to 1.35, and consequently we may allow a cubic yard to the ton. If

we add the earth and rock removed in order to reach the coal, we shall

have a yearly amount of excavation for this one object equal to more

than thirty times the volume of the pyramid of Cheops. These are

wonderful achievements of human industry; but the rebuilding of Chicago

within a single year after the great fire--not to speak of the

extraordinary material improvements previously executed at that

city--surpasses them all, and it probably involved the expenditure of a

sum of muscular and of moral energy which has never before been exerted

in the accomplishment of a single material object, within a like

period.]

Draining of Lincolnshire Fens.

The draining of the Lincolnshire fens in England, which has converted

about 400,000 acres of marsh, pool, and tide-washed flat into

ploughland and pasturage, is a work, or rather series of works, of great

magnitude, and it possesses much economical, and, indeed, no trifling

geographical, importance. Its plans and methods were, at least in part,

borrowed from the example of like improvements in Holland, and it is, in

difficulty and extent, inferior to works executed for the same purpose

on the opposite coast of the North Sea, by Dutch, Frisie, and Low German

engineers. The space I can devote to such operations will be better

employed in describing the latter, and I content myself with the simple

statement I have already made of the quantity of worthless and even

pestilential land which has been rendered both productive and salubrious

in Lincolnshire, by diking out the sea, and the rivers which traverse

the fens of that country.

The almost continued prevalence of west winds upon both coasts of the

German Ocean occasions a constant set of the currents of that sea to the

east, and both for this reason and on account of the greater violence of

storms from the former quarter, the English shores of the North Sea are

less exposed to invasion by the waves than those of the Netherlands and

the provinces contiguous to them on the north. The old Netherlandish

chronicles are filled with the most startling accounts of the damage

done by the irruptions of the ocean, from west winds or extraordinarily

high tides, at times long before any considerable extent of seacoast was

diked. Several hundreds of those terrible inundations are recorded, and

in many of them the loss of human lives is estimated as high as one

hundred thousand. It is impossible to doubt that there must be enormous

exaggeration in these numbers; for, with all the reckless hardihood

shown by men in braving the dangers and privations attached by nature to

their birthplace, it is inconceivable that so dense a population as such

wholesale destruction of life supposes could find the means of

subsistence, or content itself to dwell, on a territory liable, a dozen

times in a century, to such fearful devastation. There can be no doubt,

however, that the low continental shores of the German Ocean very

frequently suffered immense injury from inundation by the sea, and it is

natural, therefore, that the various arts of resistance to the

encroachments of the ocean, and, finally, of aggressive warfare upon its

domain, and of permanent conquest of its territory, should have been

earlier studied and carried to higher perfection in the latter

countries, than in England, which had less to lose or to gain by the

incursions or the retreat of the waters.

Indeed, although the confinement of swelling rivers by artificial

embankments is of great antiquity, I do not know that the defence or

acquisition of land from the sea by diking was ever practised on a large

scale until systematically undertaken by the Netherlanders, a few

centuries after the commencement of the Christian era. The silence of

the Roman historians affords a strong presumption that this art was

unknown to the inhabitants of the Netherlands at the time of the Roman

invasion, and the elder Pliny's description of the mode of life along

the coast which has now been long diked in, applies precisely to the

habits of the people who live on the low islands and mainland flats

lying outside of the chain of dikes, and wholly unprotected by

embankments of any sort.

Origin of Sea-dikes.

It has been conjectured, and not without probability, that the causeways

built by the Romans across the marshes of the Low Countries, in their

campaigns against the Germanic tribes, gave the natives the first hint

of the utility which might be derived from similar constructions applied

to a different purpose. [Footnote: It has often been alleged by eminent

writers that a part of the fens in Lincolnshire was reclaimed by

sea-dikes under the government of the Romans. I have found no ancient

authority in support of this assertion, nor can I refer to any passage

in Roman literature in which sea-dikes are expressly mentioned otherwise

than as walls or piers, except that in Pliny (Hist. Nat. xxxvi. 24),

where it is said that the Tyrrhenian Sea was excluded from the Lucrino

Lake by dikes. Dugdale, whose enthusiasm for his subject led him to

believe that recovering from the sea land subject to be flooded by it,

was of divine appointment, because God said: "Let the waters under the

heavens be gathered together unto one place and let the dry land

appear," unhesitatingly ascribes the reclamation of the Lincolnshire

fens to the Romans, though he is able to cite but one authority, a

passage in Tacitus's Life of Agricola which certainly has no such

meaning, in support of the assertion.--History of Embankment and

Drainage, 2d edition, 1772.] If this is so, it is one of the most

interesting among the many instances in which the arts and enginery of

war have been so modified as to be eminently promotive of the blessings

of peace, thereby in some measure compensating the wrongs and sufferings

they have inflicted on humanity. [Footnote: It is worth mentioning, as

an illustration of the applicability of military instrumentalities to

pacific art, that the sale of gunpowder in the United States was smaller

during the late rebellion than before, because the war caused the

suspension of many public and private improvements, in the execution of

which great quantities of powder were used for blasting.

The same observation was made in France during the Crimean war, and it

is alleged that, in general, not ten per cent. of the powder

manufactured on either either side of the Atlantic is employed for

military purposes.

The blasting for the Mount Cenis tunnel consumed gunpowder enough to

fill more than 200,000,000 musket cartridges. It is a fact not

creditable to the moral sense of modern civilization, that very many of

the most important improvements in machinery and the working of metals

have originated in the necessities of war, and that man's highest

ingenuity has been shown, and many of his most remarkable triumphs over

natural forces achieved, in the contrivance of engines for the

destruction of his fellow-man. The military material employed by the

first Napoleon has become, in less than two generations, nearly as

obsolete as the sling and stone of the shepherd, and attack and defence

now begin at distances to which, half a century ago, military

reconnaissances hardly extended. Upon a partial view of the subject, the

human race seems destined to become its own executioner--on the one

hand, exhausting the capacity of the earth to furnish sustenance to her

taskmaster; on the other, compensating diminished production by

inventing more efficient methods of exterminating the consumer. At the

present moment, at an epoch of universal peace, the whole civilized

world with the happy exception of our own country, is devoting its

utmost energies, applying the highest exercise of inventive genius, to

the production of new engines of war; and the last extraordinary rise in

the price of iron and copper is in great part due to the consumption of

these metals in the fabrication of arms and armed vessels. The simple

substitution of sheet-copper for paper and other materials in the

manufacture of cartridges has increased the market-price of copper by a

large percentage on its former cost.

But war develops great civil virtues, and brings into action a degree

and kind of physical energy which seldom fails to awaken a new

intellectual life in a people that achieves great moral and political

results through great heroism and endurance and perseverance. Domestic

corruption has destroyed more nations than foreign invasion, and a

people is rarely conquered till it has deserved subjugation.] The

Lowlanders are believed to have secured some coast and bay islands by

ring-dikes and to have embanked some fresh-water channels, as early as

the eighth or ninth century; but it does not appear that sea-dikes,

important enough to be noticed in historical records, were constructed

on the mainland before the thirteenth century. The practice of draining

inland accumulations of water, whether fresh or salt, for the purpose of

bringing under cultivation the ground they cover, is of later origin,

and is said not to have been adopted until after the middle of the

fifteenth century. [Footnote: Staring, Voormaals en Thans, p. 150.]

Gain and Loss of Land in the Netherlands.

The total amount of surface gained to the agriculture of the Netherlands

by diking out the sea and by draining shallow bays and lakes, is

estimated by Staring at three hundred and fifty-five thousand bunder or

hectares, equal to eight hundred and seventy-seven thousand two hundred

and forty acres, which is one-tenth of the area of the kingdom.

[Footnote: Idem, p. 163. Much the largest proportion of the lands so

reclaimed, though for the most part lying above low-water tidemark, are

at a lower level than the Lincolnshire fens, and more subject to

inundation from the irruptions of the sea.] In very many instances the

dikes have been partially, in some particularly exposed localities

totally, destroyed by the violence of the sea, and the drained lands

again flooded. In some cases the soil thus painfully won from the ocean

has been entirely lost; in others it has been recovered by repairing or

rebuilding the dikes and pumping out the water. Besides this, the weight

of the dikes gradually sinks them into the soft soil beneath, and this

loss of elevation must be compensated by raising the surface, while the

increased burden thus added tends to sink them still lower. "Tetens

declares," says Kohl, "that in some places the dikes have gradually sunk

to the depth of sixty or even a hundred feet." [Footnote: Die Inseln und

Marschen der Herzogthamer Schleswig und Holstein, iii., p. 151.] For

these reasons, the processes of dike-building have been almost

everywhere again and again repeated, and thus the total expenditure of

money and of labor upon the works in question is much greater than would

appear from an estimate of the actual cost of diking-in a given extent

of coast-land and draining a given area of water-surface. [Footnote:

The purely agricultural island of Pelworm, off the coast of Schleswig,

containing about 10,000 acres, annually expends for the maintenance of

its dikes not less than L6,000 sterling, or nearly $30,000.--J. G. Kohl,

Inseln und Marschen Schleswig's und Holstein's, ii., p. 394.

