There is something at first sight rather ridiculous in the idea of
eating a fossil. To be sure, when the frozen mammoths of Siberia were
first discovered, though they had been dead for at least 80,000 years
(according to Dr. Croll's minimum reckoning for the end of the great ice
age), and might therefore naturally have begun to get a little musty,
they had nevertheless been kept so fresh, like a sort of prehistoric
Australian mutton, in their vast natural refrigerators, that the wolves
and bears greedily devoured the precious relics for which the
naturalists of Europe would have been ready gladly to pay the highest
market price of best beefsteak. Those carnivorous vandals gnawed off the
skin and flesh with the utmost appreciation, and left nothing but the
tusks and bones to adorn the galleries of the new Natural History Museum
at South Kensington. But then wolves and bears, especially in Siberia,
are not exactly fastidious about the nature of their meat diet.
Furthermore, some of the bones of extinct animals found beneath the
stalagmitic floor of caves, in England and elsewhere, presumably of
about the same age as the Siberian mammoths, still contain enough animal
matter to produce a good strong stock for antediluvian broth, which has
been scientifically described by a high authority as pre-Adamite jelly.
The congress of naturalists at Tübingen a few years since had a smoking
tureen of this cave-bone soup placed upon the dinner-table at their
hotel one evening, and pronounced it with geological enthusiasm
'scarcely inferior to prime ox-tail.' But men of science, too, are
accustomed to trying unsavoury experiments, which would go sadly against
the grain with less philosophic and more squeamish palates. They think
nothing of tasting a caterpillar that birds will not touch, in order to
discover whether it owes its immunity from attack to some nauseous,
bitter, or pungent flavouring; and they even advise you calmly to
discriminate between two closely similar species of snails by trying
which of them when chewed has a delicate _soupçon_ of oniony aroma. So
that naturalists in this matter, as the children say, don't count: their
universal thirst for knowledge will prompt them to drink anything, down
even to _consommé_ of quaternary cave-bear.
There is one form of fossil food, however, which appears constantly upon
all our tables at breakfast, lunch, and dinner, every day, and which is
so perfectly familiar to every one of us that we almost forget entirely
its immensely remote geological origin. The salt in our salt-cellars is
a fossil product, laid down ages ago in some primæval Dead Sea or
Caspian, and derived in all probability (through the medium of the
grocer) from the triassic rocks of Cheshire or Worcestershire. Since
that thick bed of rock-salt was first precipitated upon the dry floor of
some old evaporated inland sea, the greater part of the geological
history known to the world at large has slowly unrolled itself through
incalculable ages. The dragons of the prime have begun and finished
their long (and Lord Tennyson says slimy) race. The fish-like saurians
and flying pterodactyls of the secondary period have come into existence
and gone out of it gracefully again. The whole family of birds has been
developed and diversified into its modern variety of eagles and titmice.
The beasts of the field have passed through sundry stages of mammoth
and mastodon, of sabre-toothed lion and huge rhinoceros. Man himself has
progressed gradually from the humble condition of a 'hairy arboreal
quadruped'--these bad words are Mr. Darwin's own--to the glorious
elevation of an erect, two-handed creature, with a county suffrage
question and an intelligent interest in the latest proceedings of the
central divorce court. And after all those manifold changes, compared to
which the entire period of English history, from the landing of Julius
Cæsar to the appearance of this present volume (to take two important
landmarks), is as one hour to a human lifetime, we quietly dig up the
salt to-day from that dry lake bottom and proceed to eat it with the
eggs laid by the hens this morning for this morning's breakfast, just as
though the one food-stuff were not a whit more ancient or more dignified
in nature than the other. Why, mammoth steak is really quite modern and
commonplace by the side of the salt in the salt-cellar that we treat so
cavalierly every day of our ephemeral existence.
