Despite his ignorance of the cause, there was something in the sound that denoted danger; and, instinctively influenced by this idea, the young officer rose from his seat upon the log; and, untying his horse, leaped into the saddle. It was not with the intention of moving away from the spot—for the moon was not visible as yet—but with the knowledge that on horseback he would be the better prepared for any event that might arise. Still further to provide against possible danger, he unbuckled the strap of his carbine, and tried whether the piece was primed and in order. Don Rafael, although young, had seen some military service on the northern frontier of Mexico—where Indian warfare had taught him the wisdom of keeping habitually upon his guard.

Again he heard the wild lugubrious scream rising above the roar of the waters; and perceived that his horse, hearing it also, trembled between his thighs!

Coupling the sound with the strange spectacle to which he had just been a witness, the young officer could not help feeling a slight sensation of fear. He was a Creole, brought up consequently in the midst of ecclesiastical superstition, scarce less monstrous and absurd than that of pure paganism itself. He had heard in his youth how animals in presence of beings of the other world are seized with a shivering—such as that exhibited at the moment by his own horse—and he could almost fancy that the scene he had just witnessed was some evocation of the Prince of Darkness, to which the lugubrious sounds now reaching him were the response.

But Don Rafael was one of those bold spirits whom fear may visit but not subdue; and he remained immobile in his saddle, without showing any further symptoms of apprehension than by the twitching of his lips against his cigar, the light of which at intervals gleamed like a meteor through the darkness.

While thus patiently waiting the moonlight, the horseman fancied that he heard other sounds, and of a different import. Human voices they appeared to be; and it at once occurred to him, that it might be the two men whom he had disturbed and driven from their incantations. The voices were each moment more distinctly uttered; and it was evident that the speakers were approaching him. He perceived that it was probable they would come out somewhere near where he was stationed; and in order to have the advantage of a preliminary survey, in case they might turn out to be enemies, he drew his horse back under the darker shadow of the trees—placing himself in such a position that he commanded a view of the path.

The voices he heard were in reality those of the Indian and negro or Costal and Clara: for it need scarce be told that it was they who were the heroes of the mysterious spectacle of which Don Rafael had been the sole spectator.

The two worthies, on being interrupted in their pagan ceremony by the shower of pebbles, had given up the performance; and were now threading their way through the thicket to reach the road beyond it.

The Indian was venting his wrath against the unknown personage who had intruded upon their sacred devotions, and who had very probably hindered the Siren of the dishevelled hair from showing herself. The negro appeared to be equally indignant; but his anger was probably only pretended.

“Is it only at the first appearance of a new moon that the Siren shows herself?” inquired Clara, as if the opportunity for seeing her had escaped them.

“Of course,” replied Costal, “only then; but if there is a profane person in the neighbourhood—and by profane I mean a white—the spirit will not appear.”