The original cost of the dikes of Pelworm is not stated. "The greatest

part of the province of Zeeland is protected by dikes measuring 250

miles in length, the maintenance of which costs, in ordinary years, more

than a million guilders [above $400,000] ... The annual expenditure for

dikes and hydraulic works in Holland is from five to seven million

guilders" [$2,000,000 to $2,800,000].--Wild, Die Niederlande, i., p. 62.

One is not sorry to learn that the Spanish tyranny in the Netherlands

had some compensations. The great chain of ring-dikes which surrounds a

large part of Zeeland is due to the energy of Caspar de Robles, the

Spanish governor of that province, who in 1570 ordered the construction

of these works at the public expense, as a substitute for the private

embankments which had previously partially served the same

purpose.--Wild, Die Niederlande, i., p. 62.]

Loss of Land by Incursions of Sea.

On the other hand, by erosion of the coast-line, the drifting of

sand-dunes into the interior, and the drowning of fens and morasses by

incursions of the sea--all caused, or at least greatly aggravated, by

human improvidence--the Netherlands have lost a far larger area of land

since the commencement of the Christian era than they have gained by

diking and draining. Staring despairs of the possibility of calculating

the loss from the first-mentioned two causes of destruction, but he

estimates that not less than six hundred and forty thousand bunder, or

one million five hundred and eighty-one thousand acres, of fen and marsh

have been washed away, or rather deprived of their vegetable surface and

covered by water; and thirty-seven thousand bunder, or ninety-one

thousand four hundred acres, of recovered land, have been lost by the

destruction of the dikes which protected them. [Footnote: Staring,

Voormaals en Thans, p. 163.] The average value of land gained from the

sea is estimated at about nineteen pounds sterling, or ninety dollars,

per acre; while the lost fen and morass was not worth more than one

twenty-fifth part of the same price. The ground buried by the drifting

of the dunes appears to have been almost entirely of this latter

character, and, upon the whole, there is no doubt that the soil added by

human industry to the territory of the Netherlands, within the

historical period, greatly exceeds in pecuniary value that which has

fallen a prey to the waves during the same era.

Upon most low and shelving coasts, like those of the Netherlands, the

maritime currents are constantly changing, in consequence of the

variability of the winds, and the shifting of the sand-banks, which the

currents themselves now form and now displace. While, therefore, at one

point the sea is advancing landward, and requiring great effort to

prevent the undermining and washing away of the dikes, it is shoaling at

another by its own deposits, and exposing, at low water, a gradually

widening belt of sands and ooze. The coast-lands selected for diking-in

are always at points where the sea is depositing productive soil. The

Eider, the Elbe, the Weser, the Ems, the Rhine, the Maas, and the

Schelde bring down large quantities of fine earth. The prevalence of

west winds prevents the waters from carrying this material far out from

the coast, and it is at last deposited northward or southward from the

mouth of the rivers which contribute it, according to the varying drift

of the currents.

Marine Deposits.

The process of natural deposit which prepares the coast for diking-in is

thus described by Staring: "All sea-deposited soil is composed of the

same constituents. First comes a stratum of sand, with marine shells, or

the shells of mollusks living in brackish water. If there be tides, and,

of course, flowing and ebbing currents, mud is let fall upon the sand

only after the latter has been raised above low-water mark; for then

only, at the change from flood to ebb, is the water still enough to form

a deposit of so light a material. Where mud is found at great depths,

as, for example, in a large proportion of the Ij, it is a proof that at

this point there was never any considerable tidal flow or other current.

... The powerful tidal currents, flowing and ebbing twice a day, drift

sand with them. They scoop out the bottom at one point, raise it at

another, and the sand-banks in the current are continually shifting. As

soon as a bank raises itself above low-water mark, flags and reeds

establish themselves upon it. The mechanical resistance of these plants

checks the retreat of the high water and favors the deposit of the earth

suspended in it, and the formation of land goes on with surprising

rapidity. When it has risen to high-water level, it is soon covered

with grasses, and becomes what is called schor in Zeeland, kwelder in

Friesland. Such grounds are the foundation or starting-point of the

process of diking. When they are once elevated to the flood-tide level,

no more mud is deposited upon them except by extraordinary high tides.

Their further rise is, accordingly, very slow, and it is seldom

advantageous to delay longer the operation of diking." [Footnote:

Voormaals en Thans, pp. 150, 151. According to Reventlov, confercae

first appear at the bottom in shoal water, then, after the deposit has

risen above the surface, Salicornia herbacea. The Salicornia is followed

by various sand-plants, and so the ground rises, by Poa distans and Poa

maritum, and finally common grasses establish themselves.--Om

Markdannelsen poa Vestkyeten of Slesvig, pp. 7, 8.]

Sea-dikes of the Netherlands.

The formation of new banks by the sea is constantly going on at points

favorable for the deposit of sand and earth, and hence opportunity is

continually afforded for enclosure of new land outside of that already

diked in, the coast is fast advancing seaward, and every new embankment

increases the security of former enclosures. The province of Zeeland

consists of islands washed by the sea on their western coasts, and

separated by the many channels through which the Schelde and some other

rivers find their way to the ocean. In the twelfth century these islands

were much smaller and more numerous than at present. They have been

gradually enlarged, and, in several instances, at last connected by the

extension of their system of dikes. Walcheren is formed of ten islets

united into one about the end of the fourteenth century. At the middle

of the fifteenth century, Goeree and Overflakkee consisted of separate

islands, containing altogether about ten thousand acres; by means of

above sixty successive advances of the dikes, they have been brought to

compose a single island, whose area is not less than sixty thousand

acres. [Footnote: Staring, Voormaals en Thans, p, 152. Kohl states that

the peninsula of Diksand on the coast of Holstein consisted, at the

close of the last century, of several islands measuring together less

than five thousand acres. In 1837 they had been connected with the

mainland, and had nearly doubled in area.--Inseln u. Marschen Schlene,

Holst., iii., p. 202]

In the Netherlands--which the first Napoleon characterized as a deposit

of the Rhine, and as, therefore, by natural law, rightfully the property

of him who controlled the sources of that great river--and on the

adjacent Frisie, Low German, and Danish shores and islands, sea and

river dikes have been constructed on a grander and more imposing scale

than in any other country. The whole economy of the art has been there

most thoroughly studied, and the literature of the subject is very

extensive. For my present aim, which is concerned with results rather

than with processes, it is not worth while to refer to professional

treatises, and I shall content myself with presenting such information

as can be gathered from works of a more popular character.

The superior strata of the lowlands upon and near the coast are, as we

have seen, principally composed of soil brought down by the great rivers

I have mentioned, and either directly deposited by them upon the sands

of the bottom, or carried out to sea by their currents, and then, after

a shorter or longer exposure to the chemical and mechanical action of

salt-water and marine currents, restored again to the land by tidal

overflow and subsidence from the waters in which it was suspended. At a

very remote period the coast-flats were, at many points, raised so high

by successive alluvious or tidal deposits as to be above ordinary

high-water level, but they were still liable to occasional inundation

from river-floods, and from the seawater also, when heavy or

long-continued west winds drove it landwards. The extraordinary

fertility of this soil and its security as a retreat from hostile

violence attracted to it a considerable population, while its want of

protection against inundation exposed it to the devastations of which

the chroniclers of the Middle Ages have left such highly colored

pictures. The first permanent dwellings on the coast-flats were erected

upon artificial mounds, and many similar precarious habitations still

exist on the unwalled islands and shores beyond the chain of dikes.

River embankments, which, as is familiarly known, have from the earliest

antiquity been employed in many countries where sea-dikes are unknown,

were probably the first works of this character constructed in the Low

Countries, and when two neighboring streams of fresh water had been

embanked, the next step in the process would naturally be to connect the

river-walls together by a transverse dike or raised causeway, which

would serve as a means of communication between different hamlets and at

the same time secure the intermediate ground both against the backwater

of river-floods and against overflow by the sea. The oldest true

sea-dikes described in historical records, however, are those enclosing

islands in the estuaries of the great rivers, and it is not impossible

that the double character they possess as a security against maritime

floods and as a military rampart, led to their adoption upon those

islands before similar constructions had been attempted upon the

mainland.