The way salt got originally deposited in these great rock beds is very
well illustrated for us by the way it is still being deposited in the
evaporating waters of many inland seas. Every schoolboy knows of course
(though some persons who are no longer schoolboys may just possibly have
forgotten) that the Caspian is in reality only a little bit of the
Mediterranean, which has been cut off from the main sea by the gradual
elevation of the country between them. For many ages the intermediate
soil has been quite literally rising in the world; but to this day a
continuous chain of salt lakes and marshes runs between the Caspian and
the Black Sea, and does its best to keep alive the memory of the time
when they were both united in a single basin. All along this intervening
tract, once sea but now dry land, banks of shells belonging to kinds
still living in the Caspian and the Black Sea alike testify to the old
line of water communication. One fine morning (date unknown) the
intermediate belt began to rise up between them; the water was all
pushed off into the Caspian, but the shells remained to tell the tale
even unto this day.
Now, when a bit of the sea gets cut off in this way from the main ocean,
evaporation of its waters generally takes place rather faster than the
return supply of rain by rivers and lesser tributaries. In other words,
the inland sea or salt lake begins slowly to dry up. This is now just
happening in the Caspian, which is in fact a big pool in course of being
slowly evaporated. By-and-by a point is reached when the water can no
longer hold in solution the amount of salts of various sorts that it
originally contained. In the technical language of chemists and
physicists it begins to get supersaturated. Then the salts are thrown
down as a sediment at the bottom of the sea or lake, exactly as crust
formed on the bottom of a kettle. Gypsum is the first material to be so
thrown down, because it is less soluble than common salt, and therefore
sooner got rid of. It forms a thick bottom layer in the bed of all
evaporating inland seas; and as plaster of Paris it not only gives rise
finally to artistic monstrosities hawked about the streets for the
degradation of national taste, but also plays an important part in the
manufacture of bonbons, the destruction of the human digestion, and the
ultimate ruin of the dominant white European race. Only about a third of
the water in a salt lake need be evaporated before the gypsum begins to
be deposited in a solid layer over its whole bed; it is not till 93 per
cent. of the water has gone, and only 7 per cent. is left, that common
salt begins to be thrown down. When that point of intensity is reached,
the salt, too, falls as a sediment to the bottom, and there overlies the
gypsum deposit. Hence all the world over, wherever we come upon a bed
of rock salt, it almost invariably lies upon a floor of solid gypsum.
The Caspian, being still a very respectable modern sea, constantly
supplied with fresh water from the surrounding rivers, has not yet begun
by any means to deposit salt on its bottom from its whole mass; but the
shallow pools and long bays around its edge have crusts of beautiful
rose-coloured salt-crystals forming upon their sides; and as these
lesser basins gradually dry up, the sand, blown before the wind, slowly
drifts over them, so as to form miniature rock-salt beds on a very small
scale. Nevertheless, the young and vigorous Caspian only represents the
first stage in the process of evaporation of an inland sea. It is still
fresh enough to form the abode of fish and mollusks; and the
irrepressible young lady of the present generation is perhaps even aware
that it contains numbers of seals, being in fact the seat of one of the
most important and valuable seal-fisheries in the whole world. It may be
regarded as a typical example of a yet youthful and lively inland sea.
The Dead Sea, on the other hand, is an old and decrepit salt lake in a
very advanced state of evaporation. It lies several feet below the level
of the Mediterranean, just as the Caspian lies several feet below the
level of the Black Sea; and as in both cases the surface must once have
been continuous, it is clear that the water of either sheet must have
dried up to a very considerable extent. But, while the Caspian has
shrunk only to 85 feet below the Black Sea, the Dead Sea has shrunk to
the enormous depth of 1,292 feet below the Mediterranean. Every now and
then, some enterprising De Lesseps or other proposes to dig a canal from
the Mediterranean to the Dead Sea, and so re-establish the old high
level. The effect of this very revolutionary proceeding would be to
flood the entire Jordan Valley, connect the Sea of Galilee with the Dead
Sea, and play the dickens generally with Scripture geography, to the
infinite delight of Sunday school classes. Now, when the Dead Sea first
began its independent career as a separate sheet of water on its own
account, it no doubt occupied the whole bed of this imaginary engineers'
lake--spreading, if not from Dan to Beersheba, at any rate from Dan to
Edom, or, in other words, along the whole Jordan Valley from the Sea of
Galilee and even the Waters of Merom to the southern desert. (I will not
insult the reader's intelligence and orthodoxy by suggesting that
perhaps he may not be precisely certain as to the exact position of the
Waters of Merom; but I will merely recommend him just to refresh his
memory by turning to his atlas, as this is an opportunity which may not
again occur.) The modern Dead Sea is the last shrunken relic of such a
considerable ancient lake. Its waters are now so very concentrated and
so very nasty that no fish or other self-respecting animal can consent
to live in them; and so buoyant that a man can't drown himself, even if
he tries, because the sea is saturated with salts of various sorts till
it has become a kind of soup or porridge, in which a swimmer floats,
will he nill he. Persons in the neighbourhood who wish to commit suicide
are therefore obliged to go elsewhere: much as in Tasmania, the
healthiest climate in the world, people who want to die are obliged to
run across for a week to Sydney or Melbourne.
