found, of a kind to endear them to a critical public already
sufficiently scandalized by their general mode of behaviour to their
inoffensive neighbours. As mothers, indeed, gossip itself had not a
word of blame to whisper against them; but as wives, their conduct was
distinctly open to the severest animadversion. The males of the garden
spider, as in many other instances, are decidedly smaller than their
big round mates; so much so is this the case, indeed, in certain
species that they seem almost like parasites of the immensely larger
sack-bodied females. Now, just as the worker bees kill off the drones
as soon as the queen-bee has been duly fertilized, regarding them as of
no further importance or value to the hive, so do the lady-spiders not
only kill but eat their husbands as soon as they find they have no
further use for them. Nay, if a female spider doesn't care for the
looks of a suitor who is pressing himself too much upon her fond
attention, her way of expressing her disapprobation of his appearance
and manners is to make a murderous spring at him, and, if possible,
devour him. Under these painful circumstances the process of courtship
is necessarily to some extent a difficult and delicate one, fraught
with no small danger to the adventurous swain who has the boldness to
commend himself by personal approach to these very fickle and irascible
fair ones. It was most curious and exciting, accordingly, to watch the
details of the strange courtship, which we could only observe in the
case of the cruel Eliza, the rather gentler Lucy having been already
mated, apparently, before she took up her quarters in our climbing
white rose-bush. One day, however, a timid-looking male spider, with
inquiry and doubt in every movement of his tarsi, strolled tentatively
up on the neat round web where Eliza was hanging, head downward as
usual, all her feet on the thread, on the look-out for house-flies. We
knew he was a male at once by his longer and thinner body, and by his
natural modesty. He walked gingerly on all eights, like an arachnid
Agag, in the direction of the object of his ardent affections, with a
most comic uncertainty in every step he took towards her. His claws
felt the threads as he moved with anxious care; and it was clear he was
ready at a moment's notice to jump away and flee for his life with
headlong speed to his native obscurity if Eliza showed the slightest
disposition, by gesture or movement, to turn and rend him. Now and
again, as he approached, Eliza, half coquettish, moved her feet a short
step, and seemed to debate within her own mind in which spirit she
should meet his flattering advances--whether to accept him or to eat
him. At each such hesitation, the unhappy male, fearing the worst, and
sore afraid, would turn on his heel and fly for dear life as fast as
eight trembling legs would carry him. Then, after a minute or two, he
would evidently come to the conclusion that he had wronged his
lady-love, and that her movement was one of true, true love rather than
of carnivorous and cannibalistic appetite. At last, as I judged, his
constancy was rewarded, though his ominous disappearance very shortly
afterwards made me fear for the worst as to his final adventures.
In the end, Eliza laid a large number of eggs in a silken cocoon, in
shape a balloon, and secreted, like the web, by her invaluable
spinnerets. Indeed, the real reason--I won't say excuse--for the
rapacity and Gargantuan appetite of the spider lies, no doubt, in the
immense amount of material she has to supply for her daily-renewed
webs, her home, and her cocoon, all which have actually to be spun out
of the assimilated food-stuffs in her own body; to say nothing of the
additional necessity imposed upon her by nature for laying a trifle of
six or seven hundred eggs in a single summer. And, to tell the truth,
Lucy and Eliza seemed to us to be always eating. No matter at what hour
one looked in upon them, they were pretty constantly engaged in
devouring some inoffensive fly, or weaving hateful labyrinths of hasty
cord round some fiercely-struggling wasp or some unhappy beetle.
We weren't fortunate enough, I regret to say, to see Eliza's eggs hatch
out from the cocoon; but in other instances, especially in Southern
Europe, I have noticed the little heap of well-covered ova, glued
together into a mass, and attached to a branch or twig by stout silken
cables. If you open the cocoon when the young spiders are just hatched,
they begin to run about in the most lively fashion, and look like a
living and moving congeries of little balls or seedlets. The common
garden spider lays some seven hundred or more such eggs at a sitting,
and out of those seven hundred only two on an average reach maturity
and once more propagate their kind. For if only four lived and throve,
then clearly, in the next generation, there would be twice as many
spiders as in this; and in the generation after that again, four times
as many; and then eight times; and so on _ad infinitum_, until the
whole world was just one living and seething mass of common garden
spiders.