At some points of the coast, various contrivances, such as piers, piles,

and, in fact, obstructions of all sorts to the ebb of the current, are

employed to facilitate the deposit of slime, before a regular enclosure

is commenced. Usually, however, the first step is to build low and cheap

embankments, extending from an older dike, or from high ground, around

the parcel of flat intended to be secured. These are called summer

dikes. They are erected when a sufficient extent of ground to repay the

cost has been elevated enough to be covered with coarse vegetation fit

for pasturage. They serve both to secure the ground from overflow by the

ordinary flood-tides of mild weather, and to retain the slime deposited

by very high water, which would otherwise be partly carried off by the

retreating ebb. The elevation of the soil goes on slowly after this; but

when it has at last been sufficiently enriched, and raised high enough

to justify the necessary outlay, permanent dikes are constructed by

which the water is excluded at all seasons. These embankments are

constructed of sand from the coast-dunes or from sand-banks, and of

earth from the mainland or from flats outside the dikes, bound and

strengthened by fascines, and provided with sluices, which are generally

founded on piles and of very expensive construction, for drainage at low

water. The outward slope of the sea-dikes is gentle, experience having

shown that this form is least exposed to injury both from the waves and

from floating ice, and the most modern dikes are even more moderate in

the inclination of the seaward scarp than the older ones. [Footnote: The

inclination varies from one foot rise in four of base to one foot in

fourteen.--Kohl, iii., p. 210.] The crown of the dike, however, for the

last three or four feet of its height, is much steeper, being intended

rather as a protection against the spray than against the waves, and the

inner slope is always comparatively abrupt.

The height and thickness of dikes varies according to the elevation of

the ground they enclose, the rise of the tides, the direction of the

prevailing winds, and other special causes of exposure, but it may be

said that they are, in general, raised from fifteen to twenty feet above

ordinary high-water mark. The water-slopes of river-dikes are protected

by plantations of willows or strong semi-aquatic shrubs or grasses, but

as these will not grow upon banks exposed to salt-water, sea-dikes must

be faced with stone, fascines, or some other revetement. [Footnote: The

dikes are sometimes founded upon piles, and sometimes protected by one

or more rows of piles driven deeply down into the bed of the sea in

front of them. "Triple rows of piles of Scandinavian pine," says Wild,

"have been driven down along the coast of Friesland, where there are no

dunes, for a distance of one hundred and fifty miles. The piles are

bound together by strong cross-timbers and iron clamps, and the

interstices filled with stones. The ground adjacent to the piling is

secured with fascines, and at exposed points heavy blocks of stone are

heaped up as an additional protection. The earth-dike is built behind

the mighty bulwark of this breakwater, and its foot also is fortified

with stones." ... "The great Helder dike is about five miles long and

forty feet wide at the top, along which runs a good road. It slopes down

two hundred feet into the sea, at an angle of forty degrees. The highest

waves do not reach the summit, the lowest always cover its base. At

certain distances, immense buttresses, of a height and width

proportioned to those of the dike, and even more strongly built, run

several hundred feet out into the rolling sea. This gigantic artificial

coast is entirely composed of Norwegian granite."--Wild, Die

Niederlande, i., pp. 61, 62.] Upon the coast of Schleswig and Holstein,

where the people have less capital at their command, they defend their

embankments against ice and the waves by a coating of twisted straw or

reeds, which must be renewed as often as once, sometimes twice a year.

The inhabitants of these coasts call the chain of dikes "the golden

border," a name it well deserves, whether we suppose it to refer to its

enormous cost, or, as is more probable, to its immense value as a

protection to their fields and their firesides.

When outlying flats are enclosed by building new embankments the old

interior dikes are suffered to remain, both as an additional security

against the waves, and because the removal of them would be expensive.

They serve, also, as roads or causeways, a purpose for which the

embankments nearest the sea are seldom employed, because the whole

structure might be endangered from the breaking of the turf by wheels

and the hoofs of horses. Where successive rows of dikes have been thus

constructed, it is observed that the ground defended by the more ancient

embankments is lower than that embraced within the newer enclosures, and

this depression of level has been ascribed to a general subsidence of

the coast from geological causes; [Footnote: A similar subsidence of the

surface is observed in the diked ground of the Lincolnshire fens, where

there is no reason to suspect a general depression from geological

causes.] but the better opinion seems to be that it is, in most cases,

due merely to the consolidation and settling of the earth from being

more effectually dried, from the weight of the dikes, from the tread of

men and cattle, and from the movement of the heavy wagons which carry

off the crops. [Footnote: The shaking of the ground, even when loaded

with large buildings, by the passage of heavy carriages or artillery, or

by the march of a body of cavalry or even infantry, shows that such

causes may produce important mechanical effects on the condition of the

soil. The bogs in the Netherlands, as in most other countries, contain

large numbers of fallen trees, buried to a certain depth by earth and

vegetable mould. When the bogs are dry enough to serve as pastures, it

is observed that trunks of these ancient trees rise of themselves to the

surface. Staring ascribes this singular phenomenon to the agitation of

the ground by the tread of cattle. "When roadbeds," observes he, "are

constructed of gravel and pebbles of different sizes, and these latter

are placed at the bottom without being broken and rolled hard together,

they are soon brought to the top by the effect of travel on the road.

Lying loosely, they undergo some motion from the passage of every

wagon-wheel and the tread of every horse that passes over them. This

motion is an oscillation or partial rolling, and as one side of a pebble

is raised, a little fine sand or earth is forced under it, and the

frequent repetition of this process by cattle or carriages moving in

opposite directions brings it at last to the surface. We may suppose

that a similar effect is produced on the stems of trees in the bogs by

the tread of animals."--De Bodem van Nederland, i., pp. 75, 76.

It is observed in the Northern United States, that when soils containing

pebbles are cleared and cultivated, and the stones removed from the

surface, new pebbles, and even bowlders of many pounds weight, continue

to show themselves above the ground, every spring, for a long series of

years. In clayey soils the fence-posts are thrown up in a similar way,

and it is not uncommon to see the lower rail of a fence thus gradually

raised a foot or even two feet above the ground. This rising of stones

and fences is popularly ascribed to the action of the severe frosts of

that climate. The expansion of the ground, in freezing, it is said,

raises its surface, and, with the surface, objects lying near or

connected with it. When the soil thaws in the spring, it settles back

again to its former level, while the pebbles and posts are prevented

from sinking as low as before by loose earth which has fallen under

them. The fact that the elevation spoken of is observed only in the

spring gives countenance to this theory, which is perhaps applicable

also to the cases stated by Staring, and it is probable that the two

causes above assigned concur in producing the effect.

The question of the subsidence of the Netherlandish coast has been much

discussed. Not to mention earlier geologists, Venema, in several essays,

and particularly in Het Dalen van de Noordelijke Kuststreken van ons

Land, 1854, adduces many facts and arguments to prove a slow sinking of

the northere provinces of Holland. Laveleye (Affaissement du sol at

envasement des fleuves survenus dans les temps historiques, 1859), upon

a still fuller investigation, arrives at the same conclusion. The

eminent geologist Staring, however, who briefly refers to the subject in

De Bodem van Nederland, i., p. 356 et seqq., does not consider the

evidence sufficient to prove anything more than the sinking of the

surface of the polders from drying and consolidation.--See Elisee

Reclus, La Terre, vol. i., pp. 730, 732.]

Notwithstanding this slow sinking, most of the land enclosed by dikes is

still above low-water mark, and can, therefore, be wholly or partially

freed from rain-water, and from that received by infiltration from

higher ground, by sluices opened at the ebb of the tide. For this

purpose the land is carefully ditched, and advantage is taken of every

favorable occasion for discharging the water through the sluices. But

the ground cannot be effectually drained by this means, unless it is

elevated four or five feet, at least, above the level of the ebb-tide

because the ditches would not otherwise have a sufficient descent to

carry the water off in the short interval between ebb and flow, and

because the moisture of the saturated sub-soil is always rising by

capillary attraction. Whenever, therefore, the soil has sunk below the

level I have mentioned, and in cases where its surface has never been

raised above it, pumps, worked by wind or some other mechanical power,

must be very frequently employed to keep the land dry enough for

pasturage and cultivation. [Footnote: The elevation of the lands

enclosed by dikes--or polders, as they are called in Holland--above

low-water mark, depends upon the height of the tides or, in other words,

upon the difference between ebb and flood. The tide cannot deposit earth

higher than it flows, and after the ground is once enclosed, the decay

of the vegetables grown upon it and the addition of manures do not

compensate the depression occasional by drying and consolidation. On the

coast of Zeeland and the islands of South Holland, the tides, and of

course the surface of the lands deposited by them, are so high that the

polders can be drained by ditching and sluices, but at other points, as

in the enclosed grounds of North Holland on the Zuiderzee, where the

tide rises but three feet or even less, pumping is necessary from the

beginning.--Staring, Voormaals en Thans, p. 152]

DRAINING OF THE LAKE OF HAARLEM.

