Bull discovered that what seemed firm ground beneath him, as he started to round a precipice, might after all be the effect of the mirage.
Added to this was another difficulty.

As he wound slowly, about midday, up the last reach, with the summit just above him, the wind carried masses of cloud over the crest and into his face.

He walked alternately in a bewildering, driving fog and then in an air made crazy with electricity.

Again and again, from one side or the other, he started when the storm boomed and cannonaded down a ravine and then belched out into the open.

All this time the babel of the winds overhead never ceased, and the force of the storm cut up under him with such violence that he was almost raised from the earth.
Then an unexpected barrier obtruded--a literal mountain of ice was before him.