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XXX. Obfervations on the Rclipfe of the Sun 
of Auguft 5, 1766, made at Colombes, 
the Obfervatory of the Marquis of Cour- 
tenvaux, 20 0 W'efl of the Royal Obferva- 
tory at Paris, and in Lat, 48°55'2 8 // . 
By M. MefTier, Aflronomer to the Marine 
of France, of the Royal Academy of Sciences 
at Paris, and F. R. S. Fratifated . by 
M. Maty, M. D. Sec . R. S. 
Rc a dNov. 2 6, T HE Marquis of Courtenvaux having 
-*• defired me to obferve the eclipfe of 
the 5th of Auguft 1766, in his Obfervatory, I got 
thither fome days before the obfervation, in order to 
verify the clocks, by correfponding altitudes of the 
fun, and by its tranftts, with an inftrument placed in the 
plane of the meridian. It is a common refractor of 
5 feet focus, which does not vary a fecond from the 
plane of the meridian. The day of the eclipfe, and the 
next day, I took a great many correfponding alti- 
tudes, and likewife obferved the fun with the tranfit 
inftrument. The fky was perfectly clear at the time 
of thefe obfervations, as well as during the eclipfe. 
The clock which I made ufe of was adjuftedto the 
mean time; it goes very regularly. For the obfer- 
vation of the eclipfe, I employed an excellent Grego- 
rian telefcope of two feet focus, conftruded in Eng- 
land by the celebrated Mr. Short. The tube was 
L 1 2 mounted 