The substitution of steam-engines for the feeble and uncertain action of

windmills, in driving pumps, has much facilitated the removal of water

from the polders as well as the draining of lakes, marshes, and shallow

bays, and thus given such an impulse to these enterprises, that not less

than one hundred and ten thousand acres wore reclaimed from the waters,

and added to the agricultural domain of the Netherlands, between 1815

and 1855. The most important of these undertaking was the draining of

the Lake of Haarlem, and for this purpose some of the most powerful

hydraulic engines over constructed were designed and executed.

[Footnote: The principal engine, of 500 horse-power, drove eleven pumps

with a total delivery of 31,000 cubic yards per hour.--Wild, Die

Netherland, i., p. 87.] The origin of this lake is unknown. It is

supposed by some geographers to be a part of an ancient bed of the

Rhine, the channel of which, as there is good reason to believe, has

undergone great changes since the Roman invasion of the Netherlands; by

others it is thought to have once formed an inland marine channel,

separated from the sea by a chain of low islands, which the sand washed

up by the tides has since connected with the mainland and converted into

a continuous line of coast. The best authorities, however, find

geological evidence that the surface occupied by the lake was originally

a marshy tract containing within its limits little solid ground, but

many ponds and inlets, and much floating as well as fixed fen.

In consequence of the cutting of turf for fuel, and the destruction of

the few trees and shrubs which held the loose soil together with their

roots, the ponds are supposed to have gradually extended themselves,

until the action of the wind upon their enlarged surface gave their

waves sufficient force to overcome the resistance of the feeble barriers

which separated them, and to unite them all into a single lake. Popular

tradition, it is true, ascribes the formation of the Lake of Haarlem to

a single irruption of the sea, at a remote period, and connects it with

one or another of the destructive inundations of which the Netherland

chronicles describe so many; but on a map of the year 1531, a chain of

four smaller waters occupies nearly the ground afterwards covered by the

Lake of Haarlem, and they have most probably been united by gradual

encroachments resulting from the improvident practices above referred

to, though no doubt the consummation may have been hastened by floods,

and by the neglect to maintain dikes, or the intentional destruction of

them, in the long wars of the sixteenth century.

The Lake of Haarlem was a body of water not far from fifteen miles in

length, by seven in greatest width, lying between the cities of

Amsterdam and Leyden, running parallel with the coast of Holland at the

distance of about five miles from the sea, and covering an area of about

45,000 acres. By means of the Ij, it communicated with the Zuiderzee,

the Mediterranean of the Netherlands, and its surface was little above

the mean elevation of that of the sea. Whenever, therefore, the waters

of the Zuiderzee were acted upon by strong north-west winds, those of

the Lake of Haarlem were raised proportionally and driven southwards,

while winds from the south tended to create a flow in the opposite

direction. The shores of the lake were everywhere low, and though

between the years 1767 and 1848 more than $1,700,000 had been expended

in checking its encroachments, it often burst its barriers, and produced

destructive inundations. In November, 1836, a south wind brought its

waters to the very gates of Amsterdam, and in December of the same year,

in a north-west gale, they overflowed twenty thousand acres of land at

the southern extremity of the lake, and flooded a part of the city of

Leyden. The depth of water in the lake did not, in general, exceed

fourteen feet, but the bottom was a semi-fluid ooze or slime, which

partook of the agitation of the waves, and added considerably to their

mechanical force. Serious fears were entertained that the lake would

form a junction with the inland waters of the Legmeer and Mijdrecht,

swallow up a vast extent of valuable soil, and finally endanger the

security of a large proportion of the land which the industry of Holland

had gained in the course of centuries from the ocean.

For this reason, and for the sake of the large addition the bottom of

the lake would make to the cultivable soil of the state, it was resolved

to drain it, and the preliminary steps for that purpose were commenced

in the year 1840. The first operation was to surround the entire lake

with a ring-canal and dike, in order to cut off the communication with

the Ij, and to exclude the water of the streams and morasses which

discharged themselves into it from the land side. The dike was composed

of different materials, according to the means of supply at different

points, such as sand from the coast-dunes, earth and turf excavated from

the line of the ring-canal, and floating turf, [Footnote: In England and

New England, where the marshes have been already drained or are of

comparatively small extent, the existence of large floating islands

seems incredible, and has sometimes been treated as a fable, but no

geographical fact is better established. Kohl (Inseln und Marschen

Schleswig-Holsteins, iii., p. 309) reminds us that Pliny mentions among

the wonders of Germany the floating islands, covered with trees, which

met the Roman fleets at the mouths of the Elbe and the Weser. Our author

speaks also of having visited, in the territory of Bremen, floating

moors, bearing not only houses but whole villages. At low stages of the

water these moors rest upon a bed of sand, but are raised from six to

ten feet by the high water of spring, and remain afloat until, in the

course of the summer, the water beneath is exhausted by evaporation and

drainage, when they sink down upon the sand again.

Staring explains, in an interesting way, the whole growth, formation,

and functions of floating fens or bogs, in his very valuable work, De

Bodem van Nederland, i., pp. 36-43. The substance of his account is as

follows: The turf and the surface of the fens, is stillness of the

water. Hence they are not found in running streams, nor in pools so

large as to be subject to frequent agitation by the wind. For example,

not a single plant grew in the open part of the Lake of Haarlem, and

fens cease to form in all pools as soon as, by the cutting of the turf

for fuel or other purposes, their area is sufficiently enlarged to be

much acted on by wind. When still water above a yard deep is left

undisturbed, aquatic plants of various genera, such as Nuphar, Nymphaea,

Limnanthemum, Stratiotes, Polygonum, and Potamogeton, fill the bottom

with roots and cover the surface with leaves. Many of the plants die

every year, and prepare at the bottom a soil fit for the growth of a

higher order of vegetation, Phragmites, Acorus, Sparganium, Rumex,

Lythrum, Pedicularis, Spiraea, Polystichum, Comarum, Caltha, etc., etc.

In the course of twenty or thirty years the muddy bottom is filled with

roots of aquatic and marsh plants, which are lighter than water, and if

the depth is great enough to give room for detaching this vegetable

network, a couple of yard for example, it rises to the surface, bearing

with it, of course, the soil formed above it by decay of stems and

leaves. New genera now appear upon the mass, such a Carex, Menyanthes,

and others, and soon thicky cover it. The turf has now acquired a

thickness of from two to four feet, and is called in Groningen lad; in

Friesland, til, tilland, or drifftil; in Overijsse, krag; and in

Holland, rietzod. It floats about as driven by the wind, gradually

increasing in thickness by the decay of its annual crops of vegetation,

and in about half a century reaches the bottom and becomes fixed. If it

has not been invaded in the meantime by men or cattle, trees and

arborescent plants, Alnus, Salix, Myrica, etc., appear, and these

contribute to hasten the attachment of the turf to the bottom, both by

their weight and by sending their roots quite through into the ground."

This is the regular method employed by nature for the gradual filling up

of shallow lakes and pools, and converting them first into morass and

then into dry land. Whenever, therefore, man removes the peat or turf,

he exerts an injurious geographical agency, and, as I have already said,

there is no doubt that the immense extension of the inland seas of

Holland in modern times is owing to this and other human imprudences.

"Hundreds of hectares of floating pastures," says our author, "which

have nothing in their appearance to distinguish them from grass-lands

resting on solid bog, are found in Overijssel, in North Holland, and

near Utrecht. In short, they occur in all deep bogs, and wherever deep

water is left long undisturbed."

In one case a floating island, which had attached itself to the shore,

continued to float about for a long time after it was torn off by a

flood, and was solid enough to keep a pond of fresh water upon it sweet,

though the water in which it was swimming had become brackish from the

irruption of the sea. After the hay is cut, cattle are pastured, and

occasionally root-crops grown upon these islands, and they sometimes

have large trees growing upon them.

When the turf or peat has been cut, leaving water less than a yard deep,

Equisetum limosum grows at once, and is followed by the second class of

marsh plants mentioned above. Their roots do not become detached from

the bottom in such shallow water, but form ordinary turf or peat. These

processes are so rapid that a thickness of from three to six feet of

turf is formed in half a century, and many men have lived to mow grass

where they had fished in their boyhood, and to cut turf twice in the

same spot. In Ireland the growth of peat is said to be much more rapid.

