Man has become master of the earth' s surface. He is constantly probing into the earth' s depths and into the atmosphere' s upper reaches. Yet it is doubtful whether man, with 'all of his intelligence and vigor, holds his planetary seat with greater assurance than a vast tribe of small, many-legged animals that pass their lives at his feet--the spiders. Spiders are among the miracles of science. They dwell at higher altitudes than any other creature their size or lager. On the slopes of Mount Everest, at an altitude of twenty-two thousand feet-- five thousand feet above the vegetation line--lives a species of black spider only a quarter of an inch long. This is an incredible environment for creatures so delicately constructed. To protect themselves from the chill of night, they take shelter in crevices where the twenty-four-hour variation in temperature is only twelve degrees, as against forty-four on the outside. Spiders inhabit others unlikely places--rabbit burrows, flowers, anthills, and the desolate, drafty aeries of eagles. They have been found soaring through the air five miles above the earth. One species has been discovered in an African cavern move than two thousand feet underground. The author thinks that spiders ______.