“Being the first European traveller undertaking so long a journey in this part of the world, _I will not put my discoveries to the hazard, by exposing myself to the casualties of long and unnecessary residence and delays in any one place_, and propose staying no longer at Bornou than till the month of September, when I shall proceed to Cashna with the great caravan, which always about that time of the year sets out from Bornou for Soudan. “I cannot yet decide on my further procedure on leaving Soudan, or Cashna, but you may depend on my best intentions and wishes to give full satisfaction to the Society. “Consider this letter as the last for this year, or perhaps as the last before my arrival at some port on the coast of Africa. March the 24th I sent a long letter from Tripoly, and being by a good opportunity, have no doubt of its arriving safe.[12] “In addition to what I stated in my letter of the 24th of March, I have to observe, that in the small-pox, the application used here to preserve the eyes of children, consists of what they term _samsuc_, (tamarinds,) and _zurenbula zigollan_, (onions,) and this with good effect, as I am told. “I have more particularly made inquiry respecting venereal disorders, and can confirm what I before wrote, that salts and coloquintida, (in Arabic _handal_) are specific remedies for that disease in this country, and used in the manner I described. “From every information I can collect, the natives of Fezzan are not susceptible of venereal infection more than once in their lives. It is singular, that notwithstanding there is a great difference as to the nature of this disease, between poxes brought here by the caravan from Soudan, and by those from Tripoly and Cairo, yet never (or at least very seldom,) can a man get these two sorts one after the other in the course of his life. “Some days past I spoke to a man who had seen Mr. Brown in Darfoor; he gave me some information respecting the countries he travelled through, and told me, that the communication of the Niger with the Nile was not to be doubted, but that this communication before the rainy season was very little in those parts; the Niger being at the dry period reposing, or _non fluens_. “Not long ago, the same custom was observed at Bornou as in ancient times at Cairo, ‘a girl very richly dressed, was thrown into the river Niger.’ “Comparing my enquiries as to Soudan, and its communication with the western and south-western coasts of Africa, it must lay generally by the way of Nyffé and Jerba, and be twelve times greater than that between Fezzan and Soudan. “I recommend myself to your remembrance, and assuring you of my great esteem, am “SIR, “Your most obedient, “FREDERICK HORNEMAN.” _Right Hon. Sir Joseph Banks, K. B. President of the Royal Society, &c._