Elisee Reclus, La Terre, i., 591, 592. But see Asbjornsen, Torv og

Torvdrift, ii., 29, 30.

Captain Gilliss says that before Lake Taguataga in Chili was drained,

there were in it islands composed of dead plants matted together to a

thickness of from four to six feet, and with trees of medium size

growing upon them. These islands floated before the wind "with their

trees and browsing cattle."--United States Naval Astronomical Expedition

to the Southern Hemisphere, i., pp. 16, 17.] fascines being everywhere

used to bind and compact the mass together. This operation was completed

in 1848, and three steam-pumps were then employed for five years in

discharging the water. The whole enterprise was conducted at the expense

of the state, and in 1853 the recovered lands were offered for sale for

its benefit. Up to 1858, forty-two thousand acres had been sold at not

far from sixteen pounds sterling or seventy-seven dollars an acre,

amounting altogether to L661,000 sterling or $3,200,000. The unsold

lands were valued at more than L6,000 or nearly $30,000, and as the

total cost was L764,500 or about $3,700,000, the direct loss to the

state, exclusive of interest on the capital expended, may be stated at

L100,000 or something less than $500,000.

The success of this operation has encouraged others of like nature in

Holland. The Zuid Plas, which covered 11,500 acres and was two feet

deeper than the Lake of Haarlem, has been drained, and a similar work

now in course of execution on an arm of the Scheld, will recover about

35,000 acres.

In a country like the United States, of almost boundless extent of

sparsely inhabited territory, such an expenditure for such an object

would be poor economy. But Holland has a narrow domain, great pecuniary

resources, an excessively crowded population, and a consequent need of

enlarged room and opportunity for the exercise of industry. Under such

circumstances, and especially with an exposure to dangers so formidable,

there is no question of the wisdom of the measure. It has already

provided homes and occupation for more than five thousand citizens, and

furnished a profitable investment for a private capital of not less than

L400,000 sterling or $2,000,000, which has been expended in improvements

over and above the purchase money of the soil; and the greater part of

this sum, as well as of the cost of drainage, has been paid as a

compensation for labor. The excess of governmental expenditure over the

receipts, if employed in constructing ships of war or fortifications,

would have added little to the military strength of the kingdom; but the

increase of territory, the multiplication of homes and firesides which

the people have an interest in defending, and the augmentation of

agricultural resources, constitute a stronger bulwark against foreign

invasion than a ship of the line or a fortress armed with a hundred

cannon.

Draining of the Zuiderzee.

I have referred to the draining of the Lake of Haarlem as an operation

of great geographical as well as economical and mechanical interest. A

much more gigantic project, of a similar character, is now engaging the

attention of the Netherlandish engineers. It is proposed to drain the

great salt-water basin called the Zuiderzee. This inland sea covers an

area of not less than two thousand square miles, or about one million

three hundred thousand acres. The seaward half, or that portion lying

north-west of a line drawn from Enkhuizen to Stavoren, is believed to

have been converted from a marsh to an open bay since the fifth century

after Christ, and this change is ascribed, partly if not wholly, to the

interference of man with the order of nature. The Zuiderzee communicates

with the sea by at least six considerable channels, separated from each

other by low islands, and the tide rises within the basin to the height

of three feet. To drain the Zuiderzee, these channels must first be

closed and the passage of the tidal flood through them cut off. If this

be done, the coast currents will be restored approximately to the lines

they followed fourteen or fifteen centuries ago, and thero can be little

doubt that an appreciable effect will thus be produced upon all the

tidal phenomena of that coast, and, of course, upon the maritime

geography of Holland.

A ring-dike and canal must then be constructed around the landward side

of the basin, to exclude and carry off the freshwater streams which now

empty into it. One of these, the Ijssel, a considerable river, has a

course of eighty miles, and is, in fact, one of the outlets of the

Rhine, though augmented by the waters of several independent

tributaries. These preparations being made, and perhaps transverse dikes

erected at convenient points for dividing the gulf into smaller

portions, the water must be pumped out by machinery, in substantially

the same way as in the case of the Lake of Haarlem. [Footnote: The

dependence of man upon the aid of spontaneous nature, in his most

arduous material works, is curiously illustrated by the fact that one of

the most serious difficulties to be encountered in executing this

gigantic scheme is that of procuring brushwood for the fascines to be

employed in the embankments. See Diggelen's pamphlet, "Groote Werken in

Nederland."] No safe calculations can be made as to the expenditure of

time and money required for the execution of this stupendous enterprise,

but I believe its practicability is not denied by competent judges,

though doubts are entertained as to its financial expediency. [Footnote:

The plan at present most in favor is that which proposes the drainage of

only a portion of the southern half of the Zuiderzee, which covers not

far from 400,000 acres. The project for the construction of a ship-canal

directly from Amsterdam to the North Sea, now in course of execution,

embraces the drainage of the Ij, a nearly land-locked basin

communicating with the Zuiderzee and covering more than 12,000 acres.

See official reports on these projects in Droogmaking vom het zuidelyk

gedeelte der Zuiderzee, te s' Gravenhage, 1868, 4to.] The geographical

results of this improvement would be analogous to those of the draining

of the Lake of Haarlem, but many times multiplied in extent, and its

meteorological effects, though perhaps not perceptible on the coast,

could hardly fail to be appreciable in the interior of Holland.

The bearing of the works I have noticed, and of others similar in

character, upon the social and moral, as well as the purely economical,

interests of the people of the Netherlands, has induced me to describe

them more in detail than the general purpose of this volume may be

thought to justify; but if we consider them simply from a geographical

point of view, we shall find that they are possessed of no small

importance as modifications of the natural condition of terrestrial

surface. There is good reason to believe that before the establishment

of a partially civilized race upon the territory now occupied by Dutch,

Frisic, and Low German communities, the grounds not exposed to

inundation were overgrown with dense woods; that the lowlands between

these forests and the sea-coasts were marshes, covered and partially

solidified by a thick matting of peat-plants and shrubs interspersed

with trees; and that even the sand-dunes of the shore were protected by

a vegetable growth which, in a great measure, prevented the drifting and

translocation of them.

The present causes of river and coast erosion existed, indeed, at the

period in question; but some of them must have acted with less

intensity, there were strong natural safeguards against the influence of

marine and fresh-water currents, and the conflicting tendencies had

arrived at a condition of approximate equilibrium, which permitted but

slow and gradual changes in the face of nature. The destruction of the

forests around the sources and along the valleys of the rivers by man

gave them a more torrential character. The felling of the trees, and the

extirpation of the shrubbery upon the fens by domestic cattle, deprived

the surface of its cohesion and consistence, and the cutting of peat for

fuel opened cavities in it, which, filling at once with water, rapidly

extended themselves by abrasion of their borders, and finally enlarged

to pools, lakes, and gulfs, like the Lake of Haarlem and the northern

part of the Zuiderzee. The cutting of the wood and the depasturing of

the grasses upon the sand-dunes converted them from solid bulwarks

against the ocean to loose accumulations of dust, which every sea-breeze

drove farther landward, burying, perhaps, fertile soil and choking up

water-courses on one side, and exposing the coast to erosion by the sea

upon the other.

Geographical Effect of Physical Improvements in the Netherlands.

The changes which human action has produced within twenty centuries in

the Netherlands and the neighboring provinces, are, certainly of no

small geographical importance, considered simply as a direct question of

loss and gain of territory. They have also, as we shall see hereafter,

undoubtedly been attended with some climatic consequences, they have

exercised a great influence on the spontaneous animal and vegetable life

of this region, and they cannot have failed to produce effects upon

tidal and other oceanic currents, the range of which may be very

extensive. The force of the tidal wave, the height to which it rises,

the direction of its currents, and, in fact, all the phenomena which

characterize it, as well as all the effects it produces, depend as much

upon the configuration of the coast it washes, and the depth of water,

and form of bottom near the shore, as upon the attraction which

occasions it. Every one of the terrestrial conditions which affect the

character of tidal and other marine currents has been very sensibly

modified by the operations I have described, and on this coast, at

least, man has acted almost as powerfully on the physical geography of

the sea as on that of the land. [Footnote: See, on the influence of the

artificial modification of the coast-line on tides and other marine

currents, Staring, De Bodem van Nederland, i., p. 279.]

Ancient Hydraulic Works.

