Admiral Clay looked keenly into the piercing black eyes of the Doctor.
"I know something of you by reputation, Bird," he said slowly, "and I will follow your advice. Will you tell me why you make this particular suggestion?"
"So that I can work in that solarium to-night without interruption," replied Dr. Bird. "I have some tests which I wish to carry out while it is still dark. If my results are negative, forget what I have told you. If they yield any information, I will be glad to share it with you at the proper time. Now get the President out of that solarium and tell me when the coast is clear."
The Admiral donned a dressing gown and stepped out of the room. He returned in fifteen minutes.
"The solarium is at your disposal, Doctor," he announced. "Shall I accompany you?"
"If you wish," assented Dr. Bird as he picked up his apparatus and strode out of the room.
In the solarium he glanced quickly around, noting the position of each of the articles of furniture.
"I presume that the President always sleeps with his head in this direction?" he remarked, pointing to the pillow on the disturbed bed.
The Admiral nodded assent. Dr. Bird opened the bag which he had packed in his laboratory, took out a sheet of cardboard covered with a metallic looking substance, and placed it on the pillow. He stepped back and donned a pair of smoked glasses, watching it intently. Without a word he took off the glasses and handed them to the Admiral. The Admiral donned them and looked at the pillow. As he did so an exclamation broke from his lips.