drop of sweet water at
the command of the two seamen, would inevitably be lost. So important
did it appear to Mark to make sure of a portion of this great essential,
at least, that he would have proposed towing down to the reef, or
island, a few casks, had the dingui been heavy enough to render such a
project practicable. After talking over these several points still more
at large, Mark and Bob descended from the summit of the crater, made
half of its circuit, and returned to their boat.

As the day continued calm, Mark was in no hurry, but passed half an hour
in sounding the little bay that was formed by the sunken rocks that lay
off the eastern, or weather end of the Crater Reef, as, in a spirit of
humility, he insisted on calling that which everybody else now calls
Mark's Reef. Here he not only found abundance of water for all he
wanted, but to his surprise he also found a sandy bottom, formed no
doubt by the particles washed from the surrounding rocks under the
never-ceasing abrasion of the waves. On the submerged reef there were
only a few inches of water, and our mariners saw clearly that it was
possible to secure the ship in this basin, in a very effectual manner,
could they only have a sufficiency of good weather in which to do it.

After surveying the basin, itself, with sufficient care, Bob pulled the
dingui back towards the ship, Mark sounding as they proceeded. But two
difficulties were found between the points that it was so desirable to
bring in communication with each other. One of these difficulties
consisted in a passage between two lines of reef, that ran nearly
parallel for a quarter of a mile, and which were only half a
cable's-length asunder. There was abundance of water between these
reefs, but the difficulty was in the course, and in the narrowness of
the passage. Mark passed through the latter four several times, sounding
it, as it might be, foot by foot, and examining the bottom with the eye;
for, in that pellucid water, with the sun near the zenith, it was
possible to see two or three fathoms down, and nowhere did he find any
other obstacle than this just mentioned. Nor was any buoy necessary, the
water breaking over the southern end of the outer, and over the northern
end of the inner ledge, and nowhere else near by, thus distinctly noting
the very two points where it would be necessary to alter the course.

The second obstacle was much more serious than that just described. It
was a reef wi