y stopped or repelled by a wind in the
contrary direction: It is also well known, that the limits of the
trade-winds vary not only at different seasons of the year, but
sometimes at the same season, in different years.

There is therefore no reason to suppose that south-westerly winds,
within these limits, are caused by the vicinity of large tracts of land,
especially as they are always accompanied with a large swell, in the
same direction in which they blow; and we find a much greater surf
beating upon the shores of the south-west side of the islands that are
situated just within the limits of the trade-wind, than upon any other
part of them.

The tides about these islands are perhaps as inconsiderable as in any
part of the world. A south or S. by W. moon makes high water in the bay
of Matavai at Otaheite; but the water very seldom rises perpendicularly
above ten or twelve inches.

The variation of the compass I found to be 4 deg. 46' easterly, this being
the result of a great number of trials made with four of Dr Knight's
needles, adapted to azimuth compasses. These compasses I thought the
best that could be procured, yet when applied to the meridian line, I
found them to differ not only one from another, sometimes a degree and a
half, but the same needle, half a degree from itself in different trials
made on the same day; and I do not remember that I have ever found two
needles which exactly agreed at the same time and place, though I have
often found the same needle agree with itself, in several trials made
one after the other. This imperfection of the needle, however, is of no
consequence to navigation, as the variation can always be found to a
degree of accuracy, more than sufficient for all nautical purposes.

SECTION XX.

_A Description of several other Islands in the Neighbourhood of
Otaheite, with various Incidents; a dramatic Entertainment; and many
Particulars relative to the Customs and Manners of the Inhabitants_.[38]

[Footnote 38: Several additional particulars respecting the islands here
spoken of, are given on the authority of the missionary account, and
other works, to which it is unnecessary to refer particularly.--E.]

After parting with our friends, we made an easy sail, with gentle
breezes and clear weather, and were informed by Tupia, that four of the
neighbouring islands, which he distinguished by the names of _Huaheine,
Ulietea, Otaha,_ and _Bolabola_ lay at the distance of between o