what is in some measure necessary in order to arrive at the utmost
accuracy, is a good watch; but for common use, and where that strict
accuracy is not required, this may be dispensed with. I have observed
before, in this journal, that this method of finding the longitude is not
so difficult but that any man, with proper application, and a little
practice, may soon learn to make these observations as well as the
astronomers themselves. I have seldom known any material difference between
the observations made by Mr Wales, and those made by the officers at the
same time*.

[See Vol I. p40. "Which is nearly the same difference as the day
before..."]

In observing the variation of the magnetic needle, we found, as usual, our
compasses differ among themselves, sometimes near 2°; the same compass too,
would sometimes make nearly this difference in the variation on different
days, and even between the morning and evening of the same day, when our
change of situation has been but very little. By the mean of the
observations which I made about Erromango; and the S.E. part of these
islands, the variation of the compass was 10° 5' 48" E.; and the mean of
those made about Tierra del Espiritu Santo, gave 10° 5' 30" E. This is
considerably more than Mr Wales found it to be at Tanna. I cannot say what
might occasion this difference in the variation observed at sea and on
shore, unless it be influenced by the land; for I must give the preference
to that found at sea, as it is agreeable to what we observed before we made
the islands, and after we left them.

CHAPTER VIII.

_An Account of the Discovery of New Caledonia, and the Incidents that