The waters of the Dead Sea are thus in the condition of having already
deposited almost all their gypsum, as well as the greater part of the
salt they originally contained. They are, in fact, much like sea water
which has been boiled down till it has reached the state of a thick
salty liquid; and though most of the salt is now already deposited in a
deep layer on the bottom, enough still remains in solution to make the
Dead Sea infinitely salter than the general ocean. At the same time,
there are a good many other things in solution in sea water besides
gypsum and common salt; such as chloride of magnesia sulphate of
potassium, and other interesting substances with pretty chemical names,
well calculated to endear them at first sight to the sentimental
affections of the general public. These other by-contents of the water
are often still longer in getting deposited than common salt; and, owing
to their intermixture in a very concentrated form with the mother liquid
of the Dead Sea, the water of that evaporating lake is not only salt but
also slimy and fetid to the last degree, its taste being accurately
described as half brine, half rancid oil. Indeed, the salt has been so
far precipitated already that there is now five times as much chloride
of magnesium left in the water as there is common salt. By the way, it
is a lucky thing for us that these various soluble minerals are of such
constitution as to be thrown down separately at different stages of
concentration in the evaporating liquid; for, if it were otherwise, they
would all get deposited together, and we should find on all old salt
lake beds only a mixed layer of gypsum, salt, and other chlorides and
sulphates, absolutely useless for any practical human purpose. In that
case, we should be entirely dependent upon marine salt pans and
artificial processes for our entire salt supply. As it is, we find the
materials deposited one above another in regular layers; first, the
gypsum at the bottom; then the rock-salt; and last of all, on top, the
more soluble mineral constituents.
The Great Salt Lake of Utah, sacred to the memory of Brigham Young,
gives us an example of a modern saline sheet of very different origin,
since it is in fact not a branch of the sea at all, but a mere shrunken
remnant of a very large fresh-water lake system, like that of the
still-existing St. Lawrence chain. Once upon a time, American geologists
say, a huge sheet of water, for which they have even invented a
definite name, Lake Bonneville, occupied a far larger valley among the
outliers of the Rocky Mountains, measuring 300 miles in one direction by
180 miles in the other. Beside this primitive Superior lay a second
great sheet--an early Huron--(Lake Lahontan, the geologists call it)
almost as big, and equally of fresh water. By-and-by--the precise dates
are necessarily indefinite--some change in the rainfall, unregistered by
any contemporary 'New York Herald,' made the waters of these big lakes
shrink and evaporate. Lake Lahontan shrank away like Alice in
Wonderland, till there was absolutely nothing left of it; Lake
Bonneville shrank till it attained the diminished size of the existing
Great Salt Lake. Terrace after terrace, running in long parallel lines
on the sides of the Wahsatch Mountains around, mark the various levels
at which it rested for awhile on its gradual downward course. It is
still falling indeed; and the plain around is being gradually uncovered,
forming the white salt-encrusted shore with which all visitors to the
Mormon city are so familiar.
