But at that moment I was thinking of nothing but the pleasure of taking a cruise in the yacht, in the company of a man in whom I was naturally interested.  I was passionately fond of the sea, and had already learned from the Berwick sea-going folk how to handle small craft, and the management of a three-oar vessel like this was an easy matter to me, as I soon let Sir Gilbert know.  Once outside the river mouth, with a nice light breeze blowing off the land, we set squaresail, mainsail, and foresail and stood directly out to sea on as grand a day and under as fair conditions as a yachtsman could desire; and when we were gaily bowling along Sir Gilbert bade me unpack the basket which had been put aboard from the hotel—­it was a long time, he said, since his breakfast, and we would eat and drink at the outset of things.  If I had not been hungry myself, the sight of the provisions in that basket would have made me so—­there was everything in there that a man could desire, from cold salmon and cold chicken to solid roast beef, and there was plenty of claret and whisky to wash it down with.  And, considering how readily and healthily Sir Gilbert Carstairs ate and drank, and how he talked and laughed while we lunched side by side under that glorious sky, gliding away over a smooth, innocent-looking sea, I have often wondered since if what was to come before nightfall came of deliberate intention on his part, or from a sudden yielding to temptation when the chance of it arose—­and for the life of me I cannot decide!  But if the man had murder in his heart, while he sat there at my side, eating his good food and drinking his fine liquor, and sharing both with me and pressing me to help myself to his generous provision—­if it was so, I say, then he was of an indescribable cruelty which it makes me cringe to think of, and I would prefer to believe that the impulse to bring about my death came from a sudden temptation springing from a sudden chance.  And yet—­God knows it is a difficult problem to settle!

For this was what it came to, and before sunset was reddening the western skies behind the Cheviots.  We went a long, long way out—­far beyond the thirty-fathom line, which is, as all sailors acquainted with those waters know, a good seven miles from shore; indeed, as I afterwards reckoned, we were more than twice that distance from Berwick pier-end when the affair happened—­perhaps still further.  We had been tacking about all the afternoon, first south, then north, not with any particular purpose, but aimlessly.  We scarcely set eyes on another sail, and at a little after seven o’clock in the evening, when there was some talk of going about and catching the wind, which had changed a good deal since noon and was now coming more from the southeast, we were in the midst of a great waste of sea in which I could not make out a sign of any craft but ours—­not even a trail of smoke on the horizon.  The flat of the land had long since disappeared:  the upper