inevitable.

The approach of the white man was evidently a surprise to the savages.
The middle one, who held the long-bow and arrows, fell back several
paces, as if about to break into flight or dart among the trees so
invitingly near, but something must have been said by his companions to
check him, for he stopped abruptly, and not only came back to his first
position, but advanced a couple of paces beyond. The noise from the
rapids prevented the Professor hearing their voices, though the
unusually clear moonlight told him that some utterance had passed
between them.

The first ominous act on the part of the natives was by this archer,
who deliberately drew an arrow from over his shoulder and fitted it
against the string of his bow. The fact that the missile was
undoubtedly coated at the end with a virus more deadly than that of the
rattlesnake or cobra was enough to render the would-be friend
uncomfortable and to increase his alertness.

At the same time that the archer went through this significant
preliminary, his companions shifted their grasp upon their javelins in
a manner that was equally suggestive.

While carrying these primitive weapons, the fingers closed around the
centre of gravity, that naturally being more convenient, but when about
to hurl them, the hand was shoved further toward the head. Both
natives thus shifted their right hands, though, they still held them
horizontal at their thighs, from which position they could be brought
aloft in the twinkling of an eye.