early australian voyages-第7章
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es 33 minutes of longitude。 This island was so called from Prince Maurice； being before known by the name of Cerne。 It is about fifteen leagues in circumference； and has a very fine harbour； at the entrance of which there is one hundred fathoms water。 The country is mountainous； but the mountains are covered with green trees。 The tops of these mountains are so high that they are lost in the clouds； and are frequently covered by thick exhalations or smoke that ascends from them。 The air of this island is extremely wholesome。 It is well furnished with flesh and fowl； and the sea on its coasts abounds with all sorts of fish。 The finest ebony in the world grows here。 It is a tall； straight tree of a moderate thickness； covered with a green bark； very thick； under which the wood is as black as pitch； and as close as ivory。 There are other trees on the island； which are of a bright red； and a third sort as yellow as wax。 The ships belonging to the East India Company commonly touch at this island for refreshments on their passage to Batavia。
I left this island on the 8th of October； and continued my course to the south to the latitude of 40 degrees or 41 degrees； having a strong north…west wind； and finding the needle vary 23； 24； and 25 degrees to the 22nd of October； I sailed from that time to the 29th to the east； inclining a little to the south； till I arrived in the latitude of 45 degrees 47 minutes south； and in the longitude of 89 degrees 44 minutes； and then observed the variation of the needle to be 26 degrees 45 minutes towards the west。
As our author was extremely careful in this particular； and observed the variation of the needle with the utmost diligence； it may not be amiss to take this opportunity of explaining this point； so that the importance of his remarks may sufficiently appear。 The needle points exactly north only in a few places； and perhaps not constantly in them； but in most it declines a little to the east； or to the west； whence arises eastern and western declination： when this was first observed； it was attributed to certain excavations or hollows in the earth； to veins of lead； stone； and other such…like causes。 But when it was found by repeated experiments that this variation varied； it appeared plainly that none of those causes could take place； since if they had； the variation in the same place must always have been the same； whereas the fact is otherwise。
Here at London； for instance； in the year 1580； the variation was observed to be 11 degrees 17 minutes to the east； in the year 1666； the variation was here 34 minutes to the west； and in the year 1734； the variation was somewhat more than 1 degree west。 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
