“I let myself down to the ledge, and found that it was impossible to retain a seat on it unless in one particular position.  This fact confirmed my preconceived idea.  I proceeded to use the glass.  Of course, the ‘twenty-one degrees and thirteen minutes’ could allude to nothing but elevation above the visible horizon, since the horizontal direction was clearly indicated by the words, ‘northeast and by north.’  This latter direction I at once established by means of a pocket-compass; then, pointing the glass as nearly at an angle of twenty-one degrees of elevation as I could do it by guess, I moved it cautiously up or down, until my attention was arrested by a circular rift or opening in the foliage of a large tree that overtopped its fellows in the distance.  In the centre of this rift I perceived a white spot, but could not, at first, distinguish what it was.  Adjusting the focus of the telescope, I again looked, and now made it out to be a human skull.

“On this discovery I was so sanguine as to consider the enigma solved; for the phrase ‘main branch, seventh limb, east side,’ could refer only to the position of the skull on the tree, while ’shoot from the left eye of the death’s-head’ admitted, also, of but one interpretation, in regard to a search for buried treasure.  I perceived that the design was to drop a bullet from the left eye of the skull, and that a bee-line, or in other words, a straight line, drawn from the nearest point of the trunk through ‘the shot’ (or the spot where the bullet fell), and thence extended to a distance of fifty feet, would indicate a definite point—­and beneath this point I thought it at least possible that a deposit of value lay concealed.”

“All this,” I said, “is exceedingly clear, and, although ingenious, still simple and explicit.  When you left the Bishop’s Hotel, what then?”

“Why, having carefully taken the bearings of the tree, I turned homewards.  The instant that I left ‘the devil’s seat,’ however, the circular rift vanished; nor could I get a glimpse of it afterwards, turn as I would.  What seems to me the chief ingenuity in this whole business, is the fact (for repeated experiment has convinced me it is a fact) that the circular opening in question is visible from no other attainable point of view than that afforded by the narrow ledge on the face of the rock.

“In this expedition to the ‘Bishop’s Hotel’ I had been attended by Jupiter, who had no doubt observed, for some weeks past, the abstraction of my demeanor, and took especial care not to leave me alone.  But on the next day, getting up very early, I contrived to give him the slip, and went into the hills in search of the tree.  After much toil I found it.  When I came home at night my valet proposed to give me a flogging.  With the rest of the adventure I believe you are as well acquainted as myself.”

“I suppose,” said I, “you missed the spot, in the first attempt at digging, through Jupiter’s stupidity in letting the bug fall through the right instead of through the left eye of the skull.”