The hydraulic works of the Netherlands and of the neighboring states are

of such magnitude that--with the exception of the dikes of the

Mississippi--they quite throw into the shade all other known artificial

arrangements for defending the land against the encroachments of the

rivers and the sea, and for reclaiming to the domain of agriculture and

civilization soil long covered by the waters. But although the recovery

and protection of lands flooded by the sea seems to be an art wholly of

Netherlandish origin, we have abundant evidence that, in ancient as well

as in comparatively modern times, great enterprises more or less

analogous in character have been successfully undertaken, both in inland

Europe and in the less familiar countries of the East.

In many cases no historical record remains to inform us when or by whom

such works were constructed. The Greeks and Romans, the latter

especially, were more inclined to undertake and carry out stupendous

material enterprises than to boast of them; and many of the grandest and

most important constructions of those nations are absolutely unnoticed

by contemporary annalists, and are first mentioned by writers living

after all knowledge of the epochs of the projectors of these works had

perished. Thus the aqueduct known as the Pont du Gard, near Nimes,

which, though not surpassing in volume or in probable cost other

analogous constructions of ancient and of modern ages, is yet among the

most majestic and imposing remains of ancient civil architecture, is not

so much as spoken of by any Roman author, [Footnote: One reason for the

silence of Roman writers in respect to great material improvements which

had no immediate relation to military or political objects, is doubtless

the contempt in which mechanical operations and mechanical contrivances

were held by that nation of spoilers. Even the engineer, upon whose

skill the attack or defence of a great city depended, was only

praefectus fabrum, the master-artisan, and had no military rank or

command. This prejudice continued to a late period in the Middle Ages,

and the chiefs of artillery were equally without grade or title as

soldiers.

"The occupations of all artisans," says Cicero, "are base, and the shop

can have nothing of the respectable." De Officiis, 1, i., 42. The

position of the surgeon relatively to the physician, in England, is a

remnant of the same prejudice, which still survives in full vigor in

Italy, with regard to both trade and industry. See p. 6, ante.] and we

are in absolute ignorance of the age or the construction of the

remarkable tunnel cut to drain Lake Copais in Boeotia. This lake, now

reduced by sedimentary deposit and the growth of aquatic and

semi-aquatic vegetation to the condition of a marsh, was originally

partially drained by natural subterranean outlets in the underlying

limestone rock, many of which still exist. But these emissaries, or

katavothra, as they are called in both ancient and modern Greek, were

insufficient for the discharge of the water, and besides, they were

constantly liable to be choked by earth and vegetables, and in such

cases the lake rose to a height which produced much injury. To remedy

this evil and secure a great accession of fertile soil, at some period

anterior to the existence of a written literature in Greece and ages

before the time of any prose author whose works have come down to us,

two tunnels, one of them four miles long, and of course not inferior to

the Torlonian emissary in length, were cut through the solid rock, and

may still be followed throughout their whole extent. They were repaired

in the time of Alexander the Great, in the fourth century before Christ,

and their date was at that time traditionally referred to the reign of

rulers who lived as early as the period of the Trojan war.

One of the best known hydraulic works of the Romans is the tunnel which

serves to discharge the surplus waters of the Lake of Albano, about

fourteen miles from Rome. This lake, about six miles in circuit,

occupies one of the craters of an extinct volcanic range, and the

surface of its waters is about nine hundred feet above the sea. It is

fed by rivulets and subterranean springs originating in the Alban Mount,

or Monte Cavo, the most elevated peak of the volcanic group just

mentioned, which rises to the height of about three thousand feet. At

present the lake has no discoverable natural outlet, and it is not known

that the water ever stood at such a height as to flow regularly over the

lip of the crater. It seems that at the earliest period of which we have

any authentic memorials, its level was usually kept by evaporation, or

by discharge through subterranean channels, considerably below the rim

of the basin which encompassed it, but in the year 397 B.C., the water,

either from the obstruction of such channels, or in consequence of

increased supplies from unknown sources, rose to such a height as to

flow over the edge of the crater, and threaten inundation to the country

below by bursting through its walls. To obviate this danger, a tunnel

for carrying off the water was pierced at a level much below the height

to which it had risen. This gallery, cut entirely with the chisel

through the rock for a distance of six thousand feet, or nearly a mile

and one-seventh, is still in so good condition as to serve its original

purpose. The fact that this work was contemporaneous with the siege of

Veii, has given to ancient annalists occasion to connect the two events,

but modern critics are inclined to reject Livy's account of the matter,

as one of the many improbable fables which disfigure the pages of that

historian. It is, however, repeated by Cicero and by Dionysius of

Halicarnassus, and it is by no means impossible that, in an age when

priests and soothsayers monopolized both the arts of natural magic and

the little which yet existed of physical science, the Government of

Rome, by their aid, availed itself at once of the superstition and of

the military ardor of its citizens to obtain their sanction to an

enterprise which sounder arguments might not have induced them to

approve.

Still more remarkable is the tunnel cut by the Emperor Claudius to drain

the Lake Fucinus, now Lago di Celano, in the former Neapolitan

territory, about fifty miles eastward of Rome. This lake, as far as its

history is known, has varied very considerably in its dimensions at

different periods, according to the character of the seasons. It lies

2,200 feet above the sea, and has no visible outlet, but was originally

either drained by natural subterranean conduits, or kept within certain

extreme limits by evaporation. In years of uncommon moisture it spread

over the adjacent soil and destroyed the crops; in dry seasons it

retreated, and produced epidemic disease by poisonous exhalations from

the decay of vegetable and animal matter upon its exposed bed. Julius

Caesar had proposed the construction of a tunnel to lower the bed of the

lake and provide a regular discharge for its waters, but the enterprise

was not actually undertaken until the reign of Claudius, when--after a

temporary failure, from errors in levelling by the engineers, as was

pretended at the time, or, as now appears certain, in consequence of

frauds by the contractors in the execution of the work--it was at least

partially completed. From this imperfect construction, it soon got out

of repair, but was restored by Hadrian, and is said to have answered its

design for some centuries. [Footnote: The fact alluded to in a note on

p. 97, ante, that since the opening of a communication between Lake

Celano and the Garigliano by the works noticed in the text, fish, of

species common in the lake, but not previously found in the river, have

become naturalized in the Garigliano, is a circumstance of some weight

as evidence that the emissary was not actually open in ancient times;

for if the waters had been really connected, the fish of the lake would

naturally have followed the descending current and established

themselves in the river as they have done now.] In the barbarism which

followed the downfall of the empire, it again fell into decay, and

though numerous attempts were made to repair it during the Middle Ages,

no tolerable success seems to have attended any of these efforts until

the present generation.

Draining of Lake Celano by Prince Torlonia.

Works have been some years in progress and are now substantially

completed, at a cost of about six millions of dollars, for restoring, or

rather enlarging and rebuilding, this ancient tunnel, upon a scale of

grandeur which does infinite honor to the liberality and public spirit

of the projectors, and with an ingenuity of design and a constructive

skill which reflect the highest credit upon the professional ability of

the engineers who have planned the works and directed their execution.

The length of the Roman tunnel was 18,634 feet, or rather more than

three miles and a half, but as the new emissary is designed to drain the

lake to the bottom, it must be continued to the lowest part of the

basin. It will consequently have a length of not less than 21,000 feet,

and, of course, is among the longest subterranean galleries in Europe.

Many curious particulars in the design and execution of the original

work have been observed in the course of the restoration, but these

cannot here be noticed. The difference between the lowest and highest

known levels of the surface of the lake is rather more than forty feet

and the difference between the areas covered by water at these levels is

not less than nine thousand acres. The complete drainage of the lake,

including the ground occasionally flooded, will recover, for

agricultural occupation, and permanently secure from inundation, about

forty-two thousand acres of as fertile soil as any in Italy. [Footnote:

Springs rising in the bottom of the lake have materially impeded the

process of drainage, and some engineers believe that they will render

the complete discharge of the waters impossible. It appears that the

earthy and rocky strata underlying the lake are extremely porous, and

that the ground already laid dry on the surface absorbs an abnormally

large proportion of the precipitation upon it. These strata, therefore,

constitute a reservoir which contributes to maintain the spring fed

chiefly, no doubt, by underground channels from the neighboring

mountains. But it is highly probable that, after a certain time, the

process of natural desiccation noticed in note to p. 20, ante, will

drain this reservoir, and the entire removal of the surface-water will

then become practicable.] The ground already dry enough for cultivation

furnishes occupation and a livelihood for a population of 16,000

persons, and it is thought that this number will be augmented to 40,000

when the drainage shall be completely effected.

