Judge Jarriquez had all the time been absorbed in working at the puzzle--and was no further advanced--and had forgotten the time of repast and the time of repose, when there came a knock at his study door.

It was time. An hour later, and all the cerebral substance of the vexed magistrate would certainly have evaporated under the intense heat into which he had worked his head.

At the order to enter--which was given in an impatient tone--the door opened and Manoel presented himself.

The young doctor had left his friends on board the jangada at work on the indecipherable document, and had come to see Judge Jarriquez. He was anxious to know if he had been fortunate in his researches. He had come to ask if he had at length discovered the system on which the cryptogram had been written.

The magistrate was not sorry to see Manoel come in. He was in that state of excitement that solitude was exasperating to him. He wanted some one to speak to, some one as anxious to penetrate the mystery as he was. Manoel was just the man.

"Wir," said Manoel as he entered, "one question! Have you succeeded better than we have?"

"Sit down first," exclaimed Judge Jarriquez, who got up and began to pace the room. "Sit down. If we are both of us standing, you will walk one way and I shall walk the other, and the room will be too narrow to hold us."

Manoel sat down and repeated his question.

"No! I have not had any success!" replied the magistrate; "I do not think I am any better off. I have got nothing to tell you; but I have found out a certainty."

"What is that, sir?"

"That the document is not based on conventional signs, but on what is known in cryptology as a cipher, that is to say, on a number."

"Well, sir," answered Manoel, "cannot a document of that kind always be read?"

"Yes," said Jarriquez, "if a letter is invariably represented by the same letter; if an _a,_ for example, is always a _p,_ and a _p_ is always an _x;_ if not, it cannot."

"And in this document?"

"In this document the value of the letter changes with the arbitrarily selected cipher which necessitates it. So a _b_ will in one place be represented by a _k_ will later on become a _z,_ later on an _u_ or an _n_ or an _f,_ or any other letter."

"And then?"

"And then, I am sorry to say, the cryptogram is indecipherable."

"Indecipherable!" exclaimed Manoel. "No, sir; we shall end by finding the key of the document on which the man's life depends."

Manoel had risen, a prey to the excitement he could not control; the reply he had received was too hopeless, and he refused to accept it for good.

At a gesture from the judge, however, he sat down again, and in a calmer voice asked:

"And in the first place, sir, what makes you think that the basis of this document is a number, or, as you call it, a cipher?"

"Listen to me, young man," replied the judge, "and you will be forced to give in to the evidence."

The magistrate took the document and put it before the eyes of Manoel and showed him what he had done.

"I began," he said, "by treating this document in the proper way, that is to say, logically, leaving nothing to chance. I applied to it an alphabet based on the proportion the letters bear to one another which is usual in our language, and I sought to obtain the meaning by following the precepts of our immortal analyst, Edgar Poe. Well, what succeeded with him collapsed with me."

"Collapsed!" exclaimed Manoel.

"Yes, my dear young man, and I at once saw that success sought in that fashion was impossible. In truth, a stronger man than I might have been deceived."

"But I should like to understand," said Manoel, "and I do not----"

"Take the document," continued Judge Jarriquez; "first look at the disposition of the letters, and read it through."

Manoel obeyed.

"Do you not see that the combination of several of the letters is very strange?" asked the magistrate.

"I do not see anything," said Manoel, after having for perhaps the hundredth time read through the document.