This was Mr Somerton's story:
'You know roughly, both of you, that this expedition of mine was undertaken with the object of tracing something in connection with some old painted glass in Lord D---'s private chapel. Well, the starting-point of the whole matter lies in this passage from an old printed book, to which I will ask your attention.'
And at this point Mr Somerton went carefully over some ground with which we are already familiar.
'On my second visit to the chapel,' he went on, 'my purpose was to take every note I could of figures, lettering, diamond-scratchings on the glass, and even apparently accidental markings. The first point which I tackled was that of the inscribed scrolls. I could not doubt that the first of these, that of Job--'There is a place for the gold where it is hidden'--with its intentional alteration, must refer to the treasure; so I applied myself with some confidence to the next, that of St John--'They have on their vestures a writing which no man knoweth.' The natural question will have occurred to you: Was there an inscription on the robes of the figures? I could see none; each of the three had a broad black border to his mantle, which made a conspicuous and rather ugly feature in the window. I was nonplussed, I will own, and but for a curious bit of luck I think I should have left the search where the Canons of Steinfeld had left it before me. But it so happened that there was a good deal of dust on the surface of the glass, and Lord D---, happening to come in, noticed my blackened hands, and kindly insisted on sending for a Turk's-head broom to clean down the window. There must, I suppose, have been a rough piece in the broom; anyhow, as it passed over the border of one of the mantles, I noticed that it left a long scratch, and that some yellow stain instantly showed up. I asked the man to stop his work for a moment, and ran up the ladder to examine the place. The yellow stain was there, sure enough, and what had come away was a thick black pigment, which had evidently been laid on with the brush after the glass had been burnt, and could therefore be easily scraped off without doing any harm. I scraped, accordingly, and you will hardly believe--no, I do you an injustice; you will have guessed already--that I found under this black pigment two or three clearly-formed capital letters in yellow stain on a clear ground. Of course, I could hardly contain my delight.
'I told Lord D--- that I had detected an inscription which I thought might be very interesting, and begged to be allowed to uncover the whole of it. He made no difficulty about it whatever, told me to do exactly as I pleased, and then, having an engagement, was obliged--rather to my relief, I must say--to leave me. I set to work at once, and found the task a fairly easy one. The pigment, disintegrated, of course, by time, came off almost at a touch, and I don't think that it took me a couple of hours, all told, to clean the whole of the black borders in all three lights. Each of the figures had, as the inscription said, 'a writing on their vestures which nobody knew'.
'This discovery, of course, made it absolutely certain to my mind that I was on the right track. And, now, what was the inscription? While I was cleaning the glass I almost took pains not to read the lettering, saving up the treat until I had got the whole thing clear. And when that was done, my dear Gregory, I assure you I could almost have cried from sheer disappointment. What I read was only the most hopeless jumble of letters that was ever shaken up in a hat. Here it is:
St John. RDIIEAMRLESIPVSPODSEEIRSETTAAESGIAVVNR
'Blank as I felt and must have looked for the first few minutes, my disappointment didn't last long. I realized almost at once that I was dealing with a cipher or cryptogram; and I reflected that it was likely to be of a pretty simple kind, considering its early date. So I copied the letters with the most anxious care. Another little point, I may tell you, turned up in the process which confirmed my belief in the cipher. After copying the letters on Job's robe I counted them, to make sure that I had them right. There were thirty-eight; and, just as I finished going through them, my eye fell on a scratching made with a sharp point on the edge of the border. It was simply the number xxxviii in Roman numerals. To cut the matter short, there was a similar note, as I may call it, in each of the other lights; and that made it plain to me that the glass-painter had had very strict orders from Abbot Thomas about the inscription, and had taken pains to get it correct.
'Well, after that discovery you may imagine how minutely I went over the whole surface of the glass in search of further light. Of course, I did not neglect the inscription on the scroll of Zechariah--'Upon one stone are seven eyes', but I very quickly concluded that this must refer to some mark on a stone which could only be found in situ, where the treasure was concealed. To be short, I made all possible notes and sketches and tracings, and then came back to Parsbury to work out the cipher at leisure. Oh, the agonies I went through! I thought myself very clever at first, for I made sure that the key would be found in some of the old books on secret writing. The Steganographia of Joachim Trithemius, who was an earlier contemporary of Abbot Thomas, seemed particularly promising; so I got that, and Selenius's Cryptographia and Bacon's De Augmentis Scientiarum, and some more. But I could hit upon nothing. Then I tried the principle of the 'most frequent letter', taking first Latin and then German as a basis. That didn't help, either; whether it ought to have done so, I am not clear. And then I came back to the window itself, and read over my notes, hoping almost against hope that the Abbot might himself have somewhat supplied the key I wanted. I could make nothing out of the colour or pattern of the robes. There were no landscape backgrounds with subsidiary objects; there was nothing in the canopies. The only resource possible seemed to be in the attitudes of the figures. 'Job,' I read: 'scroll in left hand, forefinger of right hand extended upwards. John: holds inscribed book in left hand; with right hand blesses, with two fingers. Zechariah: scroll in left hand; right hand extended upwards, as Job, but with three fingers pointing up.' In other words, I reflected, Job has one finger extended, John has two, Zechariah has three. May not there be a numeral key concealed in that? My dear Gregory,' said Mr Somerton, laying his hand on his friend's knee, 'that was the key. I didn't get it to fit at first, but after two or three trials I saw what was meant. After the first letter of the inscription you skip one letter, after the next you skip two, and after that skip three. Now look at the result I got. I've underlined the letters which form words:
'Do you see it? 'Decem millia auri reposita sunt in puteo in at...' (Ten thousand [pieces] of gold are laid up in a well in...), followed by an incomplete word beginning at. So far so good. I tried the same plan with the remaining letters; but it wouldn't work, and I fancied that perhaps the placing of dots after the three last letters might indicate some difference of procedure. Then I thought to myself, 'Wasn't there some allusion to a well in the account of Abbot Thomas in that book the Sertum?' Yes, there was: he built a puteus in atrio (a well in the court). There, of course, was my word atrio. The next step was to copy out the remaining letters of the inscription, omitting those I had already used. That gave what you will see on this slip:
'Now, I knew what the first three letters I wanted were namely, rio--to complete the word atrio; and, as you will see, these are all to be found in the first five letters. I was a little confused at first by the occurrence of two i's, but very soon I saw that every alternate letter must be taken in the remainder of the inscription. You can work it out for yourself; the result, continuing where the first 'round' left off, is this:
'rio domus abbatialis de Steinfeld a me, Thoma, qui posui custodem super ea. Gare qui la touche.
'So the whole secret was out:
'Ten thousand pieces of gold are laid up in the well in the court of the Abbot's house of Steinfeld by me, Thomas, who have set a guardian over them. Gare qui la touche.
'The last words, I ought to say, are a device which Abbot Thomas had adopted. I found it with his arms in another piece of glass at Lord D---'s, and he drafted it bodily into his cipher, though it doesn't quite fit in point of grammar.