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under 16 degrees, and diftance from Islamabad about 420 G. miles. The outline of this whole coaft has been traced by Captain Ritchie, under the fame direction, and in the fame manner, as the coafts on the weft fide of the Bay. He made the difference of longitude 2° 32′ east from Islamabad; placing Cape Negrais in 94 27′ Mr. Dalrymple, who has taken uncommon pains to ascertain the bearing of this coaft, from journals, and a variety of sketches and remarks, makes the difference of longitude 2° 34', or only 2' different from Mr. Ritchie. The result of this laborious enquiry, corrected by a nicely difcriminating judgment, corroborates, in the ftrongest manner, Capt. Ritchie's calculation; and affords a degree of fatisfaction next to that of an actual obfervation.

I mean to have it understood that Capt. Ritchie's chart of this coast, is to be taken only as a general outline, being imperfect as a coafting chart. The river of Aracan is taken from Mr. Dalrymple's printed collection: as are fome of the particular bendings of the coaft, and the north fide of Cheduba, from his MSS.

Capt. Ritchie's latitude of Cape Negrais, is more fouthwardly than it is commonly taken at, by 10 minutes; which I cannot account for, as his obfervations of latitude are generally exact.

At this point, my materials for ascertaining the intermediate longitudes of places on the eastern side of the Bay, fail me: and I have been under the neceffity, in a great measure, of fubftituting judgment for fact, between Cape Negrais and the next place of obfervation, Mergui: which place, as it is given by M. D'Apres in his new Neptune Orientale, is in 98° 20' east longitude, or 3° 53′ eaft from Cape Negrais. M. D'Anville allows 4 degrees; which comes within 7 minutes of mine; but although we agree nearly in the aggregate, we differ widely in point of particulars.

* The longitude of this Cape was reckoned by M. D'Anville only 93° 16': fo that the New Map increases the diftance between the mouth of the Sinde (or Indus) and Cape Negrais, z degrees and 12 minutes of longitude.

The

The MS. charts that I have confulted, make the difference of longitude in queftion, 4° 30' on a medium; which is 37' more than I make it. And M. D'Apres makes it 4° 19′.

The disagreement in particulars between M. D'Anville's account and mine, arifes in the part between Cape Negrais, and the coast of Martaban. It happens that this coaft lies in a direction fo far from meridional, and at the fame time the tides and currents of the feveral mouths of the Ava river, do so disturb and falfify the fhip's reckonings, that the true diftance can never be afcertained that way, in the ordinary courfe of navigation. Plans of the Perfaim and Syrian Rivers, as high up as the cities of thofe names respectively, have been already published in Mr. Dalrymple's collection and, fortunately, I have been able to obtain tracings of the continuations of thofe rivers (which are the two extreme branches of the Ava river) to the place where they separate from the main river, at about 150 G. miles from the fea. The bearings of the two branches interfect each other at an angle of about 60 degrees; and therefore, by the help of the latitude, may be used, in correcting the length of the coaft between Negrais and Syrian. The Perfaim, or Negrais branch, was traced by that accurate obferver, Capt. George Baker, in his way to Ava in 1755I have not been able to learn by whom the Syrian branch was traced; but by the orthography of the words in the map, the author appears to have been a Dutchman.

The refult of these bearings, corrected by the latitude, as fet forth in the Syrian map, gives difference of longitude from Negrais Point, to the mouth of the Syrian river, 2° 18' eaft; which is about 13' less than M. D'Apres makes it, and 24′ less than M. D'Anville, Some of the MS. charts make the difference still more.

The mouths of the Ava river, which form an assemblage of low iflands, like thofe of the Ganges, are defcribed from feveral MS. charts of Mr. Dalrymple's, collated with M. D'Apres' new chart.

From

From the mouth of the Syrian river to the coast of Martaban, în latitude 15° I have copied from the new chart of M. D'Apres, published a very short time before his death. The figure of the coaft is quite new.

Between the aforefaid latitude and Tavai Point, our charts are very imperfect; but generally agree in giving the coast a direction of fouth, a very little eastwardly.

From Tavai Point to Mergui, the coaft is taken from a MS. chart compiled by the late Mr. Howe,

Mergui is placed, as I have faid before, according to M. D'Apres' observation: that is, in longitude 98° 20'; latitude 12° 9'.