But why should the water have become briny? Why should the evaporation
of an old Superior produce at last a Great Salt Lake? Well, there is a
small quantity of salt in solution even in the freshest of lakes and
ponds, brought down to them by the streams or rivers; and, as the water
of the hypothetical Lake Bonneville slowly evaporated, the salt and
other mineral constituents remained behind. Thus the solution grew
constantly more and more concentrated, till at the present day it is
extremely saline. Professor Geikie (to whose works the present paper is
much indebted) found that he floated on the water in spite of himself;
and the under sides of the steps at the bathing-places are all encrusted
with short stalactites of salt, produced from the drip of the bathers as
they leave the water. The mineral constituents, however, differ
considerably in their proportions from those found in true salt lakes of
marine origin; and the point at which the salt is thrown down is still
far from having been reached. Great Salt Lake must simmer in the sun for
many centuries yet before the point arrives at which (as cooks say) it
begins to settle.
That is the way in which deposits of salt are being now produced on the
world's surface, in preparation for that man of the future who, as we
learn from a duly constituted authority, is to be hairless, toothless,
web-footed, and far too respectable ever to be funny. Man of the present
derives his existing salt-supply chiefly from beds of rock-salt
similarly laid down against his expected appearance some hundred
thousand æons or so ago. (An æon is a very convenient geological unit
indeed to reckon by; as nobody has any idea how long it is, they can't
carp at you for a matter of an æon or two one way or the other.)
Rock-salt is found in most parts of the world, in beds of very various
ages. The great Salt Range of the Punjaub is probably the earliest in
date of all salt deposits; it was laid down at the bottom of some very
ancient Asiatic Mediterranean, whose last shrunken remnant covered the
upper basin of the Indus and its tributaries during the Silurian age.
Europe had then hardly begun to be; and England was probably still
covered from end to end by the primæval ocean. From this very primitive
salt deposit the greater part of India and Central Asia is still
supplied; and the Indian Government makes a pretty penny out of the dues
in the shape of the justly detested salt-tax--a tax especially odious
because it wrings the fraction of a farthing even from those unhappy
agricultural labourers who have never tasted ghee with their rice.
The thickness of the beds in each salt deposit of course depends
entirely upon the area of the original sea or salt-lake, and the length
of time during which the evaporation went on. Sometimes we may get a
mere film of salt; sometimes a solid bed six hundred feet thick.
Perfectly pure rock-salt is colourless and transparent; but one doesn't
often find it pure. Alas for a degenerate world! even in its original
site, Nature herself has taken the trouble to adulterate it beforehand.
(If she hadn't done so, one may be perfectly sure that commercial
enterprise would have proved equal to the occasion in the long run.) But
the adulteration hasn't spoilt the beauty of the salt; on the contrary,
it serves, like rouge, to give a fine fresh colour where none existed.
When iron is the chief colouring matter, rock-salt assumes a beautiful
clear red tint; in other cases it is emerald green or pale blue. As a
rule, salt is prepared from it for table by a regular process; but it
has become a fad of late with a few people to put crystals of native
rock-salt on their tables; and they decidedly look very pretty, and have
a certain distinctive flavour of their own that is not unpleasant.
Our English salt supply is chiefly derived from the Cheshire and
Worcestershire salt-regions, which are of triassic age. Many of the
places at which the salt is mined have names ending in _wich_, such as
Northwich, Middlewich, Nantwich, Droitwich, Netherwich, and Shirleywich.
This termination _wich_ is itself curiously significant, as Canon Isaac
Taylor has shown, of the necessary connection between salt and the sea.
The earliest known way of producing salt was of course in shallow pans
on the sea-shore, at the bottom of a shoal bay, called in Norse and
Early English a wick or wich; and the material so produced is still
known in trade as bay-salt. By-and-by, when people came to discover the
inland brine-pits and salt mines, they transferred to them the familiar
name, a wich; and the places where the salt was manufactured came to be
known as wych-houses. Droitwich, for example, was originally such a
wich, where the droits or dues on salt were paid at the time when
William the Conqueror's commissioners drew up their great survey for
Domesday Book. But the good, easy-going mediæval people who gave these
quaint names to the inland wiches had probably no idea that they were
really and truly dried-up bays, and that the salt they mined from their
pits was genuine ancient bay-salt, the deposit of an old inland sea,
evaporated by slow degrees a countless number of ages since, exactly as
the Dead Sea and the Great Salt Lake are getting evaporated in our own
time.