What keeps them down, then, in the end to their average number? What
prevents the development of the whole seven hundred? The simple answer
is, continuous starvation. As usual, nature works with cruel
lavishness. There are just as many spiders at any given minute as there
are insects enough in the world or in their area to feed upon. Every
spider lays hundreds of eggs, so as to make up for the average infant
mortality by starvation, or by the attacks of ichneumon flies, or by
being eaten themselves in the young stage, or by other casualties. And
so with all other species. Each produces as many young on the average
as will allow for the ordinary infant mortality of their kind, and
leave enough over just to replace the parents in the next generation.
And that's one of the reasons why it's no use punishing Lucy and Eliza
for their misdeeds in this world. Kill them off if you will, and before
next week a dozen more like them will dispute with one another the
vacant place you have thus created in the balanced economy of that
microcosm the garden.
Our observations upon Lucy and Eliza, however, had the effect of making
us take an increased interest thenceforth in spiders in general, which
till that time we had treated with scant courtesy, and set us about
learning something as to the extraordinary variety of life and habit to
be found within the range of this single group of arthropods, at first
sight so extremely alike in their shapes, their appearance, their
morals, and their manners. It's perfectly astonishing, though, when one
comes to look into it in detail, how exceedingly diverse spiders are in
their mode of life, their structure, and the variety of uses to which
they put their one extremely distinctive structural organ, the
spinnerets. I will only say here that some spiders use these peculiar
glands to form light webs by whose aid, though wingless, they float
balloon-wise through the air; that others employ them to line the sides
of their underground tunnels, and to make the basis of their
marvellously ingenious earthen trap-doors; that yet others have learnt
how to adapt these same organs to a subaquatic existence, and to fill
cocoons with air, like miniature diving bells; while others, again,
have taught themselves to construct webs thick enough to catch and hold
even creatures so superior to themselves in the scale of being as
humming-birds and sunbirds. This extraordinary variety in the
utilization of a single organ teaches once more the same lesson which
is impressed upon us elsewhere by so many other forms of organic
evolution: whatever enables an animal or plant to gain an advantage
over others in the struggle for life, no matter in what way, is sure to
survive, and to be turned in time to every conceivable use of which its
structure is capable, in the infinite whirligig of ever-varying nature.
MUD.
Even a prejudiced observer will readily admit that the most valuable
mineral on earth is mud. Diamonds and rubies are just nowhere by
comparison. I don't mean weight for weight, of course--mud is 'cheap as
dirt,' to buy in small quantities--but aggregate for aggregate. Quite
literally, and without hocus-pocus of any sort, the money valuation of
the mud in the world must outnumber many thousand times the money
valuation of all the other minerals put together. Only we reckon it
usually not by the ton, but by the acre, though the acre is worth most
where the mud lies deepest. Nay, more, the world's wealth is wholly
based on mud. Corn, not gold, is the true standard of value. Without
mud there would be no human life, no productions of any kind: for food
stuffs of every description are raised on mud; and where no mud exists,
or can be made to exist, there, we say, there is desert or sand-waste.
Land, without mud, has no economic value. To put it briefly, the only
parts of the world that count much for human habitation are the mud
deposits of the great rivers, and notably of the Nile, the Euphrates,
the Ganges, the Indus, the Irrawaddy, the Hoang Ho, the Yang-tse-Kiang;
of the Po, the Rhone, the Danube, the Rhine, the Volga, the Dnieper; of
the St. Lawrence, the Mississippi, the Missouri, the Orinoco, the
Amazons, the La Plata. A corn-field is just a big mass of mud; and the
deeper and purer and freer from stones or other impurities it is the
better.
But England, you say, is not a great river-mud field; yet it supports
the densest population in the world. True; but England is an
exceptional product of modern civilization. She can't feed herself: she
is fed from Odessa, Alexandria, Bombay, New York, Montreal, Buenos
Ayres--in other words, from the mud fields of the Russian, the
Egyptian, the Indian, the American, the Canadian, the Argentine rivers.
Orontes, said Juvenal, has flowed into Tiber; Nile, we may say
nowadays, with equal truth, has flowed into Thames.
There is nothing to make one realize the importance of mud, indeed,
like a journey up Nile when the inundation is just over. You lounge on
the deck of your dahabieh, and drink in geography almost without
knowing it. The voyage forms a perfect introduction to the study of
mudology, and suggests to the observant mind (meaning you and me) the
real nature of mud as nothing else on earth that I know of can suggest
it. For in Egypt you get your phenomenon isolated, as it were, from all
disturbing elements. You have no rainfall to bother you, no local
streams, no complex denudation: the Nile does all, and the Nile does
everything. On either hand stretches away the bare desert, rising up in
grey rocky hills. Down the midst runs the one long line of alluvial
soil--in other words, Nile mud--which alone allows cultivation and life
in that rainless district. The country bases itself absolutely on mud.