All the remainder of the coaft, to Junkfeilon; and the whole Mergui Archipelago, is from M. D'Apres.

I NEXT proceed to the chain of islands that extend from Cape Negrais to Sumatra; and are known by the names of the Preparis, Cocos, Andaman, and Nicobar iflands.

Capt. Ritchie, after leaving Negrais, proceeded agreeably to his inftructions, to describe the fituation and extent of the islands that compose this chain.

None of them are more than 84 G. miles diftant from each other; fo that he needed never to be more than 41 miles from land: nor, in all probability, as he failed with a fair wind, more than 8 hours out of fight of it; and that but once during the voyage; that is to fay, between the little Andaman and the Nicobar iflands. In other places, the distance between the lands is commonly much lefs: fo that the meridional direction of the course, and other circumftances, render this line of much ufe in correcting the longitudes, not only of the islands themselves, but of Sumatra alfo;

and,

and, had it been continued as was intended, to Acheen, would have answered the purpose completely.

Paffing the Preparis and Cocos islands, Capt. Ritchie proceeded to Narcondam, to fix its pofition: then back again to Cocos; down the east side of the great Andaman, (which he found to be almost a degree of latitude longer than was before supposed) then up the weft fide of it, almoft to the latitude of 12°: when finding the attempt to circumnavigate the island, might prove fatal to the remainder of his work, he proceeded fouthward; defcribing the extent, figure and pofitions of the little Andaman and the Nicobars, till he came to the fouth point of the great (or fouthmoft) Nicobar. Here the wind fuddenly changed to the fouth, and prevented him from determining the respective positions of the southern Nicobar and Acheen: which is the more mortifying, as one day's fair wind would have enabled him to accomplish it.

The result of this line of bearing is, that the fouth end of the Great Nicobar, is in longitude 94° 21'; that is, only 6 minutes east from Cape Negrais.

The pofition of Acheen Head, or King's Point (the N. W. point of Sumatra) has hitherto been deduced from its bearing and distance from Malacca, the nearest place of obfervation; and its longitude according to this deduction, is 95° 30' according to M. D'Apres, Now the bearing of Acheen from Malacca, being in a direction of more than 60 degrees from the meridian, and the distance 450 G. miles; little reliance could be placed on the result of it, if it did not happen that the refpective pofitions of the fouthern Nicobar, and of Pouloo Ronde (an island near Acheen) the one deduced from Negrais Point, and the other from Malacca, agreed nearly with their reputed bearing and distance from each other. For, of two MS. charts which I have examined, the one makes 1°1', the other 1° 2' difference of longitude between them; and thefe being laid down apparently without any attempt to support a fyftem,

a fyftem, may be fuppofed to be agreeable to experiment. The bearings and distances in thefe MS. charts are

In one S. 56 E.

And in the other S. 56. E.

72 G. miles
75

And according to the deduced longitudes abovementioned, the bearing and distance is S. 58. E.

79

making the difference of longitude 1o 5', or only 3 minutes different from the MS. charts. So that there cannot be any great error in the longitude of Acheen, as laid down in M. D'Apres', and in my map: a difference of a few miles, in the distance of 8 degrees, being much less than could be expected in such a series of deductions. M. D'Apres makes the bearing and diftance between the fouth Nicobar and Pouloo Ronde S 57° 30' E. 97 G. miles; or difference of longitude 1° 22', that is, 22′ more than the MS. charts. It must be observed, that he reckons the fouth end of the Nicobar

miles farther to the north than the truth; occafioned by his making the island fo much too little in extent: for the north end is in its true latitude. Had the fouth point of the island been in its true latitude, the bearing of Pouloo Ronde would have been more eastwardly, and the distance only 93, instead of 97: and if, on the contrary, he has enlarged his distance on the original bearing, to make it answer to the latitude, the original distance could have been only 85 miles.

I have said before that Capt. Ritchie went no higher up the west fide of the great Andaman, than about the latitude of 12°. The remainder of that coaft, as well as the paffage through the islands at the north end of it, is from a MS. chart lent me by Mr. Dalrymple; and which carries with it the greatest appearance of truth, on a comparison of the fouth and fouth west parts of the Great Andaman in this chart, with the fame parts in the chart of Capt. Ritchie.

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