"Boarts?" Nelson repeated. "What are they?"
"Boarts," Brandt told him, "are industrial diamonds—black, imperfectly crystallized stones, but far more valuable to us than flawless diamonds from Tiffany's on Fift' Avenue. They are needed for making machine tools. They come from northern Brazil—and our supply is low."
"I should think we could get a shipment of these boarts direct from Brazil—through the blockade," Nelson said, "without taking the risk of capturing a United States navy cruiser."
"There are other things Germany needs desperately on board the Carethusia," Brandt explained. "Vanadium and nickel and hundreds of barrels of lard oil for machine-tool lubrication. Our agents have been watching the convoys closely for weeks for just such a cargo as the Carethusia is taking over."
"Can we trust Androka?" Nelson asked, with a sudden note of suspicion in his voice.
"Yes," Brandt assured him. "Of all men—we can trust Androka!"
"But he's a Czech," Nelson argued.
"The gestapo takes care of Czechs and Poles and Frenchmen and other foreigners whom it chooses as its agents," Brandt pointed out. "Androka has a daughter and other relations in Prague. He knows that if anything misfires, if there is the slightest suspicion of treachery on his part, his daughter and the others will suffer. Androka's loyalty is assured!"
Nelson turned to watch the forward fighting top of the Comerford. The masked German seamen were installing some sort of apparatus up there—a strange-looking object that looked something like an old-fashioned trench mortar, and which connected with cables to the room that served as Androka's laboratory and workshop.
Another crew was installing radio apparatus in the mizzentop turret.