In Order To
Find The Variation Of The Needle With The Least Error Possible, The
Seamen Take This Method:
They observe the point the sun is in by
the compass, any time after its rising, and then take
The altitude
of the sun; and in the afternoon they observe when the sun comes to
the same altitude, and observe the point the sun is then in by the
compass; for the middle, between these two, is the true north or
south point of the compass; and the difference between that and the
north or south upon the card, which is pointed out by the needle, is
the variation of the compass, and shows how much the north and
south, given by the compass, deviates from the true north and south
points of the horizon. It appears clearly, from what has been said,
that in order to arrive at the certain knowledge of the variation,
and of the variation of that variation of the compass, it is
absolutely requisite to have from time to time distinct accounts of
the variation as it is observed in different places: whence the
importance of Captain Tasman's remarks, in this respect,
sufficiently appears. It is true that the learned and ingenious Dr.
Halley has given a very probable account of this matter; but as the
probability of that account arises only from its agreement with
observations, it follows those are as necessary and as important as
ever, in order to strengthen and confirm it.
CHAPTER III: REMARKS ON THE VARIATION OF THE NEEDLE.
On the 6th of November, I was in 49 degrees 4 minutes south
latitude, and in the longitude of 114 degrees 56 minutes; the
variation was at this time 26 degrees westward; and, as the weather
was foggy, with hard gales, and a rolling sea from the south-west
and from the south, I concluded from thence that it was not at all
probable there should be any land between those two points. On
November 15th I was in the latitude of 44 degrees 33 minutes south,
and in the longitude of 140 degrees 32 minutes. The variation was
then 18 degrees 30 minutes west, which variation decreased every
day, in such a manner, that, on the 21st of the same month, being in
the longitude of 158 degrees, I observed the variation to be no more
than 4 degrees. On the 22nd of that month, the needle was in
continual agitation, without resting in any of the eight points;
which led me to conjecture that we were near some mine of loadstone.
This may, at first sight, seem to contradict what has been before
laid down, as to the variation, and the causes of it: but, when
strictly considered, they will be found to agree very well; for when
it is asserted that veins of loadstone have nothing to do with the
variation of the compass, it is to be understood of the constant
variation of a few degrees to the east, or to the west: but in
cases of this nature, where the variation is absolutely irregular,
and the needle plays quite round the compass, our author's
conjecture may very well find place: yet it must be owned that it
is a point far enough from being clear, that mines of loadstone
affect the compass at a distance; which, however, might be very
easily determined, since there are large mines of loadstone in the
island of Elba, on the coast of Tuscany.
CHAPTER IV: HE DISCOVERS A NEW COUNTRY TO WHICH HE GIVES THE NAME
OF VAN DIEMEN'S LAND.
On the 24th of the same month, being in the latitude of 42 degrees
25 minutes south, and in the longitude of 163 degrees 50 minutes, I
discovered land, which lay east-south-east at the distance of ten
miles, which I called Van Diemen's Land. The compass pointed right
towards this land. The weather being bad, I steered south and by
east along the coast, to the height of 44 degrees south, where the
land runs away east, and afterwards north-east and by north. In the
latitude of 43 degrees 10 minutes south, and in the longitude of 167
degrees 55 minutes, I anchored on the 1st of December, in a bay,
which I called the Bay of Frederic Henry. I heard, or at least
fancied I heard, the sound of people upon the shore; but I saw
nobody. All I met with worth observing was two trees, which were
two fathoms or two fathoms and a half in girth, and sixty or sixty-
five feet high from the root to the branches: they had cut with a
flint a kind of steps in the bark, in order to climb up to the
birds' nests: these steps were the distance of five feet from each
other; so that we must conclude that either these people are of a
prodigious size, or that they have some way of climbing trees that
we are not used to; in one of the trees the steps were so fresh,
that we judged they could not have been cut above four days.
The noise we heard resembled the noise of some sort of trumpet; it
seemed to be at no great distance, but we saw no living creature
notwithstanding. I perceived also in the sand the marks of wild
beasts' feet, resembling those of a tiger, or some such creature; I
gathered also some gum from the trees, and likewise some lack. The
tide ebbs and flows there about three feet. The trees in this
country do not grow very close, nor are they encumbered with bushes
or underwood. I observed smoke in several places; however, we did
nothing more than set up a post, on which every one cut his name, or
his mark, and upon which I hoisted a flag. I observed that in this
place the variation was changed to 3 degrees eastward. On December
5th, being then, by observation, in the latitude of 41 degrees 34
minutes, and in the longitude 169 degrees, I quitted Van Diemen's
Land, and resolved to steer east to the longitude of 195 degrees, in
hopes of discovering the Islands of Solomon.
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