“Mr. Bell,” she asked. “What have you learned that will clear my father’s name?”

Bell answered in a voice pitched low with sympathy. He was kindly yet direct. “Forgive me, but I must report that your father did indeed sign out a quantity of iodine from the laboratory store.”

“He was an engineer,” she protested. “He was a scientist. He signed for chemicals from the laboratory every day.”

“Powdered iodine was an essential ingredient of the explosive that detonated the smokeless powder in his piano. The other was ammonia water. The porter noticed a bottle missing from his cleaning closet.”

“Anyone could have taken it.”

“Yes, of course. But there are indications that he mixed the chemicals in his private washroom. Stains on a towel, a volatile powder on his toothbrush, residue in his shaving mug.”

“How can you know all this?” she asked, blinking away angry tears. “The Navy won’t let me near his office. They turned away my lawyer. They even barred the police from the Gun Factory.”

“I gained admittance,” said Bell.

A male secretary wearing a vest, bow tie, banded shirtsleeves, and a double-action Colt in a shoulder holster entered urgently. “Beg your pardon, Mr. Van Dorn. The commandant of the Washington Navy Yard is calling on the telephone, and he’s hopping mad.”

“Tell the operator to switch the line to this telephone. Excuse me, Miss Langner . . . Van Dorn here. Good afternoon, Commandant Dillon. How are you today? . . . You don’t say?”

Van Dorn listened, casting Miss Langner a reassuring smile.

“. . . Well, if you’ll forgive me, sir, such a general description could fit half the tall men in Washington . . . It could even describe a gentleman right here in my office as we speak. But I assure you that he does not look like he’s been at fisticuffs with the United States Marines—unless the Corps turns out a lesser breed of Leatherneck than in my day.”

Isaac Bell put his hand in his pocket.

When Joseph Van Dorn next replied to the caller, it was with a benign chuckle, though if the commandant had seen the chill in his eyes he might have retreated hastily.

“No, sir. I will not ‘produce’ an employee of mine on your sentries’ assertion that they caught a private detective red-handed. Clearly the man in my office was not ‘caught’ as he is standing here in front of me . . . I will register your complaint with the Navy Secretary when we lunch tomorrow at the Cosmos Club. Please convey my warmest regards to Mrs. Dillon.”

Van Dorn replaced the earpiece on its hook, and said, “Apparently, a tall, yellow-haired gent with a mustache knocked down some navy yard sentries who attempted to detain him.”

Bell displayed a row of even white teeth. “I imagine he’d have surrendered quietly if they hadn’t tried to beat him up.” He turned back to Dorothy Langner, his expression gentler. “Now, Miss Langner. There is something I must show you.”