"Please read out that number."
"No. 1863."
"What do you say as to the identity of the handwritings, professor?"
"I give it as my conviction that they are the same. The capital Q——"
"Never mind the capital Q," interrupted Shagarach. "We admit that the formula was written by the accused."
"Retain the autograph for one moment," said the district attorney. "There was another article submitted to you for comparison. What was that?"
"A blotting-pad," said the professor, holding it up in his fingers and showing a clean side, bearing the reversed impressions of two or three lines of writing.
"Will you kindly hold that up to the mirror you have brought and read what may be read of the writing taken up by the pad?"
"Looks to me as if it came from the back of a postal card. Just fits that size and says:
"'Dear Aronson: The lock that I told you about still sticks. Please come and open it. I will not trust it to an ordinary locksmith.
"ROBERT FLOYD.'"