The discoveries in his last journeys, covering the periods from 1858 to 1864, and from 1866 to 1873, were as brilliant and fruitful as his earlier work, but not so astonishing, because his first years were given to revealing the broader aspects of Africa and its tribes, while his later labors were devoted to more detailed research in a smaller field. This region, about as large as Mexico and Central America, extends north and south, from Tanganyika to the Zambesi, and covers the wide region of the Congo sources between Nyassa and Lake Bangweolo. The greatest results were the discovery of Lake Nyassa and the Shire River, now the water route into East Central Africa; Lakes Bangweolo and Mwero; and the mapping of the eastern part of the sources of the Upper Congo, which Livingstone believed to the day of his death were the ultimate fountains of the Nile. Livingstone's "Last Journeys" was published from the manuscript which his faithful servants brought to the seacoast with the mortal remains of their gentle master. Not far from the south coast of Bangweolo stands a wooden construction to which is affixed a bronze tablet bearing the simple inscription, "Livingstone died here. Ilala, May 1, 1873." It has taken the place of the tree under which he died, and where his heart, which had been so true to Africa, was buried. As the tree was nearly dead, the section bearing the rude inscription cut by one of his servants was carefully removed and is now in London. Livingstone's geographical delineations were remarkably accurate, considering the inadequate surveying instruments with which he worked. Dr. Ravenstein, one of the greatest authorities on African cartography, has said: "I should be loath to reject Livingstone's work simply because the ground which he was the first to explore has since his death been gone over by another explorer." It would be marvellous, however, if in the course of twenty years of exploration he had not made some blunders. His map of Lake Bangweolo, for example, was very inaccurate. The Lokinga Mountains, which he mapped to the south of the lake, have not been found by later explorers. These imperfections resulted from the fact that his map of Bangweolo and its neighborhood was largely based upon native information. He knew that his map was inadequate, and as soon as he was able to travel he returned to Bangweolo to complete his survey. He was making straight for the true outlet of the lake, and was within thirty-five miles of it when one morning his servants found him in his lowly straw hut, dead on his knees. If Livingstone had lived a few weeks longer and been able to travel, he and not Giraud would have given us the true map of Bangweolo. As a whole, Livingstone's work in geography, anthropology, and natural history, stands the test of time. No river in Africa has yet been laid down with greater accuracy than the Zambesi as delineated by this explorer.