The new tunnel follows the line of the Claudian emissary--which though

badly executed was admirably engineered--but its axis is at a somewhat

lower level than that of the old gallery, and its cross-section is about

two hundred and fifteen square feet, allowing a discharge of about 2,400

cubic feet to the second, while the Roman work had a cross-section of

only one hundred and two square feet, with a possible delivery of 424

cubic feet to the second.

In consequence of the nature of the rock and of the soil, which had been

loosened and shattered by the falling in of much of the crown and walls

of the old tunnel--every stone of which it was necessary to remove in

the progress of the work--and the great head of water in the lake from

unusually wet seasons, the technical difficulties to be surmounted were

most baffling and discouraging in character, and of such extreme gravity

that it may well be doubted whether the art of engineering has anywhere

triumphed over more serious obstacles. This great "victory of

peace"--probably the grandest work of physical improvement ever effected

by the means, the energy, and the munificence of a single individual--is

of no small geographical and economical, as well as sanitary,

importance, but it has a still higher moral value as an almost unique

example of the exercise of public spirit, courage, and perseverance in

the accomplishment of a noble and beneficent enterprise by a private

citizen. [Footnote: The draining of Lake Celano was undertaken by a

company, but Prince Alessandro Torlonia of Rome bought up the interest

of all the shareholders and has executed the entire work at his own

private expense. Montricher, the celebrated constructor of the great

aqueduct of Marseilles, was the engineer who designed and partly carried

out the plans, and after his lamentable death the work has been directed

with equal ability by Bermont and Brisse.--See Leon De Rothou,

Prosciugamento del Lago Fucino, 8vo. Firenza, 1871.]

The crater-lake of Nemi, in the same volcanic region as that of Albano,

is also drained by a subterranean tunnel probably of very ancient

construction, and the Valle-Riccia appears to have once been the basin

of a lake long since laid dry, but whether by the bursting of its banks

or by human art we are unable to say.

The success of the Lake Celano tunnel has suggested other like

improvements in Italy. A gallery has been cut, under circumstances of

great difficulty, to drain Lake Agnano near Naples, and a project for

the execution of a similar operation on the Lake of Perugia, the ancient

Trasimenus, which covers more than 40,000 acres, is under discussion.

Many similar enterprises have been conceived and executed in modern

times, both for the purpose of reclaiming land covered by water and for

sanitary reasons. [Footnote: A considerable work of this character is

mentioned by Captain Gilliss as having been executed in Chili, a country

to which we should hardly have looked for an improvement of such a

nature. The Lake Taguataga was partially drained by cutting through a

narrow ridge of land, not at the natural outlet, but upon one side of

the lake, and eight thousand acres of land covered by it were gained for

cultivation.--U. S. Naval Astronomical Expedition to the Southern

Hemisphere, i., pp. 16, 17.

Lake Balaton and the Neusiedler Sea in Hungary have lately been, at

least partially, drained.

The lakes of Neuchatel, Bienne, and Morat, in Switzerland, have been

connected and the common level of all of them lowered about four feet.

The works now in operation will produce, in the course of the year 1874,

a further depression of four feet, and recover for agricultural use more

than twelve thousand acres of fertile soil.] They are sometimes attended

with wholly unexpected evils, as, for example, in the case of Barton

Pond, in Vermont, and in that of a lake near Ragunda in Sweden, already

mentioned on a former page. Another still less obvious consequence of

the withdrawal of the waters has occasionally been observed in these

operations. The hydrostatic force with which the water, in virtue of its

specific gravity, presses against the banks that confine it, has a

tendency to sustain them whenever their composition and texture are not

such as to expose them to softening and dissolution by the infiltration

of the water. If, then, the slope of the banks is considerable, or if

the earth of which they are composed rests on a smooth and slippery

stratum inclining towards the bed of the lake, they are liable to fall

or slide forward when the mechanical support of the water is removed,

and this sometimes happens on a considerable scale. A few years ago the

surface of the Lake of Lungern, in the Canton of Unterwalden, in

Switzerland, was lowered by driving a tunnel about a quarter of a mile

long through the narrow ridge, called the Kaiserstuhl, which forms a

barrier at the north end of the basin. When the water was drawn off, the

banks, which are steep, cracked and burst, several acres of ground slid

down as low as the water receded, and even the whole village of Lungern

was thought to be in no small danger. [Footnote: In the course of the

year 1864 there were slides of the banks of the Lake of Como, and in one

case the grounds of a villa near the water suffered a considerable

displacement. More important slips occurred at Fesiolo on the shore of

Lago Maggiore in 1867 and 1869, and on the Lake of Orta in 1868. These

occurrences excited some apprehensions in regard to the possible effects

of projects then under discussion for lowering the level of some of the

Italian lakes, to obtain an increased supply of water for irrigation and

as a mechanical power, but as it was not proposed to depress the surface

below the lowest natural low-water level, there seems to have been

little ground for the fears expressed.

See, for important observations on the character and probable results of

these projects, Tagliasecchi, Nostizie etc. del Canali dell' Alta

Lombardia, Milano, 1871.

Jacini says: "A large proportion of the water of the lakes, instead of

discharging itself by the Ticino, the Adda, the Oglio, the Mincio,

filters through the silicious strata which underlie the hills, and

follows subterranean channels to the plain, where it collects in the

fontanili, and being thence conducted into the canals of irrigation,

becomes a source of great fertility."--La Proprieta Fondiaria, etc.,

p.144. The quantity of water escaping from the lakes by infiltration

depends much on the hydrostatic pressure on the bottom and the walls of

the lake-basins, and consequently the depression of the lake surface,

diminishing this pressure, would diminish the infiltration. Hence it is

possible that the lowering of the level of these lakes would manifest

itself in a decreased supply of water for the springs, fontanili, and

wells of Lombardy.]

Mountain Lakes.

Other inconveniences of a very serious character have often resulted

from the natural wearing down, or, much more frequently, the imprudent

destruction, of the barriers which confine mountain lakes. In their

natural condition, such basins serve both to receive and retain the

rocks and other detritus brought down by the torrents which empty into

them, and to check the impetus of the rushing waters by bringing them to

a temporary pause; but if the outlets are lowered so as to drain the

reservoirs, the torrents continue their rapid flow through the ancient

bed of the basins, and carry down with them the sand and gravel with

which they are charged, instead of depositing their burden as before in

the still waters of the lakes.

It is a common opinion in America that the river meadows, bottoms, or

intervales, as they are popularly called, are generally the beds of

ancient lakes which have burst their barriers and left running currents

in their place. It was shown by Dr.

Dwight, many years ago, that this is very far from being universally

true; but there is no doubt that mountain lakes were of much more

frequent occurrence in primitive than in modern geography, and there are

many chains of such still existing in regions where man has yet little

disturbed the original features of the earth. In the long valleys of the

Adirondack range in Northern New York, and in the mountainous parts of

Maine, eight, ten, and even more lakes and lakelets are sometimes found

in succession, each emptying into the next lower pool, and so all at

last into some considerable river. When the mountain slopes which supply

these basins shall be stripped of their woods, the augmented swelling of

the lakes will break down their barriers, their waters will run off, and

the valleys will present successions of flats with rivers running

through them, instead of chains of lakes connected by natural canals.

A similar state of things seems to have existed in the ancient geography

of France. "Nature," says Lavergne, "has not excavated on the flanks of

our Alps reservoirs as magnificent as those of Lombardy; she had,

however, constructed smaller but more numerous lakes, which the

improvidence of man has permitted to disappear. Auguste de Gasparin

demonstrated more than thirty years ago that many natural dikes formerly

existed in the mountain valleys, which have been swept away by the

waters." [Footnote: Economie Rurale de la France, p. 289.]

Many Alpine valleys in Switzerland and Italy present unquestionable

evidence of the former existence of chains of lakes in their basins, and

this may be regarded as a general fact in regard to the primitive

topography of mountainous regions. Where the forests have not been

destroyed, the lakes remain as characteristic features of the

geographical surface. But when the woods are felled, these reservoirs

are sooner or later filled up by wash from the shores, and of course

disappear. Geologists have calculated the period when the bottom of the

Lake of Geneva will be levelled up and its outlet worn down. The Rhone

will then flow, in an unbroken current, from its source in the great

Rhone glacier to the Mediterranean Sea.

Draining of Swamps.

The reclamation of bogs and swamps by draining off the surface-water is

doubtless much more ancient than the draining of lakes. The beneficial

results of the former mode of improvement are more unequivocal, and

balanced by fewer disadvantages, and, at the same time, the processes by

which it is effected are much simpler and more obvious. It has

accordingly been practised through the whole historical period, and in

recent times operations for this purpose have assumed a magnitude, and

been attended with economical as well as sanitary and geographical

effects, which entitle them to a high place in the efforts of man to

ameliorate the natural conditions of the soil he occupies.

