known, thanks to the observations made by the intelligent travellers who have visited the country of late years. It is not very complex, but is extremely interesting; the granite and other rocks of similar character not there appearing as a central mass or distributed at intervals to mark lines of elevation. Granitic rock is confined to the outer wall that incloses the continent; it there reaches to considerable elevations, but does not form a mountain chain; it is the nucleus of the broad rim which encloses the central lands.

Forming part of the wall are other mineral accumulations of no trifling importance. Coal is there, and limestone, and iron ore; resources which, being in a country where water is not scarce, must ultimately have commercial value. These and the basaltic rocks, that in some places abound, decompose into a rich soil which, under a tropical sun and with tropical rain, will support a vegetation of the richest kind. On the coast is calcareous tufa, and the remains of ancient coral dispersed or grown over an old granite gravel. Modern shells are found on raised beaches near the western shores. A band of trappean rock with occasional hot springs next succeeds, and then comes a belt of sandstone rocks with coal and iron ore; mica schist and other slates come next, and these lie on the edge of the granite which forms the principal table-land. Within this belt in the great central plateau are masses of conglomerate and gravel of various kinds with occasional marks of marine action; an ancient sea bottom of schistose rock with granite peeping up at intervals. Large quantities of calcareous tufa have also been found in the interior. Commencing either from the east or west shore, this, with local modifications, is the description of a great section from the coast to the central depression.

Occasionally there are salt plains, and some of the lakes contain water which, in the dry season, is salt, though potable during and after rains. There are also deposits of gypsum. The vast swamps that now cover half the land during the

rains were once a sea bottom; but the sea has drained off, slowly perhaps, but almost entirely, during the elevations that have brought the country to its present level. It is only here and there that a small depression, not communicating with the general drainage, has retained the salt water.

In the north, under the equator, the geological structure is altogether unknown, nor would it be safe to speculate upon it.

We have spoken only in this article of the country, not at all of the people, of Africa. That subject is too important and too wide to be treated except in a special manner; but we may recommend the reader interested concerning it to study Captain Burton's chapters at the close of his volume ;-they abound in useful information.

On the whole, then, we may conclude that vast progress has already been made in the way of African discovery. On the north the Sahara has been visited, and the Guinea coast has been explored in various directions, so that we have some idea of its nature. But it yet remains to connect the oases, and to determine elevations on several lines of travel. We still also know absolutely nothing of the southern limit of the Sahara from Lake Tchad to the western branch of the Nile. We are ignorant of the limits of the desert between Timbuctu and Senegal; and we know little of the western part of the desert immediately south of Morocco; but we do know that all these will be very difficult investigations.

A somewhat important blank still exists in our maps between the course of the White Nile, as now laid down, and the shores of the Indian Ocean. It is possible that the coast range here assumes the character of a great mountain group, rising from an elevated table-land; but no reliable European traveller has ever set foot on the country within these limits and returned to tell his story.

For some distance south of the equator there is still a large and important district unknown, which may probably

be thickly peopled, well watered, well wooded, and even not without cultivation. In the interior of the continent there are other large tracts, probably without any chain of lofty mountains, or vast sheets of water, or gigantic rivers, but which no traveller has yet been able to penetrate. This is the true land of the negro-the hunting-ground which supplies the great slave-markets on both sides of the continent-the unknown and unapproachable resort of the most hopeless forms of paganism, and the habitation at once of the most fierce and gigantic of the apes, and of the lowest families of the human race.

that old

And there still remains problem, the one that has for centuries evaded complete solution. Whence proceeds the flood of water that for tens of thousands of years has borne along the fertilizing mud of the Nile to be deposited in Egypt? Does it connect itself with the central equatorial tracts and shallow basins? Does it come down from Victoria Nyanza, the lake recently discovered by Captain Speke? Does it proceed from snowy mountains on the east side of the great unexplored belt? On all these points we are still likewise ignorant. The sources of the Nile have still to be discovered, but their discovery now seems very near.1

