The Admiral applied his eye to the instrument and looked long and earnestly.
"There are some lines there, Doctor," he said, "but your instrument is badly out of adjustment. They are in what should be the ultra-violet sector, according to your scale."
"I forgot to tell you that this is a fluoroscopic spectroscope designed for the detection of ultra-violet lines," replied Dr. Bird. "Those lines you see are ultra-violet, made visible to the eye by activation of a radioactive compound whose rays in turn impinge on a zinc blende sheet. Do you recognize the lines?"
"No, I don't."
"Small wonder; I doubt whether there are a dozen people who would. I have never seen them before, although I recognize them from descriptions I have read. Bolton, come here. Sight along this instrument and through that plate of glass which Carnes is holding and tell me what office that window belongs to."
Bolton sighted as directed up at the side of the State, War and Navy Building.
"I can't tell exactly at this time of night, Doctor," he said, "but I'll go into the building and find out."
"Do so. Have you a flashlight?"
"Yes."