After the condenser was finished Felicia took a deep interest in helping Roger to find leaks in the system. Roger taught her to squirt oil from an oil can over the different points and to interpret bubbles rising from the resulting oil flow as leaks. It was the quaintest sight in the world to see the slender little figure in blue overalls, brown head running over with short curls, crawling like a little lizard over the greasy pipes while Roger followed with pipe wrench, cold chisel and peen hammer. After Roger began work on the engine, Felicia became a sort of plumber's assistant and a clever one, at that.
Sometimes Charley came late in the afternoon to take Felicia home. She would perch on the edge of the work bench and talk to Roger about the work in a voice and with an unself-conscious manner so like her small sister's that Roger, his restless mind on the problems of his work, often confused the two girls in his thoughts and answered or directed them indiscriminately. And Charley would chuckle as she watched him.
The day in May that the men began a test for oil leaks in the absorber dawned with a promise of ferocious heat. Felicia appeared as usual but admitted that she had come over Charley's protest.
"We'll have to leave off work at eleven, and not begin again until three as Dick suggested, if this heat keeps up," observed Ernest.
"Then we'll begin work at dawn," said Roger, with a sigh. "Every minute counts, old man."
About nine o'clock Charley came panting down the trail.
"Felicia must come home at once," she cried. "There's a big sand storm coming. Dick is getting the stock under cover as fast as he can."
The men dropped their tools hurriedly and looked up the valley. A great gray cloud was approaching so rapidly that as they gazed they caught the sound of its increasing roar. The sky, which had been sapphire of an unusual translucence that morning, turned all in a moment to a sullen red gray. There was a dry rattle of lizards and horned toads scuttling into the roots of grease wood and cactus.
"You mustn't try to go home, Charley," exclaimed Roger.
"But I must! Dick and his alfalfa! He can't be alone!"
But Dick was destined to spend the day in solitude. With a very Niagara of sound the sand storm struck the camp. Charley and Felicia ran for the living tent where the men shortly joined them. They closed the flaps and settled to a day of discomfort. The engine house would have been more comfortable than the tent but it was too cumbered with machinery now to be used as a sitting room. There was no work that could be done indoors. The heat was stifling, a hundred and six the thermometer over the washstand trunk reported. The tent rocked and bellied, bellied and flapped with reverberations like drum-beats. Felicia was frightened at first and hid her head in Charley's lap. Charley herself was white-lipped, less, Ernest thought, from fear of the storm than from that vague apprehension about Dick that never seemed to leave her.