back
over his shoulder.

They pushed on with all their vim. Meanwhile it grew very dark and
forbidding. Will could not remember ever to have seen the day
swallowed up in the gathering shades of night so quickly before. It
appalled the boy, for he did not possess the same unconquerable nature
as Frank.

One crash of thunder followed another in rapid succession. The very
earth under their flying feet seemed to quiver with the concussions.
Lightning shot downward with such vivid flashes that it fairly blinded
them; so that Will's soul was filled with awe.

"Frank, oh, Frank!" cried the boy in the rear.

"All right, Will, what is it?" replied the other, who kept glancing
back at very brief intervals to make sure his chum still ran at his
heels, for he feared that should they ever be separated in that
gathering gloom it would be impossible for them to come together
again.

"Do you think we can make it?" demanded the other, with a touch of
despair in his voice, for the situation looked frightfully appalling
to Will.

"Sure we will!" he was immediately assured in Frank's most cheery
fashion. "Right now I can see the first of the rocks. Given two more
minutes at the most and we'll be able to crawl under a shelf, and lie
there as snug as two bugs in a rug."

Frank did not feel any too sanguine himself, but he would not let Will
know of any fears he possessed regarding the possibility of their not
finding the shelter among the rocks after all.

A terrific peal of thunder drowned their conversation for a brief
interval, but they were pushing resolutely forward all the while.
Frank was straining those keen eyes of his to some purpose. He knew
they were at the border of the rough, rocky section now. If only they
could run upon the friendly outcropping shelf which he remembered to
have seen at the time they passed before, they would find shelter.

All would have been easy enough had they been given ordinary daylight
so as to look around them. The gathering gloom made it very difficult
to see twenty feet away with any degree of certainty. Frank was being
guided partly by instinct, and the knowledge that he had taken his
right bearings to start with.

"Frank, I felt the first drop of rain!" shrilled Will, filled with a
new fear, for he was afraid that his pet camera would be ruined should
they be soaked to the skin, which was a calamity terrible enough to
break his heart.

Frank did not need to be told of the falling ra