The crops are raised on it; the houses and villages are built of it;
the land is manured with it; the very air is full of it. The crude
brick buildings that dissolve in dust are Nile mud solidified; the red
pottery of Assiout is Nile mud baked hard; the village mosques and
minarets are Nile mud whitewashed. I have even seen a ship's bulwarks
neatly repaired with mud. It pervades the whole land, when wet, as mud
undisguised; when dry, as dust-storm.
Egypt, says Herodotus, is a gift of the Nile. A truer or more pregnant
word was never spoken. Of course it is just equally true, in a way,
that Bengal is a gift of the Ganges, and that Louisiana and Arkansas
are gifts of the Mississippi; but with this difference, that in the
case of the Nile the dependence is far more obvious, far freer from
disturbing or distracting details. For that reason, and also because
the Nile is so much more familiar to most English-speaking folk than
the American rivers, I choose Egypt first as my type of a regular
mud-land. But in order to understand it fully you mustn't stop all your
time in Cairo and the Delta; you mustn't view it only from the terrace
of Shepheard's Hotel or the rocky platform of the Great Pyramid at
Ghizeh: you must push up country early, under Mr. Cook's care, to Luxor
and the First Cataract. It is up country that Egypt unrolls itself
visibly before your eyes in the very process of making: it is there
that the full importance of good, rich black mud first forces itself
upon you by undeniable evidence.
For remember that, from a point above Berber to the sea, the dwindling
Nile never receives a single tributary, a single drop of fresh water.
For more than fifteen hundred miles the ever-lessening river rolls on
between bare desert hills and spreads fertility over the deep valley in
their midst--just as far as its own mud sheet can cover the barren
rocky bottom, and no farther. For the most part the line of demarcation
between the grey bare desert and the cultivable plain is as clear and
as well-defined as the margin of sea and land: you can stand with one
foot on the barren rock and one on the green soil of the tilled and
irrigated mud-land. For the water rises up to a certain level, and to
that level accordingly it distributes both mud and moisture: above it
comes the arid rock, as destitute of life, as dead and bare and lonely
as the centre of Sahara. In and out, in waving line, up to the base of
the hills, cultivation and greenery follow, with absolute accuracy, the
line of highest flood-level; beyond it the hot rock stretches dreary
and desolate. Here and there islands of sandstone stand out above the
green sea of doura or cotton; here and there a bay of fertility runs
away up some lateral valley, following the course of the mud; but one
inch above the inundation-mark vegetation and life stop short all at
once with absolute abruptness. In Egypt, then, more than anywhere else,
one sees with one's own eyes that mud and moisture are the very
conditions of mundane fertility.
Beyond Cairo, as one descends seaward, the mud begins to open out
fan-wise and form a delta. The narrow mountain ranges no longer hem it
in. It has room to expand and spread itself freely over the surrounding
country, won by degrees from the Mediterranean. At the mouths the mud
pours out into the sea and forms fresh deposits constantly on the
bottom, which are gradually silting up still newer lands to seaward.
Slow as is the progress of this land-forming action, there can be no
doubt that the Nile has the intention of filling up by degrees the
whole eastern Mediterranean, and that in process of time--say in no
more than a few million years or so, a mere bagatelle to the
geologist--with the aid of the Po and some other lesser streams, it
will transform the entire basin of the inland sea into a level and
cultivable plain, like Bengal or Mesopotamia, themselves (as we shall
see) the final result of just such silting action.
It is so very important, for those who wish to see things "as clear as
mud," to understand this prime principle of the formation of mud-lands,
that I shall make no apology for insisting on it further in some little
detail; for when one comes to look the matter plainly in the face, one
can see in a minute that almost all the big things in human history
have been entirely dependent upon the mud of the great rivers. Thebes
and Memphis, Rameses and Amenhotep, based their civilisation absolutely
upon the mud of Nile. The bricks of Babylon were moulded of Euphrates
mud; the greatness of Nineveh reposed on the silt of the Tigris. Upper
India is the Indus; Agra and Delhi are Ganges and Jumna mud; China is
the Hoang Ho and the Yang-tse-Kiang; Burmah is the paddy field of the
Irrawaddy delta. And so many great plains in either hemisphere consist
really of nothing else but mud-banks of almost incredible extent,
filling up prehistoric Baltics and Mediterraneans, that a glance at the
probable course of future evolution in this respect may help us to
understand and to realize more fully the gigantic scale of some past
accumulations.
