The soil was very light and sandy, but it was covered with a thick growth of grass, which prevented the mules' feet or the waggon-wheels from sinking, so that the travelling was nearly, if not quite as rapid as it had been along the road. A sharp lookout was maintained for signs indicative of their approach to the neighbourhood of plantations, and two or three bridle-paths, evidently leading to such, were crossed; but at length they reached the welcome skirts of the forest without having had the least cause to suppose that they had been observed. In the meantime, however, a heavy bank of thundercloud had been observed rapidly gathering on the southern horizon, and the runaways had scarcely plunged a mile into the forest before the heavens were obscured, and it at once became so pitch-dark that it was utterly impossible for them to proceed. The mules were consequently pulled up, and the three adventurers made what few preparations were possible for their protection from the coming storm. Soon the low threatening rumble of the thunder was heard, and then, as it rapidly increased in volume of sound, bright flashes of light were seen blazing out beyond the interweaving branches of the trees. The storm, as in all tropical countries, quickly gathered force and intensity, and very soon it was raging in all its fury above and around them. The loud reverberating roll of the thunder was incessant, the lightning flashed with ever-increasing rapidity, and at last the entire atmosphere seemed to be in one continued tremulous glare of unearthly light. The mules started and quivered, as the lightning-flashes grew more rapid and intense; and finally they became so terrified that George had as much as he could do to restrain them from bolting, and so dashing themselves, the waggon, and its occupants to pieces against the trees. The storm was at its fiercest when suddenly the party found themselves enveloped in a blinding blaze of greenish-blue light; simultaneously there came a terrific rattling crash, as though the universe had burst asunder; the occupants of the waggon--blinded, and deafened by the dazzling brilliancy of the flash and the tremendous report which accompanied it--felt themselves hurled violently to the earth, and then followed oblivion. CHAPTER SIXTEEN. THE PURSUIT.