to C. Delamhre, 369 



I am therefore mistrastful of the longitude of Cumana^ as 

 given me by my time-keeper. When I arrived from the Cana- 

 ries at the Continent, I found the longitude to be 4h. 26' 4"; 

 and tlie observations of M. Fidalgo, who observed emersions 

 at Trinidad, hut not at Cumana, give still more ; viz. 4 h. 

 26' 16". Fidalgo found Trinidad 55" 16' 32" to the west of 

 Cadiz, and Cumana 2M I' 25" to the west of Puerta Espana. 

 But the map of Trinidad, published at London, from the 

 excellent observations of M. De Charucca, makes Puerta 

 Espana 61'' 22' west from London. I am of opinion, there- 

 fore, that, in constructing the map, the authors had before 

 them the calculations by Lalande of the occultation of Alde- 

 baran, observed at Porto Rico on the 21st of October 1793 ; 

 for the capital of Porto Rico is by the time-keepers 4° 34' to 

 the west of Puerta Espana, calculating the longitude by that 

 of Porto Rico 63*^ 48' 15''; and for Cumana 66^ 29' 40" to 

 the west of Paris. The five eclipses of the satellites which I 

 send you must throw light on this subject ; and in my opi- 

 nion the longitude of Cumana will not be much beyond 

 4h. 25' 20". Unfortunately, the eclipse of the sun, which 

 I completely observed on the 2Slh of September at Cumana, 

 making the horns pass along the horizontal and vertical wires, . 

 was not visible in Europe. I observed the end at 8 h. 14^ 22" 

 mean time; the time certain to 1" nearly, having taken cor- 

 responding heights the same day. 



At Carras (Plaza della S. Trinidad) lat. 10° 31' 4", I ob- 

 served : 



The immersion of the first satellite, Dec. 7, 1799, at 16 h. 

 ir 57" true time. 



Of the third satellite, Dec. 7, at 17 h. 1 1' 36" true time. 



The emersion of the first satellite, Jan 17, 1800, at 11 h. 

 14' 8" mean time. 



Of the second satellite, Jan. 28, at 7 h. 58' 8" mean time. 



Of the fourth satellite, Jan. 18, at 8h. 13' 3" mean tipie. 



At the Valle del Tuy al Pic della Cocuiza, lat. 10M7' 23'V 



The emersion of the first satellite, Feb. 9, 1800, at llh, 

 26' 57" mean time. 



Of the third satellite on the 10th of February, at 7 h. 58 

 50 mean time. 



Vol. IX. A But 



