The charts so late as the year 1752, represented the difference of longitude between these two places, to be only 3° 48'; that is, 1° 5' lefs than the truth. And this diminution of the longitude, while the difference of latitude continued right, gave the sea coast between the mouths of the Ganges, a direction of two points, or 221 degrees more northwardly than the truth; which doubtless occasioned the lofs of many ships, who trusted to the information. From Islamabad, in longitude 91° 55′, latitude 22° 20′, the coasts of Aracan and Pegu take a SSE course to Cape Negrais, the extreme point of Pegu to the south-west; the latitude of which is under 16 degrees, and distance from Islamabad about 420 G. miles. The outline of this whole coast has been traced by Capt. Ritchie, under the same direction, and in the same manner, as the coasts on the west side 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 coast 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 inquiry, corrected by a nicely-discriminating judgment, corroborates, in the strongest manner, Capt. Ritchie's calculation; and affords a degree of satisfaction next to that of an actual observation. 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 coasting chart. Many particulars on this coast are taken from Mr. Dalrymple's collection, both printed and MS.: particularly, the river of Aracan, the east side of Cheduba, and the passage between it and the main; and a variety of particulars on the coast of Ava. Some of the names of places were also misconceived by Capt. Ritchie. The longitude of this Cape was reckoned by M. D'Anville only 93° 16′′: so that the New Map increases the distance between the mouth of the Sinde (or Indus) and Cape Negrais, 2 degrees and 7 minutes of longitude. Capt. Ritchie's latitude of Cape Negrais, or Pagoda Point, is more southwardly than it is commonly taken at, by 10 minutes; which I cannot account for, as his observations of latitude are generally exact. I have placed this Cape (by which I mean the south extremity of the coast of Ava) in 15° 57', by the mean of 6 different accounts, varying from 15° 51′, to 16° 4. Capt. Ritchie's was 15° 52′ 30′′. 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 necessity, in a great measure, of substituting judgment for fact, between Cape Negrais and the next place of observation, 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′ east 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 MS. charts that I have consulted, make the difference of longitude in question, 4° 30' on a medium; which is 37′ more than I make it. M. D'Apres makes it 4° 19′. The disagreement in particulars between M. D'Anville's account and mine, arises in the part between Cape Negrais, and the coast of Martaban. It happens that this coast lies in a direction so far from meridional, and at the same time the tides and currents of the several mouths of the Ava river, do so disturb and falsify the ships' reckonings, that the true distance can never be ascertained that way in the ordinary course of navigation. Plans of the Persaim and Syrian rivers, as high up as the cities of those names respectively, have been already published in Mr. Dalrymple's collection; and, fortunately, I have been able to obtain tracings of the continuations of those 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 sea. The bearings of the two branches intersect each other at an angle of about 60 degrees; and, there fore, by the help of the latitude, may be used in correcting the length of the coast between Negrais and Syrian. The Persaim, or Negrais branch, was traced by that accurate observer, Capt. George Baker, in his way to Ava, in 1755. I 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 result of these bearings, corrected by the latitude, as set forth in the Syrian map, gives difference of longitude from Negrais Point, to the mouth of the Syrian river, 2° 21′ east; which is about 10' less than M. D'Apres makes it, and 21′ lefs 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 islands, like those of the Ganges, are described from several MS. charts of Mr. Dalrymple's, collated with M. D'Apres' new chart. From the mouth of the Syrian river to the coast of Martaban, in 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 coast is quite new. Between the aforesaid latitude and Tavai Point, our charts are very imperfect; but generally agree in giving the coast a direction of south, a very little eastwardly. From Tavai Point to Mergui, the coast is taken from a MS. chart compiled by the late Mr. Howe. Mergui is placed, as I have said before, according to M. D'Apres' observation: that is, in longitude 98° 20′; latitude 12° 9′. All the remainder of the coast, to Junkseilon: 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 Islands. Capt. Ritchie, after leaving Negrais, proceeded agreeably to his instructions, to describe the situation and extent of the islands that compose this chain. None of them are more than 84 G. miles distant from each other; so that he needed never to be more than 42 miles from land: and that but once during the voyage; that is to say, between the Little Andaman and the Nicobar Islands. In other places, the distance between the lands is commonly much lefs: so that the meridional direction of the course, and other circumstances, render this line of much use in correcting the longitudes, not only of the islands themselves, but of Sumatra also; and had it been continued, as was intended, to Acheen, would have answered the purpose completely. Passing the Preparis and Cocos islands, Capt. Ritchie proceeded to Narcondam, to fix its position: 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 west side of it, almost to the latitude of 12°: when finding the attempt to circumnavigate the island might prove fatal to the remainder of his work, he proceeded southward; describing the extent, figure, and positions of the Little Andaman and the Nicobars, till he came to the south point of the Great (or southmost) Nicobar. Here the wind suddenly changed to the south, 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 south end of the Great Nicobar, is in longitude 94° 23' 30"; that is, only 3' 30" west from Cape Negrais. G The position of Acheen Head, or King's Point (the NW point of Sumatra), has hitherto been deduced from its bearing and distance from Malacca, the nearest place of observation; 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 respective positions of the southern 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 1o 1', the other 1° 2' difference of longitude between them; and these being laid down apparently without any attempt to support a system, may be supposed to be agreeable to experiment. The bearings and distances in these MS. charts are In one And according to the deduced longitudes abovementioned, the bearing and distance is S 56 E-76 So that there cannot be any great error in the longitude of Acheen, as laid down in M. D'Apres' and in my map; if this sort of coincidence can be reckoned a proof of accuracy: 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 distance between the south 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 south end of this Nicobar 9 miles farther to the north than the truth; occasioned by his making the island so much too little in extent: for the north end is in its true latitude. Had the south point of the island been in its true latitude, the bearing of Pouloo Ronde would have been more eastwardly, and the distance |