Such, nevertheless, is actually the case. A good-sized Caspian used to
spread across the centre of England and north of Ireland in triassic
times, bounded here and there, as well as Dr. Hull can make out, by the
Welsh Mountains, the Cheviots, and the Donegal Hills, and with the Peak
of Derbyshire and the Isle of Man standing out as separate islands from
its blue expanse. (We will beg the question that the English seas were
then blue. They are certainly marked so in a very fine cerulean tint on
Dr. Hull's map of Triassic Britain.) Slowly, like most other inland
seas, this early British Caspian began to lose weight and to shrivel
away to ever smaller dimensions. In Devonshire, where it appears to have
first dried up, we get no salt, but only red marl, with here and there a
cubical cast, filling a hole once occupied by rock-salt, though the
percolation of the rain has long since melted out that very soluble
substance, and replaced it by a mere mould in the characteristic square
shape of salt crystals. But Worcestershire and Cheshire were the seat of
the inland sea when it had contracted to the dimensions of a mere salt
lake, and begun to throw down its dissolved saline materials. One of the
Cheshire beds is sometimes a hundred feet thick of almost pure and
crystalline rock-salt. The absence of fossils shows that animals must
have had as bad a time of it there as in the Dead Sea of our modern
Palestine. The Droitwich brine-pits have been known for many centuries,
since they were worked (and taxed) even before the Norman Conquest, as
were many other similar wells elsewhere. But the actual mining of
rock-salt as such in England dates back only as far as the reign of King
Charles II. of blessed memory, or more definitely to the very year in
which the 'Pilgrim's Progress' was conceived and written by John Bunyan.
During that particular summer, an enterprising person at Nantwich had
sunk a shaft for coal, which he failed to find; but on his way down he
came unexpectedly across the bed of rock-salt, then for the first time
discovered as a native mineral. Since that fortunate accident the beds
have been so energetically worked and the springs so energetically
pumped that some of the towns built on top of them have got undermined,
and now threaten from year to year, in the most literal sense, to cave
in. In fact, one or two subsidences of considerable extent have already
taken place, due in part no doubt to the dissolving action of rain
water, but in part also to the mode of working. The mines are approached
by a shaft; and, when you get down to the level of the old sea bottom,
you find yourself in a sort of artificial gallery, whose roof, with all
the world on top of it, is supported every here and there by massive
pillars about fifteen feet thick. Considering that the salt lies often a
hundred and fifty yards deep, and that these pillars have to bear the
weight of all that depth of solid rock, it is not surprising that
subsidences should sometimes occur in abandoned shafts, where the water
is allowed to collect, and slowly dissolve away the supporting columns.
Salt is a necessary article of food for animals, but in a far less
degree than is commonly supposed. Each of us eats on an average about
ten times as much salt as we actually require. In this respect popular
notions are as inexact as in the very similar case of the supply of
phosphorus. Because phosphorus is needful for brain action, people jump
forthwith to the absurd conclusion that fish and other foods rich in
phosphates ought to be specially good for students preparing for
examination, great thinkers, and literary men. Mark Twain indeed once
advised a poetical aspirant, who sent him a few verses for his critical
opinion, that fish was very feeding for the brains; he would recommend a
couple of young whales to begin upon. As a matter of fact, there is more
phosphorus in our daily bread than would have sufficed Shakespeare to
write 'Hamlet,' or Newton to discover the law of gravitation. It isn't
phosphorus that most of us need, but brains to burn it in. A man might
as well light a fire in a carriage, because coal makes an engine go, as
hope to mend the pace of his dull pate by eating fish for the sake of
the phosphates.
The question still remains, How did the salt originally get there? After
all, when we say that it was produced, as rock-salt, by evaporation of
the water in inland seas, we leave unanswered the main problem, How did
the brine in solution get into the sea at all in the first place? Well,
one might almost as well ask, How did anything come to be upon the earth
at any time, in any way? How did the sea itself get there? How did this
planet swim into existence at all? In the Indian mythology the world is
supported upon the back of an elephant, who is supported upon the back
of a tortoise; but what the tortoise in the last resort is supported
upon the Indian philosophers prudently say not. If we once begin thus
pushing back our inquiries into the genesis of the cosmos, we shall find
our search retreating step after step _ad infinitum_. The negro
preacher, describing the creation of Adam, and drawing slightly upon
his imagination, observed that when our prime forefather first came to
consciousness he found himself 'sot up agin a fence.' One of his hearers
ventured sceptically to ejaculate, 'Den whar dat fence come from,
ministah?' The outraged divine scratched his grey wool reflectively for
a moment, and replied, after a pause, with stern solemnity, 'Tree more
ob dem questions will undermine de whole system ob teology.'
