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I should have given the preference to Murdoch's,
Spain, the Spanish establishments on the north
west coast of America, establishments which are insulated, and may be considered as colonies dependant on the metropolis of Mexico. To exhibit in the same map the missions of New California would have required an additional eight degrees of
* 1.25987 In. English. Trans. WOL, I. C
longitude; for the most-northern point of the
--------- - - -—am-m-m-mool GEOGRAPHICAL INTRODUCTION. xix
lished, the old manner of computing the latitudes, a single individual would in vain oppose the torrent, in publishing latitudes expressed in centesimal parts. It is to be hoped, however, that the introduction of the metrical system, fixed by the arrété of the 13 Brumaire, year IX, will become gradually general. The degrees of longitude which I indicate are computed to the west of the meridian of the Imperial Observatory at Paris. If the great body of the public were not averse to even the most useful innovations, I should have preferred, to the meridian of Paris, the universal meridian proposed by one of the first geometricians of the age", founded on the movement of the great axis of the solar ellipsis. This universal meridian is 185° 30' to the east of Paris, which is 166° 46' 12" of the ancient sexagesimal division. It passes, consequently, by the South Sea, 12' to the east of the isle of Erromanga, which belongs to the archipelago of the Holy Ghost (du Saint Esprit). The introduction of a universal meridian, founded on nature itself, which would not shock the national vanity of Europeans, is so much the more to be desired, that we every day see augmented the number of first meridians arbitrarily traced on maps. Spain, for several years back, reckons five: Cadiz, the most in use with navigators; Carthagena; the new observatory at the isle of Leon; the college of Nobles at Madrid, introduced by the beautiful maps of M. Antillon; and the point de la Galera at the island of Trinidad. To these five meridians might be added other two which pass through the Spanish possessions, and have been adopted by a great number of geographers: I mean the meridian of Teneriffe and of the island of Fer. The latter occasions inevitable confusion, d’Anville placing it between the town of Fer and Cape West. So that there are seven first meridians, without reckoning Toledo, in the sole dominions of the king of Spain. I have followed, in the denomination of the seas which wash the coasts of Mexico, the ideas proposed by M. Fleurieu in his observations on the hydrographical division of the globe; a work in which the most enlarged views are united to a profound historical erudition. The Spanish names have often been added to facilitate the reading of travels written in Spanish. In drawing up the map of Mexico, I began by assembling together all the points fixed by astronomical observations, from which I formed a view, which, for the better appretiating the degree of confidence which the results deserve, indicates the nature of the observation and the name of the observer. The number of these points amounts to 74, of which 50 are situated in the interior of the country. Of this latter class there were only fifteen known before my arrival at Mexico in the month of April, 1803. It may be useful to discuss some of the thirty-three points whose position is determined by my own observations, and which are all comprised between the 16° 50' and 20° o' of latitude, and the 98° 29 and 103° 12 of longitude. While we are fixing these positions, we shall enter into some historical details respecting the extraordinary errors which have been propagated to this day in the most recent and current maps.
* Exposition du Systeme du Monde, par Laplace, p. 19.
Several meridian altitudes of the sun and stars gave me for the latitude of the capital at the convent of St. Augustin", 9° 25'45". The longitude deduced from the eclipses of the satellites of Jupiter, from the distances from the moon to the sun, from transference of the time from Acapulco, and from a trigonometrical operation for estimating the difference of meridians between Mexico and the port of Vera Cruz, is 6° 45' 42" or 101° 25' 30". I shall observe once for all, that I rely on the numbers which result from the very careful calculations of M. Oltmanns, a distinguish
* The great gate of the cathedral church of Mexico is 12" farther north, and 10’’ farther east, than the convent of St. Augustin, near which I made my observations