November 14^th

Nevertheless, though his title to fame is every-where confessed, few at this day, with the exception of some arduous students, are practically conversant with its grounds. Leibnitz was one of the chief intellectual forces of his age, but as a force he was more remarkable for quantity than intensity. He busied himself in a multitude of pursuits and he excelled in all, but he produced no master-piece �nothing of which it could be said, It is the best of its kind. He was a universal genius; his intellect was as capacious as harmonious, and a store-house for all knowledge; but his mind was lost by reason of its universal sympathies. To be remembered for ever by some work requires that the whole energy, at least for a time, be given to one work. 'Even great parts,' says Locke, writing of Leibnitz in 1697, 'will not master any subject without great thinking.'

Leibnitz was the son of a professor of jurisprudence in the university of Leipsic, in which city he was born in 1646. He was a precocious child, and from his boyhood displayed that love of learning and speculation which distinguished him through life. He gives an amusing account of his efforts when a youth of fifteen, during long solitary walks in the wood of Rosenthal, near Leipsic, to adjust the claims of the Ancients and Moderns�of Aristotle and Descartes, and the reluctance with which, when conciliation was impossible, he was compelled to make an election. His talents, as manifested at the university, and his publications, early brought him into notice, and found him patrons among the princes of Germany. He travelled over the continent, visited England, and everywhere made the acquaintance of men of science and letters. An amusing anecdote is told of him when at sea in a tempest off the Italian coast. The sage captain attributed the storm to the presence of the heretical German, and presuming him ignorant of the Italian language, began to deliberate with the crew on the propriety of throwing the Lutheran Jonah overboard. Leibnitz, with much presence of mind, got hold of a rosary and began to tell his beads with vehement devotion. The ruse saved him. At N�rnberg, he heard of a society of alchemists who were prosecuting a search for the philosopher's stone. He wished to join them, and compiled a letter from the writings of the most celebrated alchemists and sent it to them. The latter consisted of the most obscure terms he could find, and of which, he says, he did not understand a syllable. The illuminati, afraid to be thought ignorant, invited him to their meetings and made him their secretary. Though Leibnitz could thus quiz the alchemists, he believed, to the end of his life, in the reality of the object of their labours.

In the leisure which various pensions secured him, he followed his versatile inclinations with incessant assiduity. Metaphysics, physics, mathematics, jurisprudence, theology, philology, history, antiquities, the classics, all shared his attention, and in all of these branches of knowledge the world heard his voice with respect. The ancient languages he knew well, and was tolerably acquainted with more than half-a-dozen of the modern. He had notions about calculating machines, about improved watches, about a universal alphabet, about hydraulic engines, about swift carriages, by which the journey of one hundred and fifty miles, between Amsterdam and Hanover, might be done in twenty-four hours; and about a hundred other things. He dabbled in medicine, in everything; there was nothing, in fact, in which he could not be interested. In his Protogena, he throws out thoughts, which, Dean Buckland observes, contain the germ of some of the most enlightened speculations in geology. His memory was quick and tenacious; he made notes as he read, but he had seldom to refer to them, for he seemed to forget nothing. George I used to call him his living dictionary. At the age of seventy, he could recite hundreds of lines of Virgil without an error.

In mathematics, if anywhere, his genius shewed itself supreme, and between him and Sir Isaac Newton a bitter controversy broke out as to the credit of the invention of the differential calculus. The question has been thoroughly and tediously debated, but the following points are now considered as tolerably clear:

1. That the system of fluxion invented by Newton is essentially the same as the differential calculus invented by Leibnitz, differing only in notation;
2. That Newton possessed the secret of fluxions as early as 1665, nineteen years before Leibnitz published his method, and eleven years before he communicated it to Newton;
3. That both Leibnitz and Newton discovered their methods independently of each other, but that Newton had priority; and
4. That although the honour belongs to both, yet, as in every other great invention, they were but the individuals who combined the scattered rays of their predecessors, and gave a method, a notation, and a name to the doctrine of infinitesimal quantities.

