“The fifty-third palace is the Palazzo Chettechi. Look in that French monograph, Les Palais de Venise Moderne. See if it is mentioned there.”

I turned hurriedly to the index.

“Yes, it is mentioned. But, confound it, the palace was torn down and rebuilt in 1805.”

“And down with it tumbles your cunning little house of cards,” commented the dealer cynically.

“After all, that solution was too obvious to be reasonable,” I retorted cheerfully, though I felt the disappointment keenly. “But look here, St. Hilary”–I was consulting the Bible again–“there are four thirties mentioned. Perhaps the second couple of thirties has some significance. Does the fifty-third palace bring us to a corner of the Grand Canal, or should we find ourselves in the middle of the block?”

“We should find ourselves at the junction of the Grand Canal and the Rio di Lucca.”

“Good! And if you counted sixty palaces up the Rio di Lucca, will that old chart tell the palace you would arrive at?”

“The Palazzo Giuliano.”

“The Palazzo Giuliano might contain our landmark on its wall just as well as any other.”

“It might,” he cried, consulting the monograph on the palaces of modern Venice again, “only it happens that the façade of that palace was rebuilt in the eighteenth century. Again your little house of cards crumbles about your ears, my dear Hume.”