The methods by which the draining of marshes is ordinarily accomplished

are too familiar, and examples of their successful employment too

frequent, to require description, and I shall content myself, for the

moment, with a brief notice of some recent operations of this sort which

are less generally known than their importance merits.

Within the present century more than half a million acres of swamp-land

have been drained and brought under cultivation in Hungary, and works

are in progress which will ultimately recover a still larger area for

human use. The most remarkable feature of these operations, and at the

same time the process which has been most immediately successful and

remunerative, is what is called in Europe the regulation of

water-courses, and especially of the River Theiss, on the lower course

of which stream alone not less than 250,000 acres of pestilential and

wholly unproductive marsh have been converted into a healthful region of

the most exuberant fertility.

The regulation of a river consists in straightening its channel by

cutting off bends, securing its banks from erosion by floods, and, where

necessary, by constructing embankments to confine the waters and prevent

them from overflowing and stagnating upon the low grounds which skirt

their current. In the course of the Theiss about sixty bends, including

some of considerable length, have been cut off, and dikes sufficient for

securing the land along its banks against inundation have been

constructed.

Many thousand acres of land have been recently permanently improved in

Italy by the draining of swamps, and extensive operations have been

projected and commenced on the lower Rhone, and elsewhere in France,

with the same object. [Footnote: Very interesting and important

experiments, on the practicability of washing out the salt from seacoast

lands too highly impregnated with that mineral to be fit for

cultivation, are now in progress near the mouth of the Rhone, where

millions of acres of marshy soil can easily be recovered, if these

experiments are successful.

See Duponchel, Traite d'Hydraulique et de Geologie agricoles. Paris,

1868, chap. xi. and xii.

In the neighborhood of Ferrara are pools and marshes covering nearly two

hundred square miles, or a surface more than equal to eight American

townships. Centrifugal steam-pumps, of 2,000 horse-power, capable of

discharging more than six hundred and fifty millions of gallons of water

per day have lately been constructed in England for draining these

marshes. This discharge is equal to an area of 640 acres, or a mile

square, with nearly three feet of water.] But there is probably no

country where greater improvements of this sort have either been lately

effected, or are now in course of accomplishment, than in our own. Not

to speak of well-known works on the New Jersey seacoast and the shores

of Lake Michigan, the people of the new State of California are engaging

in this mode of subduing nature with as much enterprise and energy as

they have shown in the search for gold. The Report of the Agricultural

Department of the United States for January, 1872, notices, with more or

less detail, several highly successful experiments in California in the

way of swamp-drainage and securing land from overflow, and it appears

that not far from 200,000 acres have either very recently undergone or

will soon be subjected to this method of improvement.

Agricultural Draining.

I have commenced this chapter with a description of the dikes and other

hydraulic works of the Netherland engineers, because both the immediate

and the remote results of such operations are more obvious and more

easily measured, though certainly not more important, than those of much

older and more widely diffused modes of resisting or directing the flow

of waters, which have been practised from remote antiquity in the

interior of all civilized countries. Draining and irrigation are

habitually regarded as purely agricultural processes, having little or

no relation to technical geography; but we shall find that they exert a

powerful influence on soil, climate, and animal and vegetable life, and

may, therefore, justly claim to be regarded as geographical elements.

Superficial draining is a necessity in all lands newly reclaimed from

the forest. The face of the ground in the woods is never so regularly

inclined as to permit water to flow freely over it. There are, even on

the hillsides, small ridges depressions, partly belonging to the

original distribution of the soil, and partly occasioned by

irregularities in the growth and deposit of vegetable matter. These, in

the husbandry of nature, serve as dams and reservoirs to collect a

larger supply of moisture than the spongy earth can at once imbibe.

Besides this, the vegetable mould is, even under the most favorable

circumstances, slow in parting with the humidity it has accumulated

under the protection of the woods, and the infiltration from neighboring

forests contributes to keep the soil of small clearings too wet for the

advantageous cultivation of artificial crops. For these reasons, surface

draining must have commenced with agriculture itself, and there is

probably no cultivated district, one may almost say no single field,

which is not provided with artificial arrangements for facilitating the

escape of superficial water, and thus carrying off moisture which, in

the natural condition of the earth, would have been imbibed by the soil.

All these processes belong to the incipient civilization of the

ante-historical periods, but the construction of subterranean channels

for the removal of infiltrated water marks ages and countries

distinguished by a great advance in agricultural theory and practice, a

great accumulation of pecuniary capital and a density of population

which creates a ready demand and a high price for all products of rural

industry. Under draining, too, would be most advantageous in damp and

cool climates, where evaporation is slow, and upon soils where the

natural inclination of surface does not promote a very rapid flow of the

surface-waters. All the conditions required to make this mode of rural

improvement, if not absolutely necessary, at least profitable, exist in

Great Britain, and it is, therefore, very natural that the wealthy and

intelligent farmers of England should have carried this practice

farther, and reaped a more abundant pecuniary return from it, than those

of any other country.

Besides superficial and subsoil drains, there is another method of

disposing of superfluous surface-water, which, however, can rarely be

practised, because the necessary conditions for its employment are not

of frequent occurrence. Whenever a tenacious water-holding stratum rests

on a loose, gravelly bed so situated as to admit of a free discharge of

water from or through it by means of the outcropping of the bed at a

lower level, or of deep-lying conduits leading to distant points of

discharge, superficial waters may be carried off by opening a passage

for them through the impervious into the permeable stratum. Thus,

according to Bischof, as early as the time of King Rene, in the first

half of the fifteenth century, when subsoil drainage was scarcely known,

the plain of Paluns, near Marseilles, was laid dry by boring, and

Wittwer informs us that drainage is effected at Munich by conducting the

superfluous water into large excavations, from which it filters through

into a lower stratum of pebble and gravel lying a little above the level

of the river Isar. [Foonote: Physikalische Geographie, p. 288. This

method is now frequently employed in France. Details as to the processes

will be found in Mangon Pratique du Drainage, pp. 78 et seqq. Draining

by driving down stakes mentioned in a note in the chapter on the Woods,

ante, is a process of the same nature.

In the United States, large tracts of marshy ground, and even shallow

lakes of considerable extent, have been sufficiently drained not only

for pasturage but for cultivation, without resort to any special

measures for effecting that end. The ordinary processes of rural

improvement in the vicinity, such as felling woods upon and around such

grounds, and the construction of roads, the side ditches of which act as

drains, over or near them, aided now and then by the removal of a fallen

tree or other accidental obstruction in the beds of small streams which

flow from them, often suffice to reclaim miles square of unproductive

swamp and water. See notes on p. 20, and on cedar swamps, p. 208, ante.]

So at Washington, in the western part of the city, which lies high above

the rivers Potomac and Rock Creek, many houses are provided with dry

wells for draining their cellars and foundations. These extend through

hard, tenacious earth to the depth of thirty or forty feet, when they

strike a stratum of gravel, through which the water readily passes off.

This practice has been extensively employed at Paris, not merely for

carrying off ordinary surface-water, but for the discharge of offensive

and deleterious fluids from chemical and manufacturing establishments. A

well of this sort received, in the winter of 1832-'33, twenty thousand

gallons per day of the foul water from a starch factory, and the same

process was largely used in other factories. The apprehension of injury

to common and artesian wells and springs led to an investigation on this

subject by Girard and Parent Duchatelet, in the latter year. The report

of these gentlemen, published in the Annales des Ponts et Chaussees for

1833, second half-year, is full of curious and instructive facts

respecting the position and distribution of the subterranean waters

under and near Paris; but it must suffice to say that the report came to

the conclusion that, in consequence of the absolute immobility of these

waters, and the relatively small quantity of noxious fluid to be

conveyed to them, there was no danger of the diffusion of such fluid if

discharged into them. This result will not surprise those who know that,

in another work, Duchatelet maintains analogous opinions as to the

effect of the discharge of the city sewers into the Seine or the waters

of that river. The quantity of matter delivered by them he holds to be

so nearly infinitesimal, as compared with the volume of water of the

river, that it cannot possibly affect it to a sensible degree, and

therefore cannot render the Seine water unfit for drinking. [Foonote:

Coste found, in his experiments on pisciculture, that the fermentation,

which takes place in the water of the Seine in consequence of the

discharge of the drains into the river, destroyed a large proportion of

the eggs of fish in his breeding basins. Analysis of Seine water by

Boussingault in 1855 detected a considerable quantity of ammonia.]

Meteorological Effects of Draining.