As a theologian and metaphysician, Leibnitz was eclectic rather than original. His temper was truly catholic; he differed from others with reluctance; and it seemed to be one of his keenest delights to reconcile apparent contraries. Hence one of his schemes was the incorporation of the various sects of Protestantism, preparatory, if possible, to the inclusion of Rome, with concessions, in one grand Christian community. In philosophy, he had a doctrine called Pre-established Harmony, by which he professed to explain the relations between Deity, the Human Mind, and Nature. It met with wide discussion and some acceptance in the lifetime of Leibnitz, but Pre-established Harmony has long passed out of memory except in histories of philosophy.

One of the warmest admirers of Leibnitz was Sophia Charlotte, wife of Frederick, the first king of Prussia, a great lover of show and ceremony, for which his consort had a quiet contempt. Leibnitz called her 'one of the most accomplished princesses of earth,' and by the world she was known as the republican and philosophic queen. To Leibnitz, 'la grand Leibnitz,' as she styled him, she resorted for counsel in all her theological and philosophical difficulties, and not seldom to his perplexity, wanting to know, he said: 'le pourquoi du pourquoi' (the why of the why). Wearied with the emptiness of courtiers, she wrote on one occasion: 'Leibnitz talked to me about the infinitely little; man Dieu, as if I did not know enough of that!' This bright soul died at thirty-six, to the great grief of Leibnitz. On her death-bed she said she was very happy; that the king would have a fine opportunity for display at her funeral; and, above all, that now she was going to satisfy her curiosity about a great many things of which Leibnitz could tell her nothing. With many other crowned heads Leibnitz held intercourse more or less intimate. Peter the Great consulted him as to the best means for the civilisation of Russia, and rewarded his suggestions with the title of Councillor of State, and a pension of a thousand roubles.

Leibnitz was only able to get through his multi-form business by persistent assiduity. He carried on a most extensive correspondence, and wrote his letters with great care, sometimes three or four times over, and made them the repositories of his most valued ideas and conjectures. His life was sedentary almost beyond example. Sometimes for weeks together he would not go to bed, but sat at his desk till a late hour, then took two or three hours of sleep in his chair, and resumed work at early dawn. He was a bachelor, and had no fixed hours for his meals; but sent to a tavern for food, when hungry and at leisure. His head was large and bald, his hair fine and brown, his face pale, his sight short, his shoulders broad, and his legs crooked and ungainly. He was spare and of middle height, but in walking, he threw his head so far forward as to look from behind like a hunch-back. His neglect of exercise told severely on him as he advanced in life. He became plagued with rheumatic gout, his legs ulcerated, and he aggravated his ailment by compressing afflicted parts with wooden vices to stop the circulation of the blood, and dull the sense of pain. He died in Hanover in 1716, in his seventieth year, from the effects, it is said, of an untried medicine of his own concoction. He was buried on the esplanade of his native city of Leipsic, where a monument, in the form of a temple, with the simple inscription, 'Ossa Leibnitii,' marks the spot.

DISCOVERY OF THE SOURCES OF THE NILE

It is curious to look back to the days when Bruce the traveller published his celebrated work on Africa, and claimed to have discovered the true sources of the mysterious river which flows so many hundreds of miles through that continent. Comparing that narrative with one which has appeared in 1863, we see that Bruce was in the wrong; that he may have discovered a source but not the source; and that a long series of intermediate investigations was needed to arrive at a true solution of the interesting problem. No blame to James Bruce for all this. He was really a sagacious and enter-prising man; and although some doubt was thrown upon his truthfulness during his life, he is now believed to have been veracious to the extent of his knowledge. His error concerning the sources of the Nile may well be excused, considering the harassing difficulties of the problem.

