173 



Santa Cruz at 12 h 42' 11". Tofino made the same observa- 

 tion at Cadiz at 13 h 22' 26*, Difference of the meridians 

 0 h 40' 15". The same day the immersion of the third satellite 

 was observed at Santa Cruz at 15 h 52' 51" ; at Cadiz at 

 16 h 32' 54*. Difference, 0 h 40' 3". The mean of these 

 three observations of satellites, which had not yet been pub- 

 lished, makes Santa Cruz 18° 36' 45" west of Paris, in reck- 

 oning with Mr. de Borda for Cadiz 8° 36' 0", conformably 

 to the observation of the annular eclipse of the Sun in 1764, 

 calculated by Du Sejour. But the real longitude of the old 

 observatory of Cadiz being, according to a great number of 

 occultations of stars* calculated by Messrs. Triesnecker and 

 Oltmanns, 8° 37' 37" 5 we have thence by the satellites 18° 

 38 y 22" for the longitude of Santa Cruz. Varela and Tofino 

 made use of two telescopes two feet and a half long, by Dol- 

 lond, with which these two observers had often obtained at 

 Cadiz exactly the same results. Two observations of the 

 first and second satellites, made by P. Feuillee, in 1724, at 

 Laguna and Orotava, and compared with the observations of 

 Maraldi at Paris, give 18° 36' 36* and 18° 29' 11 "for Santa 

 Cruz in Teneriffe ; supposing, with Borda, Laguna to be 

 2' 50", and Orotava 16' 5" west of the Mole of Santa Cruz 

 (Mem. de F Acad., 1746, p. 123). These data, combined 

 with the chronometrical results, concur in proving what I 

 have enlarged on elsewhere, that the longitude of the Mole 

 is probably not less than 18° 33', or greater than 18° 36' or 

 18° 38'. Mr. de Borda, speaking in his journal of Captain 

 Cook, whom he had the pleasure to meet at the Canaries, 

 adds, " I cannot conceive why this celebrated navigator, 

 who was acquainted with the determinations of the travellers 

 who preceded him, persists in stating, that the port of Santa 

 Cruz is in 18° 51' 0" " (Third Voyage, vol. i, p. 19). Be- 



* Rec. d'Obs. Astron., t. i, p. 25. Espinosa, Memorias 

 de los Navigantes, t. i, p. 45. 



2 h 2 



