The Nile.--The Trembling Mountain.--A Remembrance of the Country.--The Narratives of the Arabs.--The Nyam-Nyams.--Joe's Shrewd Cogitations.--The Balloon runs the Gantlet.--Aerostatic Ascensions.--Madame Blanchard.

"Which way do we head?" asked Kennedy, as he saw his friend consulting the compass.

"North-northeast."

"The deuce! but that's not the north?"

"No, Dick; and I'm afraid that we shall have some trouble in getting to Gondokoro. I am sorry for it; but, at last, we have succeeded in connecting the explorations from the east with those from the north; and we must not complain."

The balloon was now receding gradually from the Nile.

"One last look," said the doctor, "at this impassable latitude, beyond which the most intrepid travellers could not make their way. There are those intractable tribes, of whom Petherick, Arnaud, Miuni, and the young traveller Lejean, to whom we are indebted for the best work on the Upper Nile, have spoken."

"Thus, then," added Kennedy, inquiringly, "our discoveries agree with the speculations of science."

"Absolutely so. The sources of the White Nile, of the Bahr-el-Abiad, are immersed in a lake as large as a sea; it is there that it takes its rise. Poesy, undoubtedly, loses something thereby. People were fond of ascribing a celestial origin to this king of rivers. The ancients gave it the name of an ocean, and were not far from believing that it flowed directly from the sun; but we must come down from these flights from time to time, and accept what science teaches us. There will not always be scientific men, perhaps; but there always will be poets."

"We can still see cataracts," said Joe.

"Those are the cataracts of Makedo, in the third degree of latitude. Nothing could be more accurate. Oh, if we could only have followed the course of the Nile for a few hours!"

"And down yonder, below us, I see the top of a mountain," said the hunter.

"That is Mount Longwek, the Trembling Mountain of the Arabs. This whole country was visited by Debono, who went through it under the name of Latif-Effendi. The tribes living near the Nile are hostile to each other, and are continually waging a war of extermination. You may form some idea, then, of the difficulties he had to encounter."

The wind was carrying the balloon toward the northwest, and, in order to avoid Mount Longwek, it was necessary to seek a more slanting current.

"My friends," said the doctor, "here is where OUR passage of the African Continent really commences; up to this time we have been following the traces of our predecessors. Henceforth we are to launch ourselves upon the unknown. We shall not lack the courage, shall we?"

"Never!" said Dick and Joe together, almost in a shout.

"Onward, then, and may we have the help of Heaven!"

At ten o'clock at night, after passing over ravines, forests, and scattered villages, the aeronauts reached the side of the Trembling Mountain, along whose gentle slopes they went quietly gliding. In that memorable day, the 23d of April, they had, in fifteen hours, impelled by a rapid breeze, traversed a distance of more than three hundred and fifteen miles.

But this latter part of the journey had left them in dull spirits, and complete silence reigned in the car. Was Dr. Ferguson absorbed in the thought of his discoveries? Were his two companions thinking of their trip through those unknown regions? There were, no doubt, mingled with these reflections, the keenest reminiscences of home and distant friends. Joe alone continued to manifest the same careless philosophy, finding it QUITE NATURAL that home should not be there, from the moment that he left it; but he respected the silent mood of his friends, the doctor and Kennedy.

About ten the balloon anchored on the side of the Trembling Mountain, so called, because, in Arab tradition, it is said to tremble the instant that a Mussulman sets foot upon it. The travellers then partook of a substantial meal, and all quietly passed the night as usual, keeping the regular watches.

On awaking the next morning, they all had pleasanter feelings. The weather was fine, and the wind was blowing from the right quarter; so that a good breakfast, seasoned with Joe's merry pranks, put them in high good-humor.

The region they were now crossing is very extensive. It borders on the Mountains of the Moon on one side, and those of Darfur on the other--a space about as broad as Europe.

"We are, no doubt, crossing what is supposed to be the kingdom of Usoga. Geographers have pretended that there existed, in the centre of Africa, a vast depression, an immense central lake. We shall see whether there is any truth in that idea," said the doctor.

"But how did they come to think so?" asked Kennedy.

"From the recitals of the Arabs. Those fellows are great narrators--too much............