Of all theoretical discoverers, the man who ran in 200 miles of Lake and placed them on a height of some 4000 feet at the north-west end of Lake Nyassa, deserves the highest place. Dr. Beke, in his guess, came nearer the sources than most others, but after all he pointed out where they would not be found. Old Nile played the theorists a pretty prank by having his springs 500 miles south of them all! I call mine a contribution, because it is just a hundred years (1769) since Bruce, a greater traveller than any of us, visited Abyssinia, and having discovered the sources of the Blue Nile, he thought that he had then solved the ancient problem. Am I to be cut out by some one discovering southern fountains of the river of Egypt, of which I have now no conception? David Livingstone. [The tiresome procrastination of Mohamad and his horde was not altogether an unmixed evil. With so many new discoveries in hand Livingstone had an opportunity for working out several problems, and instituting comparisons between the phenomena of Inner Africa and the well-marked changes which go on in other parts of the world. We find him at this time summing them up as follows:--] The subject of change of climate from alteration of level has not received the investigation it deserves. Mr. Darwin saw reason to believe that very great alterations of altitude, and of course of climate, had taken place in South America and the islands of the Pacific; the level of a country above the sea I believe he thought to be as variable as the winds. A very great alteration of altitude has also taken place in Africa; this is apparent on the sea-coast of Angola, and all through the centre of the country, where large rivers which once flowed southwards and westwards are no longer able to run in these directions: the general desiccation of the country, as seen in the beds of large rivers and of enormous lakes, tells the same tale. Portions of the east coast have sunk, others have risen, even in the Historic Period. The upper or northern end of the Red Sea has risen, so that the place of the passage of the children of Israel is now between forty and fifty miles from Suez, the modern head of the Gulf. This upheaval, and not the sand from the desert, caused the disuse of the ancient canal across the Isthmus: it took place since the Mohamadan conquest of Egypt. The women of the Jewish captivities were carried past the end of the Red Sea and along the Mediterranean in ox-waggons, where such cattle would now all perish for want of water and pasture; in fact, the route to Assyria would have proved more fatal to captives then than the middle passage has been to Africans since. It may be true that, _as the desert is now_, it could not have been traversed by the multitude under Moses--the German strictures put forth by Dr. Colenso, under the plea of the progress of science, assume that no alteration has taken place in either desert or