the Deposito admits 1°23′ of difference of longitude. I have constantly followed the observations of M. Ferrer, in reducing the longitude of Tanuagua on that of Santander.

The territory comprised between the ports of Acapulco and Vera Cruz, between Mexico, Guanaxuata, the valley of Santiago and Valladolid, between the volcano of Jorullo and the Sierra de Toluco, is constructed from a great number of geodesical surveys, taken by me either with a sextant or the graphometer of Adams. The part

contained between Mexico, Zacatecas, Fresnillo, Sombrerete, and Durango, is founded on a manuscript plan which M. Oteyza had the goodness to construct for me, from materials collected by him in his journey to Durango. Having marked with great exactness the rhombs and the distances estimated from the pace of the mules, his plan merits undoubtedly some confidence, particularly as the positions of Guanaxuata and S. Juan de Rio were corrected by direct observations of my own, inde- \ pendent of one another. By this means it became easy to convert time into distance, and to ascertain the value of the leagues of the country.

The journals of MM. Rivera, Lafora, and Mascaro, which we have already cited, were of assistance for the provincias internas, particularly for the routes from Durango to Chihuahua, and from thence to Santa Fe and Arispe in the province of Sonora. However, these materials could only be

employed after long discussions and comparisons with the data collected by M. Velasquez in his expedition to California. The routes of Rivera very often differ a good deal from those of M. Mascaro; and we are particularly embarrassed as to the difference of meridians between Mexico and Zacatecas, or between Santa Fe and Chihuahua, as we shall afterwards have occasion to explain.

The geography of Sonora has been rectified by M. Costanzo. This philosopher, as modest as he is profound, has for thirty years been collecting whatever is connected with the geographical knowledge of this vast kingdom. He is the only engineer officer who has addicted himself to discussions on the difference in longitude of the most distant points from the capital. He has himself formed very interesting plans, in which we may perceive how far ingenious combinations may, to a certain point, supply the want of astronomical observations. I render this justice to M. Costanzo with the more pleasure, as I have seen many manuscript maps in Mexico, of which the scales of longitude and latitude appeared merely as an accidental ornament.

The following is an enumeration of the maps and plans consulted by me for the detail of my map; I think I have brought together every thing of importance which existed up to 1804.

Carte manuscrite de la Nouvelle Espagne, dressée par ordre du vice-roi Buccarelli, par MM.

Costanzo et Mascaro *. It comprehends the immense space between the 39° and 42° of latitude, and extends from Cape Mendocino to the mouth of the Mississipi. Much care appears to have been bestowed on this work, which has served me for the Moqui, for the environs of the Rio Nabajoa, and for the route of the Chevalier la Croix in 1778, from Chihuahua to Cohahuila and Texas.

Mapa del Azobispado de Mexico, por Don Jose Antonio de Alzate †, a manuscript map drawn up in 1768, and revised by the author in 1772, and which, so far at least as I have examined it, is very bad. Several mining places are to be found in t, which are interesting for the mineralogist.

I have made no use of the map of New Spain, published at Paris in 1765, by M. de Fer, nor of that of Governor Pownall, published in 1777, nor even of the map of Siguenza, which the academy of Paris engraved under the name of Alzate, and which has been hitherto looked on as the best map. of Mexico.

Carte generale de la nouvelle-Espagne from the 14° to the 27° of latitude, drawn up by M.

* Manuscript map of New Spain constructed by order of the Viceroy Buccarelli, by MM. Costanzo and Mascaro

Trans.

Map of the archbishopric of Mexico, by Don Joseph Antonio de Alzate. Trans.

* General map of New Spain.

Costanzo. This manuscript map is valuable for an acquaintance with the coast of Sonora. I consulted it also for the part which stretches out from Acapulco to Tehuantepec.

Carte manuscrite des côtes depuis Acapulco iusqu à Sonzonate*, executed by the brigantine Activo, in 1794.

Carte manuscrite de toute la nouvelle Espagne, dressée par M. Velasquez, en 1772 †. It comprises the countries situated between the 19° and 34 of latitude, between the mouth of the Rio Colorado, and the meridian of Cholula. It was destined to exhibit the situation of the most remarkable mines of New Spain, particularly those of Sonora.

Carte manuscrite d'une partie de la Nouvelle Espagne, from the parallel of Tehuantepec to that of Durango, drawn up by order of the viceroy Revellagigedo, by Don Carlos de Urutia. This is the only map of the country which exhibits the division into intendancies, and it has been very useful to me in this respect.

Mapa de la Provincia de la Compañia de Jesus de Nueva España ||, engraved at Mexico in 1765.

* Manuscript map of the coast from Acapulco to Sonzonate. Trans.

+ Manuscript map of the whole of New Spain, drawn up by M. Velasquez in 1772. Trans.

Manuscript map of a part of New Spain. Trans.

Map of the Jesuits' province of New Spain. Trans,

Is it by mere accident that this map, so bad in other respects, places Mexico at 278° 26′ of longitude, while the same capital is fixed at 270° of longitude, in the map which bears the title of Mapa de distancias de los lugares principales de Nueva España *, engraved by the Jesuits at la Puebla de los Angeles, in 1755 ?

I found at Rome, Provincia Mexicana apud Indos ordinis Carmelitarum (erecta 1588) Romæ 1738. Mexico is there placed in 20° 28′ of latitude!

Father Pichardo de San Felipe Neri, a very well informed ecclesiastic, who possesses the small quadrant of the Abbé Chappe, was so kind as to furnish me with two manuscript maps of New Spain, the one by Velasquez, and the other by Alzate. They both differ from the map engraved by the academy of Paris, and are curious, as they exhibit the situation of several remarkable mining places.

Environs de Mexico; a map of Siguenza, republished by Alzate in 1786. Another map of the valley of Mexico is to be found annually in the almanac, entitled la Guia de Foresteros (the Stranger's Guide); it is by M. Mascaro. Neither these two plans, nor the one published by Lopez in 1785,exhibit the lakes in their actual situations

* Map of distances of the principal places of New Spain. Trans.