Glancing at a map of Africa, we see that the Nile is formed by several branches, which meet in Nubia, and flow northward through Egypt into the Mediterranean. The puzzle has been to determine which of the branches ought to be considered as the true Nile, and which mere affluents or tributaries. The easternmost of the chief or important branches, the Atbara, rises in about 12� N. lat., 40� E. long; and joins the main river near 18� N. lat., 34� E. long. It was visited by Salt and by Pearce, and has been often noticed by travellers in Abyssinia. The middle, or second of the three branches, known as the Bahr-el-Azrek, or Blue Nile, is, par excellence, the river of Abyssinia, winding through and about that country in a very remarkable way. Bruce traced it upwards until it became a mere streamlet in 11� N. lat., 37� E. long., near the village of Geesh, whence it flows by Sennaar to its junction with the greater Nile at Khartoum. The westernmost, and largest branch, the Bazar-el-Abiad, or White Nile, is extremely circuitous in its route, winding through the countries of Darfur and Kordofan in a very intricate way.

Now it is the Bahr-el-Azrek, or Blue Nile, which Bruce considered to be the true or original river, and which, on the 14^th of November 1770, he believed himself to have traced up to its source. In the preface to his Travels (written in 1790, and, as is supposed, not so accurately as if he had allowed less than twenty years to elapse) he said:

'I hope that what I have said will be thought sufficient to convince all impartial readers that these celebrated sources have, by a fatality, remained to our days as unknown as they were to antiquity; no good or genuine voucher having yet been produced capable of proving that they were before discovered, or seen by the curious eye of any traveller, from the earliest ages to this day. And it is with confidence I propose to my reader, that He will consider me as still standing at the fountain, and patiently hear from me the recital of the origin, course, nature, and circumstances of this the most famous river in the world, which he will in vain seek from books, or from any other human authority whatever, and which by the care and attention I have paid to the subject, will, I hope, be found satisfactory here.'

Bruce was all the more proud of his achievement, because the ancients had believed that the Bahr-el-Abiad was the true Nile, an opinion which he claimed to have shewn fallacious. The ancients were right, however, and Bruce wrong. Step by step the White Nile has been traced to points nearer and nearer to the equator, and therefore nearer to its source. Linant, in 1827, ascended as far as Aleis, in 15� N. lat. In 1842, Werne, heading an expedition sent out by the pacha of Egypt, reached to 5� N. lat., and was told by the natives that the source was still far distant. In 1845, M. D'Abbadie thought he had reached the source of the Nile; but Beke afterwards shewed that the stream traced by D'Abbadie was only an affluent of the Bahr-el-Abiad, and expressed an opinion that the real source is even beyond the equator. M. Knoblecher, who had a missionary establishment at Khartoum, went up the White Nile as far as 4� N. lat., and saw that river still far away to the south-west.

The grand discovery of all, that the Nile really rises in south latitude, and crosses the equator, was made by Captains Grant and Speke, whose names have become thereby renowned throughout Europe. In 1858, Captain Speke reached a very beautiful lake, the Victoria Nyanza, while journeying westward from Zanzibar. The head of this lake is three degrees south of the equator. He found the lake to be a large sheet of fresh water, lying on a plateau or table-land, from 3000 to 4000 feet above the level of the sea. The lake, to use the language of Captain Speke, 'looked for all the world like the source of some great river; so much so, indeed, that I at once felt certain in my own mind it was the source of the Nile, and noted it accordingly.' It was the bold guess of a sagacious and experienced man. The Victoria Nyanza, so far as we can now tell, is really the head-water of the Nile, being fed immediately by a range of lofty mountains in the interior. Strictly speaking, perhaps, we ought not even yet to speak of the actual source of the Nile, which is still further south. than the lake; but it is at anyrate shewn that the Nile flows uninterruptedly from the lake to the Mediterranean, through no less than thirty-four degrees of latitude, and along a course exceeding 2000 miles in length, in a straight line, and perhaps 3000, allowing for windings. Captain Speke was prevented from putting his speculation to the test in 1859 or 1860; but in 1861 and 1862, accompanied by Captain Grant, he traced the course of the grand river down from the lake to the ocean�not actually keeping the stream in view the whole of the way, but touching it repeatedly here and there, in such a way as to leave no doubt that it is the Nile.

Thus the somewhat magniloquent terms in which Bruce announced his discoveries have not proved to be justified. The post of honour is to be given, not to the Blue Nile, but to the White Nile, and at a point nearly a thousand miles further south than was reached by Bruce.

November 15th