"You've got me, unless, as Stuart himself explains, he is in for a long prison term and knows the diamonds won't do him any good."

"But he could leave them where they are and run the chance of finding them when he gets out. If they are well concealed it is unlikely anybody would discover them. I don't get it at all."

Scowling, Mr. Burton lapsed into a silence so forbidding that Christopher dared not interrupt it, and accordingly the two sat without speaking until Mr. Corrigan was announced.

It took not a moment to see the inspector was more than wontedly excited.

"Where is this remarkable communication?" demanded he without preliminary. "Humph! Looks as though it had been through the wars, doesn't it! A scrap of paper some convict had concealed, most likely, together with the stump of a pencil. Those fellows are pretty clever; and Stuart probably got some chap whose sentence was up to mail it when he went out. He would hardly risk sending information like this by anybody except one of his own kind. And even then he would have to be pretty certain his messenger could be trusted. It was taking a big chance. Sometimes, however, there is honor among thieves."

"Do you think the letter is genuine?" inquired Mr. Burton.

"How, genuine? That it tells the truth, you mean? Yes, I do. I think Stuart was prompted to return the ring for the very reasons he states—he took a fancy to Christopher, and he saw the diamonds would now be of no use to him."

"But he could have left them where they are."

"For a term of ten or twelve years? But think, Mr. Burton, of the changes liable to take place in that time. The building might be torn down and replaced by another, or it might be converted into a business block; or, again, fire might destroy it. In any of these cases the jewels would be lost to Stuart. Moreover, even if he tried to recover them years hence, it might be very difficult to do so. He weighed all these considerations, you may be sure, before he sent that letter. Still I am not sure they were the factors primarily influencing him. He liked Christopher and evidently wished to do him a good turn. Such men as he often have soft streaks in them—impulses for good."

"You mean to follow up the clew then?"