Watson makes a grab for the phone, automatically, and while he fumbles it a bit, he doesn't drop it either. "Gray's is still published? Truly? And you have it--"

He stops mid-sentence, and squints down at the phone screen with a degree of astonishment. "Good heavens, you really do have it on your telephone. Rather different from my old edition, of course."

Cautiously, he touches the screen, since that was how César had navigated through it, and soon finds out how to turn the "pages." "I suppose," Watson says doubtfully, "lending me your telephone is out of the question."