, as I understand it, is available to
whoever first finds it, now that the real owners, whoever they were,
have given it up."

"I guess you're right there," said Mr. Damon. "I'm no sea lawyer, but I
believe that in this case finding is keeping."

"And there isn't one chance in a hundred that Hardley can get another
submarine here to start the search," went on Tom. "Of course it's
possible, but not very probable."

"He might get an ordinary diving outfit and try," Ned suggested.

"Not many ordinary divers would take a chance going down in the open
sea to the depth the Pandora is supposed to lie," Tom said. "But, with
all that, we have the advantage of being on the ground, and I'm going
to make use of that advantage right away."

He gave orders at once for the M. N. 1 to proceed, and this she did on
the surface. It was decided to steam along on the open sea until the
exact nautical position desired was reached. This position was the same
Mr. Hardley had indicated, but that position was not before attained,
owing to an error in the calculations.

As all know, to get to a certain point on the surface of the ocean,
where there is no land to give location, a navigator has to depend on
mathematical calculations. The earth's surface is divided by imaginary
lines. The lines drawn from the north to the south poles are called
meridians of longitude. They are marked in degrees, and indicate
distance east or west of the meridian of, say, Greenwich, England,
which is taken as one of the centers. The degrees are further divided
into minutes and seconds, each minute being a sixtieth of a degree and
each second, naturally, the sixtieth of a minute.

Now, if a navigator had to depend only on the meridian lines indicating
distance east and west, he might be almost any distance north or south
of where he wanted to go. So the earth is further divided into sections
by other imaginary lines called parallels of latitude. As all know,
these indicate the distance north or south of the middle line, or the
equator. The equator goes around the earth at the middle, so to speak,
running from east to west, or from west to east, according as it is
looked at. The meridian of Greenwich may be regarded as a sort of half
equator, running half way around the earth in exactly the opposite
direction, or from north to south.

The place where any two of these imaginary lines, crossing at right
angles, meet may be exactly determined by the science of