CHAPTER TWENTY THREE.
THE SALT SPRING.
"We had now arrived on the banks of the salt creek; but as we saw thecliff close by, and knew that we must be near the spring which suppliedthis little rivulet, we resolved to travel on to the fountain-head. Afew hundred yards farther brought us to the spring, and it was wellworth travelling a little farther to see.
"Near the bottom of the cliff were several round objects, looking likehalf globes, or bowls turned upon their mouths. They were of a whitishcolour, resembling white quartz rock; and of all sizes, from that of alarge baking oven to the size of a wooden dish. In the top of eachthere was a round cavity--like a little crater of a volcano--and in thisthe blue water bubbled and boiled as though a hot fire was in the groundunderneath them. There were in all nearly twenty of these, but many ofthem were without the crater-like cavity in the top; and through thelatter, 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 thewater itself, which had been depositing the sediment that formed themfor many, many years. Around some of them there grew beautiful plantsand shrubs, whose leaves and flowers hung over, trailing in the water;and from the cliff above long vines crept out, covered with gay scarletblossoms. Bushes of wild currants grew all around, and the fragrance oftheir leaves scented the air. It was altogether a sweet, cool spot, andfilled us with feelings of enjoyment.
"After we had satisfied our curiosity in examining these objects, weprepared to make our salt. Frank and Harry collected armfuls of drywood for the fire, while Cudjo erected a crane in his usual fashion.Upon this the kettle was suspended, and filled with crystal water out ofone of the natural basins. The fire soon blazed under it, and we hadnothing more to do than wait until the evaporation should be completedby boiling.
"For this purpose we chose a spot where the ground was carpeted with asoft 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, intruth, to anxiety. It might not be salt after all. The water tastedsalt--that is true. But so, too, would water impregnated by thesulphate of magnesia or the sulphate of soda. When evaporated we mightfind 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!' rejoinedhis mother, with a knowing smile.
"`Bah!' returned he, with a grin upon his face, `I hope it won't turnout 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 ofthese well-known specifics. `I would rather it should turn outsaltpetre and sulphur. Then we could make lots of gunpowder.'
"Harry was a great shot--as we have seen--and one of his fears was, thatour stock of powder would run out.
"`Do not wish for that, Harry,' said his mother. `Gunpowder we can dovery well without. Let us hope for something more necessary to us atpresent.'
"With such-like conversation we passed the time, while we watched thesteaming kettle with feelings of anxious expectation.
"For myself, I had some reliance upon a fact which I had observed yearsbefore, and had regarded as singular. It was this. I believe theCreator has so disposed it, that salt, so essential to animal life, isto be found in all parts of the globe, either in rocks, springs,standing lakes, incrustations, or in the ocean itself. No part of theearth, of great extent, is without it; and I had noticed in the interiorterritories of the American continent--where the sea is too distant tobe visited by animals--that Nature has provided numerous salt springs,or `licks,' as they are termed in the language of the country. Thesesprings from time immemorial have been the meeting-places of the wildcreatures of the forest and prairie, who resort thither to drink theirwaters, or lick the saline soil through which these waters run. Hencetheir common name of `licks.' Here, then, was a valley whosefour-footed inhabitants never roamed beyond its borders. I feltconfident that Nature had provided for their wants and cravings bygiving them everything necessary to their existence, and, among othernecessities, that one which we were now in search of ourselves--salt.In other words, but that this was a salt spring, or there existed someother such in the valley, these creatures would not have been foundwithin 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--thehand of the Creator. It rendered them confident that, when we hadevaporated our water, we should get salt for our pains.
"`Papa,' inquired Frank, who was a great naturalist, `I should like toknow what makes this little rivulet run salt water.'
"`No doubt,' I replied, `the water you see gushing forth has just beenpassing through vast beds or rock-salt, and has become impregnated withit.'
"`Rock-salt! and is the salt we use found in rocks?'
"`Not all of it, though great quantities are. There are beds ofrock-salt found in many countries--in England, and the East Indies, inRussia, and Hungary, and Spain; and it has also been discovered in vastquantities in this very Desert we are now dwelling in. These beds ofrock-salt, when worked to supply salt, are called salt-mines. The mostcelebrated are in Poland, near the city of Cracow. These have beenworked for seven hundred years; and there is enough left in them tosupply all the world for many centuries yet to come. These mines aresaid to be very beautiful--lit up, as they are, by numerous lamps. Therock has been excavated by the miners into all sorts of shapes. Houses,chapels, columns, obelisks, and many other ornamental forms ofbuildings, have been made; and these, when illuminated by lamps andtorches, 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 onsuch subjects, `I never saw any of this rock-salt. How is it that itcomes 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 therock; in others, however, the rock is not pure salt, but mixed withother substances, as oxide of iron and clay. In these cases it is firstdissolved in water, to separate it from such impurities, and thenevaporated 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 towhat substances may be found mixed with it. It is often yellow, andflesh-coloured, and blue.'
