Bill pulled.
"Now just go on pulling like that. I shall get it directly. Not hard, you know, but just keeping up the strain."
His fingers went at it again busily.
And then suddenly the whole row of shelves, from top to bottom, swung gently open towards them.
"Good Lord!" said Bill, letting go of the shelf in his amazement.
Antony pushed the shelves back, extracted Ussher from Bill's fingers, replaced him, and then, taking Bill by the arm, led him to the sofa and deposited him in it. Standing in front of him, he bowed gravely.
"Child's play, Watson," he said; "child's play."
"How on earth-"
Antony laughed happily and sat down on the sofa beside him.
"You don't really want it explained," he said, smacking him on the knee; "you're just being Watsonish. It's very nice of you, of course, and I appreciate it."