tigers!"

A few steps more brought the two adventurers out into the open ground;
and close to the spot where the dragoon captain was sitting silently on
his horse. The red coal glowing at the end of his cigar shone at
intervals in the darkness, lighting up his face, and the gold band of
lace that encircled his hat. Clara was the first to perceive this
unexpected apparition.

"Look, Costal!" said he, hastily grasping his companion by the arm, and
whispering in his ear; "look there! As I live, the diadem of the
Siren!"

The Indian turned his eyes in the direction indicated, and there, sure
enough, beheld something of a circular shape, shining in the glow of a
reddish-coloured spot of fire.

He might have been as much puzzled to account for this strange
appearance as was his companion; but at that moment the moon shot up
from behind the bank of clouds that had hitherto hindered her from being
seen, and the figures of both horse and rider were brought fully into
the light.

CHAPTER THIRTEEN.

WHO GOES THERE?

At a glance Costal saw what the strange object was--a broad band of gold
lace encircling a _sombrero_, and placed, Mexican fashion, around the
under edge of the brim. The cigar illuminating the lace had deceived
the negro, guiding him to the idea of a diadem!

"_Carajo_!" muttered Costal between his teeth, "I told you so. Did I
not say that some profane white had hindered the Siren from appearing?"

"You were right," replied Clara, ashamed at the mistake he had made, and
from that time losing all belief in the _genius_ of the cascade.

"An officer!" murmured Costal, recognising the military equipments of
the dragoon, who, with a carbine in one hand, and his bridle in the
other, sat smoking his cigar, as immoveable as a statue.

"Who goes there?" cried Costal, saluting him in a loud, bold voice.

"Say, rather, who stands there?" responded Don Rafael, with equal
firmness, at the same moment that he recognised in the speaker the
Indian whose incantation he had witnessed.

"Delighted to hear you speak at last, my fine fellows," continued the
dragoon in his military off-hand way, at the same time causing his horse
to step forward face to face with the adventurers.

"Perhaps we are not so much pleased to hear you," replied Costal
roughly, as he spoke, shifting his gun from one shoulder to the other.

"Ah! I am sorry for that," rejoined the dragoon, smiling frankly
through his thick moustache, "f