"`How pretty it must be!' exclaimed Harry; `like precious stones, Ideclare.'
"`Yes, it is a precious stone,' rejoined his brother; `more precious, Itake it, than all the diamonds in the world. Is it not, papa?'
"`You are quite right,' I replied. `Salt-rock is more valuable to thehuman race than diamonds; though they, too, have an _absolute_ value,besides their value as a mere ornament. There are some important usesin arts and manufactures to which they can be applied.'
"`But, papa,' again inquired Frank, determined to know everything hecould about the article of salt, `I have heard that salt is made ofsea-water. Is it so?'
"`Vast quantities of it.'
"`How is it made?'
"`There are three ways of obtaining it:--First, in warm climates, wherethe sun is strong, the sea-water is collected into shallow pools, andthere left until it is evaporated by the sun's rays. The ground wherethese pools are made must neither be muddy nor porous, else the saltwould get mixed with the mud and sand. Of course the people whomanufacture it in this way take care to choose firm, hard ground for thebottoms of their pools. There are sluices attached to these pools bywhich any water that may not evaporate is drawn off. Salt is made inthis manner in many southern countries--in Spain
and Portugal, inFrance, and other countries that lie around the Mediterranean; also inIndia, China, Siam, and the island of Ceylon.
"`The second way of making salt from sea-water is precisely the same asthat I have described--except that, instead of these artificial pools,the evaporation takes place in broad tracts of country over which thesea has spread in time of high springtides. When the sea falls again toits proper level, it leaves behind it a quantity of water in thesetracts, which is evaporated by the sun, leaving behind it fields of puresalt. Nothing remains to be done but to scrape this salt into heaps andcart it off; and at the next spring-tide a fresh influx of sea-waterproduces a new crop of salt, and so on. This kind is better than thatwhich is made in the artificial pools--though neither of them is equalto the salt of the mines. They are both known in commerce under thename of "bay-salt," to distinguish them from the "rock-salt" of themines. Great natural beds of the bay-salt are found in the Cape deVerde islands; also in Turk's island and Saint Martin's in the WestIndies, 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 allsalt; besides, it is far more expensive to manufacture salt in this waythan to buy it from other countries. Indeed, this last plan would neverbe adopted, were it not that some foolish governments force their peopleto pay a heavy duty for importing salt into their country, thus makingit still cheaper for them, costly as it is, to manufacture the articleat home.'
"`What makes the sea salt, papa?'
"`That is one of the phenomena about which naturalists have a differenceof opinion. Some of them say there are vast beds of salt at the bottomwhich keep the water always impregnated. I think this notion is verychildish; and they who hold it offer only childish arguments to supportit. Others assert that the salt water of the ocean is a primitivefluid--that it was always as it now is--which you will perceive isgiving no reason at all, more than saying, "it is salt, because it wassalt always." This is an equally irrational theory. Others, again,believe that the saltness of the ocean is caused by the flowing into itof salt rivers. These, I think, hold the true opinion; butunfortunately they have failed, as far as I know, to answer theobjections which have been raised against it. Your papa has reflected agood deal upon this subject, and believes that he can explain away allthe difficulties that oppose this last theory. Probably he may take anearly opportunity of doing so; but it will require more time than he canspare at present.'
"`Is the sea equally salt at all places?' inquired the philosopherFrank, after a short pause, during which he had been busily reflectingon what had been said.
"`No; it is more so at the Equator than in the colder regions around thePoles. 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 theoryregarding the rivers of which we have just spoken. The difference ofsaltness 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 onehundred pounds of sea-water, it will yield you about three pounds and ahalf of salt.'
"`But are there not many lakes and brine-springs that contain a fargreater proportion than that?'
"`Many. There is a large lake lying in this very Desert, to thenorth-west of where we are, called the "Great Salt Lake." The waters ofthat lake are more than one-third pure salt. There are many springs andrivers that contain a greater proportion than the ocean itself. It isto 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 scumwas floating on the top, very much like crystals of ice forming uponhalf 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 bestever shipped from Turk's Island."