I had the good fortune to see my discoveries placed on a stable basis before they were brought to a close, by the astronomical observations of Dr. Vogel, who was sent out by Her Britannic Majesty’s Government for the purpose of joining the expedition; and I have only to regret that this gentleman was not my companion from the beginning of my journey, as exact astronomical observations, such as he has made, are of the utmost importance in any geographical exploration. By moving the generally-accepted position of Kúkawa more than a degree to the westward, the whole map of the interior has been changed very considerably. The position assigned by Dr. Vogel to Zínder gives to the whole western route, from Ghát through the country of Ásben, a well-fixed terminating point, while at the same it serves to check my route to Timbúktu. If, however, this topic be left out of consideration, it will be found that the maps made by me on the journey, under many privations, were a close approximation to the truth. But now all that pertains to physical features and geographical position has been laid down, and executed with artistic skill and scientific precision, by Dr. Petermann. The principal merit which I claim for myself in this respect is that of having noted the whole configuration of the country; and my chief object has been to represent the tribes and nations with whom I came in contact, in their historical and ethnographical relation to the rest of mankind, as well as in their physical relation to that tract of country in which they live. If, in this respect, I have succeeded in placing before the eyes of the public a new and animated picture, and connected those apparently savage and degraded tribes more intimately with the history of races placed on a higher level of civilization, I shall be amply recompensed for the toils and dangers I have gone through. My companion, Dr. Overweg, was a clever and active young geologist; but, unfortunately, he was deficient in that general knowledge of natural science which is required for comprehending all the various phenomena occurring on a journey into unknown regions. Having never before risked his life on a dangerous expedition, he never for a moment doubted that it might not be his good fortune to return home in safety; and he therefore did not always bestow that care upon his journal which is so desirable in such an enterprise. Nevertheless, almost all his observations of latitude have been found correct, while his memoranda, if deciphered at leisure, might still yield a rich harvest.