« 이전계속 »
The next marked « is the communication of Capt. Hains, of the Honorable East India Company's Service, and that which follows it marked / is unaccompanied by letter. The following letter contains Capt. Hains's remarks :—
Jerusalem Coffee House, Oct. 22nd, 1841. Sir.—I have worked the log of the Ship Charlotte, as printed in the Nautical Magazine for this month, from Madeira to the shoal on which she was lost April 19th, 1840, and beg to enclose the result.
In working the log up, I have of course availed myself of the daily observation for the latitude to correct the dead-reckoning, but the longitude I have brought on by account from the position of the ship at noon April 11th together with the bearings of Madeira and the Desertas, and which bearings agree tolerably well both in latitude and longitude with the noon observation on that day.
The variation of the compass I have taken from my own journals and observations, in passing over nearly the same track in the H.C. Ship Lowther Castle, under my command in 1833.
Some difference occurs between my work and that of the printed log which probably arises from a misprint. See the log of the 15th April, the course is slated to be due south 119 miles, the latitude by account 25° 25'N. making a difference of only 78 miles of latitude, whereas the latitude by account should have been the same as by observation, viz. 24° 24' N. Again the longitude by chronometer on the previous day the 14th April, is put down 21° 33' W. whereas I should think it ought to be 20° 33' W. I have therefore not used the daily longitude by Chronometer to correct the longitude by dead-reckoning.
From the spot where the Charlotte foundered, (the boats having laid to all nighl) the Island of Bonavista is stated to have borne N.W. at daylight. This appears to be impossible, for the Island of Sal bears by compass N.W., and Bonavista W.S.W., unless the ship after striking, and prior to foundering had run many miles to the southward.
By referring to the Admiralty chart, corrected to 1830, it will be seen that H.M.S. Leven in the year 1819 nearly passed over the spot where the Charlotte was lost, when cruising for the Bonetta Rocks.
The latitude brought on from noon April 18th, nearly agrees with the Portuguese position of the above rocks, and also with that assigned to them by Horsburgh in his chart of the North Atlantic, but the longitnde differs considerably from Horsburgh, and agrees nearer with the Portuguese account.
If the Charlotte's longitude be correct, it is possible that the reef on which she struck, may be the long-looked for Bonetta Rocks, and which. lay further to the westward than has been hitherto supposed.
I am, &c.,
To the Editor, $c. Com. H.C.S.
Ship Charlotte at noon April 11th, 1840, Lat. obs. 32° 31' N.
Madeira, south point bearing N.W. Long, means of Chro. 16 21 W. Desertas, south point W.N.W.
It ought to be remarked that but little dependence can be placed upon the Charlotte's dead-reckoning, scarcely a single log being correctly added up.
I make the.latitude and longitude by account, at 8 P.m., April 19tb, when the ship struck—lat. 16" 19' N., long. 21° 41' W.
The Charlotte's chronometers appear to have gone regularly, inasmuch as the difference between Nos. 288 and 784, during seven days, but slightly varied.
NB.—It does not appear in entering the daily longitude by chronometer in the log-book whether the longitude shown by No. 288 or 784, or the means be used.
If an error exists, as I suppose, on the 14th of April, the longitnde by account, corrected by the longitude by chronometer, and brought on to 8 P.m. 19th, will then be 21° 54' west
Long, per means of chronometer brought on, noon Ap. 18, 22 15
Mean longitude 22 4 30 W. Latitude of shoal 16° 19' north, longitude 22° 05' west.
[The longitude on the 14th is evidently ns Capt. Hains states it 20° 33' on the 14th, perhaps an oversight; whereas the error on the 15th is something more.— Ed. N.M.]
We have yet to state, that the position1! of the Charlotte each day at noon, we have placed as a, first on the list. It is obvious, that our reasoning on the positions of the vessel, must depend on the observations for latitude and-chronometers as they stand recorded in the log. We know nothing further of them, than appears there. But, we conclude that the longitude of Madeira being so well known, enabled the Charlotte to obtain a new rate for her chronometers, which would be given by her departure, as recorded in the log and the sea rates she would thus obtain, would l>e far better than those which she sailed with, for they do not appear to have been very good, although the chronometers appear to he so.
The quantities in the table are also set down to the nearest minute, as being evidently considered to be quite near enough for the common purposes of navigation, in such vessels as the Charlotte. To say that there is a rock in a certain position is one thing, and toprove that there is not, is another. There can be no question as to which is the most difficult task; therefore, if in performing the latter we should be found rather discursive or lengthy, our readers we trust will fiud an excuse for us in the importance of the subject.
