C j s8 1 
Ead from Paris. Thefe are the reafons which make 
me believe that the longitude of Selenginfk cannot be 
made lefs than (^S 7 ' S°" f rom meridian of our 
Royal Obfervatory. This being fuppofed, the ob- 
fervation of Mr. Rutnowlki compared with mine 
would give io T for the horizontal parallax of the 
Sun in the month of June, and 1 0^26 for that par- 
allax when the Sun is at the mean didance. ’Tis 
true, the fame obfervation, compared with that of 
Medi Mafon and Dixon, would much reduce this par- 
allax’; and therefore it can be of no ufe to decide 
the quedion, unlefs we hadfome from Africa or from 
the adjacent feas. 
I have one, which I have not dared yet to lay be- 
fore our Academy ; it appears to me a downright phe- 
nomenon. As it was made at the ide of France or 
Mauritius, it might pretend to the glory of deciding 
between Meff. Mafon and Dixon and me ; but it is 
fuch a one as can only at mod; determine how far the 
difference of lights or that of telefcopes could ex- 
tend or fhorten the duration of the exit. I am ac- 
quainted with the obferver,Mr. de Seligny, an officer 
in the ferviceof the Ead India company; andl think I 
can anfwer for his capacity, talents, zeal and accu- 
racy. He had noindrument but an eight foot telef- 
cope, and an excellent clock: this he regulated by 
altitudes of the Sun taken the 5th and 6th of June 
with Hadley’s quadrant. That method is not dridtly 
true, but our oblerver could do no better; and belides, 
whether the clock went too fad by a few feconds 
more or lefs, the difference cannot at all affed: the 
duration obferved by Mr.de Seligny. His clock on 
the 5th of June about 3 o’clock advanced 18"; upon 
the 
4 
