To these causes, also, was due a suspicious nervousness which made him see danger where it did not exist.

The rustling of a falling leaf caused him to start and glance furtively to one side, and at a soft stir of the leaves under a breath of wind, or a slight movement of the sleeping ponies, he started and grasped his rifle with closer grip.
All this was natural; but there came a moment, not far from midnight, when there remained no doubt that some person or animal was moving stealthily through the grove, near where he was standing.

It will be remembered that his position was such that the trunk of the large oak acted as an impenetrable screen between him and the camp-fire, which was burning so vigorously that its rays penetrated to a greater or less degree beyond him.

Thus he could see anything moving within the circle of illumination, while he was as invisible to the keenest-eyed warrior as if the night was without a ray of light.
The first warning was through the sense of hearing.

He had been deceived so many times that he suspected his fancy was playing with him again, but the faint _tip, tip_ continued until such explanation was amiss.
"It is an Indian or a wild beast," was his belief.
The next minute he knew that, whatever it was, its position was between him and the outer edge of the grove.