er place, still, upon comparing their
journals, there would always appear a day's difference between them; and if
they were to keep continually sailing on, one always towards the west, and
the other always towards the east, every time they might meet or cross each
other, they would increase the difference between them by an additional
day.

Whence it follows, that if two ships were to leave England on the same day,
one sailing east by the Cape of Good Hope, and the other west by Cape Horn,
returning home respectively by the opposite capes; and if both were to
arrive again in England at the same time, there would be found in the
reckoning of the eastern vessel two entire days more than in that of the
western vessel. Nor would this difference be merely theoretic or imaginary;
on the contrary, it would be a real and substantial gain on the part of the
eastern vessel: her crew would have consumed two whole rations of
breakfast, dinner, and supper, and swallowed two days' allowance of grog
more than the other crew; and they would have enjoyed two nights more
sleep.

But all this is not an answer to H's question; what he wants to know is
whether the day at the Antipodes is twelve hours in advance or in arrear of
our day and, whichever it is, why is it?

But here H. is not sufficiently explicit. His question relates to a
practical fact, and therefore he should have been more particular in
designating the exact habitable place to which it referred. Our Antipodes,
strictly speaking, or rather the antipodal point to Greenwich Observatory,
is 180deg of east (or west) longitude, and 51deg 28' &c. of south latitude.
But this is not the only point that differs by exactly twelve hours in time
from Greenwich; all places lying beneath the meridian of 180deg, "our
Periaeci" as well as "our Antipodes," are similarly affected, and to them
the same question would be applicable. H. is right, however, in assuming
that, with respect to that meridian, the decision must be purely arbitrary.
It is as though two men were to keep moving round a circle in the same
direction, with the same speed, and at diametrically opposite points; it
must be an arbitrary decision which would pronounce that either was in
advance, or in arrear, of the other.

Regarding, then, the meridian of 180deg as the neutral point, the most
rational system, so far as British settlements are concerned, is to reckon
longitude both ways, from 0deg to 180deg, east and west from