For the Indians warned him of a hole in the floor which (they told him) was an unfathomable abyss.

And lo and behold, when he turned the magnesium light upon it, the said abyss was just about eight feet deep.

But it is no wonder that the poor Indians with their little smoky torches should make such mistakes; no wonder, too, that they should be afraid to enter far into those gloomy vaults; that they should believe that the souls of their ancestors live in that dark cave; and that they should say that when they die they will go to the Guacharos, as they call the birds that fly with doleful screams out of the cave to feed at night, and in again at daylight, to roost and sleep.
Now, it is these very Guacharo birds which are to me the most wonderful part of the story.

The Indians kill and eat them for their fat, although they believe they have to do with evil spirits.

But scientific men who have studied these birds will tell you that they are more wonderful than if all the Indians' fancies about them were true.