The skull of the lion having been secured, the _Flying Fish_ rose into the air, immediately after breakfast, and an hour was devoted to the thorough examination of the remaining extent of the patch of rocks, to ascertain whether any further specimens of the big carnivora had taken up their abode upon it. But no more were to be found, and the southward journey was therefore resumed at the leisurely speed of about fifteen knots, the noon observation for latitude showing that the ship had entered the tropic of Cancer shortly after eleven o'clock that morning. The remainder of that day passed uneventfully, as did the next, with the exception that, the ship having been raised to an altitude of two thousand feet above the surface of the earth, in order that the travellers might be above and out of the layer of highly heated air produced by the reflection of the sun's rays from the surface of the sand, they again caught sight of the Nile, which swam into view on their left hand during the forenoon of the second day, near the little village of Dashi, and remained in sight thereafter until they descended to earth for the night, some twenty-five miles west of the town of New Dongola. Here they were again treated to the spectacle of a superb desert sunset. This leisurely mode of progression, however, was beginning to pall somewhat upon the travellers, or rather, upon the male portion of them. It was altogether too uneventful for their taste; moreover, their appetite for sport had been whetted afresh by their experience among the rocks, and as they sat at dinner that night they unanimously decided that, as the climate seemed to agree thoroughly with little Ida--who was growing better and stronger every day--they would waste no further time in dawdling, but would forthwith make the best of their way to the spot where, on their previous cruise, they had seen that wonderful animal the unicorn, almost precisely the creature depicted in the royal arms of Great Britain, and endeavour to secure a specimen or two. Accordingly, after spending a very enjoyable evening in the music-saloon, the ladies retired to rest about midnight, while the men, producing their large-scale map of Africa, carefully laid down upon it the course, and measured off the distance necessary to carry them to the point which they desired to reach. This ascertained, Mildmay--who usually performed the duties of navigator--ascended to the pilot-house and, injecting a sufficient quantity of vapour into the air-chambers to produce the required vacuum, caused the ship to rise to a height of ten thousand feet into the calm belt, sent the engines ahead, gradually raising their speed to the maximum, and meanwhile heading the ship upon her proper course. Then he returned below, and reported to Sir Reginald what he had done, and all hands retired to their respective cabins for the night, quite confident, from past experience, of the ship's ability to