“And there are two rosettes between two of the loops of the well in the garden. You grasp the importance of the discovery, I hope. It means that we have to study the photographs from quite a different point of view. All we have to do now is to find in the various backgrounds some significant mark that is paralleled in the various landmarks about Venice that lead to the casket.”

“Are you not a little too sanguine, St. Hilary? These twelve marks are often most obscure. In the fifth and the eleventh hours there are no marks whatever.”

“That is true,” replied St. Hilary thoughtfully. “This discovery by itself is quite useless. If we could have found the mark of the fifth hour we could have begun at this fourth hour. But since that is missing––”

“And I suppose it is useless for us to think of beginning with the landmarks of the last hours, even if we could find them in the background. The last of the landmarks would be almost certainly found not in the open air, but in the interior of some palace.”

“There is another difficulty that has just occurred to me,” continued St. Hilary. “We have been taking it for granted that we start from the Pillar of San Marco in the Piazzetta. I still think that it is reasonable that the search begins there. If that be true, we find ourselves in the fourth hour at the Campo San Salvatore, but the landmark of the sixth hour brings us back to the balcony of San Marco in the Piazza again. In the next hour we simply stroll a few feet away to the Campanile. In that case the mad clock-maker has been leading us about in a senseless circle. He may have been mad, but he was not as mad as that.”

“Then you think the wisest thing is for us to search for the second landmark? It does not seem particularly promising. So far as I can see, it is merely a curtain, with a conventional decoration of what appears to be more like two husks of corn than anything else I can think of. One of these husks is perpendicular; the other horizontal.”

“I see no reason why we should not begin with the sixth hour,” asserted St. Hilary.

“I think we may begin at any one of them with an equal chance of success,” I said hopelessly. “This search of ours is like nothing so much as hunting for twelve needles in twenty thousand haystacks.”

And it turned out that I was right. For several days we made no farther progress. We became so utterly fatigued and weary of looking for we knew not what that we saw nothing. We took to wandering vaguely about the canals and the streets. A restlessness urged us out at all hours in search of these vague landmarks. Every morning after breakfast we set out somewhere. Every evening we returned discouraged. And so a month passed, and we were no nearer to the da Sestos casket.

CHAPTER XVIII