Over the loose hot sand, amidst this shadeless mockery of a forest, Carmena swung steadily along at her graceful stride. Her movements seemed as lacking in effort as the lope of a coyote or the bound of a cat. Lennon would not have realized how greatly she was exerting herself had he not seen how frequently she drank from her canteen.
No one of white blood, however thoroughly inured to thirst, can walk fast under the blistering sun, in the bone-dry air of the desert, without need of much water. Lennon, though riding, was no less parched than the girl. He was fresh from a moist climate, and the Gila monster poison had put him into a feverish condition. Hard as he tried, he could not resist drinking. His canteen was emptied even sooner than Carmena's.
This was little past mid-afternoon. They had left the sahuaros behind and were coming down among widely scattered salt bushes to the border of an utterly barren alkali flat. For the first time since the stop in the mesquite, Carmena halted her quick advance. But it was not to rest. The feverish crimson of Lennon's face sobered her reassuring smile. She peered searchingly back along the trail, glanced at the sun, and hastily transferred to their empty canteens all but a quart from the full canteen on the saddlehorn.
"We've got to make it last till sundown, Jack," she warned. "Then, if only we can hold our lead, we'll be able to keep going all night."
Lennon drew out two half dollars. "How about trying these in our mouths?"
"They'll help," she replied, and she took one. "Be ready to tie your neckerchief over your nose, soon as we strike the alkali."
The wisdom of this advice was evident when they started out across the snow-white flat. Every step stirred up clouds of alkali dust that hung about the fugitives like thick smoke. The impalpable powder penetrated their clothes, smarted in their eyes, and all but choked them, even behind the veiling neckerchiefs.
Before they had half crossed the fearful dust flat Carmena was walking as slowly as the pony. At the far side she sank down beside a thick-stemmed cactus. Lennon, half delirious from fever, sought to spring off, with the vague idea of forcing her to ride. He succeeded only in tumbling upon the sand. The startled pony shied clear. With a smothered cry, Carmena leaped up to grasp his bridle.
"Close call!" she gasped at Lennon. "If he'd made off—no show for us at all."
Lennon was too far gone for speech. His canteen was already half empty. Carmena gave him a sip from her own and dragged him around until his head lay in the small blot of shade made by a cactus stem. Half an hour passed before he was able to get back into the saddle. But the rest appeared to have fully restored the girl's strength. She set off at a pace that again forced the pony into an occasional jog.