Five minutes later we were speeding gaily away, with the wind over our starboard quarter and the sheets eased well off, the gig, with her finer lines and lighter freight, revealing so marked a superiority in speed over the longboat, in the light weather and smooth water with which we were just then favoured, that she was compelled to luff and shake the wind out of her sails at frequent intervals to enable us to keep pace with her.  Meanwhile, the pirate brig, which, like ourselves, had gone off before the wind, had sunk below the horizon to the level of her lower yards.  I had, between whiles, been keeping the craft under fairly steady observation, for what Simpson had said relative to the behaviour of her captain, and the attitude of doubt and suspicion which the latter had exhibited when leaving the _Dolores_, had impressed me with the belief that he would possibly cause a watch to be maintained upon the schooner until she should sink, with the object of assuring himself that none of us had escaped to tell the tale of his atrocious conduct.  As I have already mentioned, the _Dolores_ happened to founder at the precise moment of sunset, and in those latitudes the duration of twilight is exceedingly brief.  Still, following upon sunset there were a few minutes during which the light would be strong enough to enable a sharp eye on board the distant brig, especially if aided by a good glass, to detect the presence of the two boats under sail; and I was curious to see whether anything would occur on board the brig to suggest that such a discovery had been made.  For a few minutes nothing happened; the brig's canvas, showing up clear-cut and purple almost to blackness against the gold and crimson western sky, revealed no variation in the direction in which she was steering; but presently, as I watched the quick fading of the glowing sunset tints, and noted how the sharp silhouette of the brig's canvas momentarily grew more hazy and indistinct, I suddenly became aware of a lengthening out of the fast- fading image, and I had just time to note, ere they merged into the quick-growing gloom, that the two masts had separated, showing that the brig had shifted her course and was now presenting a broadside view to us.  That I was not alone in marking this change was evidenced a moment later when, as we drew up alongside the gig, which had been waiting for us, Simpson hailed me with the question: