HISTORY OF MAURITIUS. 
387 
“ February 11. At 7 h 2' 45" in the evening, the emersion of the same satellite. 
“ 13. At 15 h 43' 10", emersion of the third satellite. Jupiter is plunged in a thick 
mist. 
« 16. At i4 h 28' 12", emersion of the first satellite in fair weather. 
** 25. At io h 52" 16", emersion of the same. 
li Not possessing the knowledge of all the observations which have been made, 
at the same time, in the different places of the world, I shall not discuss here the 
longitude which is to result from it. In the mean time, however, if we add to these 
observations, those which M. d’Apres made in 1751, it may be supposed that, with¬ 
out any sensible error, the difference of the meridian of Paris, and of St. Denis in 
the Isle of Bourbon, or of Cape Bernard, is g* 1 3' -, and consequently the eastern 
longitude 53 0 7' or 8'. 
Determination of the Longitude of the Island of Madeira , by the Eclipses of 
Jupiter’s Satellites , observed by M. Bory , Lieutenant in the Royal Navy , 
compared with those of M. I’Abbe de la Caille , in the Isle of Franceby M, 
de Lisle. 
“ M. Bory having observed two immersions of the first satellite of Jupiter, and 
one of the third, at Funchal, the capital of the Island of Madeira, towards the end 
of the year 1753, and at the commencement of the year 1754, I compared them 
with those of the Abbe de la Caille, in the Isle of France, which are the only ones 
that I have found to correspond with those of M. Bory. 
“ When I speak of corresponding observations, I understand not only , those 
which have been made precisely at the same time, for such are not to be found; 
but it is well known, that in the use of the observations of the satellites of Jupiter 
for the longitudes, particularly those of the first, the observations, which were made 
after two or three revolutions, may be employed, when such as are simultaneous 
cannot be obtained. But, fortunately, the results that I have drawn from the three 
observations of M. Bory, agreed within a few seconds; which justifies the use that 
I have made of them, in comparing them with those of the Abbe e la Caille, with 
the difference of two or three revolutions. 
K In order to reduce to the meridian of Paris the difference which I have found 
in the Isle of France and the Island of Madeira, I must suppose a known longitude 
aD 2 
