These positions were discussed in the Recueil d’Observations Astronomiques, which were jointly published by M. Oltmanns and myself, vol. ii. p. 7, 11, 18, 56, 66, 68, 109, 112. Cape Morant, which, according to M. de Puységur, is in 17° 57° 45" of latitude, and 78° 35' 23” of longitude, was placed by M. Poirson 5' farther to the east. The more easterly position is justified by several Spanish maps.

As to the position of the town of Washington, we have not thought proper to adopt the longitude assigned to it by the Connoissance des Temps for the year 1812, which is 78° 57' 30" or half a degree too far to the east. Were this position accurate, the geographers of the United States would be at a loss where to place Baltimore and Cape Hatteras. The occultation of Aldebaran, of the 21st January 1793, observed at Washington, was calculated by Lalande, who deduced from it, no doubt, the longitude of 5h 15' 51"; but the calculation was made a second time by M. Wurm", who found 5h 17' 16", or 79° 19' 0". This last result agrees very well with the observation of an eclipse of the sun made by M. Ellicot, in 1791, at George Town, near Washington, to the west, which gives 5h 17' 40" or 79° 25' 0",

* Zach, Mon. Corresp. 1803, Nov. p. 382.

Although we have in general availed ourselves of the map of Arrowsmith for the eastern part of the United States, some slight changes have however been made from the researches of M. Ebeling, and information obtained by M. de Volney in his journey to the west of the Alleghanys.

The north-west coast of North America, from Cape Saint Lucas to Cape Saint Sebastian, was traced agreeably to the learned researches of M. Oltmanns, in his work on the Geography of the New Continent". We have attended to the bearings of Vancouver and Alexander Malaspina. The longitude of the Island of Guadaloupe appears somewhat doubtful. An Ukase which issued in 1799, under the reign of the Emperor Paul the 1st, declares that all the coast situated to the north of the parallel of 55° belongs to the Russian government. In this Ukase, the north-west coast is constantly called the north-east coast of America; an extraordinary denomination, which was believed to be justifiable from this circumstance, “that from Kamtschatka, we must sail to the east to find America.” Storch’s Russland, B. I. S. 145, 163, 265, and 297.

Although the results adopted by M. Oltmanns in the great Table of positions placed at the head of our Recueil d’Observations Astronomiques, do not sensibly differ from those which I have given above, (vol. i. p. cxxxiv.–cxlv.,) it will be of utility however to specify here, the rectified longitudes of eight points of the Western COaSt.

Names of Places. Longitude.
O z zz
Acapulco - - || 102 9 33
San Blas - - || 107 35 48
San Josef - - || 112 1 8
Cape San Lucas - || 112 10 88
Cape Mendocino - 126 49 30

Punta del Año Nuevo 124, 43 53
Monterey - - || 124, 11 21
Nootka - - 128 57 1

In the map of the points of separation *, the isthmus of Panama was in great part traced from the astronomical and trigonometrical operations of M. M. Fidalgo, Noguera, and Tiscar. See the beautiful map published by the board of longitude of Madrid, in 1805, under the title of Carta esserica del mar de las Antillas y de las costas de Tierra Firme desde la isla de la Trinidad hasta el golfó de Honduras. According to the investigations of the expedition of Fidalgo, the Bay of Mandinga extends towards the south, to the 9°9′ of north latitude, and the Town of Panama is 7 to the east of the Town of Portobello. Don Jorge Juan concluded from his bearings in the river Chagre, that Panama was situated 31' to the west of Portobello". According to the more recent map of the deposito, the isthmus is only 15 to the south of the Bay of Mandinga, or 14,258 toises in breadth; while by the map of La Cruz, this breadth is 55 or 52,277 toises. Notwithstanding the great confidence which the bearings of the coast by M. Fidalgo undoubtedly merit, we must not forget, that his operations embrace only absolutely the northern coasts, which have not been hitherto connected with the southern coast by a chain of triangles, or by the transference of time. It is however by these means only, or by a great corresponding number of observations of satellites and occultations of stars, that we can be enabled to resolve the important problem of the difference of longitude between Panama and Portobello. I call this an important problem, because the longitude of Panama has an influence on the mouth of the Rio Chepo, and consequently on the po