We have now before ns the authority on which the Bonetla Rock has assumed a new position on the charts. It stands at the head of the list of days' works as A 1, to use a nautical phrase, divested of that mysterious importance in which all such accounts are enveloped in the absence of the reasoning or demonstrative part of the question. Now we should be paying those gentlemen who have sent us their days' works a very bad compliment, after the trouble they have taken to work the Charlotte's log, if we were to adopt the Charlotte's position of the rock as the true one, in preference to any one of theirs. Were we even inclined to do so, each would have a fair right to consider his own just as good as the Charlotte's, and thus, besides the places it has already had, there would be at once five more new ones for it. But we are not inclined to do any such thing. There is quite sufficient evidence in the Charlotte's log to convince us that, that position is worth nothing. When we consider the unsatisfactory agreement in general, between her reckoning and those of the five beneath it, the serious discrepancies on several days, the ready manner in which a current of nearly two knots an hour is brought in to make up for an imaginary dificiency of distance, arising from a mistake in calculation, and which is designated by Mr. Livingstone as "a gratuitous assumption, and irreconcilable with facts," the absence of the chronometers, except on the last two days; all these are sufficient in our estimation, to justify us in pronouncing that the Charlotte's position for the Bonetta Rock is no less "a gratuitous assumption," than the current of forty-one miles above-mentioned. Indeed, with reference to that entry in the log, such a mode of accounting for a mistake cannot but occasion a smile, if it were not for the consideration, that it is to such navigators as make them, that the property of individuals, and the lives of seamen are intrusted by this country; and, perhaps, we may add, by this country alone! If we are not wrong in thus discarding the Charlotte's position of the Bonetta, we certainly should be so in adopting it as true, in preference to the positions assigned to it by those of our subscribers who have so considerately taken the subject in hand for us. But a deference to these, with the reasons we have pointed out, render such a conclusion unavoidable.
Before we quit this part of the subject, we must not omit to observe, that the Charlotte's position of the rock appears, we are informed by the owner, in her captain's protest; and so it may be concluded we presume, did the place which the Madeline assigned to it, and all the vessels severally gone before her, each laying it down as it seemed right to each. Certain it is that it cannot be in all of them. But we have a word to add about protests;—the Lorton Rock, in the Providence N.E. channel, has shewn how much faith is to be placed in them. In our volume for 1839, at p. 810, in alluding to Capt. Vidal's search for the Bonetta Rock, we said, "We recollect a case of this kind (saying sunken rocks exist where they do not) which occurred in the West Indies, and which we ourselves have recorded of a vessel, stated to have been lost on a rock in the very middle of the Providence N.E. Channel, and this was the Lorton Rock. The account of it may be found in our volume for 1833, (p. 561) ; there it stands with our very careful precautionary remarks warning navigators against it. We might have entertained certain suspicious about it in our innocence on such matters, but we did our duty, and in the very next volume, a few months after, we had to record Capt. Owen's refutation of its existence. (See p. 131, vol. 1834.) Happily for our Nassau ships, the Lorton t ballast, and certain iron pipes on board of her as cargo, were found on Egg Island Reef, and the bugbear of a doubtful danger, lodged six feet under water, and no bigger than a 'boat's bottom,' was consigned to oblivion, instead of worrying them (if they were not in the secret,) by its appearance in the very fairway of the channel from Nassau." We said more than this at the same time, concerning the Bonetta; all of which as yet we have found no reason to alter. But we adduce this passage as an instance of the faith to be placed in protests as to the position of sunken dangers. But where after all is the Bonetta Rock? Good service has been rendered in helping us to find it, and perhaps with such assistance we may be able to do so withont sending another ship after it 1 We have said it is not in the position which the Charlotte's log assigns to it, recomputed as it has been by so many of our contributors.
It is quite clear that the only instance of a current being taken into the Charlotte's account is that to which we have already alluded as no current. The days' works are computed with the mere distance given by the log, down to the time when the vessel struck, and thence the position of the rock is inferred. And yet it is notorious to any experienced seaman, that there is a dangerous current in that part of the ocean passed through by the Ch.irlotte. The charts too, that we have seen, caution the seaman, by well-known indications in the shape of arrows, to be on his guard, shewing the general direction in which it sets. But as the first authority on currents, let us refer to the late Major Rennell's valuable work, "On the Currents of the Ocean," and see what he says. Although not a seaman, he bequeathed to seamen a most important work compiled from a large mass of good practical experience, with an assiduity and perseverance which is very rarely to be met with. Our ground is between Madeira and the Cape