There was no water in that place and the gang grumbled badly; but it was not long before the reason of his choice was fairly obvious.
Tracks across the desert have a way of curving from point to point, no more following a straight course than the cow-paths do in other lands.

Where there is a rock, or some peculiar conformation of the ground to attract attention, men and beasts will head for it, attracted somewhat after the fashion of a compass-needle by a lodestone or lump of iron.
There was a rock shaped like a flattened egg beyond the track, two or three hundred yards away from us.

It stood all alone in a dazzling wilderness that was doubtless green at certain seasons of the year, but now was bone-dry and glittering with flakes of mica.

Close beside that ran a track worn by camels and horses, and the shadow of that great rock in a weary land was plainly a halting-place.
Our men wanted to cross over and take advantage of the shade it would give as the sun climbed higher, but Grim refused to let them; whereat Ayisha went into a shrewish rage, and ordered her four men to take up her tent and pitch it over by the rock whether Grim permitted it or not.

So they obeyed her, and Grim said nothing.
The rest of us set about cooking breakfast after the morning prayers were over.