And those lakes-at one time believed to exist in Central Africa, but now found near the coast; by some supposed to form a kind of continuous chain parallel with the coast; by others believed to be variable, detached, and unimportant, and connected with

1 Captain Speke, accompanied by Captain Grant, are now in the interior of Africa endea vouring to make their way from Lake Nyanza northwards to the White Nile, where they hope to meet Mr. Petherick, in the autumn of this year, and clear up the Nile problem.

mountain chains-What know we of these? Something, no doubt; and that something highly suggestive; but the details of the coast drainage of the two sides of the dark continent are still far from being clearly made out; and the time and extent of their increase, if really periodical, requires much further elucidation.

The Mountains of the Moon, where are they to be placed in our maps? Originally inserted under the equator, ranging east and west, they have been hypothetically transferred to form a north and south part of the coast range in the countries south of Abyssinia. Their very existence is uncertain. At any rate, if there is such a chain, its position and elevation have yet to be determined.

The vast network of waters which for want of other outlet connect themselves with the Zambesi-a river whose debouchure is unworthy of the interior water system it partially drains-what is this and does it connect also with the Niger and the Nile? Do the three great rivers of Africa proceed originally from the overflow of some central pool of stagnant water under the equator, swollen by the monsoon rains; or are they in their sources kept distinct; and do they drain independently the northeast, north-west, and south of the vast African basin?

Such are some of the queries the geographer must still ask when told of the progress of discovery in Africa. Some of them are now in course of being answered. being answered. Not less different in point of accuracy will the map of Africa appear when these matters are distinctly made out, than are the best modern maps, when compared with the hypothetical productions dating half a century back.

THAT gold-the popular representative, the special currency, of Fortuneshould owe its discovery to one of her spoilt children in an idle hour, is what we might expect. The amount of genius necessary to detect the glittering grains seems moderate, and the mental labour in mounting to the use of the pick and crusher not severe. The means and the end seem to lie tolerably close together; and, if we were asked at a venture to name a discovery that had been made by the joint instrumentality of Indolence and Chance, we should most probably say "Gold."

a

We should be wrong. If we had said "Steam Engines" we should have been nearer the mark. California, the first of the many El Dorados of the day, yielded its earliest golden harvest to anything but idle hands. In September of the year 1847 an enterprising expatriated Frenchman, one Suter by name, "squatter" in the then almost desert region, is dreaming little of the yellow treasure lying in profusion at his feet. His "only care" is that his contractor, Mr. Marshall, shall make a good job of the sawmill he is building him on the American fork of the Sacramento. And there seem doubts about it. The dam and race have been constructed. The water is let on; but the tail race is found too narrow to permit the water to escape fast enough. Marshall, to save labour, lets the water directly into the race, and a great bed of mud and gravel is speedily thrown up at the foot of it. This bed contained particles of-what? Can they believe their senses? It is Hu-s-h!! In October the "enterprising and expatriated" is taking counsel with his contractor how they may best keep a certain secret-a secret by the way that poor porous human nature never yet was able to hold long. Another month and the Culloma Sawmill is about the last

subject of the gallant Suter's care. Το use the phraseology of a writer on the spot, "the whole district was moving on the mines." Six thousand diggers, earning from 31. 10s. to 50l. a day, are at work within a radius of a mile; and every spade, shovel, pick, bowl, and even warming pan, that can be got at, is busy-getting gold.

Paullo majora canamus. Let us turn to the loftier realms of Science and see how discovery is managed there.

Newton is the greatest of great names, and we are fortunate in having his own experience upon the point. At the time when men were lost in wonder at the grandeur of his discoveries it occurred happily to some one to ask him, "how he came to make them." The question was not perhaps a very wise one; but it elicited a notable reply: "By always thinking of them," said the great philosopher. "I keep the subject of my inquiry constantly before me, and wait till the first dawning opens gradually by little and little into a full and clear light."

