“When we left Fort Hall we had three-quarters of a tank,” said the girl.

There could be a leak in the gas tank, but the man didn’t bring up that possibility. Instead, he checked the oil. Without a word he pulled out the dipstick, wiped it between his left thumb and forefinger like the old mechanics, put it back in and withdrew it again to examine the level of the oil.

“It’s fine,” he concluded, his tone as detached as possible.

The girl turned her head to one side, listening intently in the spot where the gas pump was.

As unobtrusively as he could, Jack slipped his oil-stained fingers in the left-hand pocket of his jeans; he hoped he would find an old Kleenex there, but his fingers encountered nothing, and he had no choice but to wipe them on the white lining of the pocket.

“Listen!” said the girl. “Do you hear something?”

“No — oh, now I do! A kind of whistling.”

“Like a teakettle when the water’s starting to boil?”

“Exactly.”

“Crap!” she said. “It’s a vapour lock.”

She listened a second time.

The man awaited her explanation.

“When I was trying to avoid the road mice,” she said, “I pushed the engine a little too hard and it heated up, so some of the gas vapourized; the sound you hear now is the vapour whistling inside.”

She pointed to the gas pump.

“The vapour fills the pump and prevents the gas from getting to the carburetor,” she said.

“What can we do?”

“I’m not sure. What would you do if you were by yourself?”

“Me?” he asked. “I’d stand by the road, on the soft shoulder, and I’d flag someone down to help me and then . . .”

“And then?”

“Then a truck would stop a — big ten-ton Mack — and out of it would step a tall girl with hair as black as a stove and legs as long and thin as a grasshopper’s and she’d come and take a look at the motor and then we’d make an important decision.”

“What’s that?”

“We’d decide not to do anything. We’d find a little spot in the shade and we’d have a beer or we’d, well, we’d do certain very pleasant things, taking our time, and meanwhile the engine would cool down and the problem . . .”

“. . . would solve itself,” she said. “That’s not a bad idea, but . . .”

“But?”

“There’s another possibility: if the gas isn’t getting through, it could also be because the filter on the gas pump is clogged.”

“We have to clean the filter?” he asked, wiping his brow.

They weren’t even moving, yet they were both soaked in sweat just from standing in the sun.