late Mr. Lincoln's (commander of the brig Inca,) and his mate's information, I believe in the existence of the Bonetta rocks, or shoal; and in addition, when commanding the brig Jane in April 1824, I pursued very nearly the same track as the Charlotte; had too, fine weather, smooth water, clear atmosphere, numerous observations for magnetic variation, taken under favorable auspices, and with good instruments.

I append the result of my calculations, in which I applied the variation according to my own observations, and have not attempted the greatest accuracy in computation, as the rough manner in which the Jog is given did not seem to require it.

I had hoped the old plan of two hours' logs and half-knots had been nearly abandoned in the merchant service.

To the Editor, &c.

I have, &c.,

ANDREW LIVINGSTONE,

Teacher of Navigation, Nautical Astronomy, &c. and late master-mariner.

The point of departure is assumed from the latitude stated as observed, and the mean of the chronometric longitudes, “nearly," as in lat. 32° 31' N. and long. 16° 21′ W.

One mile less than the log distance up to 8h. P.M., is allowed because the vessel struck at 7h. 50m. P.M., and consequently going at the rate of six knots hourly, exactly gives one knot for ten minutes.

The chronometric longitude is that carried on by account from noon of the 18th.

The shoal's position-lat. 16° 17′ N., and by account 21° 47′ W., or by chronometer combined with account 22° 06'. The chronometer being to the westward of account 0° 14'. The current of S. 15° W., 41' on the 15th seems a gratuitous assumption, and irreconcilable with facts.

The next marked d is from a gentleman, signed A. Broadhurst, who accompanied his work with the following letter:

3, Rodney Terrace, Mile End West, 6th Oct., 1841. SIR. Having worked the days' works of the Charlotte, from the day of her leaving Madeira, I forward them for your information, shouldyou not have received them from any of your correspondents. As there is no mention of variation made in her log, I have allowed the quantity marked on Horsburgh's charts, which I have always found correct. The longitude is taken from the mean of her two chronometers.

The above is the exact latitude given in your excellent work* of the Bonetta shoal, and as the longitude of the Charlotte differs only four miles from that assigned to it, there can now be no doubt of the existence of it. Horsburgh does not mention it in the last edition of his directory. I find, on referring to the log of the H.C.S. Canning, in April, 1822, we must have passed close to it, as at 4h. 30m. P.M. 21st April, we were in latitude 16° 19′ north, longitude 22° 23' west, with the centre of Bonavista bearing W.b.S., six or seven leagues, and the peak of Sal N.N.W., but did not perceive any appearance of danger. I have, &,

* February number for 1837, p. 101.

A. BROADHURST.

The next markede is the communication of Capt. Hains, of the Honorable East India Company's Service, and that which follows it marked ƒ 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 stated 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 night) 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 longitude 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.

To the Editor, &c.

I am, &c.,

H. HAINS,

Com. H.C.S.

Lat. obs. 32° 31' N.

Ship Charlotte at noon April 11th, 1840,

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.

No. 784

I make the latitude and longitude by account, at 8 P.M., April 19th, 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.

No. April 11th, noon. 288 shewed 16° 15′ 15"W.

Diff.

April 18th, noon.

784 16 27 00 W.} 11′ 45′′ (288 shewed 21° 47′ 45" W.

Longitude shewn by

each Chronometer.

No. 288

Diff.

22 00 00 W. 12° 15′

784

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

Latitude of shoal 16° 19' north, longitude 22° 05' west.

[The longitude on the 14th is evidently as Capt. Hains states it 20° 33' on the 14th, perhaps an oversight; whereas the error on the 15th is something more.— ED. N.M.]

They will therefore stand thus:-a, Charlotte; b, McDougal; c, Livingstone; d, Broadhurst; e, Hains; and f, Usborne.

We have yet to state, that the positions 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 be far better than those which she sailed with, for they do not appear to have been very good, although the chronometers appear to be 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 find an excuse for us in the importance of the subject.

We have now before us the authority on which the Bonetta 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