An instance of this kind is Lake N'gami; for the waters of the lake when low become brackish.

The largest quant.i.ties of salt have been found in the deepest hollows or in the lowest valleys, where there is no outlet. Livingstone cites an instance of a fountain, the temperature of which was upwards of 100.

This fountain, though strongly impregnated with salt, had no deposit, because situated on a flat portion of the country.

When these salt deposits occur in a flat country with a tufa layer covering the soil, a chemical change takes place in the soil; the tufa is dissolved and the ground kept in a state unfavorable to the growth of plants.

Livingstone discovered one large salt pan with a deposit of salt an inch and a half in thickness. This deposit contained bitter salt in addition, probably the nitrate of lime. In order to make the deposit wholesome and palatable, the natives mix the salt with the juice of a gummy plant.

They then place the mixture in the sand and build a fire over it to bake it. The action of the fire renders the lime insoluble and tasteless.

The natives in the vicinity of this salt pan keep large flocks of sheep and goats at various points on the outskirts of the desert. These flocks thrive wonderfully wherever salt and bushes are to be found.

The milk of goats does not coagulate readily, like that of cows, on account of its rich quality. The natives have discovered that by mixing a tea made from the fruit of a special plant with the milk of goats they can cause it to coagulate quickly.

It is the custom among some of the natives to put the milk into sacks of untanned hide from which the hair has been removed. When these sacks are hung in the sun the milk soon thickens. The whey is then drawn off by a plug at the bottom of the sack. Fresh milk is then added, until a thick sour curd fills the sack. When one becomes accustomed to this, its taste is delicious.

The richer natives mix this milk with the porridge they make from their meal. It is considered very nutritious and strengthening, and takes the place of our roast beef for nutriment.

The natives, in speaking scornfully of those who are poor or weak, use the expression, "They are water-porridge men;" since they cannot afford to mix their porridge in the approved way, and hence cannot expect to gain strength.

Speaking of other sections of the country, Livingstone tells us that he found some portions capped by a conglomerate rock mixed with iron. In many places the iron looked as if it had been melted; for the rounded ma.s.ses resembled slag in an iron foundry, and the under surface was smooth and even.

Probably this deposit was of an aqueous origin; for it contained water-worn pebbles of various kinds. These were generally small in size.

Below the conglomerate lay a ma.s.s of pale red, hardened sandstone, and beneath that a layer of what are called trap rocks. Lowest of all lay a coa.r.s.e-grained sandstone, which contained a few pebbles. Occasionally a white rock of lime formation was found, and also banks of loose, round pebbles of quartz.

The land slopes contained bogs surrounded by clumps of straight, lofty evergreen trees, which looked extremely graceful on a ground of yellowish gra.s.s. Many of these bogs pour forth a solution of iron. These exhibit the prismatic colors upon their surface.

It would be of interest to note the curious conditions and formations of the soil in other sections, but we must pa.s.s on to other views.

Those of you who are interested in the life of Livingstone will find many features of the soil described in the journals this explorer bequeathed to the world.

CHAPTER x.x.x.

THE MINERALS OF AFRICA.

For many years the knowledge of Africa was so indefinite that it was difficult to determine how rich the continent might be in minerals.

Gold and silver had been found, but the former was believed to be more abundant than the latter, judging from the amounts brought down in the sands of the great rivers which flow through the central portions of the continent. Gold had also been found upon the coast of Guinea and in Southeast Africa.

Precious stones have been found in most of the tropical countries of the globe; but in Africa they were of rare occurrence until the discovery of diamonds in the vicinity of the Cape awakened much interest. The attention of the whole world was then called to the possible resources of the country.

Just as the discovery of gold in California drew to the gold mines many men who were anxious to acquire wealth, so the Kimberley diamond mines attracted hundreds, who, in the pursuit of fortune, forgot fatigue and hardship, lured on by visions of the future.

The largest diamond in the world, the "Excelsior," was found June, 1894, in the mines of Jagersfontein in Cape Colony, by the inspector of the mine.

Experts have p.r.o.nounced it a gem of the purest water, and its worth to be about a million sterling.

The greatest precautions were taken to have it conveyed from the mine to the coast. A squadron of the Sixteenth Lancers guarded the carriage to Cape Town; from there it was conveyed to London in the gunboat _Antelope_, and was deposited for safe keeping in one of the vaults of the Bank of England.

The stone is described as fully three inches in height and nearly three inches in breadth. Its weight is estimated at nine hundred and seventy-one carats, or about seven ounces Troy. Its color is white, with a very slightly bluish tint, and its l.u.s.ter is matchless. In the center of the stone is a very small black spot, but experts consider that it can easily be removed in the cutting.

It has been reported that the British Government has offered half a million pounds sterling for this diamond. The owners, however, have refused this offer. It has also been reported that the German Emperor will be the probable purchaser of the gem.

The great sources of the world's supply of gold have been the United States, Russia, Australia, and South Africa, together with that portion of West Africa, known as Ashantee, bordering on the Gold Coast of Guinea.

There is a curious belief among the natives of the entire Gold Coast, and Ashantee as well. The Great Spirit, it is believed, created three each of white men and women, and as many black, and placed before them a large calabash and a sealed paper. To the black men he gave the first choice. They chose the calabash. This contained gold, iron, and the choicest products of the earth; but the black race remained ignorant of their use and value. The white man became possessor of the paper, which instructed him in all things, made him the favorite of the Great Spirit, and gave him superior advantages over the black man.

The great bend in the coast of Africa, which makes room for the Gulf of Guinea, is one of the singular land formations that strikes the eye and excites the fancy.

The glowing pictures of the beautiful Gold Coast and the wonders of land and sea under the equator serve to create a taste for travel and a desire to enjoy the strange and wonderful sights to be met.

An English explorer, Alvan Millson, has recently written much to give an added interest to this coast section and to call attention to one of the many freaks of nature.

A little description will be of interest. For a distance of about five hundred miles along the Bight of Benin there is an intricate chain of waterways, which lies just at the edge of the sea.

"In many places these narrow and br.i.m.m.i.n.g channels are separated from the onslaught of the Atlantic rollers by no more than five or six level yards of shifting sand. The spray from the ocean drifts over them, and the roar of the surf is heard by the native as he glides over their calm surface in his fragile canoe.

"There are hundreds of miles of similar lagoons bordering the Gulf of Guinea farther to the west. Many rapid rivers pour into them from uplands behind, bringing down vast quant.i.ties of sand and mud.

"At the same time, the 'Guinea Current,' which resembles our Gulf Stream, brings another endless supply of sand, worn from the headlands toward the west, and this sand, heaped up at the ocean's edge, arrests the rivers just where they are about to empty into the sea, and spreads them out into a great system of deltas.

"The resistless strength of the narrow sand barriers is attributed princ.i.p.ally to the vast quant.i.ties of papyrus and water gra.s.s brought down in huge floating islands by the rivers, which take root and flourish in the sand. Only at rare intervals can a pa.s.sageway be found through the sand. And so, on this singular coast, the ocean and the rivers unite to build up and perpetuate a barrier between them."

No doubt in the Gold Coast section of the Gulf of Guinea there is this same constant carrying down of sand by the rivers. Whenever these rivers pa.s.s through gold-bearing regions, the sand carries with it vast quant.i.ties of gold grains, or scales, which have to be panned, or separated from it by washing.

We have in our reading gained some little idea of the struggles of the Dutch to obtain possession of the soil of such sections as Natal, Cape Colony, and what has been known until within a few years as the Transvaal Republic.

The Wit.w.a.tersrand may be considered the great gold-mining district of Africa. It is rapidly pushing its way to the front in the list of sources for the supply of the precious metal. This region, locally called the Rand, gives Africa the fourth place in the list of the sources of the earth's supply.

The Rand is situated in what has been known as the Transvaal Republic.

It is the home of the Dutch settlers, or Boers, but is under the rule of the British power to a great extent.

The great metropolis of the republic and of the Rand is Johannesburg. It is a regular mining center, or what is known by the miners as a "boom"

town. From a small settlement it has, in the course of a few years, grown to a city of nearly twenty thousand inhabitants, while around it cl.u.s.ters a mining camp of thirty thousand more.

The Boers are naturally a contented people, caring little for display, but fond of comfort and plenty.

They have had little ambition to dig for such treasures as the earth might hold in its depths, but have been content to till the soil and to gather the harvest or fruits of their labor, or to engage in sheep farming for the purpose of raising wool for exportation.

No doubt, too, they deemed it better policy not to attract strangers to "prospect" for treasure beneath a soil which they preferred to call their own, rather than to see it laid out in "claims" by those eager to mine for its stores.

Now that the miners have rushed into the Rand in such numbers, the Boers must feel that their own claim to the land is but a name, particularly as the largest and most profitable mines are owned by London companies.

At the close of the year 1893, the mines in the Rand were producing at the average rate of two million five hundred thousand dollars value of bullion each month.