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Caen, and my fon. It rained by intervals, as it had 
done the whole day ; the quickfilver in the barome- 
ter at noon being at 29,9 English inches, and Fahren- 
heit’s thermometer in the obfervatory at 62°, the 
wind varying from the Weft to the North.. 
I compared the going of the clock I had with me, 
with that which remained in the obfervatory by fig- 
nals repeated five times, and which agreed perfedly 
together : the fame was done after fun fet. 
At half an hour paft five, the clouds difperfed en- 
tirely : the fun fhewed itfelf in all its fplendor, and 
continued fo the remaining part of the day. 
About feven we all placed ourfelves at our inftru- 
ments j Monfieur de Rochfort made ufe of a three 
feet achromatic refrador : my fon of the 1 8 inch 
refrador : and I of the fix feet achromatic refrador 
made by Dollond, and at y h 4/ 58'', 5 of the clock, 
or 7 h 9' 3 8", 5 apparent time, 1 perceived the ex- 
ternal contads of the Sun’s and Venus’s limbs. 
As the impreftion on the Sun’s limb feemed con- 
fiderable when I perceived it, I concluded this obler- 
vation too late, which I judged to be occafioned by 
a motion of undulation, with which the fun was 
ftrongly affeded ; for this reafon, in two letters wrote 
to Paris the nth of June and the 14th of July, and 
communicated to the Academy of Sciences there, I 
do not hefttate to declare this obfervation inefficient; 
it agrees neverthelefs very well with yours made at 
Kew, and is nearly a mean between thofe of Green- 
wich, as may be feen by the table. However, I pre- 
pared myfelf with all poffible care, for the obfer- 
vation of the internal contads; and though the Sun’s 
limb moved continually up and down with a quick 
motion, 
