"We had now arrived on the banks of the salt creek; but as we saw the
cliff close by, and knew that we must be near the spring which supplied
this little rivulet, we resolved to travel on to the fountain-head. A
few hundred yards farther brought us to the spring, and it was well
worth travelling a little farther to see.
"Near the bottom of the cliff were several round objects, looking like
half globes, or bowls turned upon their mouths. They were of a whitish
colour, resembling white quartz rock; and of all sizes, from that of a
large baking oven to the size of a wooden dish. In the top of each
there was a round cavity--like a little crater of a volcano--and in this
the blue water bubbled and boiled as though a hot fire was in the ground
underneath them. There were in all nearly twenty of these, but many of
them were without the crater-like cavity in the top; and through the
latter, of course, no water escaped to the creek. These were old ones,
that had ceased to run.
"It was evident that these oven-looking mounds had been formed by the
water itself, which had been depositing the sediment that formed them
for many, many years. Around some of them there grew beautiful plants
and shrubs, whose leaves and flowers hung over, trailing in the water;
and from the cliff above long vines crept out, covered with gay scarlet
blossoms. Bushes of wild currants grew all around, and the fragrance of
their leaves scented the air. It was altogether a sweet, cool spot, and
filled us with feelings of enjoyment.
"After we had satisfied our curiosity in examining these objects, we
prepared to make our salt. Frank and Harry collected armfuls of dry
wood for the fire, while Cudjo erected a crane in his usual fashion.
Upon this the kettle was suspended, and filled with crystal water out of
one of the natural basins. The fire soon blazed under it, and we had
nothing more to do than wait until the evaporation should be completed
by boiling.
"For this purpose we chose a spot where the ground was carpeted with a
soft green turf; and upon it we all sat down to wait the result.
"I need not say that in this we had a deep interest, amounting, in
truth, to anxiety. It might not be salt after all. The water tasted
salt--that is true. But so, too, would water impregnated by the
sulphate of magnesia or the sulphate of soda. When evaporated we might
find one or other of these substances.
"`What is the sulphate of magnesia, papa?' inquired Frank.
"`Perhaps you would know it better by the name of Epsom salts!' rejoined
his mother, with a knowing smile.
"`Bah!' returned he, with a grin upon his face, `I hope it won't turn
out that. But what sort of thing, then, is the sulphate of soda?'
"`That is the scientific name for Glauber's salts.'
"`Worse still! I don't think we stand in need of either. Do we,
Harry?'
"`Not a bit of it,' responded Harry, also grinning at the thought of
these well-known specifics. `I would rather it should turn out
saltpetre and sulphur. Then we could make lots of gunpowder.'
"Harry was a great shot--as we have seen--and one of his fears was, that
our stock of powder would run out.
"`Do not wish for that, Harry,' said his mother. `Gunpowder we can do
very well without. Let us hope for something more necessary to us at
present.'
"With such-like conversation we passed the time, while we watched the
steaming kettle with feelings of anxious expectation.
"For myself, I had some reliance upon a fact which I had observed years
before, and had regarded as singular. It was this. I believe the
Creator has so disposed it, that salt, so essential to animal life, is
to be found in all parts of the globe, either in rocks, springs,
standing lakes, incrustations, or in the ocean itself. No part of the
earth, of great extent, is without it; and I had noticed in the interior
territories of the American continent--where the sea is too distant to
be visited by animals--that Nature has provided numerous salt springs,
or `licks,' as they are termed in the language of the country. These
springs from time immemorial have been the meeting-places of the wild
creatures of the forest and prairie, who resort thither to drink their
waters, or lick the saline soil through which these waters run. Hence
their common name of `licks.' Here, then, was a valley whose
four-footed inhabitants never roamed beyond its borders. I felt
confident that Nature had provided for their wants and cravings by
giving them everything necessary to their existence, and, among other
necessities, that one which we were now in search of ourselves--salt.
In other words, but that this was a salt spring, or there existed some
other such in the valley, these creatures would not have been found
within it. I took the opportunity to point out this theory to my boys,
as well as to show them--what I myself clearly recognised in it--the
hand of the Creator. It rendered them confident that, when we had
evaporated our water, we should get salt for our pains.
"`Papa,' inquired Frank, who was a great naturalist, `I should like to
know what makes this little rivulet run salt water.'
"`No doubt,' I replied, `the water you see gushing forth has just been
passing through vast beds or rock-salt, and has become impregnated with
it.'
"`Rock-salt! and is the salt we use found in rocks?'
"`Not all of it, though great quantities are. There are beds of
rock-salt found in many countries--in England, and the East Indies, in
Russia, and Hungary, and Spain; and it has also been discovered in vast
quantities in this very Desert we are now dwelling in. These beds of
rock-salt, when worked to supply salt, are called salt-mines. The most
celebrated are in Poland, near the city of Cracow. These have been
worked for seven hundred years; and there is enough left in them to
supply all the world for many centuries yet to come. These mines are
said to be very beautiful--lit up, as they are, by numerous lamps. The
rock has been excavated by the miners into all sorts of shapes. Houses,
chapels, columns, obelisks, and many other ornamental forms of
buildings, have been made; and these, when illuminated by lamps and
torches, appear as splendid and brilliant as the palaces of Aladdin.'
"`Oh! I should like so much to see them!' cried Harry, in a transport.
