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all, expences faved in many cafes, by the difference of labour be→ tween the smoothing of the direct road, and the forming of a road on the natural level. But the proportions, must of course vary with circumstances; and may be only one in ten, in a dry, open, country, and one that has a tolerably even furface: but this happens too rarely to found any general rule on. As the line of diftance increases, a greater degree of winding will take place; or, a short distance will always be on a straighter line than a long one: for in countries where the management of the roads is not arrived at a high degree of perfection, the road through a kingdom will be made up of portions, confifting of the particular roads leading from one city, or principal town, to another, although they may not lie in the general line of direction; and then there will be a general winding, added to the particular one: and the above proportion of i in 7, is applied to this compound winding. And, added to this, in very long distances, fome natural obftacle, will, very probably, oppose itself: an arm of the fea; a river of difficult paffage; a. morafs; or an impaffable ridge of mountains; and change totally the direction of the road: whilft the parts, on each fide of the obftacle, might have but an ordinary degree of winding: and it is feldom, but that one or other of these, occurs in the space of 100, or 150 miles. Probably 1 in 8* may be a pretty just general proportion for distances of about a 100 miles: that is, 8 miles by the road, will be feven direct; or what is commonly termed birdflight and where the extent is from 200 to 300 miles, 1 in 7.

Measured distances in Hindooftan, do not often occur, where, at the fame time, the true horizontal distance is given, except in Bengal and that is a country too full of deep rivers, lakes, and moraffes, to ferve as a general standard. In the Carnatic, a dryer country, the medium of winding, in diftances of about 100 miles, is in 9. In England, as far as we can trust the maps (which may

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This is M. D'Anville's idea, p. 45 and 46 of his Confidérations Géographiques.

be done, where the distance confifts chiefly of difference of latitude) 1 in 11 is the proportion, in diftances of about 100 miles; and in very great distances, fuch as Edinburgh, 1 in 7.

It may happen that the direct route may lie through a defert or an ill-governed country; in which case, travellers will avoid the way, in which famine, or robbery, threatens them, and by these means. be carried out of the true line of direction: but it is obvious that no rule can be given for fuch cafes. Upon the whole, the degree of winding, as far as depends on natural caufes, must be estimated by the compound ratio of the length of the line of distance, and of the nature of the country, as to evennefs, drynefs, and opennefs. And of course, fome local knowledge of it will be required, in order to correct the distances in a juft degree *.

The term cofs is of high antiquity; and that of coffid, or courier, appears to be derived from it. It feems that the measure of the cofs, established by the different Emperors of Hindooftan, has varied confiderably at different times; and has always been longer than the computed one. That fixed by Acbar appears to have been about 2 British miles, and a fixteenth. But of this, I have no farther proof, than what refults from the comparison of the different measures of the road between Patna and Moorfhedabad; being a portion of the great road from Delhi to Bengal, measured by order of one of the Emperors.

M. D'Anville concludes his enquiry into the length of the cofs, by determining the number in a degree, on a medium, to be 37; but it must be observed, that he had no measured lines with which he could compare his estimated distances. his estimated distances. On the other hand, in the refpective distances of Candahar, Cabul, and Attock, as defcribed by him, each degree contains 47 of Tavernier's coffes.

Those who wish for a general rule for changing horizontal diftance into road distance, in their common references to maps; may break the line of distance, (if very long) into portions of not more than 100 or 150 miles; and then add to the whole fum of the diftances, so obtained, one eighth part. Thefe portions fhould be contrived, fo as feverally to include the spaces, between the points, that diverge moft from the general line of direction of the whole road. By this means, the errors arifing from the compound winding, will be avoided.

+ Eclairciflemens, p. 14.

SECT.

SECTION I.

The SEA COASTS and ISLANDS.

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ALCUTTA is the point I fhall fet out from, as well from its being determined by feveral obfervations of longitude and latitude, as from its having a measured line of confiderable extent ftretching from it both to the caft and weft. I shall first pursue the route weftward to the mouth of the Indus; and then return to Balafore, and go eastward to the entrance of the ftrait of Malacca. Calcutta, the capital of the British poffeffions in India, as being the refidence of the General Council, has its citadel placed in latitude 22° 33′ north; and in longitude, by a medium of the observations of four different gentlemen, 88° 28′ eaft from Greenwich *.

