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 golfo 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

* Voyage dans l'Amérique meridionale, t. i. p. 99.

sition of that part or tile suf of Pomara which car-asmonds on the mer-stian of the point of Sam Blas. and tile int of Saint Ripčael de Mattingh. By fancing at the conigiration of the nor-hern and southern coasts, we easily perceive that, although -ie mein firection is nearly irom east to west, tile return of the isthmus ices not liegend on the Lititides alone. What is the height of the mountrins at the point where the Isthmus is narrowest? What is the breadth of the Isthmus it the point where the chain of mountains is le:1st elevated? These are the two great questicus which an enlighteneti government should ecd=#vour to resolve, by employing an experienced observer, whom it would be sufficient to firmish with a sextant, two time-keepers, and a barometer. No measure of elevision, ind no level has ever yet been executed in the Isthmus of Pinima; and neither the archives of Simances, nor these of the council of the Irelies, contain any paper ct importance calculated to throw the least light on the possibility of cutting canals between the two seas. It is unfair, therefore, to accuse the ministry of Madrid of a wish to conceal matters of which they have never had any more knowledge than the geographers of London and Paris.

In the small map of Choco" which exhibits the canal dug by the priest of Novita, in a district called Bocachica, I have marked as uncertain, the direction of the coast which extends from the point of San Francisco Solano to the gulf of San Miguel. It is desirable that we should know more accurately the position of Cupica where the Spanish pilot, M. Gogueneche, made his settlement. In the map of false positions we have distinguished the result drawn by M. Cassini from the observations of longitude contained in the voyage of the Abbe Chappe, which are to be found in the Connoissance des Temps for 1784, . from the result adopted by the members of , the academy of sciences who were entrusted with publishing the map of Alzate in 1772. We read on this map the following note: . “The voyage of M. Chappe to California “ was the means of correcting the position of “ different places, which it may be interesting “ to specify here: