othing happened. The fog made accurate shooting impossible, and the gun lacked its former power. The web serpent continued to course back and forth over their heads.

"Guess we'd better run for it," Forepaugh murmured.

"Go 'head!"

They cautiously left their places of concealment. Instantly the serpent was down again, persistent if inaccurate. It struck the place of their first concealment and missed them.

"Run!"

They extended their weary muscles to the utmost, but it was soon apparent that they could not escape long. A rock wall in their path saved them.

"Hole!" the Martian gasped.

Forepaugh followed him into the rocky cleft. There was a strong draft of dry air, and it would have been next to impossible to hold the Martian back, so Forepaugh allowed him to lead on toward the source of the draft. As long as it led into the mountains he didn't care.