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an error have glided into the figures 2 Perhaps the difference of meridians is 7" 30' in place of 7' 50".

The longitude of Durango should be very nearly 105° 55'. Don Juan Jose Oteyza, a young Mexican geometrician, the benefit of whose abilities I have often experienced in the course of my operation, observed there (at l’Hacienda del Ojo, 38' to the east of Durango) the termination of an eclipse of the moon, which, compared with the old tables of Mayer, gave the result which we have already indicated. The author even did not consider it as completely accurate. M. Friesen concluded from the rhombs and distances indicated in the itineraries of Brigadier Rivera and M. Mascaro, that this longitude was 5° 5' to the east of Mexico, consequently 106° 30'. The latitude of Durango appears sufficiently doubtful. Rivera and his companion Don Francisco Alvarez Bareiro pretend to have found it, by meridian altitudes of the sun, 24” 38'; Lafora, in 1766, 24°9'; but we do not know what instruments these engineers made use of If the latitude which the Count de la Laguna, M. Zarria, and the engineer Mascaro assign to the city of Zacatecas, is exact, that of Durango, deduced from the rhombs and distances, should be nearly 24° 25'.

There are several places in the northern provinces of New Spain, where the three engineers already cited made observations successively; this circumstance gives somewhat more confidence in the medium result. Chihuahua.—Latitude, 29° 11’ according to Rivera, 28° 45' according to Mascaro. Longitude deduced from the rhombs and distances, 25 to the west of Mexico. Santa Fe.—Latitude, 36° 28′ by Rivera, 369 10' by Lafora. Longitude by approximation, 52 48 in relation to the meridian of Mexico. Presidio de Janos.-Latitude, 31°30′ by Rivera, 30°50' by Mascaro. Longitude, somewhat doubtful, 7° 40' to the west of Mexico. Arispe.—Latitude, 30° 30' by Rivera, 30° 36' by Mascaro. Longitude by approximation, 9° 53 (from Mexico). Geographical combinations founded on itineraries give an additional probability to the following positions, of which MM. Mascaro and Rivera determined the latitude. These results, adopted in my map, agree with what was obtained by M.M. Bausa and Antillon. We differ, however, nearly a degree in the absolute longitude of Arispe, a city situated in the province of Sonora, as well as in the longitude of the Passo del Norte, in New Mexico. But I have to repeat, that a part of these differences arises from M. Antillon's placing in his map Mexico, Acapulco, and the mouth of Rio Gila more to the eastward than I have done.

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On the formation of militia (tropas de milicia) in the kingdom of New Spain, there was drawn up a map of the province of Oaxaca, in which several places are found marked whose latitude (according to a remark of the author) had been observed astronomically. I do not know if these latitudes are founded on meridian altitudes taken with gnomons. The map bears the name of M. Don Pedro de Laguna, lieutenant-colonel in the service of his Catholic majesty. These eleven points are partly situated on the coast between the two ports of Acapulco and Tehuantepec, partly near the coast in the interior of the country. Proceeding from west to east we find

Ometepec - - —- – 37-
Xamiltepec - - 16° 7'
Barra de Manialtepec 15° 47'
Pochutla - - - 15° 50'
Puerto Guatulco - 15° 44'
Guiechapa - - 15° 25'

• In la Misteca alta the position has been determined of S. Antonio de las Cues at 18° 3' of latitude. Teposcolula - - - - 17° 18'. Nochistlan - - - - 17° 16'. We may add the village of Acatlan in the intendancy of la Puebla at 17°58', and the city of Oaxaca at 16° 5'4" of latitude. These determinations, if they have any degree of accuracy, are so much the more precious, that from la Puebla de los Angeles to the isthmus of Panama, there was not hitherto a single point in the interior of the country whose latitude was astronomically determined. What gives us a certain degree of reliance on these positions, is the harmony which prevails between the latitudes assigned in the map. of Don Pedro Laguna and in those of M. Antillon, to the city of Tehuantepec and to Puerto Escondido. Hence the Spanish navigators at present place the former port at 16° 22', and the latter, which is in the neighbourhood of the village of Manialtepec, at 15° 50' of latitude.

Hitherto we have discussed positions founded on astronomical observations, more or less worthy of the geographer's confidence; there remains for us to indicate the maps, almost wholly manuscript, which we have employed for the different ports of the general map of New Spain.

As to the bearings and sinuosities of the western coast washed by the great ocean, from the port of Acapulco to the mouth of the Rio Colorado, and to the volcanos of the Virgins in California, I have followed the map which accompanies the account of the voyage of the Spanish navigators to the Straits of Fuca. This map, published in 1802 by the marine depot at Madrid, is founded on the operations of the corvettes of Malaspina; but the coast which stretches to the south-east of Acapulco is still very imperfectly known. The map of North

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