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mined several points in the environs of Vera Cruz and Xalappa, found for the last city 19° 31' 10" of latitude, and 99° 15' 5" of longitude. Both of us observed near the convent of St. Francis. In this fertile and cultivated region, four mountains, three of which are perpetually covered with snow, deserve the greatest attention. A knowledge of their exact position serves to connect several interesting points. The two volcanoes distinguished by the names of Puebla or Mexico (Popocatepetl and Iztaccihuatl) have been connected with the capital and the pyramid of Cholula. I found the latitude of Popocatepetl 18° 59 47, and 6" 43' 33"=100° 53' 15" of longitude; the latitude of Sierra Nepada, or Iztaccihuatl, 19° 10'0", and 6' 43' 40"= 100° 55' 0” of longitude. M. Costanzo deduced from a series of geodesical operations, 19° 11' 43 for the latitude of Iztaccihuatl, and 19° 1' 54" for that of Popocatepetl. The operations of this engineer having been made by means of a compass, and the magnetic declension depending on a great number of small local causes, we ought to be astonished at the accuracy of the results which have been obtained. These two colossal mountains, as well as the Pic d'Orizaba, being visible from the level of the pyramid of Cholula, I endeavoured very carefully to determine the position of this ancient monument. I found the latitude of the chapel which crowns the extremity of the pyramid, 19° 2' 6", and 6" 42' 14" = 100° 33' 30" of longi. tude.

M. Ferrer deduced the position of the Cofre de Perote from the geodesical operations between l’Encero and Xalappa, and found 19° 29' 14". I was able, in spite of the rigour of the season, to carry instruments on the seventh of February, 1804, to the top of this mountain, which is 384 metres * higher than the Peak of Teneriffe. I observed there the meridian altitude of the sun, which gave for l’Alto de los Caxones (43" en arc farther north than the summit or Peña del Cofre) 19° 29' 40" of latitude. The longitude was found by M. Oltmanns, who employed the angles taken by me between the Cofre and the Pic d'Orizava, 6" 37' 55", which differs but 26" in time from that fixed by M. Ferrer.

The exact knowledge of the position of the Pic d'Orizaba is of great importance for navigators on landing at Vera Cruz. The chart of the gulf of Mexico, published in 1799 by the Deposito Hydrografico at Madrid, places this mountain a degree too far to the east, at 100° 29' 45" of longitude. Angles of altitudes and azimuths taken by me, gave M. Oltmanns 19° 2' 17" of la, titude, and 99° 35' 15"=66 38' 21" of longitude. But long before me the Spanish mariners knew the true position of the Pic d'Orizaba. It would appear that the error of the map of the Seno Mericano, which passed into the French mạpt, should

* 1260 feet. Trans.

+ Carte des côtes du golfe du Mexique, d'apres les observations des Espagnols, An. 9,

be attributed to some accidental mistake on the part of the engraver.

It is corrected in the edition of M. Bausa in 1803. The name of the capital of Mexico is effaced in it, and the Pic d'Orizaba is placed at 99° 47' 30" of longitude. M. Ferrer fixes the mountain, as is proved by manuscripts in my possession, drawn up in 1793, at 19° 2' 1" of latitude, and 99° 35' 35" of longitude. The same result was also obtained by M. Isasvirivil, whose great accuracy I had occasion to know, having observed along with him at Lima and Callao in 1802.

It appears astonishing that the most recent map which we possess of that part of New Spain which we are analysing, and which bears the name of a justly esteemed author, should be the falsest of all. I speak of the large English map, which has for title, Chart of the West Indies and Spanish Dominions in North America, by Arrowsmith, published in June 1803. From Mexico to Vera Cruz the names appear to be scattered at random. The position of the Pic d'Orizaba is indicated in it in a manner which might prove dangerous to navigators. The following table gives the position of the principal points, such as this map, very beautiful in other respects, indicates them. I have added the result of my astronomical observations. The longitudes' are reckoned to the east of Vera Cruz, to avoid introducing into this comparison the absolute position of this port.

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The errors of latitude are consequently of more than half a degree. It is difficult to conceive what is meant to be designed in the map of Artowsmith by the three mountains named Orizaba, False Orizaba, and Volcano of Tlascala. They are all indicated to the north-west of the port of Vera Cruz, while the true Pic d'Orizaba (and the Mexicans know but one, called in the Azteque language Citlaltepetl) lies to the south-west of Vera Cruz, between the city of Cordoba and the villages of San Andres, San Antonio, Huatusco, and St. Jean Coscomatepec. There is added to the False Orizaba the note “ visible to the 45 leagues distance.” Now Citlaltepetl is the summit which navigators first see in approaching the coast of New Spain; consequently it might be inferred that the learned English geographer named it False Orizaba. But in this case, the latitude of this problematical mountain would be a degree false, and Orizaba would be seven marine leagues to the north of the city of Xalappa, while in reality it is only twelve to the south-south-west. Or should the Pic d'Orizaba of Arrowsmith be the Coffre de Perotte? But the Coffre lies also to the south-east, and not to the south-west of the village of Perotte. This fable of two mountains of the name of Orizaba is to be found also in the atlas of Thomas Jeffereys (The West-Indian atlas, London, 1794), where an attempt is made to convey minute information as to the road from Vera Cruz to Mexico. The latitudes are there 36' false.

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