Balafore, fituated about 101 geographical miles† from Calcutta, is the extreme point of the Bengal furvey on the SW; or on the quarter towards Madras. Col. Pearfe's return from the Carnatic, after the termination of the late war, afforded an opportunity of carrying a measured line from Madras to Balafore, which had long been a defideratum; as the exact pofitions of the intermediate stations of Mafulipatam, Vifagapatam, Ganjam, and Cattack, points on which many others eventually depended, were wanted: and although there might be no great reafon to fuppofe that Mafulipatam and

All the latitudes mentioned in this work, being north of the Equator, and all the longitudes eaft of the meridian of Greenwich, I thall in future mention only the terms latitude and longitude, leaving the fpecies of each, to be understood,

I have made ufe of Geographic miles, or thofe of 60 to a degree, in the account of the conftruction of the map; and of British ftatute miles in giving the comparative extent of countries. They are didinguished by G. miles, and B. miles.

Vifagapatam were much out of place, in the former map, yet Ganjam and Cattack were doubtful. Col. Pearfe's industry and attention have amply fupplied what was wanting, within this line. He directed the whole to be measured with a perambulator, and corrected each day's work, or at leaft, every confiderable interval, by obfervations of the latitude; and the general courfe being little more than 3 points from the meridian, the differences of latitude, were applicable to the correction of the distance thro' each particular interval: and for a check on the whole, we had already in our poffeffion, obfervations of longitude repeatedly taken at Calcutta and Madras. The whole extent of Col. Pearfe's measured line, in road distance, was near 900 British miles; a work of no finall labour.

The longitude of Fort William, the citadel of Calcutta, as abovefaid, taken at 88° 27′ 45′′*, from the medium of 4 obfervers; and that of Madras 80° 24′ 40" †, from the medium of 3 obfervers, gives a difference of meridians of 8 degrees, 3 minutes. It remains then, to compare with this, the difference of longitude found by Col. Pearfe's meafured route, as communicated by Mr. Pringle in the map drawn by him, and fent to the Eaft India House.

Balafore, by the furvey, is 1°26′ 30′′ weft of Fort William, and must therefore be in 87° 1' 30". Col. Pearse reckons it 1′ 15′′ more westerly; but I adhere to the furvey. From Balafore to Ganjam, in lat. 19° 22′, Col. Pearfe reckons 95 miles of wefting, or 1°41′ 26′′ difference of longitude; which brings Ganjam in lon. 85° 20′ 4′′. And from Ganjam to Madras he made 5° 2′ 18′′ weft: whence the

Rev. Mr. Smith

*Hon. Thomas Howe

88° 33 85 28

Medium 88° 27′ 45′′

88 24
88 26

Mr. Magee

Capt. Ritchie

To which may be added the French obfervation at Ghyretty, which place is 'eaft from

Calcutta

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longitude of Madras, would be 80° 17′ 44′′. Here is found an excefs of about 7 minutes difference of longitude, more than the ob fervations give. But in examining the map abovementioned, it appears that the difference of latitude between Ganjam and Madras by account, exceeded that by obfervation 8′ 30′′; and if this is to be imputed to excess of distance (which is highly probable) an excess of longitude must also have taken place; and this error will amount to about 6′ 48′′; or nearly the difference in queftion. This trifling error of 7 minutes in a difference of meridians of 6 degrees and a half, to whatever it may be owing; whether to overmeasurement by the wheel; variation of the compafs; defects in the inftruments; or errors in the observations of longitude; or partly to all these causes; is very immaterial, to general geography. The refult fhews, that we may confider the difference of meridians between the two places, as determined near enough for the purposes of navigation, or general Geography.

I must not omit to mention that Capt. John Ritchie, by direction of the Bengal Government, in 1770 and 1771, took the bearings and distances in a general way, from Madras to Balafore; and his refult came within one minute of the longitude by obfervation. But fome of his intervals were not well proportioned. His pofition of Mafulipatam, indeed came out only 1' to the east of Col. Pearse's ; but Vifagapatam was 7, and Ganjam 22′ more wefterly.

Although Col. Pearse's route serves to fix most of the principal places, on or near the coaft, yet oftentimes it deviated confiderably, and for a length of space, from the coaft; as between Balafore and Jagarnaut; and between Vifagapatam and Ongole. Thefe blanks. are fupplied from the materials of Capt. Ritchie, Major Stevens,. Major Polier, Mr. Cotsford, and others.

Firft, from Balafore, to Point Palmiras. This was done by Capt. Ritchie, by a series of triangles, formed by three furveying. veffels; and corrected by obfervations of latitude. The result, placed Point Palmiras, directly fouth of Balafore: that is, in lon..

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