The man swung off the yard and slid down as far as the cross-trees, while I unslung my glass and brought it to bear upon the stranger.  The rarefaction of the air bothered me a good deal, producing something of the effect of a mirage, and causing the royals of the distant vessel to stand up clear of the horizon as though there were nothing beneath them; yet, as she rose and fell with the 'scend of the sea, shapeless snow- white blotches appeared and vanished again beneath them occasionally. She was coming along very fast, however; and presently, when she took a rather broad sheer, I caught a momentary glimpse of _two_ royals and just the head of a third--the mizzen--proving conclusively that she was full-rigged--as was the _Virginia_.  But, as the skipper had surmised, she was still much too far off for identification.  I thought rapidly, and an idea occurred to me which caused me to close my glass, re-sling it, and slide down to the cross-trees.