"1

Numerous anecdotes, some not without a tinge of the ludicrous, attest the depth of the abstraction which-especially while he was occupied with his Principia-accompanied those periods of thought. For hours it is said he would sit half-dressed on the edge of his bed, lost in meditation and utterly indifferent, as it appeared, to any such material considerations as meat and drink.

Of a somewhat similar cast of mind, though destined for a widely different sphere, was James Brindley, the hydraulic engineer. What the Kosmos was to Newton, "Water-shed" was to him. A Canal was his idée fixe. It was his mission to make Canals. Not his mission only. Nature had enjoined it on the

1 Hist. Induct. Sc. II. 192.

whole human race. "What do I think Providence intended rivers for?" he said once, repeating somewhat contemptuously a question which had been aimed at him as a poser by an astute Member of a Committee of the House of Commons: "Why, to feed navigable canals, of course." He was a man of one idea; but in the realization of that idea no opposition could for one moment make him turn aside. With him, as with another great man, difficulties meant

'something to be got over." He subjected his difficulties, by the way, to a somewhat curious process. It has been customary to say of a certain class of problems, "solvitur ambulando." Brindley solved his by lying down. Having acquired a full knowledge of his data, he retired with them to his bed, and there stayed-sometimes for days together-till he had thought the plan out. He then executed it at once without model or plan. It was no affectation of eccentricity. With this singularly gifted man seclusion seems to have been actually indispensable for him when at work. He frequently declared that the excitement consequent on a visit to the play had disturbed the current of his thoughts for several days.

Such is the calibre of the heavy ordnance—our Armstrongs of Invention; on which alone we can rely for successfully investing and carrying by assault the citadel of Truth. Of a far different and lighter character are the weapons by which the coups-de-main we are about to celebrate have been executed, and several not unimportant triumphs achieved in Science and the Arts.

It is needless, we hope, to deprecate insinuations as to our being the unqualified eulogists of Lucky Accident, or encouraging "loafery" by the instances we are going to adduce of Idleness and Scampishness succeeding where Philosophy has failed. Palissy, Davy, and George Stephenson stand before us as splendid illustrations of the truth, if indeed such a truth can be supposed to need illustration, that in manufactures, as in every other department of human occupation, patient industry, courage,

and fertility of resource are after all the only reliable elements of success.

Öne element there must be in common to all invention, be the immediate causes of it what they may. There must be Genius-that particular species of Genius which Dr. Johnson 1 defined as knowing the use of tools." ... "Let "two men," he says, "one with genius, "the other with none, look together at "an overturned waggon. He who has "no genius will think of the waggon only as he sees it, that is to say over“turned, and walk on. He who has "genius will give it a glance of exami"nation that will paint it to his imagi"nation, such as it was previously to "its being overturned, and when it was "standing still, and when it was in

motion, and when it was heavy-loaded, "and when it was empty: but both "alike must see the waggon to think of "it at all."

The latter observation contains a fund for thought, and brings in review before us a host of names illustrious in arms and arts, of men whose careers have been determined, and the course of their entire lives influenced, by what to ordinary minds would have appeared only a trivial fact. A stripling is looking at a swinging lamp, and its oscillations are awakening the genius of-Galileo. A lively boy, bored to death by his mother's austerity, is escaping in the spirit from the dull monotony of her prayer by peeping through a chink in the wainscot. His little sinful eye rests upon a portion of a clock in the room beyond, and from that hour he is a mechanician. He lives to make a name as Vaucanson, Grand Master of the automatic art. A broken rafter in his father's house secures young Ferguson, the "self-taught philosopher," for the service of the arts. A piece of strange and complex mechanism is given to a workman to repair. The workman is James Watt. Flamstead, Franklin, Cartwright, a score of other examples of a like kind, suggest themselves to us at once; but for the present we are hardly so much concerned with men as with things. We proceed, therefore, without more 1 Memoirs of Dr. Burney, vol. iii. p. 7.