"`But, papa,' inquired Frank, who always sought after information on
such subjects, `I never saw any of this rock-salt. How is it that it
comes to us always crushed, or in great bricks, as if it had been baked?
Do they break it fine before it is sent to market from the mines?'
"`In some of these mines nothing more is required than to crush the
rock; in others, however, the rock is not pure salt, but mixed with
other substances, as oxide of iron and clay. In these cases it is first
dissolved in water, to separate it from such impurities, and then
evaporated back again into salt, precisely as we are doing now.'
"`What colour is the salt-rock, papa?'
"`When pure it is white; but it assumes various colours, according to
what substances may be found mixed with it. It is often yellow, and
flesh-coloured, and blue.'
"`How pretty it must be!' exclaimed Harry; `like precious stones, I
declare.'
"`Yes, it is a precious stone,' rejoined his brother; `more precious, I
take it, than all the diamonds in the world. Is it not, papa?'
"`You are quite right,' I replied. `Salt-rock is more valuable to the
human race than diamonds; though they, too, have an _absolute_ value,
besides their value as a mere ornament. There are some important uses
in arts and manufactures to which they can be applied.'
"`But, papa,' again inquired Frank, determined to know everything he
could about the article of salt, `I have heard that salt is made of
sea-water. Is it so?'
"`Vast quantities of it.'
"`How is it made?'
"`There are three ways of obtaining it:--First, in warm climates, where
the sun is strong, the sea-water is collected into shallow pools, and
there left until it is evaporated by the sun's rays. The ground where
these pools are made must neither be muddy nor porous, else the salt
would get mixed with the mud and sand. Of course the people who
manufacture it in this way take care to choose firm, hard ground for the
bottoms of their pools. There are sluices attached to these pools by
which any water that may not evaporate is drawn off. Salt is made in
this manner in many southern countries--in Spain and Portugal, in
France, and other countries that lie around the Mediterranean; also in
India, China, Siam, and the island of Ceylon.
"`The second way of making salt from sea-water is precisely the same as
that I have described--except that, instead of these artificial pools,
the evaporation takes place in broad tracts of country over which the
sea has spread in time of high springtides. When the sea falls again to
its proper level, it leaves behind it a quantity of water in these
tracts, which is evaporated by the sun, leaving behind it fields of pure
salt. Nothing remains to be done but to scrape this salt into heaps and
cart it off; and at the next spring-tide a fresh influx of sea-water
produces a new crop of salt, and so on. This kind is better than that
which is made in the artificial pools--though neither of them is equal
to the salt of the mines. They are both known in commerce under the
name of "bay-salt," to distinguish them from the "rock-salt" of the
mines. Great natural beds of the bay-salt are found in the Cape de
Verde islands; also in Turk's island and Saint Martin's in the West
Indies, and on Kangaroo Island, near the coast of Australia.
"`There is still a third plan of making salt out of the sea. That is,
by boiling the water, as we are doing; but this makes the worst of all
salt; besides, it is far more expensive to manufacture salt in this way
than to buy it from other countries. Indeed, this last plan would never
be adopted, were it not that some foolish governments force their people
to pay a heavy duty for importing salt into their country, thus making
it still cheaper for them, costly as it is, to manufacture the article
at home.'
"`What makes the sea salt, papa?'
"`That is one of the phenomena about which naturalists have a difference
of opinion. Some of them say there are vast beds of salt at the bottom
which keep the water always impregnated. I think this notion is very
childish; and they who hold it offer only childish arguments to support
it. Others assert that the salt water of the ocean is a primitive
fluid--that it was always as it now is--which you will perceive is
giving no reason at all, more than saying, "it is salt, because it was
salt always." This is an equally irrational theory. Others, again,
believe that the saltness of the ocean is caused by the flowing into it
of salt rivers. These, I think, hold the true opinion; but
unfortunately they have failed, as far as I know, to answer the
objections which have been raised against it. Your papa has reflected a
good deal upon this subject, and believes that he can explain away all
the difficulties that oppose this last theory. Probably he may take an
early opportunity of doing so; but it will require more time than he can
spare at present.'
"`Is the sea equally salt at all places?' inquired the philosopher
Frank, after a short pause, during which he had been busily reflecting
on what had been said.
"`No; it is more so at the Equator than in the colder regions around the
Poles. It is less salt in gulfs and inland seas than in the open ocean.
This I believe I can also explain, because it would support the theory
regarding the rivers of which we have just spoken. The difference of
saltness in different parts of the sea is, however, very trifling.'
"`How much salt is there in the sea-water?'
"`Three and a half per cent nearly. That is, if you boil down one
hundred pounds of sea-water, it will yield you about three pounds and a
half of salt.'
"`But are there not many lakes and brine-springs that contain a far
greater proportion than that?'
"`Many. There is a large lake lying in this very Desert, to the
north-west of where we are, called the "Great Salt Lake." The waters of
that lake are more than one-third pure salt. There are many springs and
rivers that contain a greater proportion than the ocean itself. It is
to be hoped that our own little creek here will yield better than it.--
But come! let us see how the kettle boils. We had almost forgotten it.'
"We approached our kettle, and lifted the lid. To our great joy, a scum
was floating on the top, very much like crystals of ice forming upon
half melted snow. Some of it was skimmed off and applied to our lips.
Joy! it was _salt_--the pure _chloride of sodium_--equal to the best
ever shipped from Turk's Island."