As a preliminary canter I shall trot out first the valley of the Po,
the existing mud flat best known by personal experience to the feet and
eyes of the tweed-clad English tourist. Everybody who has looked down
upon the wide Lombard plain from the pinnacled roof of Milan Cathedral,
or who has passed by rail through that monotonous level of poplars and
vines between Verona and Venice, knows well what a mud flat due to
inundation and gradual silting up of a valley looks like. What I want
to do now is to inquire into its origin, and to follow up in fancy the
same process, still in action, till it has filled the Adriatic from end
to end with one great cultivable lowland.
Once upon a time (I like to be at least as precise as a fairy tale in
the matter of dates) there was no Lombardy. And that time was not,
geologically speaking, so very remote; for the whole valley of the Po,
from Turin to the sea, consists entirely of alluvial deposits--or, in
other words, of Alpine mud--which has all accumulated where it now lies
at a fairly recent period. We know it is recent, because no part of
Italy has ever been submerged since it began to gather there. To put it
more definitely, the entire mass has almost certainly been laid down
since the first appearance of man on our earth: the earliest human
beings who reached the Alps or the Apennines--black savages clad in
skins of extinct wild beasts--must have looked down from their slopes,
with shaded eyes, not on a level plain such as we see to-day, but on a
great arm of the sea which stretched like a gulf far up towards the
base of the hills about Turin and Rivoli. Of this ancient sea the
Adriatic forms the still unsilted portion. In other words, the great
gulf which now stops short at Trieste and Venice once washed the foot
of the Alps and the Apennines to the Superga at Turin, covering the
sites of Padua, Ferrara, Bologna, Ravenna, Mantua, Cremona, Modena,
Parma, Piacenza, Pavia, Milan, and Novara. The industrious reader who
gets out his Baedeker and looks up the shaded map of North Italy which
forms its frontispiece will be rewarded for his pains by a better
comprehension of the district thus demarcated. The idle must be content
to take my word for what follows. I pledge them my honour that I'll do
my best not to deceive their trustful innocence.
It may sound at first hearing a strange thing to say so, but the whole
of that vast gulf, from Turin to Venice, has been entirely filled up
within the human period by the mud sheet brought down by mountain
torrents from the Alps and the Apennines.
A parallel elsewhere will make this easier of belief. You have looked
down, no doubt, from the garden of the hotel at Glion upon the lake of
Geneva and the valley of the Rhone about Villeneuve and Aigle. If so,
you can understand from personal knowledge the first great stage in the
mud-filling process; for you must have observed for yourself from that
commanding height that the lake once extended a great deal farther up
country towards Bex and St. Maurice than it does at present. You can
still trace at once on either side the old mountainous banks,
descending into the plain as abruptly and unmistakably as they still
descend to the water's edge at Montreux and Vevey. But the silt of the
Rhone, brought down in great sheets of glacier mud (about which more
anon) from the Furca and the Jungfrau and the Monte Rosa chain, has
completely filled in the upper nine miles of the old lake basin with a
level mass of fertile alluvium. There is no doubt about the fact: you
can see it for yourself with half an eye from that specular mount (to
give the Devil his due, I quote Milton's Satan): the mud lies even from
bank to bank, raised only a few inches above the level of the lake, and
as lacustrine in effect as the veriest geologist on earth could wish
it. Indeed, the process of filling up still continues unabated at the
present day where the mud-laden Rhone enters the lake at Bouveret, to
leave it again, clear and blue and beautiful, under the bridge at
Geneva. The little delta which the river forms at its mouth shows the
fresh mud in sheets gathering thick upon the bottom. Every day this new
mud-bank pushes out farther and farther into the water, so that in
process of time the whole basin will be filled in, and a level plain,
like that which now spreads from Bex and Aigle to Villeneuve, will
occupy the entire bed from Montreux to Geneva.
