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the position of the most northern part of the city,
the observatory of M. Ferrer being the house of
Don Jose Ignacio de la Torre, which is 30" to the
west of the fort of St. Juan d’Ulua.
This longitude is almost the same with what was
found by Don Mariana [sasvirivil, and by other
officers of the Spanish marine. It is only five
minutes en arc farther west than what is indicated
on the map of the gulf of Mexico, published in
1799 by the hydrographical board of Madrid.
M. Antillon fixes it at 98° 23' 5"; the Knowledge
of Times for the year 1808, at 98° 21' 45%.
Don Thomas Ugarte, commodore (Chef d'Es-
cadre) in the service of the king of Spain, connected
by the transference of time Vera Cruz with Porto
Rico. He assigns to the first port 98° 39' 4.5".
M. Ferrer deduced in 1791 and 1792 the longitude
of Vera Cruz from sixty series of distances from the
moon to the sun and stars: he obtained as a middle
term, 98°18'15". But it would be exceedingly in-
teresting to publish a detail of these observations,
that they might be recalculated according to the
tables of Bürg. The same observation applies to
the results published in Vancouver's voyage.
The city of Vera Cruz has shared the same fate
with Mexico and the whole of the new continent.
They have been believed 60, nay even 140 leagues
farther distant from Europe than they are in reality.
Jean Covens placed Vera Cruz at 104° 45' 0";
Alzate, in his map of New Spain, at 101° 30'.

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M. Bonne" justly complains of the want of agreement among the astronomical observations at Vera Cruz. After a long discussion he fixes on 99° 37'. This is nearly the same longitude which d'Anville and the French Neptune adopted, and it is that to which the English astronomers have long given the preference. The tables of Hamilton Moore indicate 99° 49' 47" ; but Arrowsmith (map of the Spanish possessions, 1803) makes it 98. 40, and nine years before, Mr. Thomas Jef. freys, geographer to the king of England, 100° 23' 47". If formerly the prevailing error was the assigning too great western longitudes to the American ports, the Abbé Chappe fell into the contrary extreme: he deduced from his chronometer the longitude of 97° 18' 15"f. If this observer, who possessed more zeal than accuracy, could have taken the distances from the moon to the sun, he would have perceived the error of more than a degree, into which he had been induced by an excess of confidence in his chronometer. The oldest astronomical observation at Vera Cruz (at the chateau St. Juan de Ulua) is undoubtedly that of the moon's eclipse in 1577. Comparing the end of that eclipse with a corresponding observation at Madrid, M. Oltmanns

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* Atlas pour l'ouvrage de l'Abbé Raynal, p. 11. + Voyage en Californie, p. 102. WOL. I. D

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found a difference of meridians of 6' 26", and consequently the longitude for Vera Cruz of 102° 30'". The Abbé Chappefound the latitude 19° 9, 38"t, a position too southern by three minutes. I examined the small quadrant of Chappe which remains at Mexico, in the hands of Father Pichardo; and I am by no means astonished, that, with so imperfect an instrument, his observations were so inaccurate. Other geographers formerly placed Vera Cruz 20' too far to the south. The map of New Spain of Alzate indicates even a latitude of 18° 50' 0". a


This port, the finest of all those on the coast of the great ocean, lies according to my observations (at the house of the contador Don Baltasar Alvarez Ordoño) in 16° 50'29" of latitude, and 6° 48' 24." = 102° 6' 0" of longitude. This position was deduced by M. Oltmanns from twenty-eight distances taken by me from the moon to the sun. Those of the 27th March, 1803, calculated according to the tables of Bürg, gave 6 48' 32”; . and those of the 28th March 6° 48' 21”.

The difference of meridians between Mexico and

* Memoires de l'Academie pour l'année 1726. { Voyage en Californie, p. 103.

Acapulco is, according to my chronometer, 2 54” of time. Now Mexico, having been found by the medium of my lunar distances 6° 45' 42" of longitude, there would result for Acapulco, excluding every other species of observation, 6' 48" 48". An uncertainty of 19 of time is very trifling for the comparison of two longitudes, deduced from simple distances from the moon to the sun. I found Acapulco in 1803, by the lunar tables of Mason, 102° 8' 9”. This position differs very little from what is indicated by the atlas which accompanies the voyage of the Spanish navigators to the Straits of Fuca, and which is 102° 0' 30" of longitude, and 16° 50' 0" of latitude. This atlas is founded on the operations of the expedition of Malaspina. However M. Antillon, in an excellent memoir above cited, gives a result, deduced from the same operations, which differs more than a third of a degree. He asserts, that the observations in 1791, by the astronomers who embarked in the corvettes la Des. cuberta and la Atrevida, fixed Acapulco at 102° 21' 0" of longitude; a result which appears to me less exact, though more conformable to the manuscripts left by these navigators in Mexico. They themselves deduced, from eight series of lunar distances, 102° 26'; from an immersion of the first satellite, 102° 20' 40"; and from the tranference of time" from Guajaquil, 102° 22' 0"; an ad* This chronometrical longitude of 102° 22' is also found

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mirable, but perhaps merely apparent, harmony, on account of the errors of the old lunar tables. Besides, the longitude, deduced in 1794 from the operations on board the brigantine Activo, was equally western. This expedition examined the coasts of Sonzonate and Soconusco, and fixed the longitude of Acapulco at 102° 25' 30"; though I am completely ignorant of the nature of the observations on which this longitude is founded. A note in the hand-writing of one of the astronomers of the expedition of Malaspina, left at Mexico, bears, that they thought themselves warranted to deduce, from some eclipses of satellites observed, at the same time, at the capital and Acapulco, a difference of meridians of 2' 21" in time. In placing, with the new maps of the Deposito Hydrografico, Acapulco at 102° 0', we should find Mexico 101° 24′ 45", which is, to within about 700 toises, the longitude given by the medium of all my operations. I should doubt, however, of the accuracy with which the distance from the capital to Acapulco was deduced. It is probably greater than 2' 21", though perhaps also somewhat less

in the minute plan of the port of Acapulco, drawn up by the
expedition of Malaspina, and copied at the audience of the
pilotage of Lima. It appears, in fact, that the astronomers of
this expedition had at first adopted much more western posi-
tions than those afterwards adopted by the Deposito Hydro-
grafico of Madrid. The difference for Acapulco is 20, for
Guayaquil 16, for Panama and Realexo 18, en arc.


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