However, we are not permitted humbly to imitate the prudent reticence of
the Indian philosophers. In these days of evolution hypotheses, and
nebular theories, and kinetic energy, and all the rest of it, the
question why the sea is salt rises up irrepressible and imperatively
demands to get itself answered. There was a sapient inquirer, recently
deceased, who had a short way out of this difficulty. He held that the
sea was only salt because of all the salt rivers that run into it.
Considering that the salt rivers are themselves salted by passing
through salt regions, or being fed by saline springs, all of which
derive their saltness from deposits laid down long ago by evaporation
from earlier seas or lake basins, this explanation savours somewhat of
circularity. It amounts in effect to saying that the sea is salt because
of the large amount of saline matter which it holds in solution. Cheese
is also a caseous preparation of milk; the duties of an archdeacon are
to perform archidiaconal functions; and opium puts one to sleep because
it possesses a soporific virtue.
Apart from such purely verbal explanations of the saltness of the sea,
however, one can only give some such account of the way it came to be
'the briny' as the following:--
This world was once a haze of fluid light, as the poets and the men of
science agree in informing us. As soon as it began to cool down a
little, the heavier materials naturally sank towards the centre, while
the lighter, now represented by the ocean and the atmosphere, floated in
a gaseous condition on the outside. But the great envelope of vapour
thus produced did not consist merely of the constituents of air and
water; many other gases and vapours mingled with them, as they still do
to a far less extent in our existing atmosphere. By-and-by, as the
cooling and condensing process continued, the water settled down from
the condition of steam into one of a liquid at a dull red heat. As it
condensed, it carried down with it a great many other substances, held
in solution, whose component elements had previously existed in the
primitive gaseous atmosphere. Thus the early ocean which covered the
whole earth was in all probability not only very salt, but also quite
thick with other mineral matters close up to the point of saturation. It
was full of lime, and raw flint, and sulphates, and many other
miscellaneous bodies. Moreover, it was not only just as salt as at the
present day, but even a great deal salter. For from that time to this
evaporation has constantly been going on in certain shallow isolated
areas, laying down great beds of gypsum and then of salt, which still
remain in the solid condition, while the water has, of course, been
correspondingly purified. The same thing has likewise happened in a
slightly different way with the lime and flint, which have been
separated from the water chiefly by living animals, and afterwards
deposited on the bottom of the ocean in immense layers as limestone,
chalk, sandstone, and clay.
Thus it turns out that in the end all our sources of salt-supply are
alike ultimately derived from the briny ocean. Whether we dig it out as
solid rock-salt from the open quarries of the Punjaub, or pump it up
from brine-wells sunk into the triassic rocks of Cheshire, or evaporate
it direct in the salt-pans of England and the shallow _salines_ of the
Mediterranean shore, it is still at bottom essentially sea-salt.
However distant the connection may seem, our salt is always in the last
resort obtained from the material held in solution in some ancient or
modern sea. Even the saline springs of Canada and the Northern States of
America, where the wapiti love to congregate, and the noble hunter lurks
in the thicket to murder them unperceived, derive their saltness, as an
able Canadian geologist has shown, from the thinly scattered salts still
retained among the sediments of that very archaic sea whose precipitates
form the earliest known life-bearing rocks. To the Homeric Greek, as to
Mr. Dick Swiveller, the ocean was always the briny: to modern science,
on the other hand (which neither of those worthies would probably have
appreciated at its own valuation), the briny is always the oceanic. The
fossil food which we find to-day on all our dinner-tables dates back its
origin primarily to the first seas that ever covered the surface of our
planet, and secondarily to the great rock deposits of the dried-up
triassic inland sea. And yet even our men of science habitually describe
that ancient mineral as common salt.