"Yes, sir."

The captain removed his cap, setting a tone of informality. In the light of the bulb, his eyes were deep-set and hidden. His narrow cheeks had a faint blue sheen. Hair crept from his cuffs to the back of his hands.

"You know, Sergeant, the incident between Fuchs and your medicine man sounds to me like a classic misunderstanding between races. Now you're Dr Oppenheimer's unofficial liaison with the pueblo. I can understand how you wanted to settle the problem quietly. But I hear that the Sunday after you left Fuchs, you were looking for me. Did you find me?"

"No, sir."

"You were told I was up on Bathtub Row. You looked for me there?"

"Yes, sir."

"Who did you see there?"

"No one was home, sir."

"And after that, you didn't look for me any more?"

"Slipped my mind, sir."

Augustino shook his head like an overburdened confessor.

"Sergeant, I think you've gone over the edge. You allow Fuchs to be assaulted with a gun. You couldn't have over-powered a blind man? But you do attack an officer of the Indian Service? You in an Indian dance? You! I'll tell you, Sergeant, you were already back in the hole at Leavenworth, you were buried deeper than ever until you drove up in that car." Joe followed the captain's eyes to the Plymouth.

"Sir?"

"Racing up and down the highways today, I went through Esperanza and I saw that couple in a motel courtyard. I know all the cars on the Hill. And I made a note of the licence and the time."

"We may have stopped there for coffee, sir."

"I went by the motel tonight. The coupe was still there. And now it's here and I see you have been following my instructions after all."

"It's not like that, sir."

"I don't want the sordid details of how you do it, but I do badly want every personal and intimate detail of Dr Weiss' life, her connections with the Party and her connections with Dr Oppenheimer."

"She won't tell me that stuff."

"She will. I think you have a talent with women, Sergeant. By the time you're done, I bet she tells you everything."

The lighted road seemed to shift like snow as Joe walked from the shed. He swung into the car, put it into gear and closed the door. He didn't dare look at Anna.

Horses coughed and shuffled as the Plymouth moved forward. MPs twisted in the saddle, staring. Al and Billy stood, one on each side of the car, as it rolled past the shed.

"You never gave me an answer," Anna said. "Which do you think I am, insane or a tramp?"

"Do you want to see me again?" Joe asked.

"Yes."

"Then you must be insane."

17

In the Explosive Assembly Building on Two Mile Mesa, Joe held a twenty-inch model of the Trinity bomb steady on a wrestling mat. It was a sphere of pentagonal steel plates bolted together at the edges. Foote and a private named Eberly were adding the last lenses of high explosive. The temperature inside the green Sheetrock building was about 120 degrees and all three men were stripped to the waist and wore a second, fluid skin of sweat. Foote was a baronet, and one of the more eccentric scientists on the Hill. In the sun he always wore a Mexican sombrero. In the Assembly Building he always wore a chain rattling with religious medals. Eberly was a graduate student who had first come to the Hill as a civilian scientist, then been drafted and sent right back at a quarter of his previous pay. He was gawky, with as much neck as head, and an Adam's apple that pumped with incessant outrage.

The lenses were cast wedges of Baratol and Composition B, both TNT-based explosives but with different speeds of detonation. Just as glass lenses bent and focused light, so did the sooty-gray lenses of high explosive focus their shock waves from the outer circumference of the bomb towards the centre, creating not an explosion, but an implosion. Of course, this was merely a model to be detonated on the mesa, so in place of a plutonium core was a croquet ball.

Other wrestling mats were covered with other models of the bomb in different stages of assembly, non-sparking brass tools, Radio Flyer wagons, tubs of water and bottles of warm milk. The walls bore blueprint diagrams, ghostly X-ray negatives, a portrait of the Virgin of Guadalupe, a prized picture of Hedy Latnarr in the nude and, every twenty feet, a fire extinguisher and a bucket of sand. The last two items were purely ornamental because it was understood that if there were any fire in the Assembly Building, everyone in it would be at stratocirrus level.

Foote prepared each lens, a little Kleenex into this hole, Scotch tape over that crack. After he slid each one into place, Eberly took over with a brass wrench, bolting a steel plate over the lens, pentagonal plate interlocking with plate like a puzzle being slowly solved, building up the walls of the sphere. Joe simply kept the ball from rolling.

"I hate the Army," Eberly said.

"The Army wants you to hate it," Joe said. "It's the Army system. It's what binds us into a fighting unit."

"No, it's an individual thing," Eberly insisted. "You know the new security campaign? Lesbians! Why, of all the WACs here, does Security pick out my girl and ask if she's a lesbian?"

"Joe, I do really appreciate your helping out," Foote delicately changed the subject and slid another heavy lens into place, its smaller, concave tip resting against the croquet ball. "Oppy keeps sending my boys down to Trinity. It's a hell of a place, they tell me. Jornada del Muerto, Dead Man's Journey, it used to be called by the Old Spanish. Scorpions, desert, snakes, stinging ants, hostile Indians. I keep asking how that distinguishes it from the rest of New Mexico. Saw you dance, by the way. Very impressive."

"Anything for the tourists."

"What does a man like you do after the war? Obviously, you're too old and too intelligent to be a boxer any more. You're the least likely sergeant I've ever seen."

"Groves is going to be the Atomic General. Maybe I'll be the Atomic Sergeant."

The surface of the next-to-last lens was pitted; the Baratol had cooled too fast after casting. Foote stuffed the holes with tiny wads of Kleenex.

"I didn't even know women could be homosexuals," Eberly said.

"To crush a solid ball of plutonium into a denser, supercritical mass is theoretically conceivable," Foote told Joe, "if the ball is crushed by a perfectly symmetrical shock wave, which is possible if every one of these lenses is detonated in the same millionth of a second."

" 'Critical', 'symmetrical'. It's just another bomb, right? When I took Oppy and Groves down to Trinity at Christmas, they were talking about a blast equal to about 500 tons of TNT. That's big, but that's not fantastic."

"Been upgraded. The estimate is now 5,000 tons. Another difference is that your normal, ordinary bomb will generate temperatures of a few thousand degrees. A nuclear explosion can be ten million degrees. Different animal altogether."

Foote dusted the final lens with baby talc. As he lowered it into the last hole, he steered the descending tip with a shoehorn.

"If she's a lesbian," Eberly said, "what does that make me?"

The lens stuck with an inch to go. Foote laid the last plate over the lens and picked up a rawhide-covered mallet. Sweat dripped from the end of his nose. Like a diamond cutter tapping a stone, he had to hit the obstinate lens hard enough to move it, but not so hard as to shatter the goods. In fact, considering the expense of the project, the lens was at least as valuable as a diamond. And a diamond cutter didn't have to worry about sparks.

Foote licked his lips.

"Lesbians, indeed."

He rapped the plate. The explosive lens underneath seemed to shrug and then slide into place. Eberly aligned the plate and began bolting it down.

"I think I could use the poisonous fumes of a good cigarette," Joe said and rose limply from the mat.