Two hours had passed since I left the church. St. Hilary and I had spent the time in a diligent study of the Bible. The result confirmed my theory beyond a doubt. With the exception of the scenes of the fifth and tenth hours, we had identified them all as Bible scenes. We had also found that in each story certain numbers were mentioned.

“To tell which are the significant numbers, that is the question,” said St. Hilary. “In two or three of the stories, at least, more than one set are mentioned. How can we be sure which numbers count, and which do not?”

“We can not be sure, I suppose,” I replied thoughtfully. “We can only guess. But at least we may make a reasonable guess. The goldsmith had some method in choosing them. What would be the most obvious?”

“That he should select the numbers that really counted in the various stories,” replied St. Hilary.

“I have observed that the important numbers are invariably mentioned in the first part of the story. We may go on that assumption to begin with, at any rate. Our search for the landmark of the second hour ought to begin from the Piazzetta, where the first landmark stands–that is, the lion of San Marco. Now our first numbers are 7, 30, 30. If we interpret those rightly, we shall find ourselves at the second landmark. Thence we may start for the third.”

“But the meaning of those numbers,” grumbled St. Hilary, “is extremely doubtful. They may be added to, or subtracted from, or divided or multiplied by others, and the landmark of the second hour is veiled in complete obscurity. If it were the landmark of the fourth hour, the House of the Camel, we should know what to look for.”

“But it is not,” I said impatiently. “Your precious landmark is quite useless by itself, because we have not been able to identify the Bible story of the fifth hour, and so we are ignorant of the numbers that will lead us to the landmark of the sixth. We are compelled to start at the first hour. From that point we go on to the second, and from the second to the third. As to the gap in the fifth hour, we won’t attempt to jump that until we come to it.”

The little man yawned. His dogged skepticism was maddening. The fact is, he resented my having been so fortunate as to make the great discovery. Because he had not made it himself, or helped to make it, he sulked and made endless objections.

“How do you propose to interpret the first numbers, 7, 30, 30?” he asked.

“Well,” I answered patiently, “say that they represent blocks of buildings. We go down the Grand Canal until seven blocks are passed. If we took the seventh canal to our left, and continued up that canal until thirty blocks had been passed––”

“We should find ourselves somewhere out in the lagoon,” sneered St. Hilary.

“If we passed seven blocks on our right, then, proceeding up the seventh canal until thirty blocks were passed, took the junction of the two canals at this point for a new start until thirty more blocks were passed, where should we find ourselves?”

St. Hilary consulted the map of Venice that lay before him.

“You are a little obscure, my dear Hume. But, so far as I can make it out, after you had passed your sixty little canals, if you turned to the left you would find yourself in the Jewish quarter. If you turned to the right, in the fishermen’s quarter. You may be sure that da Sestos was not quite so mad as to hide his casket in a part of the city that would be subject to demolition. You will have to try again.”

“Thirty changes of raiment and thirty sheets,” I mused. “Thirty plus thirty; why not the sixtieth palace down the Grand Canal, either left or right?”

“Within seven days,” quoted St. Hilary, closing his eyes.

“I had forgotten the seven days,” I admitted. “Well, then, why not the fifty-third palace?”

“Why the fifty-third?” demanded St. Hilary in a bored tone.

“Within seven of sixty ought to mean fifty-three,” I said quickly.

St. Hilary opened his eyes. A look of interest dawned in them. He drew toward him an old map of Venice, La Nuova Pianta di Venezia, it was called, and was published in 1689. It contained an interesting chart on which were marked all the palaces of Venice existing at that time. He began to count these palaces carefully, going down the Grand Canal toward the Rialto Bridge.

“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.”

I stared down at the table. In what other way might I read a meaning into the numbers? I picked up an envelope and began to toy with it unconsciously. It was addressed to St. Hilary. It was literally covered with erasures and directions, and had followed him half around the world. But it had found him at last, though some of the directions were of the vaguest. We ought to be as clever as a postmaster. Aside from the extraneous aids of the directory, what methods would a postmaster use?

Mechanically I began to trace the ordinary and palpable clues to the destination of any letter. First of all, there is the state or country. That is as vague as the earth itself. But the state is narrowed down to the city in the state, and the city to the street––

“I believe I have found a solution that will hold water at last, St. Hilary!” I cried.

He blinked at me skeptically.

“Let us hear it by all means.”

“Take the address on the envelope. It has suggested a possible solution to the numbers. First of all, there is the country. The country is narrowed down to the city of the country. Next comes the number of the street in the city. After that the house in the street. In other words, the direction of an envelope is narrowed to more and more defined limits.”

“An extremely accurate but not a startlingly original presentation of facts, dear boy. The connection between this envelope, for instance, and the da Sestos casket?”

“Call Venice the state; the city, the Grand Canal. Your street will then be the seventh canal; the number of the street will be the house of the landmark.”

St. Hilary’s dark eyes snapped. He was thoroughly interested at last. He drew toward him the map of Venice again. He pushed it away with an exclamation of disgust.

“Ingenious again, but not conclusive. The seventh canal flowing into the Grand Canal is a cul-de-sac. Its length is not a hundred yards, and it leads merely to the Campo San Stefano.”

“You are mistaken,” I said calmly. “You are counting the ditch that surrounds the Giardino Reale. The seventh canaletto is the Rio di Bocca. And the sixtieth palace from the junction of the Rio di Bocca and the Grand Canal will be the house of the landmark. What palace is that? Don’t tell me that that is torn down.”

“No, this one exists. It is called the Palazzo Fortunato. Come, it is time for us to do something more strenuous than talking. We will test your theory, and I think it a fairly reasonable one at last. But first of all, a bite at Florian’s. It is three o’clock. We may get no dinner.”

I had unconsciously taken the lead since my great discovery. Now I hesitated. Though I had broken my tryst with Jacqueline, I had intended seeing her this afternoon before we actually began our search. But I could not let St. Hilary begin his explorations without me. A few hours sooner or later, I persuaded myself, would not make much difference.

I know now how specious were my arguments. A woman’s love is not to be treated lightly. It is the most sacred and precious thing in the world, and she knows that it is. It does not come and go at one’s beck and call. It burns brightly so long as the flame is fed; to quench that flame is dangerous, and it is not always easy to revive it.

“I am quite ready to go with you,” I said soberly. “My gondolier is waiting below. We will let him take us to the Molo and then dismiss him. We want no witnesses or possible spies.”

“Excellent,” he murmured. “And bring along your Bible; that must be our chart and compass in our voyage of discovery.”