39 8 
HISTORY OF MAURITIUS. 
CHAPTER XXI. 
Extracts from the Observations of M. Le Gentil , Royal Academician, respecting 
the Southern Hemisphere , &c .; in a Series of Letters to M. de la Nux , Cor¬ 
respondent of the Royal Academy of Sciences, at the Isle of Bourbon. 
Isle of France, Feb. 6, 1761. 
**•#*“ I AM occupied in calculating for Rodriguez , the transit of Venus over 
the Sun, on the same principles employed to calculate it for Paris. I have found 
that, at the moment of the entrance of Venus, the centre of the Sun should be ele¬ 
vated above the horizon of Rodriguez near 2 °. 
“ The calculation of M. de la Lande, founded upon somewhat different principles, 
affords me some encouragement; for this Academician has found it to be near 8°: 
and as to the corrections that M. de la Lande has made of the astronomical tables 
of M. M. Cassini and Halley, which you must have seen in the Ephemeris of 1761, 
that I have sent you; do they appear to you to be well founded ? In short, may I 
not at least suspend my judgment as to the preference which ought to be given to 
his calculation, or mine ? 
" Another cause renders the moment of the entrance of Venus very doubtful and 
uncertain at Rodriguez: you know, as well as me, that in the seas which surround 
your isles, the months of June, July, and August, form a season when strong gales 
from the south-east to the east-south-east prevail, and which are seldom accompanied 
with a clear and serene sky; so that it very seldom happens that the Sun can be seen 
at its rising, and not often till it has attained a considerable degree of elevation; 
because these gales render the horizon misty, or form a range of clouds considerably 
above it. Such are my doubts respecting the Isle Rodriguez as a place to observe 
the entrance of Venus on the Sun; but it is very probable that I shall myself visit 
that island, as it is now the 6th of February, and I am without the hope of any 
other resource.” 
