_August 1._--We left Ajunjer early, and made five hours only, because to-morrow there is no herbage until late in the evening. How tantalising to be obliged to advance thus by short stages towards an ambuscade! We take things pretty philosophically, however, and make geological observations. Overweg (who begins to show signs of weakness) is delighted that we have at length reached a region of granite. I think I must have passed a great number of rocks of the same kind between Ghadamez and Ghât. To the eye of an ordinary observer, some of them have the same aspect as sandstone, or even limestone. This granite interests us, especially as in the direct Bornou route there appears to be none at all. Dr. Barth compares the Tuaricks of Ghât and the Haghar to lions and tigers, and the Kailouees to snakes. The comparison well hits off their outward characteristics, but, as Overweg says, we must not judge of these people by the ordinary rules of morality, or apply to them an European standard. I suspect we shall have to put up with still more extraordinary specimens of human nature. We were proceeding, engaged in noticing the various colours and forms of the granite, when there appeared advancing through the ravine ahead a number of moving figures. At first, of course, we were a little alarmed; but it turned out to be only a slave caravan--about twenty camels and forty slaves. One of the little boys had an immensely large head--quite a phenomenon. We, of course, eagerly questioned the merchants about Sahara news, and especially as to whether the Tuaricks had made their appearance at Falezlez or Tajetterat. They had neither seen nor heard of the hostile party; and perhaps we may hope that all this is a rumour. However, it looked very like truth; and, possibly, Sidi Jafel may know perfectly well that there is no occasion to hurry. The Tanelkums are now about four days in advance of us, and may receive the first brunt of the attack. These slave-dealers tell us, that from Falezlez to the place where we are to be robbed and murdered is four days of dismal desert, without water--suffering before sacrifice. We are getting into the heart of the Sahara at last. Day by day the stations become more difficult. Another caravan is to pass in a few days, which may give us more definite intelligence. I am writing to Government and to my wife; but of camels I am heartily sick. Gagliuffi's camel still sticks in my throat. It was the first to knock up. I have left it at Ghât--thirty-eight mahboubs gone. People want to make a fortune out of my poor expedition.