I looked carefully as he traced out something on the queer negative.  On it, it was easily possible, following his guidance, to read the words inscribed on the sheet of paper inside.  So admirably defined were all the details that even the gum on the envelope and the edges of the sheet of paper inside the envelope could be distinguished.

“It seems incredible,” I exclaimed, scarcely believing what I actually saw.  “It is almost like second sight.”

Kennedy smiled.  “Any letter written with ink having a mineral base can be radiographed,” he added.  “Even when the sheet is folded in the usual way, it is possible, by taking a radiograph, as I have done, stereoscopically.  Then every detail can be seen standing out in relief.  Besides, it can be greatly magnified, which aids in deciphering it if it is indistinct or jumbled up.  Some of it looks like mirror-writing.  Ah,” he continued, “here’s something interesting.”

Together we managed to trace out the contents of several paragraphs laboriously, the gist of which I give here: 

“Lima, Peru.

“Dear Whitney: 

“Matters are progressing very favorably here, considering the stoppage of business due to the war.  I am doing everything in my power to conserve our interests, and now and then, owing to the scarcity of money, am able to pick up a concession cheaply, which will be of immense value to us later.

“However, it is not so much of business that I wish to write you at the present time.  You know that my friend Senora de Moche, with her son, Alfonso, is at present in New York.  Doubtless she has already called on you and tried to interest you in her own properties here.  I need not advise you to be very careful in dealing with her.

“The other day I heard a rumour that may prove interesting to you, regarding Norton and his work here on his last trip.  As we know, he has succeeded in finding and getting out of the country an Inca dagger which, I believe, bears a very important inscription.  I do not know anything definite about it, as these people are very reticent.  But no doubt he has told you all about it by this time.  If it should prove of value, I depend on you to let me know, so that I may act at this end accordingly.

“What I am getting at is this:  I understand that from rumours and remarks of the Senora she believes that Norton took an unfair advantage during her absence.  What the inscription is I don’t know, but from the way these people down here act one would think that they all had a proprietary interest in the relic.  What it is all about I don’t know.  But you will find the Senora both a keen business woman and an accomplished antiquarian, if you have not already discovered it.

“In regard to Lockwood and Mendoza, if we can get them in on our side, it ought to prove a winning combination.  There are stories here of how de Moche has been playing on Mendoza’s passions—­she’s thoroughly unscrupulous and Don Luis is somewhat of a Don Juan.  I write this to put you on guard.  Her son, Alfonso, whom you perhaps have met also, is of another type, though I have heard it said that he laid siege to Inez Mendoza in the hope of becoming allied with one of the oldest families.