Turn mentally to the upper feeders of the Po itself, and you find the
same causes equally in action. You have stopped at Pallanza--Garoni's
is so comfortable. Well, then, you know how every Alpine stream, as it
flows, full-gorged, into the Italian lakes, is busily engaged in
filling them up as fast as ever it can with turbid mud from the
uplands. The basins of Maggiore, Como, Lugano, and Garda are by origin
deep hollows scooped out long since during the Great Ice Age by the
pressure of huge glaciers that then spread far down into what is now
the poplar-clad plain of Lombardy. But ever since the ice cleared away,
and the torrents began to rush headlong down the deep gorges of the Val
Leventina and the Val Maggia, the mud has been hard at work, doing its
level best to fill those great ice-worn bowls up again. Near the mouth
of each main stream it has already succeeded in spreading a fan-shaped
delta. I will not insult you by asking you at the present time of day
whether you have been over the St. Gothard. In this age of _trains de
luxe_ I know to my cost everybody has been everywhere. No chance of
pretending to superior knowledge about Japan or Honolulu; the tourist
knows them. Very well, then; you must remember as you go past
Bellinzona--revolutionary little Bellinzona with its three castled
crags--you look down upon a vast mud flat by the mouth of the Ticino.
Part of this mud flat is already solid land, but part is mere marsh or
shifting quicksand. That is the first stage in the abolition of the
lakes: the mud is annihilating them.
Maggiore, indeed, least fortunate of the three main sheets, is being
attacked by the insidious foe at three points simultaneously. At the
upper end, the Ticino, that furious radical river, has filled in a
large arm, which once spread far away up the valley towards Bellinzona.
A little lower down, the Maggia near Locarno carries in a fresh
contribution of mud, which forms another fan-shaped delta, and
stretches its ugly mass half across the lake, compelling the steamers
to make a considerable detour eastward. This delta is rapidly extending
into the open water, and will in time fill in the whole remaining space
from bank to bank, cutting off the upper end of the lake about Locarno
from the main basin by a partition of lowland. This upper end will then
form a separate minor lake, and the Ticino will flow out of it across
the intervening mud flat into the new and smaller Maggiore of our
great-great-grandchildren. If you doubt it, look what the torrent of
the Toce, the third assailing battalion of the persistent mud force,
has already done in the neighbourhood of Pallanza. It has entirely cut
off the upper end of the bay, that turns westward towards the Simplon,
by a partition of mud; and this isolated upper bit forms now in our own
day a separate lake, the Lago di Mergozzo, divided from the main sheet
by an uninteresting mud bank. In process of time, no doubt, the whole
of Maggiore will be similarly filled in by the advancing mud sheet, and
will become a level alluvial plain, surrounded by mountains, and
greatly admired by the astute Piedmontese cultivator.
What is going on in Maggiore is going on equally in all the other
sub-Alpine lakes of the Po valley. They are being gradually filled in,
every one of them, by the aggressive mud sheet. The upper end of
Lugano, for example, has already been cut off, as the Lago del Piano,
from the main body; and the _piano_ itself, from which the little
isolated tarn takes its name, is the alluvial mud fiat of a lateral
torrent--the mud flat, in fact, which the railway from Porlezza
traverses for twenty minutes before it begins its steep and picturesque
climb by successive zigzags over the mountains to Menaggio. Similarly
the influx of the Adda at the upper end of Como has cut off the Lago di
Mezzola from the main lake, and has formed the alluvial level that
stretches so drearily all around Colico. Slowly the mud fiend
encroaches everywhere on the lakes; and if you look for him when you
go, there you can see him actually at work every spring under your very
eyes, piling up fresh banks and deltas with alarming industry, and
preparing (in a few hundred thousand years) to ruin the tourist trade
of Cadenabbia and Bellagio.
If we turn from the lakes themselves to the Lombard plain at large,
which is an immensely older and larger basin, we see traces of the same
action on a vastly greater scale. A glance at the map will show the
intelligent and ever courteous reader that the 'wandering Po'--I drop
into poetry after Goldsmith--flows much nearer the foot of the
Apennines than of the Alps in the course of its divagations, and seems
purposely to bend away from the greater range of mountains. Why is
this, since everything in nature must needs have a reason? Well, it is
because, when the mud first began to accumulate in the old Lombard bay
of the Adriatic, there was no Po at all, whether wandering or
otherwise: the big river has slowly grown up in time by the union of
the lateral torrents that pour down from either side, as the growth of
the mud flat brought them gradually together. Careful study of a good
map will show how this has happened, especially if it has the plains
and mountains distinctively tinted after the excellent German fashion.
The Ticino, the Adda, the Mincio, if you look at them close, reveal
themselves as tributaries of the Po, which once flowed separately into
the Lombard bay; the Adige, the Piave, the Tagliamento farther along
the coast, reveal themselves equally as tributaries of the future Po,
when once the great river shall have filled up with its mud the space
between Trieste and Venice, though for the moment they empty themselves
and their store of detritus into the open Adriatic.