Here, then, I had the simple apparatus for a mystery; for, of course, the key must be made to unlock something far more uncommon than a quadrant; and I still think it a capital apparatus, had I only possessed the wit to use it properly. There was romance in this key--that was obvious enough, and I puzzled over it for some weeks, by the end of which my plot had grown to something like this: A family living in poverty, though heirs to great wealth--this wealth buried close to their door, and the key to unlock it hanging over their heads from morning to night. It was soon settled, too, that this family should be Cornish, and the scene laid on the Cornish coast, Cornwall being the only corner of the earth with which I had more than a superficial acquaintance.
So far, so good; but what was the treasure to be? And what the reason that stood between its inheritors and their enjoyment of it? As it happened, these two questions were answered together. The small library at Trinity--a delightful room, where Dr. Johnson spent many quiet hours at work upon his 'Dictionary'--is fairly rich in books of old travel and discovery; fine folios, for the most part, filling the shelves on your left as you enter. To the study of these I gave up a good many hours that should have been spent on ancient history of another pattern, and more directly profitable for Greats; and in one of them--Purchas, I think, but will not swear--first came on the Great Ruby of Ceylon. Not long after, a note in Yule's edition of 'Marco Polo' set my imagination fairly in chase of this remarkable gem; and I hunted up all the accessible authorities. The size of this ruby (as thick as a man's arm, says Marco Polo, while Maundevile, who was an artist, and lied with exactitude, puts it at a foot in length and five fingers in girth), its colour, 'like unto fire,' and the mystery and completeness of its disappearance, combined to fascinate me. No form of riches is so romantic as a precious stone with a heart in it and a history. I had only to endow it with a curse proportionate to its size and beauty, and I had all that a story-teller could possibly want.
But even a treasure hunt is a poor affair unless you have two parties vying for the booty, and a curse can hardly be worked effectively until you introduce the fighting element, and make destiny strike her blows through the passions--hate, greed, &c.--of her victims. I had shaped my story to this point: the treasure was to be buried by a man who had slain his comrade and only confidant in order to enjoy the booty alone, and had afterwards become aware of the curse attached to its possession. And the descendants of these two men were to be rivals in the search for it, each side possessing half of the clue. It was at this point that, like George IV., I invented a buckle. My buckle had two clasps, and on these the secret of the treasure was so engraved as to become intelligible only when they were united.